th 6 High Power Targetry Workshop Monday 11 April 2016 - Friday 15 April 2016 Merton College, Oxford, UK Contents Agenda…………………………………………………………………………....1 List of Delegates……………………………………………………………….10 Posters………………………………………………………………................13 Session 1: R&D Physics design, materials choices, validation of concepts…..............20 Session 2: Target design, analysis & simulations….………………......26 Session 3: Target facility & safety issues ….…………………….….......31 Session 4: Construction, fabrication, inspection, QA ……..................36 Session 5: Operations (Operational experience, Monitoring & instrumentation)……………...40 Session 6: Post Irradiation Examination (PIE)/autopsy ……………….46 NOTES…….………………………………………………………………..…...52 6th High Power Targetry Workshop / Book of Posters and Abstracts Agenda Agenda Day 1 - 11/04/2016 – Monday 0900 – 1000 Registration & Welcome refreshments (T S Eliot Theatre) 1000 – 1045 Introductions 1000 - 1015: Introduction to 6th High Power Targetry Workshop Chris Densham - STFC 1015 - 1045: Welcome talk Robert McGreevy – STFC, Director of ISIS 1045 – 1130 Plenary 1: Neutron and Muon Sources Eric PItcher - European Spallation Source 1130 – 1215 Plenary 2: Neutrino Sources Robert Zwaska – Fermilab 1215 – 1300 Plenary 3: Radioactive Ion beams Frederique Pellemoine - MSU-FRIB 1300 – 1400 Lunch (Merton dining hall) 1400 – 1445 Plenary 4: Precision experiments Robert Tschirhart – Fermilab 1445 – 1530 Plenary 5: Accelerator Driven Systems (ASD) Lei Yang - IMP of CAS 1530 – 1600 Refreshment break 1600 – 1800 Poster session 1800 – 1930 Welcome Reception (Merton Chapel) 1 6th High Power Targetry Workshop / Book of Posters and Abstracts Agenda Day 2 - 12/04/2016 – Tuesday 0850 – 1030 Session 1: R&D – physics design, materials choices, validation of concepts (Conveners: T Davenne & P Hurh) 0850 - 0910: Addressing material challenges in high-power Targetry Marilena Tomut - GSI 0910 - 0930: Experimental Results of Beryllium Exposed to Intense High Energy Proton Beam Pulses Kavin Ammigan - Fermi National Laboratory 0930 - 0950: Material studies for the high-power beam dump in the FRIB project Frederique Pellemoine - MSU-FRIB 0950 - 1010: An experiment to study the dynamic response of high density materials under intense proton beam impacts for the future design of the new Antiproton Decelerator target Claudio Torregrosa Martin - CERN 1010 - 1030: Tungsten powder as a high power proton accelerator target: in beam experiments Ottone Caretta - Rutherford Laboratory 1030 – 1100 Refreshment break 1100 – 1300 Session 1: continues 1100 - 1120: High-Power electron beam ISOL target concepts for the production of Photofission Fragments Alexander Gottberg - TRIUMF 1120 - 1140: Research and development towards a radiation-cooled target for Mu2e Peter Loveridge - STFC 1140 - 1200: High Power Target Studies at CERN-ISOLDE Tania de Melo Mendonca - CERN 1200 - 1220: Deploying gas injection in the SNS target for fatigue and pitting damage life improvement Bernie Riemer - Oak Ridge National Laboratory 1220 - 1240: Compact Sealed lithium target for accelerator-driven BNCT system kazuki tsuchida - Nagoya University, Graduate School of Engineering 1240 – 1300 Session 1 discussion 2 6th High Power Targetry Workshop / Book of Posters and Abstracts 1300 – 1350 Buffet lunch (T S Eliot Theatre) 1350 – 1535 Session 2: Target design, analysis & simulations (Conveners: N Mokhov & F Pellemoine) 1350 - 1410: HL-LHC Collimator Tests at CERN HiRadMat Facility Linus Mettler - CERN 1410 - 1430: Design and Optimisation of the ISIS TS1 Upgrade Target Dan Wilcox - STFC 1430 - 1450: The BLAIRR Irradiation Facility Hybrid Spallation Target Optimization Albert Hanson - Brookhaven National Laboratory 1450 - 1515: DUNE/LBNF Target Studies: Physics and Engineering Tristan Davenne – RAL & John Back - University of Warwick 1515 - 1535: MARS15 studies of impact of LBNF target/horn optimization on hadron absorber Sergei Striganov – Fermilab 1535 – 1600 Refreshment break 1600 – 1800 Session 2: continues 1600 - 1620: SNS mercury target fatigue life prediction with Fe-Safe/Verity software Saulius Kaminskas - Oak Ridge National Laboratory 1620 - 1640: Loop-type Pb-Bi target for High Power ISOL facilities: Optimization toward higher yields Donald HOUNGBO - SCK-CEN 1640 - 1700: Nuclear Data for Calculation of Radiation Damage and Gas Production Rates in Materials Irradiated with Intermediate and High Energy Nucleon Alexander Konobeev - Karlsruhe Institute of Technology 1700 - 1720: MARS15 developments and benchmarking related to beam-induced effects in targets Nikolai Mokhov - Fermilab 1720 - 1740: Predicting real-time peak displacement production rate at the SNS target vessel Wei Lu - Oak Ridge National Laboratory 1740 – 1800 Session 2 discussion 3 6th High Power Targetry Workshop / Book of Posters and Abstracts Agenda Day 3 - 13/04/2016 – Wednesday 0900 – 1030 Session 3: Target facility & safety issues (Conveners: E Pitcher & M Calviani) 0900 - 0920: Designs for a Simpler, More Robust LBNF Facility Sam Childress - Fermilab 0920 - 0940: J-PARC neutrino experimental facility: status and upgrade plan Taku Ishida - KEK/J-PARC 0940 - 1005: The ESS Target Station Radiological Hazard Analysis and Safety Classification Process Linda Coney - European Spallation Source (ESS) 1005 - 1030: Conceptual design of the CERN’s Search for Hidden Particles (SHiP) experiment target complex Marco Calviani – CERN 1030 – 1100 Refreshment break 1100 – 1300 Session 3: continues 1100 - 1120: Radiation protection studies for the design of the SHiP Facility Heinz Vincke - CERN 1120 - 1140: The target handling concept of the pbar-separator at FAIR Manuela Helmecke - GSI 1140 - 1200: An Integrated Remote Target Handling System for CERN’s MEDICIS Radioactive Isotope Production Facility Keith Kershaw - CERN 1200 - 1220: Results of and Methods Used in Designing the New Cold Neutron Source at SINQ Ryan Bergmann - Paul Scherrer Institut 1220 - 1240: The LIEBE target: a step toward exotic species Melanie Delonca - CERN 1240 – 1300 Session 3 discussion 1300 – 1400 Lunch (Merton dining hall) 4 6th High Power Targetry Workshop / Book of Posters and Abstracts 1400 – 1520 Session 4: Construction, fabrication, inspection, QA (Conveners: B Riemer & D Jenkins) 1400 - 1420: Experiences of Troubles and Design Improvements of Water Shroud of J-PARC Mercury Target Katsuhiro HAGA - Japan Atomic Energy Agency 1420 - 1440: SNS Target Design Improvement Drew Winder - Oak Ridge National Laboratory 1440 - 1500: Construction, fabrication, PIE and QA of the Muon and SINQ Cannelloni Targets at PSI Michael Wohlmuther - Paul Scherrer Institute 1500 - 1520: ISIS TSI Upgrade Target – Design for manufacture Leslie Jones - STFC – RAL 1520 – 1540 Refreshment break 1540 – 1700 Session 4: continues 1540 - 1600: High Energy Dump of the Super Proton Synchrotron at CERN – Present and Future designs Antonio Perillo-Marcone - CERN 1600 - 1620: Braze joint quality assurance of the beryllium beam tube window at Fermilab Kavin Ammigan - Fermi National Laboratory 1620 - 1640: J-PARC: Present Status of Muon Production Target at J-PARC/MLF/MUSE Shunsuke Makimura - J-PARC/KEK 1640 - 1700: Strategies to Improve Electron Beam Weld Quality for ISIS TS2 Targets. Arghya Dey - ISIS STFC Rutherford Appleton Laboratory 1700 – 2030 Boat trip with buffet dinner 1700 - 1730: Walk to Salters steamers 1730 - 2030: Boat trip (Salters Steamers, Folly Bridge) 5 6th High Power Targetry Workshop / Book of Posters and Abstracts Agenda Day 4 - 14/04/2016 – Thursday 0850 – 1030 Session 5: Operations - Operational Experience (Conveners: (S Makimura & J Hylen) 0850 - 0910: Present Status of the target and beam dump system at BigRIPS fragment separator Koichi Yoshida - RIKEN 0910 - 0930: ANSYS code calculations of the beam spot temperature at BigRIPS separator Zeren Korkulu - RIKEN Nishina Center 0930 - 0950: Gas Injection at SNS: Impact on Target Design and Bubble Size Distribution Determination Charlotte Barbier - ORNL 0950 - 1010: Target Strain Measurements during proton beam impact at the Spallation Neutron Source Willem Blokland - ORNL 1010 - 1030: CERN’s n_TOF neutron spallation target operating experience and future consolidation plans Marco Calviani - CERN 1030 – 1100 Refreshment break 1100 – 1300 Session 5: continues 1100 - 1120: 200 kW Liquid Lithium Neutron Source for SARAF Facility Ido Silverman - Soreq 1120 - 1140: Monitoring system for a muon rotating target at J-PARC Shiro Matoba - KEK 1140 - 1200: Operational experience and remote maintenance on T2K target Andrew Atherton - RAL 1200 - 1220: NuMI Horn Stripline failure, analysis, and recovery Patrick Hurh - Fermilab 1220 - 1240: Measurement of corrosive gas in the air in the NuMI target pile James Hylen – Fermilab 1240 – 1300 Session 5 discussion 1300 – 1400 Buffet lunch (T S Eliot Theatre) 6 6th High Power Targetry Workshop / Book of Posters and Abstracts 1400 – 1800 Tour of ISIS 1400 - 1430: Coach to Rutherford Appleton Laboratory 1730 - 1800: Coach return to Merton College 1930 – 2200 Banquet Dinner (Merton dining hall) After dinner speaker: Professor Dave Wark (University of Oxford & STFC, Director of Particle Physics) 7 6th High Power Targetry Workshop / Book of Posters and Abstracts Agenda Day 5 - 15/04/2016 – Friday 0900 – 1030 Session 6: Post Irradiation Examination (PIE)/autopsy - feedback to R&D and Design (Conveners: Y Dai & N Simos) 0900 - 0925: Tungsten for the high power spallation target at ESS Yongjoong Lee - European Spallation Source ERIC 0925 - 0945: PIE program of STIP-V tungsten specimens for ESS target engineering Jemila Habainy - European Spallation Source 0945 - 1005: Post-Irradiation Examination Sampling of SNS Mercury Target Vessel and Proton Beam Window Michael Dayton - UT-Battelle/ORNL 1005 - 1030: Materials Research and Post Irradiation Examination at the Spallation Neutron Source: Results and Status David McClintock - Oak Ridge National Laboratory 1030 – 1100 Refreshment break 1100 – 1300 Session 6: continues 1100 - 1125: Post-irradiation examination of SINQ targets Yong Dai - Paul Scherrer Institut 1125 - 1145: Post-Irradiation Examination of Ti-alloy foils in T2K OTR Andrew Casella - Pacific Northwest National Laboratory 1145 - 1205: Post-Irradiation Examination of Graphite from the NuMI NT-02 Target David Senor - Pacific Northwest National Laboratory 1205 - 1240: Experimental Investigation of Irradiation Effects in Beryllium Beam Window Viacheslav Kuksenko - University of Oxford 1240 – 1300 Session 6 discussion 1300 – 1400 Lunch (Merton dining hall) 8 6th High Power Targetry Workshop / Book of Posters and Abstracts 1400 – 1700 Discussions & hot topics 1400 - 1430: Session 1 Tristan Davenne - RAL Patrick Hurh - Fermilab 1430 - 1500: Session 2 Nikolai Mokhov - Fermilab Frederique Pellemoine - MSU-FRIB 1500 - 1530: Session 3 Eric PItcher - European Spallation Source Marco Calviani - CERN 1530 – 1600 Refreshment break 1600 – 1700 Discussions & hot topics: continues 1600 - 1630: Session 4 Bernie Riemer - Oak Ridge National Laboratory David Jenkins - STFC RAL ISIS 1630 - 1700: Session 5 Shunsuke Makimura - J-PARC/KEK James Hylen - Fermilab 1700 – 1730 Closing Plenary Presentation Chris Densham - STFC 9 6th High Power Targetry Workshop / Book of Posters and Abstracts LIST OF DELEGATES Kavin Ammigan Fermilab Andrew Atherton STFC John Back University of Warwick Olivier Bajeat GANIL Charlotte Barbier Oak Ridge National Laboratory Roger Bennett STFC Ryan Bergmann Paul Scherrer Institute Willem Blokland Oak Ridge National Laboratory Pierre Bricault TRIUMF Marco Calviani CERN Ottone Caretta STFC Andrew Casella Pacific Northwest National Laboratory Nikolaos Charitonidis CERN Sam Childress Fermilab Lester Clarke STFC Dan Coates STFC Linda Coney ESS Yong Dai PSI Tristan Davenne STFC Michael Dayton UT-Battelle/ORNL Tania CERN Melanie de Melo Mendonca Delonca Chris Densham STFC Arghya Dey STFC Jana Fetzer IKET Michael Fitton STFC Stephen Gallimore STFC Alexander Gottberg TRIUMF Jemila Habainy European Spallation Source Katsuhiro Haga Japan Atomic Energy Agency Albert Hanson BNL Manuela Helmecke GSI Donald Houngbo SCK-CEN Patrick Hurh Fermilab Wonjoo Hwang Institute for Basic Science James Hylen Fermilab Taku Ishida KEK/J-PARC David Jenkins STFC CERN 10 6th High Power Targetry Workshop / Book of Posters and Abstracts Jaewon Jeong Institute for Basic Science Xuejun Jia Institute of Physics CAS Leslie Jones STFC Saulius Kaminskas Oak Ridge National Laboratory Keith Kershaw CERN Harold Kirk BNL Yoshiaki Kiyanagi Nagoya University Klaus Knie GSI Alexander Konobeev Karlsruhe Institute of Technology Zeren Korkulu RIKEN Nishina Center Viacheslav Kuksenko University of Oxford Yongjoong Lee European Spallation Source Peter Loveridge STFC Wei Lu Oak Ridge National Laboratory Yanling Ma STFC Shunsuke Makimura J-PARC/KEK Shiro Matoba KEK David McClintock Oak Ridge National Laboratory Kirk T McDonald Princeton University Linus Mettler CERN Grant Minor TRIUMF Nikolai Mokhov Fermilab Jeremy Moor STFC Chris Nelson STFC Hiroki Okuno RIKEN Anna Orlowska STFC Bill Paley TRIUMF Frederique Pellemoine MSU-FRIB Antonio Perillo-Marcone CERN Eric Pitcher European Spallation Source Molly Probert STFC Joao Pedro Bernie Ramos CERN Riemer Oak Ridge National Laboratory David Senor Pacific Northwest National Laboratory Ido Silverman Soreq Nick Simos BNL Kristoffer Sjögreen European Spallation Source Sergei Striganov Fermilab Stephanie Thomas STFC Marilena Tomut GSI Claudio Torregrosa Martin CERN 11 6th High Power Targetry Workshop / Book of Posters and Abstracts Robert Tschirhart Fermilab Kazuki tsuchida Nagoya University Heinz Vincke CERN Helmut Weick GSI Dan Wilcox STFC Drew Winder Oak Ridge National Laboratory Michael Wohlmuther Paul Scherrer Institute Lei Yang IMPCAS Wen Yin IMPCAS Koichi Yoshida RIKEN Lei Zang University of Sheffield Robert Zwaska Fermilab 12 6th High Power Targetry Workshop / Book of Posters and Abstracts POSTERS The GANIL/SPIRAL 1 RIB production targets: present and future Olivier Bajeat GANIL The production target used for Spiral 1 at GANIL since its beginning is in carbon. It consists of a conical target made of lamellas 0.5 mm thick. The shape is designed to reach a temperature up to 2000°C as homogeneous as possible with good release. In order to produce a larger palette of radioactive beams, it is considered to use new couples beam/target. Authorization is given for new targets lighter than Niobium. Targets like Nb, SiC, CaO, NiO… have already been used in other laboratories (Isolde, Triumf, ORNL…). The specifics relating to Spiral 1 in terms of energy deposition are presented. The choice of targets that could be used or developed for Spiral 1 is discussed. HiRadMat – Test facility with high power proton beam pulses Nikos Charitonidis, Adrian Fabich CERN HiRadMat (High-Radiation to Materials) is a users’ facility at CERN SPS, designed to provide highintensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies can be tested. Since its operation start in 2012, more than 15 experiments were conducted, including target tests, collimator studies, material tests for vacuum windows and detector performance studies. The presentation will show the capabilities for tests within HiRadMat, present examples of previous experiments and outline the future plans for the facility. A spinning graphite target for Fusion Neutron Irradiation Research Tristan Davenne RAL An engineering design of DEMO, the first fusion reactor to supply power to the grid, is scheduled for completion in 2030. The plasma facing walls of the DEMO reactor will see an integrated neutron flux significantly above that experienced by materials used in fission reactors. As such it has been a long held plan to build an irradiation facility that can mimic the neutron spectrum of a fusion reaction and thus test candidate materials before specifying the DEMO plasma facing materials. The main initiative towards this has been IFMIF (International Fusion Materials Irradiation Facility) which can be considered as the gold standard in terms of mimicking the fusion neutron spectrum, flux and expected material damage levels. However it is a long way behind schedule and will not provide data in time for DEMO. An initiative by CCFE (Culham Centre for Fusion Energy) along with Oxford University Materials Science and RAL has proposed an irradiation facility known as FAFNIR (Facility for Fusion Neutron Irradiation Research) that should be able to start providing data in a time scale more aligned with DEMO. This presentation is focused on a design study (funded by PASI) of a spinning graphite target for such a facility. The primary goal of the study is to see if it is possible to generate a useful neutron flux with a target operating within the parameters of operational and prototype graphite wheel targets. 