Hisayuki Torii1 RHIC-Phenix 実験のための EMCalorimeter のテスト実験と その性能評価 Outline Introduction Beam test setup Calibration method Position dependence Resolution & Linearity Conclusion 鳥井久行, 今井憲一, 延與秀人, 後藤雄二, 斎藤直人, Terry Awes, Stefan Bathe, Damian Bucher, Henner Buesching, Mikhail Ippolitov, Edouard Kistenev, Vanessa Mexner, Thomas Peitzmann, Ullich von Poblotzki, Sebastian White 京大, 理研, BNL, Kurchatov.I, U.Muenster, ORNL

Hisayuki Torii2 Introduction RHIC-PHENIX Experiment RHIC –Heavy Ion collision  s = 200AGeV – collision  s = 200 & 500 GeV PHENIX –Muon arms –Central arms EMCal.. Photon/Electron physics

Hisayuki Torii3 Introduction - Requirements for PHENIX EMCal- Wide dynamic range to perform both H.I physics and spin physics –Energy range 1: a few hundred MeV - 20GeV for both H.I. physics and spin physics in  s = 200AGeV Thermal ,  0 - a few hundred MeV - a few GeV J/  e  e  - < 10 GeV Direct  - a few GeV - 20 GeV –Energy range 2: 10GeV - 80GeV for spin physics  s = 500GeV Direct  - a few GeV - 40 GeV W  e, Z  e  e  - 10 GeV - 60 GeV

Hisayuki Torii4 Introduction - Requirements for PHENIX EMCal - –Requirement for cross section measurement –2% uncertainty corresponds to 10% cross section measurement error because of steep P T distribution  p T = 2%   = 10% +AGS beam test< 7GeV +CERN beam test 10GeV-80GeV NEW Energy Calibration to achieve 2% accuracy 2% 10%

Hisayuki Torii5 PbSc (lead-scintillator) and PbGl (lead glass) Fine segmentation –good  /  0 separation To cover wide energy range –two different HV setting are applied for  s = 200GeV run and  s = 500GeV run PbSc 1 module (4 towers) PHENIX EM Calorimeter

Hisayuki Torii6 Beam Test Setup At the CERN SPS H6 beam line from Aug.29 to Sep (by sharing beam with ALICE/Phos group) Absolute Beam Momentum 0.6% at 40GeV/c (from uncertainties of magnet current and alignment) Beam Momentum bite % (adjustable with slits setting) Separated e /  beam (  /e < 1% ) was achieved by target & absorber setting and by CEDAR(differential  renkov) +DWC (Delayline Wire Chamber) - position measurement.   -counters select 

Hisayuki Torii7 Beam Test Setup PbSc (1SM) PbGl (4SM’s) (Shipped from BNL) (from WA98)  70cm

Hisayuki Torii8 Data set - PbSc - *PbGl - Analyzed by Muenster group *PbSc - shown in this talk

Hisayuki Torii9 Calibration method - how to translate ADC(Amplitude) to energy- Muon beam and Electron beam –Correction of gains between channels –50% -200% / channels Laser –Correction of gain drift –2 - 3% / 60 mins Position dependence –11 % /55.2mm Absolute energy –Calibrated at 20 GeV beam energy

Hisayuki Torii10 Calibration method – = (ADClow - pedestal )  (ADChigh - pedestal) – =  = = x = x

Hisayuki Torii11 Calibration method - Position Dependence - Hit position dependence of the total observed energy Difference of position dependence in several 1/4 channels are within 2% 7% (edge) - 11% (corner)  2% +It is parameterized by simple function with hit position in 1/4 channel +Correction with parameterized function make hit position dependence to be flat.  E/E = 0.5% It’s used in real data analysis Beam corner center edge 1/4 channel

Hisayuki Torii12 Calibration Method - Uncertainty - LinearityResolution –Pedestal<0.1% % –High/Low Ratio0.5%0.5% –Gain Correction (t=0) 2% (3% for  ) % –Gain Drift (t  0) 0.3%<0.2% –Position Dependence % Total 2% Uncertainty (channel by channel)

Hisayuki Torii13 Result - Resolution & Linearity GeV beam data are taken Almost symmetric peak shape

Hisayuki Torii14 Results - Resolution - Resolution Fit by HEBT only 1.0%+8.7%/  E –After subtraction of contributions momentum bite pedestal –1.3%+7.9%/  E for AGS data which is taken at less than 7GeV 1.0%+8.7%/  E 1.3%+7.9%/  E

Hisayuki Torii15 Results - Linearity - Energy responses for 20GeV - 80GeV are linear within 2% uncertainty. There is 4% deviation at 10GeV. –Attenuation in WLS fibers and effect of shower leakage compensate. –We measure energy response function with Laser system,  0,J/  mass reconstruction (PMT+FEE) (EMCal+PMT+FEE)  2% uncertainty

Hisayuki Torii16 Results - Hadron rejection - Hadron rejection was studied at 40GeV/c  +,e - beam With only energy cut at the electron peak (>36GeV) it results in ~100 factor hadron rejection It will improve using shower profile cut.

Hisayuki Torii17 Conclusion Energy resolution 1.0%+8.7%/  E for GeV Energy response for 20GeV - 80GeV is linear within 2% uncertainty With two different HV settings. At 10GeV, there is 4% deviation. We measure the response function. Requests for PHENIX EMCal was achieved