Experimental Nuclear Physics in Greece
n-TOF / ISOLDE
Rosa Vlastou
National Technical University of Athens
ECFA meeting - Athens 10/10/2008
Nuclear Physics research is carried out in 5 institutions
University
of Ioannina
Aristotle
University of
Thessaloniki
(UoI)
(AUTH)
National & Kapodistrian
University of Athens
(NKUA)
NCSR “Demokritos”
National Technical
University of Athens
(NTUA)
Main Experimental Facilities
5MV tandem Accelerator at NCSR Demokritos
Nuclear Physics laboratories at Greek Universities
Human Resources
AUTH: Expm. = 5 / Theory = 5
UOI:
Expm. = 4 / Theory = 2
NKUA: Expm. = 6 / Theory = 3
NTUA: Expm. = 3 / Theory = 0
Demokritos: Expm. = 3 / Theory = 2
----------------------------------------------------------Total (academic staff) : Expm. = 18 / Theory = 10
Other (faculty or tenured) : Expm. = 5 / Theory = 3
Post-docs : ≈ 1 per group
Post-graduate Students : ≈1-2 per group
Funding Sources
National budget : Ministry of Education, Ministry of Development, Bilateral Programs
Annual budget : ≈ 2000-3000 euros per staff member per year
Competitive Grants : National, European (FP6), NATO etc
G. Secretariat of Research & Technology : very limited for universities on Nucl. Physics
Experimental Current Research Activities
UoI – Ioannina
Basic Research
• Elastic scattering and reaction mechanisms at near barrier energies with weakly
bound nuclei - Experiments performed at NSCR Demokritos and Catania
Collaboration with : Demokritos, NTUA, Catania, Napoli, Saclay, Horia Hulubei Inst.
Elastic scattering and reaction mechanisms with
radioactive nuclei (17F ) at near barrier energies
Experiments performed at Legnaro
Structure of exotic nuclei (6,8He) by elasticinelastic scattering and direct reactions
Experiments performed at GANIL
• Investigation of nuclear reaction mechanisms in intermediate-energy heavy ion
collisions using the CHIMERA detection system, operating at LNS in Catania
Collaboration with INFN Catania, Jagellonian University Krakow
Development of statistical model codes for the description of equilibrium nucleon
and cluster decay from excited nuclei (code MECO)
• n-TOF collaboration at CERN
Experimental Current Research Activities
AUTH-Thessaloniki
Basic Research
• Nuclear Waste (237Np, 239Pu,129I, 241Am)
Transmutation experiments by using spallation
sources of different design in Dubna, Russia
Collaboration with 10 european and ex-Soviet Union groups
• nTOF collaboration at CERN
NKUA – Athens
Accelerator Science & Engineering
Nuclear, hadronic and particle physics
Experimental Current Research Activities
NTUA
Basic Research
• Neutron induced reactions on Ge, Ir, Au and Hf
isotopes leading to isomeric states
• Deuteron induced reactions on light elements
(C, N, B) relevant to materials analysis
Experiments performed at NSCR Demokritos
• ISOLDE & nTOF collaboration at CERN
INP / NCSR Demokritos
Basic Research
Nuclear Astrophysics
(Nuclear reactions for the modeling of explosive
nucleosynthesis / detection of geo-neutrinos)
Nuclear Structure
(Search for empirical proofs of shape-phase
transitions in nuclear systems)
Background in KamLAND
PRC 72, 062801(R) (2005)
Neutron Physics
(joint program with NTUA)
ISOLDE & nTOF collaboration at CERN
cross section values from 0.8 to 8 MeV
with an overall accuracy of 4%.
Detection of geo-neutrinos
APPLIED RESEARCH
A lot of effort is spent at Greek National Research Centres and Universities on
Research and Development of methods and tools targeted at specific applications
Some of the areas in which Applied Research projects are carried out are:
Development and application of Nuclear Analytical Techniques
(Greek AEC, Demokritos, NTUA, UoI, AUTH, NKUA)
Radioecology – Environmental Radioactivity
(Greek AEC, Demokritos, NTUA, UoI, AUTH, NKUA, NCME )
Nuclear Technology
(Demokritos, NTUA, AUTH)
Archaeometry - Radiodating
(Demokritos, NTUA, UoI)
Nuclear Medicine and Imaging
(UoI, NKUA)
Dosimetry
(Greek AEC, Demokritos, AUTH, NKUA)
n-TOF collaboration at CERN
The facility uses the CERN PS accelerator as a p beam driver and a Pb spallation target
to generate n, a ~200m long vacuum pipe and an experimental area equipped with
advanced detectors for the measurements of n-capture and fission cross section, beam
monitoring, dedicated high performance DAC and on-line processing systems
Proton beam
Proton beam momentum : 20GeV/c
Intensity : ~7 x 1012 p/pulse
Repetition frequency : 1 pulse/2.4sec
Pulse width : 6ns (rms)
TOF tube
Total length : ~200m
Internal diameter : [80 – 40] cm
Two collimators : neutron beam
dimension 2cm
Lead spallation target : 80 x 80 x 60 (cm3)
Cooling and moderator material : H2O
Unique Neutron beam characteristics
Neutron beam energy range : thermal-1GeV
Integrated neutron fluence : ~9x105n/p pulse
Energy resolution ΔΕ/Ε : 10-2-10-4
n-TOF collaboration
33 Institutes from Europe and US + UoI, NTUA, AUTH, Demokritos
FP5 EC-financed project
Objectives of the activity at n-TOF
1.Neutron Cross sections relevant for
nuclear astrophysics
2.Neutron Cross sections relevant for
Nuclear Waste Transmutation and related
Nuclear Technologies
3.Neutrons as probes for
Nuclear Physics
fundamental
Lead target
Experimental measurements started in 2001