13 6th High Power Targetry Workshop / Book of Posters and Abstracts Simulation of proton beam induced pressure waves in liquid metal Jana R. Fetzer, A. Class Karlsruhe Institut of Technology (KIT) The development of the liquid metal spallation target META:LIC (MEgawatt TArget: Lead bIsmuth Cooled) for the European Spallation Source (ESS) at the Karlsruhe Institute of Technology (KIT) is based on previously developed liquid metal targets such as MEGAPIE, MYRRHA and IFMIF. Insights gained from the short pulse liquid metal targets at SNS and JSNS lead to increased sensibility towards undesirable effects of proton beam induced pressure waves. In order to allow for effective simulations during the design process and to gain a more detailed understanding the Multiple Pressure Variables (MPV) method is proposed. The MPV approach is based on a single time scale multiple space scale asymptotic analysis derived for subsonic flow by an asymptotic series expansion in the Mach-number. The presentation will introduce the MPV method with focus on the formulation for liquid metal applications. Then a series of validation calculations for the META:LIC target will be used to demonstrate the advantageous features of the method emphasizing that no time-step limitation beyond those enforced by the fluid flow calculation are imposed by the acoustics. The RaDIATE Collaboration: Current status and future activity plans P. Hurh1, K. Ammigan1, N. Simos2, V. Kuksenko3, D. Senor4 1 Fermi National Accelerator Laboratory, USA 2 Brookhaven National Accelerator Laboratory, USA 3 University of Oxford 4 Pacific Northwest National Laboratory The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments), founded in 2012, has grown to over 50 participants and 11 institutions globally. The primary objective is to harness existing expertise in nuclear materials and accelerator targets to generate new and useful materials data for application within the accelerator and fission/fusion communities. Current activities include postirradiation examination of materials taken from existing beamlines (such as the NuMI primary beam window from Fermilab) as well as new irradiations of candidate target materials at low energy and high energy beam facilities. Status of current RaDIATE activities as well as future plans will be discussed. Special focus for this presentation will be on the upcoming RaDIATE irradiation at the Brookhaven Linac Isotope Producer facility (BLIP) in which multiple materials of interest to various RaDIATE participants will simultaneously be exposed to 120 – 200 MeV, high intensity proton beam. Target materials to be tested include various grades of beryllium, graphite, silicon, molybdenum TZM, iridium, titanium, luminescent-coated aluminum and others. Expected peak damage ranges from 0.04 DPA (Be) to 9 DPA (W), and helium production ranges from 90 appm (W) to 140 appm (Be). Motivation, candidate materials, irradiation parameters, and experimental set-up will be described. 14 6th High Power Targetry Workshop / Book of Posters and Abstracts Production target for Isotope Separation On-Line facility in Rare Isotope Science Project Wonjoo Hwang Institute for Basic Science Rare Isotope Science Project (RISP) was launched by the Institute for Basic Science (IBS) in 2011 in Korea. RISP is developing Isotope Separation On-Line (ISOL) target system, which consists of uranium-carbide multi-disks. Production of high purity rare isotopes is estimated by bombarding a proton beam (10 kW, 70 MeV) on the target via the proton-induced fission reaction. The target is designed to be operated at a temperature of ~2000 ˚C taking into account fast release characteristics. We are developing the lanthanum-carbide disks, as a first step, due to the difficulties of handling radioactive material. Lanthanum-carbide is synthesized by using suspension grinding and wet-mixing with multi-walled carbon nanotubes (MWCNTs) to have nano-structure. The current status and present design of the ISOL target will be briefly introduced with an overview of the RISP ISOL system. Design for handling and maintenance in radiation areas – development of CERN guidelines Keith Kershaw CERN CERN is developing guidelines for use by designers and engineers with the aim of reducing personnel radiation exposure by ensuring that equipment is designed taking into account all handling and maintenance operations during its lifetime. The guidelines concentrate on two main methods of reducing radiation exposure: either by making it possible to carry out interventions using remote handling techniques, or by ensuring that operations carried out by personnel intervening in radiation areas can be completed as rapidly and safely as possible. Inspired by remote handling compatibility guidelines and recommendations produced for ITER and elsewhere, a methodology is proposed (handling lifecycle analysis combined with recommendations for good practice) for designers to ensure that these considerations are taken into account from the conceptual design stage onwards. The proposed methodology and documentation structure will be described along with practical examples of the application of the guideline principles in recent projects. R&D activities for transmutation of long-lived fission products Hiroki Okuno RIKEN Nishina Center for accelerator-based science ImPACT Fujita program is aiming at reduction of LLFPs from the spent fuel of nuclear power plants. This program covers R&D studies with respect to target technology for the transmutation of the LLFPs. This R&D has the two main subjects. The first one is liquid lithium target for production of neutron or muon. Uniformity in thickness of liquid lithium targets is required because they will be used as internal targets in accelerators which have function of energy recovery. We have started study for suppression of surface fluctuation of the liquid lithium film generated from rectangular nozzle (W 30mm x T 1mm) by Magneto-Hydro-Dynamics (MHD) effect. Preliminary results will be reported in this workshop. The 15 6th High Power Targetry Workshop / Book of Posters and Abstracts second one is “windowless” beam window because beam windows in the high power target facility are problematic. We started studies to enlarge apertures of the plasma window. The performance of the plasma window had already proved. However its aperture is as small as 6 mm at maximum. We measured pressure difference and electron temperature with various conditions (length, aperture, gas flow rate, etc) to get the way how to enlarge its apertures. We are also studying feasibility of liquid metal window with large aperture such as more than 100 mm. We will present experimental results on plasma window and simulation results on liquid metal window. Design and Operational Feedback of the Extraction Dump of the Proton Synchrotron Booster at CERN A. Perillo-Marcone, A. Sarrió-Martínez, V. Venturi, E. Nowak, A. Manousos, V. Vlachoudis, G. Mason, E. Da Riva, M. Battistin, M. Garlasche, E. Urrutia, B. Riffaud, A. Dallocchio, M. Czapski, S. Sgobba CERN (Geneva – Switzerland) A beam dump has been designed, manufactured and installed to withstand the upgraded proton beam extracted from the Proton Synchrotron Booster at CERN, consisting of up to 1E14 protons per pulse at 2 GeV, equivalent to approximately 10 kW of heat power deposited in the device. In order to be able to efficiently release the heat deposited by the beam, the dump was made out of a cylindrical block of CuCrZr and cooled by forced ventilation. Complex calculations were made to determine the temperature distribution and thermo-mechanical loads in the dump, generated by the interaction with the beam. This paper describes the design process, material specification and manufacture details for this device. Additionally, thanks to the instrumentation installed around the dump, a preliminary operational feedback has been obtained and is presented here. Advanced High Power Neutron Converter – Spallation Source - for Radioactive Ion Beam Production J.P. Ramos, P. Bricault, A. Gottberg, R. Luis, T.M. Mendonca, L. Popescu, T. Stora CERN-ISOLDE, TRIUMF, TRIUMF, IPFN-IST, CERN-ISOLDE, SCK-CEN, CERN – ISOLDE The delivery of highly intense and pure beams of radioisotopes of (ultimately) all chemical elements, for physics research, is the mission of the ISOL facilities such as HIE-ISOLDE at CERN, ISAC at TRIUMF and the future ISOL@MYRRHA facility at SCK-CEN. As a result, these facilities are always thriving to upgrade themselves, through research and development of new ways to produce, extract and ionize the radioisotopes. In particular, the neutron converter, a spallation source which is used to induce n-rich fission fragments from uranium carbide targets, avoiding the n-deficient isobaric contaminations (which are produced irradiating directly the target with protons). In the last years new optimized geometries have been proposed for the ISOLDE neutron converter [1,2,3] and an example was tested and validated[3]. Such geometry is optimized in a way so that the protons scattered by the neutron converter don’t hit the target nearby while maximizing the neutron interaction with the target. As an example, one of the proposed geometries is a thick-walled cylindrical tube shaped target centred around a tungsten cylinder shifted downstream from the target relatively to the proton beam. Such 16 6th High Power Targetry Workshop / Book of Posters and Abstracts geometry presents many engineering challenges which will have to be validated with simulation codes (FLUKA – for isotope production and beam power deposition and ANSYS – for thermal profiles) and additional prototypes will have to be built. Additionally, designs for the very different facility target units and respective driver beam properties (high power – instantaneously or continuous) will have to be done and tested. Facilities around the world, have very different driver beam properties such as ISAC with 50kW, CW 500MeV proton beam, HIE-ISOLDE up to 2GeV pulsed proton beam and 12kW (10GW instantaneous power), ISOL@MYRRHA with 600MeV proton beam and 100 kW beam power and RISP with 160 kW, 160 MeV protons. References: [1] R. Luis, J.G. Marques, T. Stora, P. Vaz, L. Zanini, Optimization studies of the CERN-ISOLDE neutron converter and fission target system, Eur. Phys. J. A. 48 (2012) 90. [2] R.F. Luís, Radiological protection and nuclear engineering studies in multi-MW target systems, 2013. http://hdl.handle.net/10451/10713. [3] A. Gottberg, T.M. Mendonca, R. Luis, J.P. Ramos, C. Seiffert, S. Cimmino, et al., Experimental tests of an advanced proton-to-neutron converter at ISOLDE-CERN, Nucl. Instruments Methods Phys. Res. Sect. B Beam Interact. with Mater. Atoms. 336 (2014) 143–148. Target Selection for the SNS Second Target Station M.J. Rennich, C.N. Barbier, J.G. Janney, T.J. McManamy, and I. Remec Oak Ridge National Laboratory A comprehensive analysis of potential targets for the SNS Second Target Station (STS) was undertaken during 2015. This process culminated in the selection of a water cooled, rotating target. The decision was initially driven by safety and operating concerns arising from the high level of residual heat in the originally proposed fixed target. Calculations indicated that a fixed target would quickly exceed 1000 C after a loss of coolant while the larger surface area of a rotating target can passively maintain an acceptable temperature below 400 oC for over a month. A predicted operating life of over 10 years compared to one year for the fixed target is also a significant advantage for the rotating configuration. Adding further foundation for the decision to use a rotating target is the recent development of a target building configuration substantially more efficient than was possible with a fixed target. 17 6th High Power Targetry Workshop / Book of Posters and Abstracts Comparison of Measured Dynamic Strain Response of the SNS Mercury Target Vessel to Simulation Results Bernie Riemer, Willem Blokland, Saul Kaminskas Oak Ridge National Laboratory The dynamic structural response of the SNS mercury target vessel was measured for the first time with the installation of the 13th target module. Strain sensors at eight locations provided vessel response data from single pulses at several intensities and from bursts of ten pulses delivered at 60 Hz. The proportionality of strain response to pulse intensity was evaluated and found to be quite linear despite the non-linear cavitating behavior of the mercury. Measured responses were also compared to simulation results. The match is very good at the location closest to the beam axis and entrance point. At most locations further distances away from this point the simulation does well to match the dynamic character of the response but over-predicts peak strain magnitudes. At the furthest location from the beam entrance the peak response was under-predicted. Here it appeared that a resonant coupling with the mercury may be occurring that the simulation model does capture. A finding from the pulse bursts was that responses do not superpose and accumulate in magnitude. This presentation will present, compare and discuss the measured and simulated strain response data. Conceptual design of the new gas-cooled antiproton target at CERN Claudio Torregrosa Martin, Antonio Perillo-Marcone, Marco Calviani, David Horvath, Maxime Bergeret CERN Antiprotons are produced at CERN by colliding a proton beam of 26 GeV/c momentum with a fixed target made of a high density material. The current target design dates from the late 80’s and consists of a target core of 3 mm diameter iridium rods embedded in a modular Ti-6Al-4V water-cooled assembly. In the framework of the antiproton target area consolidation, a re-design of an optimized antiproton production target is on-going in order to match it to future operational conditions and improve its antiproton production yield. Ideas for the new design may include a different configuration of its target core together with a major change of its external cooling system, switching to a high-pressured gas flow. As a first step in this redesign process, CFD and thermomechanical simulations including a new external geometry of the target and possible new materials and primary proton pulses configurations are presented. SNS Target Fabrication and Quality Oversight Drew Winder, Mike Atherton, Don Abercrombie Oak Ridge National Laboratory Targets at the Spallation Neutron Source are vital for the operation of the facility. They are fabricated to print under contract at external vendors. Over the lifetime of the facility, lessons learned have shown that we need significant quality oversight to ensure the reliability of the targets. Discussion will include the roles and responsibilities of the different groups and individuals involved in target fabrication and oversight. The flows of information, approvals, and records will be presented, along with lessons learned. The goal will be to ignite discussion and share best practices between facilities. 