Comparison of 3 types of scintillator strips Miho NISHIYAMA Shinshu-U Light yield of 3 scintillator strips have been measured using b-ray source. 1. fiber read out strip ＋ radiant mirror film 2. direct read out strip ＋ radiant mirror film 3. Extruded strip (KNU) ＋ TiO 2 paint Size is 1 x 4.5 x 0.3 cm for all types.

Setup Discriminator Gate Generator 90 Sr PMT Threshold:100 [mV] Delay:95 [ns] AMP MPPC ADC Bias Voltage:78[V] Trigger scintillator Thermostatic chamber (25 ℃ ) Strip scintillator Collimator : 2 [mmφ] HPK Center of scintillator to avoid WLSF ∮

Determination of the MPPC gain using dark noise events d = 25.51±0.03 (ADC count) Gain= (6.327±0.001)×10 5 d Bias Voltage : 78 [v]

fiber read out MPPC signal (ADC counts) Number of Events Number of photoelectrons = (mean - pedestal) / d = ± 0.03

direct read out Number of photoelectrons = ±0.03 Number of Events MPPC signal (ADC counts)

Korean extruded Number of Events MPPC signal (ADC counts) Number of photoelectrons = ±0.02

Summary Observed light yields (N pe ): ・ Fiber read out : ± 0.03 ・ Direct read put : ± 0.03 ・ Extruded : ± 0.02 Extruded scintillator shows half light yield of the fiber readout strip. Plans Position scan Examine different reflector films (white, silver films used for LCD display, manufactured by Kimoto Co. Ltd.) Test 2 mm thick scintillator strips

The change of temperature Thermostatic chamber (25 ℃ ) ・ room temperature ・ temperature of Thermostatic chamber (thermometer 1) ・ temperature of Thermostatic chamber (thermometer 2)

温度変化による mean – pedestal の 変化

再現性 MPPC の取り外しあり 平均 : (2.49±0.01)×10 2