GLD Calorimeter Status Oct 学術創成会議 S. Uozumi Shinshu University FJPPL meeting held at the end of September. Preparation underway toward the ECAL beam DESY in Feb/Mar New 20 MPPC samples have been arrived ! Properties of the New MPPCs ECAL test module Topics

4 mm 1 x 1 mm 1.3 mm Front Side 3 mm The New MPPC sample New 1600 pixel MPPC with very compact package 20 samples arrived 500 more MPPCs (for ECAL test module) will be delivered in November. Old sample

Gain of the new samples Gain = C (V bias -V 0 ) / e C : Pixel capacity V 0 : breakdown voltage Peaks separation looks very good! MPPC signal for LED pulse

Variation of the Gain pixel capacity ~ 3% breakdown voltage ~ 0.3% Breakdown voltage(V)Pixel capacity(pF) Number of Samples Variation of the Uniformity looks very nice ! Mean : 23.8 fF RMS : 0.7 fF Mean : V RMS : 0.21V Number of Samples

Noise rate / Cross-talk of the new samples ● Noise rate ~ 50 – 300 kHz. ● Looks improved from the old sample X-talk vs Over voltage(V-Vo)Noise rate vs Over voltage(V-Vo) Over voltage(Vbias-Vo) Noise rate (Hz) X-talk probability 0.5 p.e.threshold 1.5 p.e.threshold 50K 100K 150K 200K 250K 300K 350K

6 Light yield of a scintillator strip with the new MPPC Trigger scintillator  -ray source ( 90 Sr) Strip size : 1 cm x 4.5 cm x 3 mm covered with 3M radiant film WLS fiber (1mm  ) readout Direct readout MPPC collimator Light yield ~ 21 p.e. Light yield ~ 13 p.e. ADC counts Light yield is large enough !

Summary The New MPPC sample arrived, performance looks very nice! Device-by-device variation over 20 samples looks great. Light yield of strip scintillator is large enough (or too large) with the new MPPC sample. Plans Toward the ECAL beam DESY in Feb / Mar 2007, Construct ECAL test module –Need to optimize the light yield of the strip scintillator –Many stuffs to be ordered Continue to study basic MPPC properties –Photon Detection Efficiency, non-linearity, stability … Build massive quality control system of many MPPCs –500 MPPCs will arrive in mid. November –Measure Gain / Noise Rate / Cross-talk of all the MPPCs