18 6th High Power Targetry Workshop / Book of Posters and Abstracts ESS Target Wheel Drive and Shaft design Kristoffer Sjögreen, Ulf Odén European Spallation Source ERIC High power and high radiation have been the driving forces during the design of the ESS Target System, taking the conceptual design in to a preliminary design ready for final design and manufacturing. Several areas have been investigated during preliminary design and the Target System concept is adjusted to the results from these investigations. The Target System includes the spallation material and the primary cooling of the spallation material. The design is based on helium cooled rotating tungsten target. The concept design is described in the Conceptual Design Report 2012 and ESS Technical Design Report 2013. The essential design requirement is to safely generate a high neutron flux based on a 5 MW, long pulse, proton beam. “Safety” considers both radiation protection to public and workers, and availability of neutrons to the scientific instruments. The power of the proton beam is somewhat greater than existing spallation sources and so existing spallation target designs used on other facilities are inappropriate. A new target design is required for the ESS facility. This presentation will give an overall view of the Target Wheel Drive and Shaft design and specific details in some of the more important areas. The detail information will focus on: The Spallation Material Design to fulfil the requirement of max 500°C and max mean stress 100 MPa during normal operation The Target Wheel Vessel Design to handle 1 MPa Helium Cooling Pressure, narrow gap to moderator, simple decommissioning and maximum neutron flux. The Shielding Design to protect electrical component and enable hands on maintenance on the Drive Unit The Drive Unit Design to position the Target Wheel in the Monolith The Target Wheel Drive & Shaft position in the Monolith to enable vacuum or Helium atmosphere in the Monolith The ETHEL experiments to determine tungsten dust formation. Test rig, different experiments and results. 19 6th High Power Targetry Workshop / Book of Posters and Abstracts Session 1: R&D – Physics design, materials choices, validation of concepts Addressing material challenges in high-power targetry Marilena Tomut GSI Helmholtzzentrum für Schwerionenforschung High-power production targets design challenges are mainly related to unknown material properties degradation in intense radiation field and its response to beam-induced thermal stress and pressure waves. Lifetime estimation is based on individual failure criteria which take into account the target performance requirements, normal operation conditions and possible accident scenarios. Current material irradiation facilities cannot reach the beam intensity planned for the future accelerator facilities. Materials scientists have to assemble a complex puzzle of experimental investigations of radiation damage effects on material structure, properties and dynamic response at high strain rates, to provide input parameters for simulations covering beam intensities and energy density that cannot be reached yet experimentally. This work summarizes the latest results obtained at GSI on radiation-induced degradation of thermomechanical properties of carbon materials, electrical resistivity and creep behaviour. Dynamic material response at high strain rates has been investigated using nanosecond and picosecond high-power laser pulses. Experimental results are integrated in simulations of dynamic thermal fracture of targets in the context of radiation damage. Experimental Results of Beryllium Exposed to Intense High Energy Proton Beam Pulses K. Ammigan1, P. Hurh1, B. Hartsell1, B. Zwaska1, C. Densham2, A. Atherton2, M. Fitton2, J. O’Dell2, T. Davenne2, P. Loveridge2, O. Caretta2, S. Roberts3, V. Kuksenko3, M. Butcher4, M. Guinchard4, M. Calviani4, R. Losito4 1 Fermi National Accelerator Laboratory, USA 2 Rutherford Appleton Laboratory, UK 3 University of Oxford, UK 4 CERN, Switzerland Beryllium is extensively used in various accelerator beam lines and target facilities as material for beam windows, and to a lesser extent, as secondary particle production targets. With increasing beam intensities of future accelerator facilities, it is critical to understand the response of beryllium under extreme conditions to reliably operate these components as well as avoid compromising particle production efficiency by limiting beam parameters. As a result, an exploratory experiment at CERN’s HiRadMat facility was carried out to take advantage of the test facility’s tunable high intensity proton beam to probe and investigate the damage mechanisms of several beryllium grades. The test matrix consisted of multiple arrays of thin discs of varying thicknesses as well as cylinders, each exposed to increasing beam intensities. This talk outlines the experimental measurements, as well as findings from Post-Irradiation-Examination (PIE) work where different imaging techniques were used to analyze and compare surface evolution and microstructural response of the test matrix specimens. 20 6th High Power Targetry Workshop / Book of Posters and Abstracts Material studies for the high-power beam dump in the FRIB project Frederique Pellemoine (1), Aida Amroussia (2), Mikhail Avilov (1), Carl J. Boehlert (2), Florent Durantel (3), Clara Grygiel (3), Jacob Kramer (1), Wolfgang Mittig (4), Isabelle Monet (3), Harsh Patel (1), Barrie Phillips (1), (1) Facility for Rare Isotope Beams FRIB, Michigan State University, East Lansing MI 48824-1321, USA (2) Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824-4437 (3) CIMAP-CIRIL, BP 5133, 14070 CAEN CEDEX 5, France (4) National Superconducting Cyclotron Lab, Michigan State University, East Lansing MI 48824-1321, United States The Facility for Rare Isotope Beams currently under construction at Michigan State University will use a 400 kW primary ion beam from a superconducting radiofrequency accelerator for in-flight production of intense beams of radionuclides. The primary beam impinges on a production target where rare isotopes are produced by nuclear reactions. Magnetic separation is used to select the isotopes of interest and separate the rare isotopes from the beam particles that did not undergo a nuclear reaction. The beam power of the unreacted primary beam can reach values of up to 325 kW. For stopping this beam a highpower beam dump has been developed a rotating water-filled drum. The beam power is absorbed by a volume of water that is contained within a rotating thin-walled shell of the drum. Water is used for both stopping the beam and cooling the shell. The drum has a diameter of 70 cm and a height of 8 cm in order to distribute the heat and radiation damage induced by the beam. The shell is made of Ti-6Al-4V alloy with a wall thickness of only 0.5 mm (about 0.02”) in order to limit the power deposition into the wall material. 3D printing will be used to fabricate this shell. A thorough knowledge of the properties of this Ti-alloy under extreme conditions (thermomechanical stress and radiation damage) is crucial to optimize the design and performance of the beam dump shell. Studies were performed to investigate heavy-ion induced radiation damage in different Ti-alloys, including the commercially available Ti-6Al-4V. The studies were performed at GANIL-CIMAP (France). Low-energy heavy ion beams were used to investigate microstructure and mechanical property changes, and test with intermediate energy heavy ions focused on creep test at different temperatures and dose. Ti-alloys are also known for the dependence of their mechanical properties on the thermomechanical processing, which can influence the microstructure (i.e. the grain size and phase composition). Because grain boundaries act as point defect sinks, it is crucial to investigate the effect of heavy-ion induced damage in the 3D printed material as it shows a different microstructure than the commercially available Ti-6Al-4V. A mechanical setup that includes a ¼ scale beam dump mockup with a 3D printed shell from Ti-6Al-4V was developed and built. This assembly will be tested at Budker Institute of Nuclear Physics (BINP), Novosibirsk, Russia, with high energy electron beam during spring 2016. This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University. 21 6th High Power Targetry Workshop / Book of Posters and Abstracts An experiment to study the dynamic response of high density materials under intense proton beam impacts for the future design of the new Antiproton Decelerator target Claudio Torregrosa Martin, Antonio Perillo-Marcone, Marco Calviani, Mark Butcher, David Horvath, Maxime Bergeret, Elvis Fornasiere, Giovanni Vorraro, Luca Gentini CERN The HRMT27-RodTarg- experiment successfully took place in November 2015, making use of the HiRadMat facility at CERN. The aim of the experiment was to impact intense proton pulses of 440GeV/c onto thin rods -8mm diameter, 140mm length- made of high density materials, such as iridium, tungsten, molybdenum and tantalum among others. The goal of the experiment was to assess the material selection for the new antiproton production target at CERN by experimentally recreating the same extreme thermal and dynamic conditions reached in its operating core as well as to validate the hydrocode simulations used for this purpose. In addition, the experiment strived for finding limits and failure mechanisms of the material of interests when exposed to these extreme conditions. To accomplish these goals the experiment relied on extensive online instrumentation. In this presentation, the authors will expose the specifications, technological and precision challenges overcome in this unique experiment, together with presentation of online data recorded and conclusions drawn from the results. Finally, plans for the future PIE which will complete this experiment will be presented. Tungsten powder as a high power proton accelerator target: in beam experiments Ottone Caretta, Tristan Davenne, Peter Loveridge, Joe Odell, Mike Fitton, Chris Densham, Adrian Fabich, Ilias Efthymiopoulos, Nikolaos Charitonidis, Bjorn Lindstrom, Lukasz Jerzy Lacny, Michael Guinchard Rutherford Appleton Laboratory A set of experiments were performed in 2015 at the HiRadMat facility at CERN exposing samples of Tungsten powder to high energy proton irradiation. The setup allowed the observation of the dynamic response of granular tungsten samples of different size distributions to the beam, both in vacuum and in a helium atmosphere. The diagnostics consisted of a High Speed Video camera (HSV) and a Laser Doppler Vibrometer (LDV) aiming at the powder’s surface and at the container’s wall respectively. The experiments were aimed at quantifying the powder response as a function of beam intensity and at identifying whether the powder lift is caused by aerodynamics, stress propagation or electrostatic repulsion High-Power electron beam ISOL target concepts for the production of Photofission Fragments A. Gottberg, P. Bricault, G. Minor, W. Paley TRIUMF The ISOL (Isotope Separation OnLine) technique delivers exotic radioisotopes for experiments in a broad range of fields from nuclear physics and astrophysics, materials science, to preclinical medical research. TRIUMF’s current flagship project, Advanced Rare IsotopE Laboratory (ARIEL), will not only dramatically increase the availability of pure radioactive ions but also enable the delivery of three isotope beams simultaneously – an unprecedented technology – enhancing the scientific output of the laboratory. With 22 6th High Power Targetry Workshop / Book of Posters and Abstracts ARIEL, the delivery of low-energy (up to 60 keV) and post-accelerated radioactive beam in excess of 9000 hours per year seems to be in reach. In addition to two targets served by 50 kW (500 MeV protons from TRIUMF’s H- cyclotron), a second independent driver – a new superconducting 1.3 GHz e-linac – will supply a third target. For the latter, up to 100 kW of 35 MeV electrons will be converted into gamma radiation for photonuclear reactions, taking on TRIUMF’s leading role in high-power ISOL technology. An advanced compact solid electron-to-gamma converter is currently being developed and tested, optimizing the thermomechanical durability as well as the gamma-ray yield and overall isotope production performance. With an expected life-time of approximately three weeks for both the converter and the ISOL production target, a remote target exchange mechanism using radiation-hard services and vacuum quick-disconnections as well as remote handling and hot-cell capabilities for maintenance, post-irradiation examinations and waste conditioning are being developed, designed and tested. Since the intrinsic properties of 35 MeV electrons are fundamentally different to MeV neutrons or 0.1 to 2 GeV protons, which are commonly used for ISOL, the design of the ARIEL electron target and its adjacent systems will differ fundamentally from any exiting design. New technology for ISOL electron targets as well as implications for existing systems will be presented and discussed. Research and development towards a radiation-cooled target for Mu2e Peter Loveridge STFC/RAL The Mu2e experiment, currently under construction, will form part of a new “muon campus” at Fermilab. For a number of years the High Power Targets Group at RAL have been working closely with Fermilab scientists and engineers to design the Mu2e primary proton beam target system. The present baseline technology choice is for a passively cooled tungsten target which operates at a sufficiently high temperature that the necessary heat transfer from the target into the surrounding heat shield may be achieved through thermal radiation alone. Adopting this passive cooling concept has meant that no active coolant or associated plant is required, the risk of coolant leaks has been eliminated and the necessary target remote handling processes are greatly simplified. However, challenges relating to continuous high temperature operation of the target must be addressed. Baseline target development activities are currently focussed on obtaining data from a physical testing programme to inform and quantify specific technical risks associated with this high temperature operation. We present the status and interim conclusions of the Mu2e target test programme, including (i) thermal emissivity measurements, (ii) ultra-high temperature thermal fatigue testing, (iii) target oxidation tests at high temperature and low pressure and (iv) research into potential target coating systems that may improve chemical resistance and/or enhance the target emissivity for improved heat transfer performance. 