Scintillator-based ILC detector R & D Status and Milestone DongHee Kim Kyungpook National University Joint Korea-Japan Collaboration KPS meeting, Spring 2007

Contents 1. Motivation 2. Current Status of R & D 3. Beam Test 4. Milestone

Motivation AIM excellent jet energy resolution - in jet measurements, use the excellent resolution of tracker, which measures bulk of the energy in a jet (“Energy/Particle Flow Algorithms”) excellent angular resolution good time resolution hermeticity Si-W calorimeter Tile-fibre calorimeter Si-scintillator hybrid

Current direction Traditional approaches (Compensation, AHCAL, …)  Well understood and established. New approaches (PFA, DHCAL, …)  All detector concepts take the new approaches.  More attractive and challenging… need much mo re effort  Optimization should be made by  Simulation studies  Hardware studies  Performance should be evaluated by  Test beam studies - How to prove jet energy resolution?  Comparison of test beam data with MC and optimize MC

Calorimeter LC Physics Performance Separation of WW and ZZ in their hadronic modes requires jet energy resolution,  E ≈ other studies indicate resolution degradation from 30% to 60% is equivalent to about 40% reduction in luminosity For PFA - material with smaller Moliere radius to reduce shower overlap - finely segmented to separate neighbouring showers - large B field and large calorimeter inner radius to separate of charged tracks

Optimization for PFA Magnetic field to bend charged particles Small ECAL Moliere radius for small lateral spread of shower Fine segmentation of ECAL/HCAL in 3-D MC truth After reconstruction MC by CALICE Cell as small as possible. Need Longitudinal Profile as well !!

Concept of strip calorimeter Sampling calorimeter with  scintillator and W for ECAL  scintillator and Pb (Fe) for HCAL Realize fine granularity (effective segmentation ~1cm x 1cm) for PFA with strip structure Huge number of readout channels for a ILC detector  ~10Mch for ECAL,  ~4Mch for HCAL This is achieved by MPPC (or SiPM) readout MPPC readout

Extruded fine scintillator strips KNU strip w/o TiO 2 KNU strip w TiO 2 Kuraray tile 1cm(width)x3mm(thickness) with hole for fiber embedding With extrusion method

Measurment of absolute Light Yield = ~ 30 photons 13.2 (ADC count / 1pe) * Q.E. # of photon from fiber = Pulse height (ADC counts) pedestal signal – = counts # of p.e. : 3.84 = / 13.2 # of photons from fiber : 3.84 / 0.13 = Sample : KNU tile 10mm x 50mm x 3mm

Light Yield Comparison photons photons Kuraray sample with 3M reflector KNU sample with TiO 2

MPPC for Readout MPPC stands for Multi-Pixel Photon Counter, being developed by HPK in collaboration with our community. Pros  Low cost (in future)  Very compact  Sensitive to the light with wavelength ~ 400 nm  High PDE (15~20% for 1600 pix)  Insensitive to magnetic field  High gain (10 5 ~10 6 )  Operational at V bias =70~80 V  Good timing resolution  Superior photon counting capability Cons  Thermal noise rate (100kHz~300kHz)  Set threshold at ~1.5 p.e.  Response is non-linear due to limited number of pixels (saturati on effect)  We currently have 1600 pix MPPC with sensitive area 1mm 2  Correction may be adapted at some level, but  MPPC with more pixels (N pix > 5000) is desired  pressure to HPK  Sensitive to temperature change   Gain /  T = 2~4 % / C o, to be improved in future  Cross-talk between pixels 4 mm 3 mm

Beam Test Plan HCAL ECAL ECAL Prototype test : 1 st DESY 2 nd Fermilab HCAL Prototype test : Fermilab 1 st stage of ECAL prototype test, 2 nd Stage of ECAL and HCAL prototype for the next few years

ECAL Beam Tests at DESY First beam test of scintillator strip ECAL with MPPC readout Performance for1-6 GeV e+  Energy resolution  Response linearity  Position resolution Experience of multi-channel (~500ch) MPPC readout Test 3 different strip types Introduction of  LED gain monitoring system  Temperature monitoring system 26 layers ~ 500 channels: 1600-pix MPPCs will be used. DESY BT (Feb 25 –Mar ) Successfully finished !

(Extruded Mega-strip under development)

3 Types of Modules tested 1. Mega-strips, WLSF readout, 13 layers 2. Mega-strips, Direct readout, 13 layers 3. Extruded strips covered by TiO 2, WLSF readout, 13 layers (KNU) Beam FR layers Examined 3 different combinations of the modules.

DESY Beam-line e + 1~6 GeV DESY II Electron Synchrotron e-e- Position scan with a movable stage Positron incident position determined with drift chambers.

Readout Electronics (developed by CALICE electronics group) CRC board (in VME crate) To DAQ PC HV supply (up to 100 V) To Slow-control PC Baseboard (6 analog boards mounted, 6 board x 18 ch = 108 ch) Strip ECAL module FPCB

Prototype Module B

Transverse&Longitudinal Profile

Shower Profile in Depth

Beam Energy Profile

Preliminary results Energy Resolution of strips from Korea RMS/Mean 1/ √E RMS/Mean 1/ √E 13.1% Raw dataAfter applying calibration constants 14.5%

Energy Resolution comparison Energy resolution Linear(%)Constant(%) 1Japan strips w/ fiber Japan strips w/o fiber Korea strips w/ fiber In overall, good results : expected good results under given material configuration Configuration 1,2 & 3 : comparable linear term but 1 is a bit bad Config 2 & 3 : rather high constant term Configuration 2 : this option may be discarded since the constant term is not controllable. Configuration 3 : the constant term can be controlled. However it is preliminary and need more analysis and inspections.

ILC NewsLine …Three different components – moulded scintillators w/ fibre, w/o fibre and a completely different system of extruded scintillators from Korea are under testing….. …The results from the Asian group’s test will be also extremely interesting …. March 29, 2007 ILC New Line

Lesson from the Beam Test Based on preliminary results (so it may be changed) Too high cost with cast scintillator Extruded strips need more R&D for fine tuning  Fiber sitting problem, reflector on edge etc..  these can be resolved.  Require Quality Control on production. Try next beam test at FNAL after resolving

ECAL Beam Test Plan at Fermilab Extend the test module (x 4 in cross-section) Performance for higher en ergy particles  E=4-120 GeV  Particle=e, , ,p Standalone test Combined test with CALIC E HCAL FNAL BT (2007– )

Scintillator Strip HCAL BT of 1m 3 HCAL module is the next projec t after the ECAL BT: (funded) Detailed plan still to be discussed. Expect/hope much closer collaboration wit h CALICE AHCAL group  the next gener ation HCAL prototype ?

Conclusion Scint-based ECAL successfully launched with first attempt Firstly show the possibility of adopting scint-based calorimetry to the ILC Problem understood  go for 2 nd stage Need more R & D but it can be resolved Extruded scintllator become inevitable option Go for larger ECAL and HCAL prototype as well

Special Thanks to Misung Chemical Company Next concrete talk by Dr. Suh this afternoon.