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

- Basic Configurations - Current R&D status - Scintillator - SiPM - Simulation - Time schedule - Future plan Contents

 Prototype for EM Calorimeter One Layer : Tungsten 20cm X 20cm X 0.3cm (example) Scintillator 1cm X 20cm X 0.2cm X 20 strips  Total : 30 Layers (~ 26 Xo)  The R&D of prototype includes scintillator, SiPM and DAQ system Basic Configuration Tungsten Scintillator

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 Current R&D Status

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 Scintillator

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 -> % 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

Scintillator Extruder Example of the Extruder

 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  FAB : 5 ~6 times / year Packaging, attaching with WLS fiber Photo sensor – SiPM(Silicon Photomultiplier)

DAQ system  The proto type has 30 layers(~26 Xo), one layer consists of 20 scintillator bars and tungsten plate  the prototype needs 600 read out channels  We have to think of how to manage these channels  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.  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  Structure Absorber : 200mm * 200mm * 3mm Scintillator : 200mm * 200mm * 2mm (We simulated plate, not strip yet)  30 layers ( ~26 X 0 )  Absorber pure W ( density = 19.3g/cm 3 ) : alloy W-Ni (W:Ni = 95:5) (density=18.7g/cm 3 ) : alloy W-Pb (W:Pb = 90:10) (density=18.5g/ cm 3 ) : alloy W-Pb (W:Pb = 75:25) (density=18.2g/ cm3) :  Effective Molier Radius from Simulation W : ~18.9mm W-Ni : ~19mm W-Pb : ~19mm : almost the same

Energy Resolution W Energy(GeV) % W-Ni Energy(GeV) % W, W-Alloy or even W-Pb(25%) may be compatible of.  Electron energy = 1, 5, 10, 20, 50, 80, 100, 200 GeV  Cut range : 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)

What to do and Future plan  Producing Extruded scintillator -> 1 st 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  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