23 6th High Power Targetry Workshop / Book of Posters and Abstracts High Power Target Studies at CERN-ISOLDE Tania M. Mendonca, Melanie Delonca, Veronique Ghetta, Etam Noah, Thierry Stora CERN – European Organization for Nuclear Research High intensity radioactive ion beams (RIBs) open up new opportunities to explore the properties of nuclei far from stability. The need for intense RIBs is the driving factor behind the development of new facilities exploiting primary beams with megawatts of beam power and, consequently, target interfaces that can accommodate such large powers. In the recent years, research and development work in high power targets has experienced important advances and new systems have been proposed and developed, notably during the EURISOL project [1]. At the CERN-ISOLDE facility, the target and ion source group dedicates part of the activities to high power targets, which include proton to neutron converters and liquid targets. Special attention is given to molten targets since they can provide the highest intensities for isotopes of certain elements due to high material density. Nonetheless, these class of targets suffer from long diffusion times, which strongly affect the extraction of short-lived isotopes. In order to cope with this limitation, a lead-bismuth eutectic (LBE) target loop equipped with a diffusion chamber has been proposed and tested offline at IPUL, Latvia, by E. Noah and co-workers. To validate the concept, a molten LBE loop will be prototyped and tested on-line at CERN-ISOLDE using a 1.4 GeV proton beam. The molten LBE concept inspired an alternative route to produce 1013 18Ne/s for the Beta Beams project [1], where a molten salt loop would be irradiated with 7 mA, 160 MeV proton beam. The concept has been validated by testing a molten fluoride salt static unit at CERN-ISOLDE using a 1.4 GeV proton beam. The investigation of the release and production of neon isotopes allowed the first measurement of the diffusion coefficient of this element in molten fluoride salts. [1] Final Report of the EURISOL Design Study 2009, J. Cornell Ed., GANIL Deploying gas injection is the SNS target for fatigue and pitting damage life improvement Bernie Riemer Oak Ridge National Laboratory This presentation will describe the goals, challenges and plans for target gas injection at the SNS. The MW class SNS mercury target works as short-pulse spallation neutron source operating at repetition frequency of 60 Hz. The micro-second pulse length drives intense pressure waves in the mercury that have two adverse effects on target vessel lifetime, namely, very high-cycle fatigue stress and cavitation pitting erosion. Reliable, high power operation of the target to supply neutrons for the science instruments is demanded by SNS sponsors. One method to reduce fatigue stress and mitigate cavitation erosion is by injecting gas into the mercury target. Already the mercury spallation target at the J-Parc Material neutron source uses gas bubble injection and significant reductions in vessel vibration have been demonstrated. Deploying gas injection in the SNS mercury target system is now recognized as essential, but several hurdles are to be overcome. For example, the mercury process system, i.e. the mercury pump, heat exchanger, piping, off-gas treatment system, was not designed for gas injection. Changes to the system must be done remotely as more than 30 GW·h of beam has been delivered and the system is now highly radioactive and contaminated. Long term goals for SNS gas injection envision up to 1% injected gas volume fraction of total flow (under standard temperature and pressure 24 6th High Power Targetry Workshop / Book of Posters and Abstracts conditions). Near term gas injection goals are less ambitious and include only small gas bubble for pressure wave mitigation. Later, protective gas walls may be deployed if additional pitting damage mitigation in the target vessel is needed. Two related difficulties with gas deployment are facility safety and gas hold-up in the process piping. Due to the lengthy and mainly horizontal pipe lengths, gas can accumulate in the piping and displace mercury in the system. A postulated accident where liquid mercury overflows the pump tank and sending it to the off-gas treatment system must be mitigated before approval is given for deployment. Compact Sealed lithium target for accelerator-driven BNCT system Kazuki Tsuchida, Yoshiaki Kiyanagi Nagoya University, Graduate School of Engineering A compact sealed lithium target is under developing for BNCT application in combination with a Dynamitron (2.8MeV, 15mA). A thin lithium layer (0.14mm) is set in an embossed tantalum plate and covered by a thin titanium foil to confine liquid lithium and radio isotopes (Be-7, T) in the target. The low-energy and high current proton beam is passing through a titanium foil and irradiated to the lithium layer. Strong turbulent flow is arose with ribs in cooling water channels of the target and had been confirmed to remove high beam flux of more than 10MW/m2. It can reduce the size of the target down to 80mm square 25 6th High Power Targetry Workshop / Book of Posters and Abstracts Session 2: Target design, analysis & simulations HL-LHC Collimator Tests at CERN HiRadMat Facility L. Mettler, A. Bertarelli, F. Carra, C. Fichera, P. Gradassi, J. Guardia, M. Guinchard, S. Redaelli, O. Sacristan CERN, Geneva The High Luminosity LHC (HL-LHC) project, a significant upgrade of LHC at CERN, leads to a substantial increase in beam power. This necessitates the development of more advanced beam cleaning and protection systems than the existing ones. Collimator materials may limit the performance of the accelerator: high RF impedance in primary and secondary collimators can lead to beam instabilities, while present tertiary collimators are of limited robustness in case of beam-induced accidents. In view of the challenging demands, new collimator designs and novel composite materials have been developed. These include molybdenum-graphite (MoGR) and copper-diamond (CuCD), both of which are excellent thermal and electrical conductors which can be coated to further reduce RF impedance. In order to qualify for HL-LHC, the materials need to withstand stringent design scenarios. In 2015 an experimental campaign was conducted at CERN’s HiRadMat facility, where full HL-LHC collimator jaws designed for the two aforementioned materials, as well as a conventional secondary collimator jaw made of carbonfibre-carbon (CFC), were impacted with intense proton beams. The experiment was instrumented with strain gauges, optical fibres, temperature sensors, ultrasound probes, water pressure and vacuum sensors, together with high-speed and high-definition cameras and laser Doppler vibrometers. Advanced numerical simulations were performed with implicit and explicit finite element codes in order to reproduce the thermal shock waves generated in the experiment. These transient thermo-mechanical analyses make use of the energy deposition computed for given beam parameters and impact position, and employ the most recent elasto-plastic material constitutive models. In spite of the extreme conditions, the new materials performed very well, surviving the specified HL-LHC design scenarios. Preliminary experimental results are presented along with a comparison with the numerical simulations. Design and Optimisation of the ISIS TS1 Upgrade Target Dan Wilcox STFC The ISIS TS1 upgrade aims to achieve a factor of 2 or more increase in neutronic performance for a modest cost. This will be achieved by using modern software and analysis techniques to improve neutronic efficiency without increasing the beam power. An essential part of this will be the development of a new and more efficient spallation target. This talk will cover the development of the current target proposal, from initial concept to detailed design, analysis and optimisation. Detailed ANSYS FEA models were created of fluid, thermal and mechanical performance. Component geometry was optimised using a combination of ANSYS DesignXplorer software and engineering judgement. The ISIS neutronics and manufacturing groups were consulted throughout the process to ensure their requirements were met. In many cases a trade-off was required between the conflicting demands of neutronic efficiency, engineering reliability and manufacturability. It is essential that the TS1 upgrade is low risk; care must be taken not to compromise 26 6th High Power Targetry Workshop / Book of Posters and Abstracts the reliability of the existing facility. FEA simulations were used to understand and design against likely target failure modes including fatigue, radiation damage and off-normal beam conditions. The BLAIRR Irradiation Facility Hybrid Spallation Target Optimization N. Simos, A. Hanson, D. Brown, M. Elbakhshwan Brookhaven National Accelerator Laboratory, USA The optimization of the “hybrid” spallation target concept/design under consideration for the Brookhaven Linear Accelerator IRRadiation facility (BLAIRR) at Brookhaven National Laboratory will be presented. BLAIRR, a complex of existing, dormant transport beamlines, target end-stations and nTOF lines comprising the Radiation Effects (REF) and the Neutral Beam Test Facility (NBTF) receives proton beams from the 200-MeV Linac just prior to their injection into the Booster. BLAIRR aims to utilize the unique capabilities rendered by the energy “tuneability” of the existing Linac (accelerating H+ or H- beams of 64, 92.6, 116.5, 139.0, 160.5, 181.0 and 200.3 MeV) for spallation with the addition of a large array of heavy ions produced at the Tandem van de Graaff and currently transferred into the Booster. The BLAIRR envisions an update of the REF and NBTF extraction beamline complex with the introduction of a novel proton energy amplification system that would allow for the incremental increases of the proton energy from the presently available (66-200MeV) up to 1 GeV an energy range optimal for spallation neutron production considering options that include superconducting RFQ or an FFAG. A novel, multi-purpose “hybrid” target consisting of W core shrouded by cooled Be is under study to enable operation and optimal performance under the various proton energy modes while optimizing for (a) spallation fast neutron spectra for use in damage and 4He embrittlement of materials considered for fusion and fast reactors, (b) performance of neutron moderating and reflector materials as well as neutron multipliers (c) neutron time of flight for cross section measurements for use in Accelerator Driven Systems (ADS) and finally (d) potential for neutron scattering measurements. Addressed in this optimization and feasibility study will be the performance of the W+Be spallation target under the different energy scenarios considering spallation neutron yield and its optimal spatial and energy distribution, W and Be irradiation damage based on on-going studies at BNL and finally, engineering challenges posed for safe, continuing operation of the target concept in the current BLAIRR facility configuration. 27 6th High Power Targetry Workshop / Book of Posters and Abstracts DUNE/LBNF Target Studies: Physics and Engineering John Back2, Tristan Davenne1, Chris Densham1, Ottone Caretta1, Peter Loveridge1, Michael Fitton1, Geoff Burton1, Joe O’Dell1 (1) RAL, (2) University of Warwick The target design for LBNF is a significant challenge as a result of the planned maximum operating beam power of 2.4MW being more than three times any existing superbeam facility. NuMI and NoVA at Fermilab are the most powerful neutrino facilities to date with NoVA currently running at 400kW, T2K is a close second at 350kW, both facilities are designed for a maximum beam power of 700 750kW. NuMI and NoVA targets both rely on water cooled graphite and the current baseline target design for LBNF is a development of the NuMI target designed for 1.2MW operation. This study looks at the applicability of two alternative target design options for achieving 2.4MW. The first is a helium cooled graphite cylinder similar to the T2K target design and the second is a helium cooled beryllium spherical array target motivated by the potential of beryllium having a higher resistance to radiation damage than graphite. We present preliminary results on neutrino flux simulations using the Geant4 simulation package. Comparisons are made between beryllium and graphite targets, as well as between the SAT and the current LBNF baseline graphite target that is based on the NuMI design. We also present some thermo-mechanical simulations of the alternative target designs. MARS15 studies of impact of LBNF target/horn optimization on hadron absorber S. Striganov, N. Mokhov Fermilab It is shown – via thorough MARS15 studies - that modifying and optimizing the target/horn configuration of the Long Baseline Neutrino Facility (LBNF) for the DUNE experiment one can substantially reduce energy deposition levels in the hadron absorber, and as a result, simplify its design and make measuring muon and neutrino spectra more accurate. Moreover, the proposed absorber – without a front spoiler and sculpting in the core aluminium blocks – can withstand a higher beam power compared to the baseline of 2.4 MW. SNS mercury target fatigue life prediction with Fe-Safe/Verity software Saulius Kaminskas Oak Ridge National Laboratory Insufficient fatigue strength of the SNS mercury target stainless steel vessel from beam pulse and thermal cyclic loads can lead to mercury leaks and premature target life termination. Neutron production and the scientific user program at SNS had been disrupted on several occasions due to such incidents. It is critical to accurately and efficiently estimate target fatigue life time limits when evaluating new design concepts that aim to improve target reliability. Fe-Safe was the first commercially available fatigue analysis software to focus on modern multiaxial strain based fatigue methods applied to Finite Element models. It identifies the locations of structure most vulnerable to cycling loadings and then estimates the maximum number of durable life cycles at those locations as well. The Verity add-on to Fe-Safe addresses the fatigue of welded joints. Its structural 28 6th High Power Targetry Workshop / Book of Posters and Abstracts stress method is based on nodal forces at the weld toe and is FE mesh insensitive. Verity is recognized and recommended by ASME for fatigue analysis of welds. These tools are now being applied to the latest designs of SNS target to evaluate fatigue under high and low cycle loadings. The application of this technology together with obtained results is to be presented. The fatigue strength of one of the previously failed targets is also evaluated with these new capabilities. Loop-type Pb-Bi target for High Power ISOL facilities: Optimization toward higher yields D. Houngbo1,2, L. Popescu1, T. Stora3, J. Vierendeels2 (1) Belgian Nuclear Research Centre (SCK•CEN), Boeretang 200, B-2400 Mol, Belgium (2) Department of Flow, Heat and Combustion Mechanics, Ghent University (UGent), St.Pietersnieuwstraat 41, B-9000 Gent, Belgium (3) CERN, 1211 Geneva 23, Switzerland In the context of the new-generation ISOL facilities like EURISOL and ISOL@MYRRHA, liquid metal target loops are proposed to deal with the high-power beam on target when increasing the primary beam intensity. In this framework, a molten Pb-Bi loop target is under development within the LIEBE project, with the main purpose of producing intense beams of isotopes with a half-life in the ms range. As part of the detailed design process of this target, optimization based on hydrodynamic effects has been conducted. Besides, ensuring an efficient release of isotopes is of crucial importance and several delayinducing processes have to be optimized. As part of the release-efficiency analysis required for the target-design optimization, we have developed a comprehensive model for isotopes release. This model takes into account the dynamics of the liquid Pb-Bi in the target in addition to diffusion and effusion of isotopes. While existing analytical solutions for diffusion are applied, an elaborate model of effusion has been developed, allowing for detailed optimization of the target geometry. The rationale, methods, simulation tools and results will be presented. The approach was used to predict the release of some Hg isotopes out of the static bath Pb target at ISOLDE-SC. A comparison of the results with experimental data will also be presented. Nuclear Data for Calculation of Radiation Damage and Gas Production Rates in Materials Irradiated with Intermediate and High Energy Nucleons A.Yu. Konobeyev, U. Fischer Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology The study of the radiation induced damage of structural materials applied in the design of spallation neutron sources and accelerators requires a detailed knowledge of displacement and gas production cross-sections for a wide energy range of primary nucleons. The report describes methods of evaluation and evaluated displacement and gas production data recently obtained in KIT. Atomic displacement cross-sections were evaluated for Be, Al, Ti, V, Cr, Fe, Ni, Cu, Zr, and W at nucleon incident energies up to several GeV. The NRT model and an advanced atomistic modelling approach combining the use of binary collision approximation model and results of molecular dynamics simulations were applied for calculation of the number of defects in materials. A particular attention was paid to the uncertainty of recoil energy distributions and resulting displacement cross-sections. 