The Status of the Scintillator-based
Calorimetry R & D Activities in Korea
DongHee Kim
Kyungpook National University
LCWS05 (SLAC) March 19, 2005
Collaboration
KOREA
Kyungpook National University
Seoul National University
SungKyunKwan University
JAPAN
Kobe University
Shin-Su University
Niigata University
Tsukuba University
RUSSIA
Dubna
Collaborators(Korea)
DongHee Kim, Kihyeon Cho, Jun Suhk Suh, Youngdo Oh,
Daejung Kong, Jieun Kim, Yuchul Yang, Sunghyun Chang,
Kukhee Han, Shabeer Mian, Adil Khan
Kyungpook National University
Soo Bong Kim, Kyungkwang Ju, Eunjoo Jun, Hyunsoo Kim,
Youngjang Lee, Byungsoo Yang, Jieun Jung
Seoul National University
Intae Yu, Jaeseung Lee, Ilsung Cho
SungKyunKwan University
Contents
-
Basic Configurations
Current R&D status
Scintillator
SiPM
Simulation
Time schedule
Future plan
Basic Configuration
‰ Prototype for EM Calorimeter
One Layer : Tungsten 20cm X 20cm X 0.3cm
(example)
Scintillator 1cm X 20cm X 0.2cm X 20 strips
Î Total : 30 Layers
(~ 26 Xo)
Tungsten
Scintillator
‰ The R&D of prototype includes
scintillator, SiPM and DAQ system
Current R&D Status
1. Survey almost done for the last several months
Scintillator, W/W-Ni(or other alloy), SiPM,
Closely collaborate with Japan group
• Scintillator:
R&D with Misung Chemical Company Ltd.
•
Tungsten:
R&D with TaeguTek Ltd
•
SiPM:
R&D with ETRI
2. SiPM/Tile R&D has been just started
3. Simulation is going on
Scintillator
• The
scintillator bars(or strips) for R&D purpose expect
to be produced during this semester
• Make sure proper chemical processes
• Compare light yield with commercially available scintillators
• Design of scintillator strip for LC prototype will be underway
• Cost
Cast
- $40-60 / kg
Extrusion - $3.5-7 / kg
Low cost plastic Scintillator
• Extruded plastic scintillator materials - low cost :
o Polymer pellets or powder must be used
- Commercial polystyrene pellets are available and cheap
- Component: Polystyrene pellets + Dopants(primary & secondary)
- Primary dopants : PT, PPO -> 1-1.5% concentration
- Secondary dopants: POPOP, bis-MSB -> 0.01-0.03% concentration
- The extrusion process can manufacture any shape
o Some disadvantage
- Poor optical quality because of
• the high particulate matter content in the polystyrene pellets
• The rapid cool-down cycle leaves the final material stressed.
→ This stress can lead to non-absorptive optical distortions in the
material that degrade the attenuation length
o We need more R&D
Extrusion Process(conventional)
Extrusion Process
All the work is done at one facility → reduces costs
By removing its exposure to another high temperature
cycle → reduces hits history of the product
→ eliminates an additional chance for scintillator
degradation
Example of the Extruder
Scintillator
Extruder
Photo sensor – SiPM(Silicon Photomultiplier)
‰ Current status for fabrication
• Preparation design and process during this semester
- simulation of electric field in Geiger and drift region
- wafer and mask
- fabracation process R&D
• Try to make sensor chip using FAB facility at ETRI.
ETRI : Electronics and Telecommunications Research Institute
‰ Process R&D
• To get parameters : geometrical and chemical parameter s
Simulation using TCAD
• R&D Æ FAB : 5 ~6 times / year
• Packaging , attaching with WLS fiber
DAQ system
‰ The proto type has 30 layers(~26 Xo), one layer consists of
20 scintillator bars and tungsten plate
Æ the prototype needs 600 read out channels
‰ We have to think of how to manage these channels
Æ Probably, VME or CAMAC system are not good
solution for beam test for 600 channels.
‰ So, the design of electronics and interface with computer
is required.
‰ We are considering R&D of electronics for QDC, TDC
and USB2 for interface with computer.
Æ need cowork with Japan group
Simulation
‰ Start simulation with
different passive absorber configurations
‰ Mokka and susygen 3.0
‰ SUSY simulation under Mokka
neutralino pair production from e+e- collision
‰ Simulation of prototype started
Tungsten-Scintillator Calorimeter using Geant 4
Simulation of TiCAL prototype
¾ Structure
Absorber : 200mm * 200mm * 3mm
Scintillator : 200mm * 200mm * 2mm
(We simulated plate, not strip yet)
Î 30 layers ( ~26 X0 )
¾ Absorber
pure W ( density = 19.3g/cm3) :
alloy W-Ni (W:Ni = 95:5) (density=18.7g/cm3) :
alloy W-Pb (W:Pb = 90:10) (density=18.5g/ cm3) :
alloy W-Pb (W:Pb = 75:25) (density=18.2g/ cm3) :
¾
Effective Molier Radius from Simulation
W : ~18.9mm
W-Ni : ~19mm
W-Pb : ~19mm
: almost the same
Energy Resolution
¾ Electron energy = 1, 5, 10, 20, 50, 80, 100, 200 GeV
¾ Cut range : 0.001 mm
W
: (15.14 ± 0.24)/sqrt(E) + (0.217 ± 0.099)
W/Ni (Ni 5%) : (15.39 ± 0.20)/sqrt(E) + (0.070 ± 0.084)
W/Pb(Pb 10%) : (15.13 ± 0.19)/sqrt(E) + (0.086 ± 0.079)
W/Pb(Pb 25%) : (14.89 ± 0.09)/sqrt(E) + (0.149 ± 0.038)
%
%
W
W-Ni
Energy(GeV)
Energy(GeV)
W, W-Alloy or even W-Pb(25%) may be compatible of.
What to do and Future plan
‰ Producing Extruded scintillator -> 1st prototype in April
‰ Fabricating sample of SiPM
‰ How to manage DAQ system for prototype
‰ Simulation for the thickness of scintillaor = 25 , 30mm
Simulation for alloy with different ratio for W:Pb and W:Ni
Î Optimize the ratio of thickness for Absorber and Scin
and absorber material.
‰ Simulation for scintillator strip
‰ Jupiter and Physics simulation
Possible target for physics simulation is SUSY
- scan the SUSY parameter space
- producing generator data in format of HEPEVT
‰ Prepare for beam test next year