and lasted 4 years
Strong Greek participation during the preparation and
commissioning of the facility
Th. Papaevangelou PhD thesis,
neutron escape line
A.University of Thessaloniki, 2006
Fission Measurements
PPACs chamber
FIC chamber
(n,f) reactions on:
232Th, 234U, 233,236U, 237Np, 241,243Am,
245Cm
Calibration measurements with: 235U, 238U
structures attributed to class-II states of
the second well of the double-humped
fission barrier of the highly deformed
nucleus 235U. Neutron energy resolution
comparable to the fine structure of the
resonance widths
D.Karadimos PhD thesis,
University of Ioannina, 2008
Neutron Capture Measurements
(n,γ) reactions on
Total Absorption Calorimeter
151Sm, 24,25,26Mg,
40 BaF2 crystals
90,91,92,93,94,96Zr,
186,187,188Os, 139La
204,206,207,208Pb, 209Bi,
232Th, 233,234U, 237Np,
240Pu,243Am
n_TOF
James
Lestone
ENDF-B/VI
f, barns
10
Ch. Lamboudis PhD thesis,
A.University of Thessaloniki, 2007
1
0.3
0.2
0.1
0.0
1
10
100
1000
10000
100000
1000000
1E7
1E8
In the framework of nTOF programme at CERN, n cross section measurements
have been performed at Institutes participating in the collaboration
a) The neutron capture cross section of the unstable
isotope 135Cs : 135Cs(n,γ)136Cs were measured at the
3.7 MV Van de Graaff – Forschunszentrum,
Karlsruhe, at thermal energies, characteristic of
helium burning scenarios for an improved s-process
analysis of the Xe-Cs-Ba region
N.Patronis PhD thesis, University of Ioannina, 2004.
b) The (n,2n) cross section measurements on 232Th and 241Am, involved in the U-Th cycle
have been performed at the 5MV tandem accelerator at NCSR “Demokritos”
G.Perdikakis PhD thesis, N.Technical University of Athens & Demokritos, 2006.
241Am(n,2n)
The n-TOF collaboration has collected some of the worldwide best
measurements on (n,f) and (n,γ) cross sections on actinides, long lived
fission fragments and other isotopes relevant to Nuclear Technology and
Nuclear Astrophysics
Accurate data of radioactive and rare samples for a wide energy range and
high resolution
~20 Publications in Scientific Journals & ~30 in conference proceedings
& a considerable number of PhD dissertations
The activity is now continuing with n-TOF-Ph2, which intends to exploit the
facility by improving the experimental conditions
• New spallation target has been built and installed
• Test runs will be carried out next month to study n beam fluence, energy resolution,
background and to verify the performance of detectors and DAQ system in beam
For Greek participants there is a severe finance problem
No support even for the MO fees!
For ISOLDE collaboration, Greece is not a member!
Nuclear Physics @ ISOLDE/CERN
(NCSR “Demokritos” and NTU Athens)
Motivation
ISOLDE is worldwide the leading facility for forefront research with Radioactive Beams
(RIBs). RIBs allow studies of fundamental questions concerning the response of nuclear
matter under “extreme” conditions. Among these the evolution of nuclear (shell)
structure away from the stability valley and the mechanisms of heavy element
nucleosynthesis in explosive environments are of outmost importance and still not yet
understood.
ISOLDE hosts a number of state-of-the art experimental devices enabling forefront
research in fields where greek scientists are interested in.
Recent activities
Evolution of shell structure in “exotic” neutron-rich Cu nuclei using for the first time
isomeric beams and the MINIBALL array (IS435 collaboration:14 European Institutions)
So far: 2 PRL papers
PRL 98, 122701 (2007)
PRL 100, 112502 (2008)
Nuclear Physics @ ISOLDE/CERN
(NCSR “Demokritos” and NTU Athens)
The Miniball spectrometer – the tool for our future activities
8 clusters of HPGe crystals
(3-fold segmented)
εγ = 20% (1 MeV), 5% (12 MeV),
Ω ≈ 2.8 π
Planned research and duties within the MINIBALL collaboration
1. Construct a plunger device for lifetime measurements of excited nuclear levels of
exotic nuclei to search for shape-phase transitions critical point symmetries) in
nuclear systems.
2. Develop He-implanted targets for capture reactions in inverse kinematics with
radioactive beams to investigate nuclear reactions relevant to nucleosynthesis
scenarios in supernovae explosions (p process)
Experimental Nuclear Physics in Greece
• Nuclear Physics experimental Research is carried out at NCSR Demokritos
as well as at International Facilities
• These activities result in a considerable number of PhD dissertations as
well as Publications in Refereed journals and Conference proceedings
• Collaborations with European facilities are well established (financial
support only by bilateral agreements, grants from abroad, and Trans-national
access programs)
• Urgent need for money so that Greek groups can actively contribute to
joint projects in n-TOF and ISOLDE facilities
Pay membership fees, traveling expenses etc
• The national support is very limited
Greek groups can hardly carry out their present responsibilities…
We could actively contribute to joint projects in future facilities like FAIR, SPIRAL2,
HI-ISOLDE, but under the present circumstances it seems impossible!
• Fragmentation of activities
most probably because of absence of national strategy in nuclear physics