29 6th High Power Targetry Workshop / Book of Posters and Abstracts Proton-, deuteron-, triton-, 3He, and -particle production cross-sections were obtained for nucleon induced reactions for 278 stable target nuclei from Li to Bi for incident energies up to 1.2 GeV using available experimental data and results of model calculations. Evaluated data were processed into ENDF and ACE formatted data and tested by means of MCNP calculations. MARS15 developments and benchmarking related to beam-induced effects in targets N. Mokhov, I. Rakhno, S. Striganov, I. Tropin Fermilab Motivated by a poor performance of intranuclear cascade models for nuclear interactions below a few tens of MeV, a new inclusive/exclusive nuclear event generator based on the TENDL library was created and implemented in the MARS15 base event generator. It is activated at 1 to 200 MeV for protons, neutrons, deuterons, tritons, 3He, 4He and gammas as projectiles, correspondingly mixed-and-matched with the CEM and LAQGSM models above 100 MeV. The DPA model was further improved to account for recombination of atoms during elastic cascading. In the model, atomic screening parameters are calculated using the Hartree-Fock form-factors and recently suggested corrections to the Born approximation. The code performance at intermediate energies for neutronics, DPA and gas production was noticeably improved. Both developments were benchmarked against data with impressive agreement achieved in most cases. The particle transport algorithms and geometry handling capabilities were also improved and extended. Predicting real-time peak displacement production rate at the SNS target vessel Wei Lu, Franz X. Gallmeier and Sarah M. Cousineau Oak Ridge National Laboratory, USA At SNS the incident proton beam is monitored by various sets of wire scans upstream of the target. Extrapolating from the measurement at the harp, a reasonable beam profile can be predicted at the proton beam window. The profile is then transported to the target using the MCNPX code and the static displacement production rates at the target vessel are calculated. But as the beam intensity and profile fluctuate, the real-time displacement production rate has to be predicted for accurately estimating the lifetime of the target vessel due to the radiation damage. In this study, it is found that the displacement production rate has proton and neutron induced components of similar magnitude. Although the proton-induced displacement production rate scales with the incident proton beam current density, the neutron-induced displacement production rate does not. The neutroninduced displacement production rate consists of two components: one scales with the proton current density while the other tends to scale with the total incident proton current. As a result, the total displacement production rate rises and falls slower than the changes in the incident peak proton beam intensity with respect to a nominal proton beam profile. Such a trend can be fairly fitted into a polynomial function. This method was adopted to predict the peak displacement production rate at the SNS target vessel. In addition, a more versatile method, a Green's function response method, is proposed to assess the proton and neutron contributions separately by folding with as delivered proton beam profiles. The displacement production at each wall of the target vessel is examined, as well as the effects of the incident proton beam energy and proton beam window material. 30 6th High Power Targetry Workshop / Book of Posters and Abstracts Session 3: Target facility & safety issues Designs for a Simpler, More Robust LBNF Facility S. Childress, N. Mokhov, S. Striganov, K. Vaziri Fermilab We consider integrated design approaches for the LBNF beam facility which provide capabilities for higher beam power limits, simpler but more robust designs, and improved access, cost, and safety features. Included are meshing physics optimized target design with a simpler hadron absorber, fail-safe beam loss control enabling more effective shielding, and optimizing the target facility footprint on the Fermilab site for cost efficiency and environmental protection. J-PARC neutrino experimental facility: status and upgrade plan T Ishida for T2K neutrino beam group KEK/J-PARC The J-PRAC neutrino experimental facility is designed to generate the world-intense neutrino beam to be supplied to the T2K, Tokai-to-Kamioka long-baseline neutrino oscillation experiment. So far the facility has realized to accept proton beam with 350 KW beam power, corresponding to 30 GeV beam kinetic energy, 1.8x1014 protons per pulse (ppp) with repetition rate of 2.5 second. It is noted that the ppp value is the world record being extracted from synchrotron. Recently a budget to upgrade magnet power supplies of the Main Ring was approved, and we have concrete timeline to realize 750 kW design power by increasing repetition rate in coming years. Furthermore, studies are being conducted to realize higher beam intensity, equivalent to 1.3 MW, for T2K-II experiment. It is the successor to T2K, aiming to observe neutrino CP violation with 3 sigma level at most, before the era of next generation neutrino projects such as Hyper-Kamiokande or DUNE. In this talk challenges of the facility to realize the MW beam operation will be presented in detail. The ESS Target Station Radiological Hazard Analysis and Safety Classification Process Linda R. Coney ESS During operations at the European Spallation Source (ESS), a high power proton beam will generate penetrating fast neutrons in the tungsten target. This will create an inventory of nuclides in the target, which means that most of the radioactivity generated at the facility will be in the target station. In order to protect ESS workers and the public from accidents with potential radiological consequences, a systematic process to identify, evaluate, and control potential radiological accidental events related to the target station has been developed. An initial qualitative hazard analysis and subsequent quantitative accident analyses are executed in order to identify the need for risk reducing measures. Functions that can prevent or mitigate the hazardous scenarios are identified. These safety functions can include passive engineered safety features, active controls and administrative controls. Structures, systems, and components (SSCs) that perform a safety function are assigned a safety class, which then mandates 31 6th High Power Targetry Workshop / Book of Posters and Abstracts certain requirements for that SSC. The Target Station radiological hazard analysis process, including the identification of safety functions and classification of SSCs, will be described with special attention given to the Target Safety System (TSS). The TSS is a safety control system that will monitor critical target system parameters and, if any deviate beyond acceptable levels, put the target into a safe state by preventing the proton beam from reaching it. Conceptual design of the CERN’s Search for Hidden Particles (SHiP) experiment target complex M. Calviani, M. Battistin, R. Betemps, J.-L. Grenard, D. Horvath, R. Jacobsson, P. Pacholek, A. Perez, A. Perillo-Marcone, A. Rakai, R. Rinaldesi, S. Sgobba, C. Strabel, V. Venturi, H. Vincke European Laboratory for Particle Physics (CERN), Geneva, Switzerland The Search for Hidden Particle (SHiP) is a newly proposed general-purpose fixed target facility at the European Laboratory for Particle Physics (CERN) (CERN-SPSC-2015-016), aimed at exploring the domain of hidden particles and studying the interaction of tau neutrinos. The experiment is based on the 400 GeV SPS proton beam impinging on a high-Z target/dump, leading to a pulse-averaged deposited power of 2.5 MW and a supercycle-average of 370 kW, qualifying the source as a non-standard high power spallation target. The present contribution will detail the conceptual design of the water-cooled SHiP production target, the material choices for the target core (composed by a hybrid solution of Ta-cladded TZM and high purity W), energy deposition and thermo-mechanical studies, CFD analyses as well as radiation damage and corrosion/erosion issues. An overview of the new associated supporting target complex facility will be provided as well, including an outline of the configuration of the target bunker and proximity shielding, radiation protection aspects, helium containment and circulation system as well as the handling needs for the SHiP target facility operation considering the extremely high activation (tens of Sv/h) expected for the most exposed equipment. A summary of the project timeline and of the planned R&D activities will also be briefly mentioned. Radiation protection studies for the design of the SHiP Facility Claudia Strabel, Heinz Vincke CERN A new general purpose facility to Search for Hidden Particles (SHiP) has recently been proposed in which a high-intensity 400 GeV, 335 kW proton beam from the SPS shall be directed to a fixed-target complex in the North Area of CERN’s Prévessin site. The SHiP target complex is located underground at a depth of about 10 m and is designed to contain most of the cascade generated by the primary beam interaction. In particular high prompt and residual dose rates call for considerable shielding and remote interventions in the target area. Also the risk and environmental impact from air, water and soil activation heavily influence the design. In order to respect the applicable CERN radiation protection legislation regarding doses to personnel as well as the environmental impact, a radiological assessment 32 6th High Power Targetry Workshop / Book of Posters and Abstracts was carried out for the design of the SHiP facility. Studies include expected prompt and residual dose rates in the various accessible areas of SHiP as well as the levels of stray radiation in the surrounding experimental and public areas. To assess the above-mentioned radiation protection aspects, extensive simulations were performed with the FLUKA Monte Carlo particle transport code. The details of these studies and their results as well as their impact on SHiP will be summarized. The target handling concept of the pbar-separator at FAIR M. Helmecke, V. Gostishchev, R. Hettinger, K. Knie GSI Helmholtzzentrum für Schwerionenforschung GmbH At FAIR, a proton beam from the SIS100 synchrotron with a kinetic energy of 29 GeV will be used for the pbar production. Every 10 seconds 2.5x1013 protons will be accelerated in the SIS100 to 29 GeV and a bunch of 50 ns duration will be formed. Antiprotons will be produced in collision of these protons with a nickel target. Behind the target a pulsed magnetic horn will be placed to collect the antiprotons emerging from the target with energies around 3 GeV and within a cone of about 80 mrad. The target consists of a stack of 5 nickel rods with 3mm diameter each surrounded by graphite. These rods are embedded in an air-cooled aluminum block. The aluminum block and its fixation have got a weight of about 40 kg. The magnetic horn consists of an Al-alloy. Since it is connected to a high voltage stripline the total weight of this assembly is about 120 kg. The target station, the magnetic horn and the target itself will be highly activated during the antiproton production. (The most activated component is the target with about 1011 Bq.) This leads to technical challenges: The access to the target hall is limited and to dismount the target or the magnetic horn these components have to be transported into a hot cell in a neighboring building. For this purpose remote handling equipment is necessary that can handle the mentioned masses in the limited space of the target hall. A target handling concept has been developed that the target and the magnetic horn are always surrounded by shielding during handling and transport. Two studies together with Kraftanlagen Heidelberg have been carried out concerning legal aspects of this concept and to prepare functional specifications of the handling components in order to obtain the operation permit. These are mainly a half-automated transport container with a railsystem to pull the components out of the target station and a shielding flask with an internal carrying frame for the transport between the buildings. Since the dose rate at the surface of the shielding flask has to be below 100µSv/h its weight is about 25t and a heavy weight transport trolley with a specific lifting gear has to be developed. 33 6th High Power Targetry Workshop / Book of Posters and Abstracts An Integrated Remote Target Handling System for CERN’s MEDICIS Radioactive Isotope Production Facility K Kershaw CERN A new medical research isotope production facility, “MEDICIS,” is currently under construction at CERN. The new facility will use the leftover particle beam of the ISOLDE facility - after it has passed through ISOLDE targets - to irradiate additional targets to produce isotopes for medical research work. In order to transfer, precisely position and store these additional targets, the isotope production process will require a new remote target handling and storage system. To ensure compatibility with radiation levels, which preclude the presence of electronics in the target handling and storage areas, the remote target handling system integrates modified versions of an industrial robot suspended from a linear axis mounted on the ceiling and industrial monorail transfer system working with custom–designed automated shielding doors, an air lock and remote handling cell. The MEDICIS facility will be briefly introduced followed by a description of the target remote handling and storage system design along with installation progress to-date. Results of and Methods Used in Designing the New Cold Neutron Source at SINQ R. M. Bergmann, U. Filges, D. Kiselev, T. Reiss, V. Talanov, M. Wohlmuther Paul Scherrer Institut Changing the configuration of the cold neutron source during a planned extended shutdown of the High Intensity Proton Accelerator (HIPA) is being consideration for improving cold neutron yield of the Swiss Spallation Neutron Source (SINQ). The cold neutron source consists of a 20 L volume of liquid D2 at approximately 25 Kelvin. Previous upgrades included adding a re-entrant hole (REH) into one side of the D2 volume to allow cold neutrons to stream uninhibited from the center of the source towards the neutron guides. Previous calculations predicted cold neutron fluence gains from 1.2 to 1.9, which have not been observed. Speculation is that the re-entrant hole is not fully voided, since it relies on radiative heating to boil D2 which in turn fills the re-entrant hole cavity, pushing the liquid D2 out. Previous calculations also relied on old cross section data which in turn lead to both over-predicting the photon heating of the D2 and over-predicted the benefit of the REH for long neutron wavelengths. During the present design phase, a new approach was also used to approximate the influence the cold source changes will have on the neutron flux exiting the neutron guides at SINQ. This method uses a precalculation (either in McStas or MCNPX) to determine energy- and angle-dependent transfer functions which are then folded with a neutron flux tally at the guides' entrances. This method gives realistic values for the guide flux without explicitly modelling the reflectivity of the neutron guides, saving time in the computation and allowing for easy re-computation of exit fluxes with different guide parameters. 34 6th High Power Targetry Workshop / Book of Posters and Abstracts Proposed configuration for the upgraded cold source include making the re-entrant hole external (ensuring that it is not filled with liquid D2), redesigning the re-entrant hole geometry, adding an orthoD2 conversion system, and replacing some structural materials with more neutronicly transparent ones. These changes are predicted to increase neutron fluence between 1.1 to 1.6 times the current levels, depending on instrument location, view, and wavelengths of interest. However, a realistic design was not yet considered and is the next step of the project. The LIEBE target: a step toward exotic species Melanie Delonca, Tania M. Mendonca, Bernard Crepieux, Nicolas Zelko, Hachem Znaidi, Thierry Stora for the LIEBE collaboration CERN – European Organization for Nuclear Research In order to explore more exotic region of the nuclei chart, large-scale facilities have been built around the world. Today, scientists collaborate to develop a new radioactive ion beam (RIB) facility, called EURISOL, which will allow the exploration of new parts of the nuclear chart. In its baseline, the EURISOL facility has a 5 MW proton Linac providing beam to three 100 kW direct targets and a 4MW neutron converter. In the frame of the EURISOL Design Study phase, a conceptual design has been proposed for the 100 kW direct targets. This target design proposes to use a Lead Bismuth Eutectic loop target, implementing a pump for the liquid circulation and a heat exchanger to extract the power deposited by the beam. Additionally, a diffusion chamber is proposed in order to allow a faster diffusion process by the mean of droplets creation. Indeed, the isotopes will diffuse faster out of a droplets than out of a liquid bath, allowing short-lived species to be extracted in higher quantities and thus, opening new physics possibilities. The development of this target has been done in the framework of a project called LIEBE (Liquid Eutectic Lead Bismuth Loop Target for Eurisol). The project has been initiated in 2012 and involves the following institutes: CERN, SCK-CEN, PSI, CEA-Saclay, IPUL, SINP and GANIL. In this presentation, the final design of the LIEBE target will be presented, emphasizing some of the main challenges of the design and the chosen solutions. Furthermore, results of shower feasibility with Lead Bismuth Eutectic at 200 degree Celsius will be shown, highlighting the achieved droplets diameter and the different regime formation expected for the LIEBE target. Finally, analytical release efficiencies for different isotopes of interest such as the 177Hg will be presented and compared with experimental results from static liquid Lead target. 35 6th High Power Targetry Workshop / Book of Posters and Abstracts Session 4: Construction, fabrication, inspection, QA Experiences of Troubles and Design Improvements of Water Shroud of J-PARC Mercury Target Katsuhiro HAGA, Hiroyuki KOGAWA, Takashi WAKUI, Takashi NAOE, Hiroshi TAKADA Japan Atomic Energy Agency In 2015, we experienced troubles twice in the water shroud of the mercury target vessel. The first trouble occurred on April 27. The dew-point sensor and the leak detector in the helium vessel which contains the mercury target rang the alarm. The water in the water shroud of the target vessel was drained and the target was moved to the maintenance area. When the water shroud was pressurized with helium gas, we found a tiny water drop growing on the lower side of the target vessel. Using a HD video camera, we also found a tiny flaw at the same place we saw a water drop. The water shroud was fabricated by fixing the outer and inner shell by diffusion bonding and seal welding. Based on the analytical evaluation of the thermal stress and the result of the visual inspection, it is assumed that part of the diffusion bonding failed during the fabrication process and the crack was produced at the weld by cyclic thermal stress during the beam operation. The spare target which has the same structure as the failed target was repaired to prevent the same trouble and installed to the target system. The second trouble occurred on November 20. This time the leak detector in the helium layer, which is the intermediate space between the mercury vessel and the water shroud of the target vessel, rang the alarm. After the investigations of the sensor data such as electrical resistance of the leak detector and the radiation monitoring, we concluded that water leaked into the helium layer, not mercury. Because the leak place is inside of the target vessel, it is very difficult to find out it. We are planning to cut part of the target vessel and look inside during this summer shutdown period. Though the reason of the second trouble is not clear, cause of these troubles are considered to be in the welding and bonding part in the high heat load area of the target vessel. In order to prevent such troubles, diffusion bonding will not be used and welding part will be minimized in the next target design. The water shroud in the front part of the target vessel where the heat load is high during the beam operation will be integrated with the mercury vessel. Parts of the target vessel will be fabricated by using the wire-EDM and the welding will be reduced drastically. The rear part is difficult to adopt the integrated design, but improved design to reduce the welding will be applied. In this presentation, outline of the water leak incidents and the new design of the mercury target of JPARC will be reported. 36 6th High Power Targetry Workshop / Book of Posters and Abstracts SNS Target Design Improvement Drew Winder, Charlotte Barbier, Steven Chae, Saulius Kaminskas, Bernie Riemer, Mark Wendel Oak Ridge National Laboratory The target vessel at the Spallation Neutron Source in Oak Ridge, Tennessee, contains and directs the flowing mercury spallation target material as it is struck by a proton beam pulse at 60 Hz. Two target vessels developed mercury leaks early in their life in 2014. The investigation points toward fatigue failures in the target vessels. The fatigue failures were located not near the beam entrance area of the target, but rather farther back, away from the center of the generated pressure pulse. At the time of the failures, multiple targets of two different designs were at various stages of manufacture. To maintain needed target inventory, changes were needed which could make use of existing parts. The design changes made to these targets under fabrication and their rationale will be presented. In addition, current progress on future target designs and concepts under consideration will be discussed. Construction, fabrication, PIE and QA of the Muon and SINQ Cannelloni Targets at PSI P. Baumann, B. Blau, S. Forss, K. Geissmann, F. Heinrich, D. Kiselev, M. Wohlmuther Paul Scherrer Institut The high intensity proton accelerator (HIPA) at PSI is serving four target stations, two meson and muon production targets, Target M and Target E and two spallation neutron sources rhe Swiss Intense Spallation Source, SINQ, and the Ultracold Neutron Source UCN. The meson targets are designed as rotating Carbon discs / wheels and receive proton beam currents of up to 2.4 mA. The spallation targets of SINQ and UCN are so-called Cannelloni Targets consisting of Zircalloy Tubes filled with Lead. In this paper we will report on fabrication, QA and operational aspects of both the meson and the Cannelloni targets. ISIS TSI Upgrade Target – Design for manufacture Leslie Jones STFC, Rutherford Appleton Laboratory The ISIS TS1 Upgrade aims to deliver a factor of 2 or more increase in neutronic performance through a redesign of the Target, Reflector and Moderator assembly. This talk focusses on converting the optimised simulated design for the TS1 Upgrade Target into a physical reality. ISIS has the advantage of having a Target Manufacturing Facility (TMF) on site and the Target Design Group (TDG) work very closely with the TMF to test design ideas and develop the necessary techniques to produce robust target designs. The experience gained from manufacturing ISIS current TS1 & TS2 targets has been invaluable in identifying potential manufacturing challenges that can be overcome at the design stage. The target design presented here is a work in progress that aims to satisfy the demands of neutronic efficiency, reliability and manufacturability as closely as possible through collaboration between the Neutronics, Engineering Simulation, Engineering Design and Manufacturing Groups. 37 6th High Power Targetry Workshop / Book of Posters and Abstracts High Energy Dump of the Super Proton Synchrotron at CERN – Present and Future designs A. Perillo-Marcone, F. Pasdeloup, G. Steele CERN (Geneva – Switzerland) The SPS high energy internal dump (TIDVG) is designed to receive beams dumps from 102.2 to 450 GeV, which translates into a heat power of up to 270 kW deposited in the dump. At present, the absorbing core is composed of 2.5 m graphite, followed by 1.0 m of aluminium, then 0.5 m of copper and finally 0.3 m of tungsten, all of which is surrounded by a water cooled copper jacket. An inspection in 2014 revealed significant beam induced damage to the Al section of the dump block. As a result, new analyses have been carried out to re-assess the performance of the current design and to improve the performance and reliability for a future device that is being re-designed. This paper summarizes the main characteristics of the present design, analyses its performance based on operational feedback and calculations and proposes a new design for a future dump to be installed in 2020 Braze joint quality assurance of the beryllium beam tube window at Fermilab K. Ammigan, K. Anderson, P. Hurh, R. Zwaska Fermi National Accelerator Laboratory, USA The pre-target beryllium beam tube window at Fermilab consists of a 0.01” thick PF-60 Be foil brazed to a stainless steel window holder. During operation, this window sees vacuum loading as well as localized beam loading, and analysis indicates stresses well below the failure stress. However, a recent window failure which occurred while pulling vacuum in the beam tube during shut down, prompted quality assurance efforts of the window assembly. With the braze bonding area a crucial factor in determining how much stress is incurred by the window during operation, CT scan images of the braze joint of multiple window assemblies from different vendors were analysed and compared. This talk discusses the findings of the QA work and reasserts the need for quality assurance of critical accelerator components in order to avoid costly repairs and accelerator downtime. 38 6th High Power Targetry Workshop / Book of Posters and Abstracts Present Status of Muon Production Target at J-PARC/MLF/MUSE Shunsuke Makimura J-PARC, KEK A pulsed muon beam with unprecedented intensity will be generated by a 3-GeV 333-microA proton beam on a muon target made of 20-mm thick isotropic graphite (IG-430) at J-PARC/MLF/MUSE (Muon Science Establishment). The energy deposited by a 1-MW proton beam is estimated to be 3.9kW on the muon target. The first muon beam was successfully generated on September 26th, 2008. Gradually upgrading the beam intensity, continuous 300-kW proton beam has been operated by a fixed target method without replacements till June of 2014. However, the lifetime of the fixed target will be less than 1 year by the proton-irradiation damage of the graphite through 1-MW proton beam operation. To extend the lifetime, a muon rotating target, in which the radiation damage is distributed to a wider area, had been developped. In the rotating target, the lifetime of bearing will have a dominant influence on the lifetime of the muon target. The disulfide tungsten are introduced as solid lubricant of the bearings. The muon rotating target was installed in September of 2014 and has been stably utilized up to 500-kW proton beam operation. A scraper, which is collimating the proton beam scatterd on the muon target, is located on downstream of the target. It was proved that thermocouples measuring temperatures of the scrapers were affected by thermal radiation of the rotating target during the proton beam operation. Therefore the radioactive scraper with a residual radiation dose of 1.2 Sv/hour at 10 cm were replaced with a new modified scraper in September of 2015. Simultaneously, developments are in progress, such as a SiC rotating target, remote handling apparatuses, in-situ monitoring system of the target, which will be introduced by Matoba in this workshop. The present status of the muon production target at JPARC/MLF/MUSE will be introduced in this presentation. Strategies to Improve Electron Beam Weld Quality for ISIS TS2 Targets Arghya Dey; Leslie Jones STFC, Rutherford Appleton Laboratory One of the electron beam welded joints on the tantalum cladding of a tungsten target has been identified as one of the areas of weakness that is causing the target life to be significantly shortened. The penetration of the weld using the existing method was found to be inadequate and the grains under the weld line were found to be significantly enlarged. In order to improve the weld penetration, a study using different settings of the weld parameters such as weld current, beam rotation and beam focus has been carried out. The study concludes that maximum weld penetration could be achieved using a combination of high weld power, sub surface focus of the electron beam and low material volume around the weld line. 39 6th High Power Targetry Workshop / Book of Posters and Abstracts Session 5: Operations Present Status of the target and beam dump system at BigRIPS fragment separator K. Yoshida, Y.Yanagisawa, Z. Korkulu, N. Fukuda and T. Kubo RIKEN Nishina Center The high-power water-cooled target and beam dump system at the BigRIPS fragment separator at RIKEN Nishina Center were designed to withstand high intensity beams up to the beam power of 82 kW which corresponds to the case of a 238U beam at 345 MeV/nucleon and intensity of 1 particle A. The energy deposit to a Be target of 5 mm thickness is expected to be 23 kW and the volume density of the deposited power in the target is 5.8 kW/mm3 if we assume the beam spot of 1 mm diameter. The remaining beam power of 59 kW is dissipated in the beam dump. The surface power density at the beam dump is expected to be 0.01 – 1 kW/mm2 since the beam is not focused at there. In order to cope with such high power densities, the water-cooled rotational target and the stationary beam dump with special cooling channels such as a swirl tube and a screw tube were developed. Two beam dumps, one for a high intensity 238U beam and one for the other beams, were designed to cope with variety of beams from 12C to 238U. These dumps had almost same structure; only the distance from the dump surface to the cooling channel was different: 1 mm for a high intensity 238U beam and 3 mm for others. The latter dump, the rotational target and the stationary ladder target for low power beams were constructed in 2007 and have been used since then with various beams from 18O to 238U with powers up to 10 kW. The design of the target and the beam dump was performed with sophisticated thermal model simulations with ANSYS code. Results of the simulations had not been well verified until recently since the available beam power remained less than 1/10 of the goal. Very recently, high-intensity 48Ca beam with beam powers up to 10 kW became available. Temperatures of the target and beam dump were measured with such intense beam in order to verify simulations at the design stage. In this paper, structures of the target and beam dump system are presented with the operational experiences with beams with powers up to 10 kW. Results of the temperature measurements for the target and the beam dump are discussed with the simulations with the ANSYS code. ANSYS code calculations of the beam spot temperature at BigRIPS separator Zeren Korkulu, Koichi Yoshida, Yoshiyuki Yanagisawa and Toshiyuki Kubo RIKEN Nishina Center The cyclotrons at RIKEN RI Beam factory (RIBF) can accelerate very heavy ions up to 345 MeV/nucleon, such as uranium. The goal beam intensity is expected to be 1 particle μA (6.2 x 1012 pps), which corresponds to a beam power of 82 kW in the case of 238U. An important aspect in increasing beam intensity is to limit the maximal temperature due to the beam energy loss in the material. The control of this energy loss in the target is proving to be one of the major challenges. 40 6th High Power Targetry Workshop / Book of Posters and Abstracts Therefore, the high power production target system was designed [1,2] and constructed in 2007 for BigRIPS separator [3,4]. The water-cooled rotational disk targets and ladder-shaped fixed targets are in operation. Because a variety of primary beams are used in BigRIPS, it is necessary to evaluate the temperature distribution by several beam nuclides. The finite element thermal analysis code, ANSYS was used to model thermal distributions in targets. The calculations of the beam spot temperature on a Be target were done for the primary beams of 48Ca, 78Kr, and 238U. Although the present primary beam intensity is much lower than the goal value, the beam spot temperature at various conditions was measured and compared with thermal simulations to examine the beam power tolerance and evaluate the cooling capacity of the water-cooled ladder-shaped fixed target. The calculated beam spot temperature on a Be target as a function of the different primary beam intensity of 48Ca, 78Kr, and 238U will be presented. [1] A. Yoshida et. al., Nucl. Instr. Meth. A 521, 65 (2004). [2] A. Yoshida et. al., Nucl. Instr. Meth. A 590, 204 (2008). [3] T. Kubo, Nucl. Instr. Meth. B 204, 97 (2003). [4] T. Kubo et. al., IEEE Trans. Appl. Supercond. 17, 1069 (2007) Gas Injection at SNS: Impact on Target Design and Bubble Size Distribution Determination Charlotte Barbier, Elvis Dominguez-Ontiveros, Bernie Riemer ,Drew Winder, Mark Wendel ORNL Target reliability is a central issue in the operation of high-power pulsed neutron scattering facilities using mercury targets, such as at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) and Japanese SNS at J-PARC. When the proton beam hits the liquid mercury target, the rapid rise in temperature on the scale of s causes an intense pressure wave in the mercury that propagates in the mercury and into the vessel wall. It has been numerically and empirically demonstrated that the presence of small bubbles in the mercury could considerably mitigate the pressure wave, and potentially the cavitation damage associated with it. In order to achieve a high power reliable target, a gas injection system will be implemented in the SNS mercury target at ORNL. The first generation gas injection system uses small orifices which have been investigated in the past at ORNL. However, the orifices have known limitations: the generated bubble size is of the order of the orifice. Consequently, very small orifices are required to generate 50-75 micron diameter bubbles and large gas back pressure must be used, which adds some safety constraint. Thus, a second gas injection system is also developed that will used swirl bubblers similar to the ones currently used at J-PARC. Swirl bubblers are capable of generating very small bubbles in mercury, require low gas pressure supply, and have been successfully deployed at J-PARC. Experiments in water and mercury for both gas injection systems will be presented. Experimental methods used to determine bubble size distribution and void fraction will be presented in details. Pressure drop across the bubblers and effect on the fluid flow will be also presented. 41 6th High Power Targetry Workshop / Book of Posters and Abstracts Target Strain Measurements during proton beam impact at the Spallation Neutron Source Willem Blokland ORNL Target Strain Measurements during proton beam impact at the Spallation Neutron Source. Several of the SNS targets have had a shorter lifetime than desired. As part of the push to increase the targets' lifetimes and further the understanding of the proton beam’s mechanical impact, a new target has been equipped with strain sensors inside the interstitial space between the mercury vessel and the water shroud. The extremely high radiation and electrically noisy environment led us to pick optical strain sensors and special care was taken to minimize the impact of the sensors and their installation on the target lifetime. We have placed accelerometers outside the target on the target mount and the mercury return line to determine if the internal dynamic strain can be measured on the outside of the target. Remote manipulators performed part of the installation, as even residual radiation from previous targets is too high for humans to come close. The optical sensors lasted long to give us measurements from different proton beam intensities. Future plans include developing optical sensors that endure higher radiation doses. To that purpose radiation-hard single mode fibers have been installed along the optical sensors to determine their longevity. This paper describes the design, installation, dataacquisition system, first results of the strain sensors and future plans. CERN’s n_TOF neutron spallation target operating experience and future consolidation plans M. Calviani, O. Aberle, Y. Body, E. Chiaveri, D. Horvath, L. Marques Antunes Ferreira, R. Losito, Y. Lupkins, A. Perillo-Marcone, S. Sgobba, V. Venturi, V. Vlachoudis European Laboratory for Particle Physics (CERN), Geneva, Switzerland The European Laboratory for Particle Physics (CERN) is equipped with a top-class, high brightness, spallation source dedicated for high-resolution neutron time of flight experiments: the n_TOF facility. The neutron production is based on a monolithic lead-based ~10 kW, water-cooled and borated water moderated target. The present contribution will detail the design, neutron performances and operating experience of the target and of its cooling station, focusing also on the continuous chemistry control of the water circuits, required in order to guarantee low corrosion rate and therefore the predicted 10 years lifetime for the target. An overview will also be provided on the new spallation target design presently under design, which will be installed during 2018-2019, and that will guarantee the operation of the n_TOF facility until the 2030s. Various design options will be described, taking into account the physics requirements as well as the operational feedbacks obtained during the past 15 years of spallation target operation. 42 6th High Power Targetry Workshop / Book of Posters and Abstracts 200 kW Liquid Lithium Neutron Source for SARAF Facility Guy Shimel, Alex Arenshtam, IIan EIiyahu, Arik Kreisel, Ido Silverman Soreq-NRC Thermal Neutron Radiography (TNR) is one application of IRR-1 5MW nuclear reactor. The TNR system has L/D of 250 with neutron flux on the imaging plane of 6*105 n/s/cm2. The Soreq Applied Research Accelerator Facility (SARAF) should be able to replace IRR-1 and provide its capabilities including thermal neutrons for a new TNR system with similar features when phase-II construction will be finished. In order to match the TNR at IRR-1, SARAF phase-II design is based on a 40 MeV, 5 mA protons/ deuterons accelerator with beam power of 0.2 MW. Several choices of target materials are available to produce neutrons with low energy light ions including graphite, beryllium and lithium. Each material has its own advantages and requires different technologies to build into a robust target. Graphite has high operating temperature and builds as rotating target to use IR radiation for cooling. Beryllium can be used in a static target form with or without beam rasterring and lithium can be used as liquid to build a flowing target with or without window. Rotating targets requires large volume which leads to large leak of neutrons from the moderator. Both static and flowing targets can be easily integrated into the moderator. Liquid targets are complex but are immune to radiation damage, blistering and thermal stresses which limit the life time of static targets. The simplicity of the static design has been the motivation for the initial choice of target for SARAF TNR. Recently, a windowless liquid lithium target has been commissioned at SARAF phase I as epithermal neutron source for astro-physical studies and medical applications. The experience with operating such target and its robustness made it the prime candidate to be the neutron source for the TNR system at SARAF. A preliminary design of a 0.2 MW liquid lithium target for a high intensity neutron source has been developed. It will be coupled to a beryllium neutron multiplier and a heavy water moderator in order to provide the thermal neutron flux to the TNR system. The presentation will present the experience gained with operation of a liquid lithium target with high power ion accelerator and the preliminary design of the high intensity neutron source. Monitoring system for a muon rotating target at J-PARC Shiro MATOBA KEK A high-intensity pulsed muon beam is generated by a 3-GeV proton beam with a graphite target at JPARC/MLF/MUSE (MUon Science Establishment). The goal of the proton beam power is 1 MW. At present, it has been achieved continuous operation at 500 kW. The energy deposition on the muon target by the 1-MW beam irradiation is estimated to be 3.9 kw. In order to disperse the damage by heating and radiation, a rotating target is adopted for the pulsed muon beam production. The current statuses of the monitoring systems for the muon rotating target are shown below. 43 6th High Power Targetry Workshop / Book of Posters and Abstracts 1) Diagnosis of the rotating system It is predicted that a life of the muon rotating target is determined by the failure of a rotary support. By using a solid lubricant made of a tungsten disulfide to bearings in rotating system of the muon target, the life of the rotation system is expected to be around 110000 hours in the rotation speed of 15rpm. We are monitoring the torque of the rotary motor in order to monitor the status of the rotation system. Recently, a motor acoustic diagnosis of by an omni-directional microphone for multiplexing of an interlock has been also initiated. Currently, we have installed the tester, and subjected to analysis of the motor sound. 2) Diagnosis of temperatures Temperatures of the muon rotating target cannot be measured with contact because a thermometer cannot be attached to the rotating body. The temperature of the muon rotating target is estimated from measurements of thermocouples irradiated by thermal radiation. The thermocouples are also placed in the rotating shaft to monitor the bearing temperature. However, the proton beam cannot be stopped rapidly in this monitoring system, when extraordinary temperatures rise happened. We are developing a real-time two-dimensional radiation thermometer to monitor the temperature quickly. 3) Diagnosis of emitted gases A quadrupole mass analyzer (Q-Mass) monitors the gas molecules emitted from the rotating target and peripherals with the proton beam irradiation. The Q-Mass has been installed on a vacuum duct of 20 m upstream of the proton beam line from the muon rotating target and is surrounded by lead and borated polyethylene blocks in order to reduce the damages of the radiation. We are investigating the relationship between the emission gases and the beam irradiation. Evaluation of the amount of a tritium by the irradiation is also carried out with the Q-Mass. Operational experience and remote maintenance of T2K target A.Atherthon, C.J Densham, M.D Fitton for T2K neutrino beam group STFC Rutherford Appleton Laboratory The operational experience of the pion production target at the T2K neutrino experiment is presented. The target core is a monolithic fine grain isotropic graphite (IG-430) rod which is helium gas cooled to allow operation at elevated operating temperatures. The helium gas cooling also mitigates thermal shock problems which would be present with liquid coolants due to the pulse intensity (Currently 1.8x1014 protons/pulse). The first T2K target was replaced during long 2013-2014 maintenance period along with the first horn-1 after receiving 6.6x1020 protons on target at 30GeV. The second T2K target has so far accumulated 4.5x1020 POT with average beam powers up to ~ 350kW (up to 2015 May). In June 2015 a helium gas leak was observed in the target cooling system and identified as a ceramic isolator on the target pipes. Testing identified a possible cause of the failure and a new design was implemented. In December 2015 the pipe was successfully replaced using remote handling techniques with assistance from expert remote handling operators from TRIUMF. 44 6th High Power Targetry Workshop / Book of Posters and Abstracts NuMI Horn Stripline failure, analysis, and recovery P. Hurh, K. Anderson Fermi National Accelerator Laboratory, USA In June, 2015 the NuMI target facility providing beam for the NOvA experiment was turned off due to an abnormal electrical pulse response in the NuMI electro-magnetic horns circuit. Subsequent investigation revealed a cracked aluminium stripline electrical conductor with evidence of arcing on the outer conductor stripline package on the downstream end of the horn 1. This horn 1 (PH1-04) was the first horn designed to run with up to 700 kW primary proton beam power and was modified from the previous MINOS 400 kW design to improve cooling characteristics. The horn, in service since September 2013, had accumulated ~27 million pulses out of a desired 50 million pulses, and was never operated above ~450 kW proton beam power. This presentation will describe failure diagnosis and recovery efforts performed to return to > 450 kW beam operations using a spare MINOS horn 1 of the 400 kW design (PH1-03). These efforts include measuring the heat transfer coefficient in the local vicinity of the stripline package on an actual horn 1 installed in a full-scale mock-up of the NuMI target chase and construction of an air duct to double the heat transfer coefficient on stripline surfaces. In addition, extensive “live-fire” vibration measurements and analysis of the NOvA 700 kW horn 1 stripline package were performed indicating that significant ring-down cycles due to under-damped vibration mode may have contributed to the failure. Finite element analysis using vibration measurement results as input was performed to predict stress and strain cycling in critical stripline locations. The results from these analyses point the way toward a successful re-design of this critical system, which will be discussed in this presentation. Measurement of corrosive gas in the air in the NuMI target pile James Hylen Fermilab Measurements are being made of corrosive gases in the air in the NuMI target pile. Comparisons are made to a model of production of such gases. The model may then be used to extrapolate to future high power target facilities, such as LBNF. This is important for selection of materials that may be used in such environments, and also to address whether there is need to switch to inert gas instead of air in such environments. 45 6th High Power Targetry Workshop / Book of Posters and Abstracts Session 6: Post Irradiation Examination (PIE)/autopsy Tungsten for the high power spallation target at ESS Yongjoong Lee, Yong Dai, Srinivasan Iyengar, Jemila Habainy European Spallation Source (JH, YL, SI), Paul Scherrer Institut (YD), Lund University (SI) The European Spallation Source (ESS), which is currently under construction in Lund, will deliver its first neutrons by 2019. The spallation material at ESS is chosen to be pure tungsten, which is cooled by pure helium. The spallation volume will be irradiated by a high power (5 MW) pulsed proton beam with a repetition rate 14 Hz. In order to distribute the thermal load and reduce the radiation damage in the tungsten volume, a large number of tungsten blocks are contained in a rotating stainless steel vessel, which is segmented into 36 parts. Nevertheless, cyclic thermo-mechanical loading caused by beam trips and beam pulses can drive the maximum temperature up to 500 °C in the tungsten blocks, which poses a challenge in designing a reliable spallation target. The choice of pure tungsten as target material is based on its high density and high atomic weight, which leads to a high neutron production density at the source. Tungsten has been used as target material at high power spallation sources such as ISIS and LANSCE, thanks to its high melting point, its relatively good thermal conductivity and its high yield stress. However, the brittle nature of tungsten and a DBTT much above room temperature puts the structural integrity of the target at risk. Furthermore, it is known that the tungsten DBTT increases with increasing radiation damage. Failure of the spallation material during operation could lead to a temperature anomaly, which could lead to a failure of the target wheel. To reduce the probability of loss of structural integrity of tungsten blocks in the high power target, a research program is set up to investigate the effect of fabrication process on the microstructure and the mechanical behaviour of powder-metallurgy pure tungsten materials, and to understand the radiation induced degradation of its material properties. The research activities have been performed in collaboration with PSI, Lund University, St. Sebastian University, GSI, ESS-Bilbao and ESS. The study on the fabrication processes and its material quality effect has been used to make a recommendation on a specific tungsten type and the vendors. The effect of high-energy proton and heavy ion irradiation on material property degradation has been used to assess the required conservatism for the 5 MW target design. In this paper, we will present an overview and the major outcome of the collaboration efforts on tungsten materials research for the support of the 5 MW class spallation target design at ESS. PIE program of STIP-V tungsten specimens for ESS target engineering Jemila Habainy, Yong Dai, Yongjoong Lee, Srinivasan Iyengar European Spallation Source (JH, YL, SI), Paul Scherrer Institut (YD), Lund University (SI) Pure tungsten has been chosen as the target material at the European Spallation Source facility in Lund. Specifically, a hot-rolled tungsten is chosen due to its low porosity and high fatigue strength. The effect of surface roughness and degree of grain deformation on the mechanical properties of the rolled tungsten is studied with the tensile samples prepared with varying test properties. 46 6th High Power Targetry Workshop / Book of Posters and Abstracts It is estimated that the tungsten target material at ESS will get maximum 2 dpa of displacement damage and 400 appm of helium yield per operational year, and it is crucial to understand the structural durability of tungsten blocks under progressive radiation damage for an optimal design of a high power target. To understand the material degradation of pure tungsten under a high-energy proton beam irradiation, a PIE program of pure tungsten has been in progress. Two tungsten bars with dimension 60 x 8 x 1 mm3 were extracted from the SINQ target at PSI, which have been irradiated in the frame of STIP-V irradiation program. The tungsten bars received a total proton charge 9.83 Ah with a peak displacement damage of about 30 dpa, during 2007 and 2008. From the irradiated tungsten bar, total 22 miniature specimens are obtained by EDM cut, 16 for bending tests, 4 for tensile tests and 2 discs for thermal conductivity measurement. Thermal, mechanical and microscopic properties of these 22 specimens are to be measured in a hot cell environment. A number of tests have been performed with low dose samples with displacement damage below 5 dpa, while tests with remaining high dose samples are still to be performed. In this paper, the observed effect of surface roughness and degree of grain deformation on the mechanical properties of the rolled tungsten, and the correlation between the preliminary PIE results with low dose specimens will be presented. Post-Irradiation Examination Sampling of SNS Mercury Target Vessel and Proton Beam Window Michael J. Dayton ORNL/SNS New Post-Irradiation Examination (PIE) sampling capabilities have been developed for both the target modules and Proton Beam Windows (PBWs) at SNS. Previously, PIE sampling of mercury target vessels has been limited to the beam entrance (nose) region. An early leak of target module #10 occurred in September 2014 after only approximately 600 MW-hrs of operation. Initial PIE efforts identified the leak location on the mercury vessel in an area of complex joint geometry that was not accessible with existing sampling tooling. In order to better understand the nature of the leak so that corrective measures can be applied, detailed investigation of the leak location was imperative. The first step was extracting the samples. Specialized remotely-handled PIE sampling tooling was designed and utilized to obtain samples of the leak location. The initial activities leading to location of the leak will be discussed along with the design development and testing of the new PIE sampling tooling. Deployment of the tooling in the Target Service Bay and the results of the sampling operation will be shown. Irradiated samples have also recently been extracted from a well-used SNS PBW. The PBW provides the boundary between the high vacuum of the accelerator and the helium atmosphere of the Core Vessel. The window material that the MW proton beam passes through is Inconel 718. A desire to investigate the material property degradation of this material at dpa levels common to SNS operation led to the development of a process and tooling to obtain material samples. Specialized remotely-handled PIE sampling tooling was designed and utilized. The design development and testing of the new PBW PIE sampling tool will additionally be covered in this presentation. Details of the sampling operation will also be presented including lessons learned from conducting the sampling of a highly-activated component outside of a hot cell environment. 47 6th High Power Targetry Workshop / Book of Posters and Abstracts Materials Research and Post Irradiation Examination at the Spallation Neutron Source: Results and Status David McClintock Oak Ridge National Laboratory The Spallation Neutron Source (SNS) maintains an extensive post irradiation examination (PIE) program to characterize the radiation-induced changes in materials of high-dose components and manage the risk of interruptions to neutron production. After removal from service, samples from the beam entrance region of SNS target modules are routinely removed and characterized. To date, specimens from five target modules have been characterized via tensile testing and electron microscopy. Target modules were also inspected remotely using high-resolution photography and articulating videoprobes to characterize the extent of cavitation-induced erosion on the mercury-facing surfaces of targets. During the past year three SNS target modules, designated Targets 10, 11, and 12, developed leaks during operation, which were remotely examined to identify the leak locations. Samples of the Target 10 leak location were removed and the failure point was characterized to determine the cause of the leak. In addition to the target PIE activities, samples were removed from the 4th operational Inconel® 718 proton beam window in preparation for full characterization via tensile testing and microscopy. The results to date and current status of the SNS PIE programs will be discussed along with plans for future PIE of SNS components. Post-irradiation examination of SINQ targets Y. Dai, K. Geissmann, P. Vontobel, M. Wohlmuther Paul Scherrer Institut, 5232 Villigen PSI, Switzerland The Swiss Spallation Neutron Source (SINQ) has been operated since 1997. Up-to-date eleven targets have been irradiated. Except for one liquid metal (lead-bismuth eutectic) target all targets are solid type, namely pure lead (Pb) cladded either with SS316L tubes or zircaloy-2 tubes. In order to improve the neutron intensity, the target configuration has been improved step-by-step by changing the target material, the composition of target pins, the target geometry, etc. In this development process, irradiation test on target pins or materials was conducted on each step to ensure that the risk caused by the changes was minimized. Accompanied with the irradiation test, post-irradiation examination (PIE) was performed on the spent targets. All the ten spent solid targets were opened in a hot-cell (ATEC) close to the SINQ target station. Visual inspections were performed on the target block and the beam window of AlMg3 safety container once a target was opened. Afterwards, some target pins, together with the pins for the SINQ Target Irradiation Program (STIP), were extracted from the target and transferred to the neutron radiography station of SINQ for detailed inspection. Large failures as such large cracks and holes on the surface of the pins could be already detected in ATEC. Detailed features of these failures and the status of the target material (Pb) and the specimens of STIP could be investigated with the neutron radiography technique. After conducting these preliminary analyses, the AlMg3 beam window and the pins were sent to the hot laboratory of PSI for further PIE which including: gamma mapping on the beam windows to determine the distribution profile of accumulated proton fluence, extraction of samples from the beam windows and target pins for various mechanical tests and microstructural analyses, mechanical testing including normally tensile and bend tests to evaluate the 48 6th High Power Targetry Workshop / Book of Posters and Abstracts irradiation-induced embrittlement effect on the beam window and cladding tubes, microstructural analyses including scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to reveal changes in microstructure of the beam window and cladding tube materials. In this presentation some details of the PIE procedures will be described and the main results of the PIE of the SINQ targets will be briefly reported. Post-Irradiation Examination of Ti-alloy foils in T2K OTR AM Casella1, DJ Senor1, DM Asner1, T Ishida2, M Hagiwara2, T Nakadaira2 (1) Pacific Northwest National Laboratory, (2)J-PARC The Tokai to Kamioka (T2K) project attempts to address current issues related to neutrino flavor oscillations by comparing the characteristics of a neutrino beam near its origin (Tokai) with its characteristics 295 km downstream at the Super-Kamiokande detector in Kamioka. An Optical Transition Radiation (OTR) monitor employing a thin metal foil as a dielectric boundary is being used to measure the position and width of the proton beam 280 mm upstream of the graphite target. The material currently used for the dielectric boundary foil is a -titanium alloy (Ti-15V-3Cr-3Sn-3Al). In order to understand how this material is expected to perform throughout the project experiments, representative 50-µm thick foils were subjected to 30 GeV (750 kW) proton beam irradiation at the Japan Proton Accelerator Research Complex (J-PARC) and subsequently transported to Pacific Northwest National Laboratory (PNNL) for Post-Irradiation Examination. The subject of the present study is the Ti-1 OTR foil, which received a total of 1.6 x 1020 protons on target with a beam sigma of 4 mm. I -6Al-4V have been conducted in fission reactors and charged particle accelerators, including low energy ion and high energy proto -Ti alloys is more limited. Previous studies on such materials included irradiation up to 0.28 displacements per atom (DPA), whereas the samples in the current study may have been irradiated to between 1 and 1.5 DPA. The present study seeks to -Ti alloy under conditions relevant to high power accelerators. The β-Ti alloys are metastable and will transform on heating into α-Ti platelets in the α+β Ti phase field and/or result in α-phase precipitation after long-term high temperature aging. Under irradiation, following displacement and diffusion of defects, phase separation and potential transformation of the β-phase similar to aging is likely to result. Because the α-phase has a lower tolerance for the β-phase stabilizers, such as Al and V, precipitates might be expected to form. In addition, low (ppm) concentrations of sulfur and phosphorus can result in the formation of Ti-S and Ti-P phases that could have deleterious effects on the alloy. Planned examinations at PNNL include Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Electron Backscatter Diffraction (EBSD), Transmission Electron Microscopy (TEM), and Atomic Force Microscopy (AFM) across the area of beam damage. Comparisons will be made to unirradiated archive material from the same parent foil. Upon completion of examinations at PNNL, the samples may be transferred to Oxford for additional micro-mechanical properties characterization. It is hoped that the information gathered from the current work may be applied toward future characterization of irradiation damage in Ti-6Al-4V alloys used at J-PARC for beam windows and target shells. The presentation will describe the status and preliminary results of the PIE campaign to date. 49 6th High Power Targetry Workshop / Book of Posters and Abstracts Post-Irradiation Examination of Graphite from the NuMI NT-02 Target DJ Senor1, AM Casella1, DM Asner1, PG Hurh2, K Ammigan2 1 Pacific Northwest National Laboratory, 2Fermi National Accelerator Laboratory The NuMI beamline at Fermi National Accelerator Laboratory (Fermilab) produced a high flux of neutrinos for various high-energy physics experiments including MINOS and MINERVA. The NT-02 target operated in the NuMI beamline from 2006 to 2009 and again in 2011. During its lifetime, the NT-02 target was subjected to proton beams at 120 GeV and up to 400 kW, and received an integrated total of 6.0 x 1020 protons on target. The target consisted of 47 POCO ZXF-5Q graphite fins mounted between parallel stainless steel cooling tubes. The proton beam struck the fins near their mid-plane to produce mesons that were electromagnetically focused and subsequently decayed into neutrinos. During the latter part of the operating lifetime of NT-02, its neutrino yield decreased by about 15%. The reduction in yield was attributed to radiation damage and/or oxidation of the graphite, and the present study is the first effort to characterize the macroscopic and microstructural condition of the graphite fins. During disassembly of the NT-02 target at Fermilab, several fins broke near their midplane. It was unclear whether the failures were caused by disassembly or were the result of cracks that occurred during operation. Two halves of broken fins, one from the upstream end of the target and one from the downstream end of the target, were selected for post-irradiation examination (PIE). For comparison, two unbroken fins, one each from the upstream and downstream ends of the target, were also selected for PIE. The four fins were packaged and shipped via Type A container to Pacific Northwest National Laboratory (PNNL) for post-irradiation characterization. The PIE plan at PNNL includes various examinations designed to elucidate mechanisms responsible for the gradual degradation in irradiation performance as well as the fractures observed after disassembly. The as-received appearance of the fins will be documented by high-resolution macro photography, and the resulting images will be used to plan subsequent sampling and characterization activities. Dimensional measurements will be made to determine if there was bulk swelling in the directions parallel and perpendicular to the incident proton beam. Surface analysis consisting of energy dispersive x-ray spectroscopy (EDS) and/or x-ray photoelectron spectroscopy (XPS) will be used to characterize the chemical composition of stains visible on the fins near fracture surfaces and near the water cooling tube solder/braze joints. Scanning electron microscopy (SEM) of the fracture surfaces will be performed to characterize crack initiation and propagation, and determine (via EDS) if the surfaces displayed chemical reactions indicating open cracks during operation. Select regions of the broken and intact fins will be sectioned and polished to document the bulk microstructure in and away from the incident proton beam. Finally, samples will be lifted out via focused ion beam (FIB) for subsequent examination by transmission electron microscopy (TEM) to discern the nature of the radiation damage in areas within the incident proton beam. Attempts will be made to determine lattice dilation via converged beam electron diffraction. This presentation provides a summary of the status, preliminary results, and future plans for PIE on the NT-02 graphite fins. 50 6th High Power Targetry Workshop / Book of Posters and Abstracts Experimental Investigation of Irradiation Effects in Beryllium Beam Window V. Kuksenko1, K. Ammigan2, C. Densham3, P. Hurh2, S. Roberts1 (1) University of Oxford, Oxford, UK; (2) Fermi National Accelerator Laboratory, Batavia, USA; (3) STFC, Rutherford Appleton Laboratory, Didcot, UK Though, design considerations for near-future multi-megawatt accelerator particles sources need data on properties and radiation induced degradation effects in beryllium, the experimental database on the behavior of beryllium in proton accelerator environments is currently very limited. Investigation of radiation damage in beryllium is one of the main objectives of the international “RaDIATE” collaboration. Different scale microscopy and atom probe tomography results from un-irradiated beryllium samples with different textures will be presented and analysed in combination with local mechanical property data from nanoindentation experiments. These microstructural data will be with those for beryllium material from the primary beam window of the NuMI beamline, which has been irradiated by 120GeV protons at 70°C up to 0.5 dpa. Results which indicate changes in fracture behaviour of the irradiated beryllium sample will be described and possible mechanisms will be analysed. Descriptions of the ongoing experimental activity and nearfuture plans will also be presented. 51 6th High Power Targetry Workshop / Book of Posters and Abstracts 52 6th High Power Targetry Workshop / Book of Posters and Abstracts 53 6th High Power Targetry Workshop / Book of Posters and Abstracts 54 6th High Power Targetry Workshop / Book of Posters and Abstracts 55 6th High Power Targetry Workshop / Book of Posters and Abstracts 56 6th High Power Targetry Workshop / Book of Posters and Abstracts 57
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