Using MPPCs for T2K fine grain detector
Using MPPCs for T2K fine grain detector
复制标题
使用 MPPC 进行 T2K 细颗粒检测器
DOI：
10.22323/1.051.0017
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
F. Retière
中科院分区：
文献类型：
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作者：
F. Retière
来自Hamamatsu Photonics的多像素光子计数器将用于读取T2K近探测器细粒探测器（FGD）的8448个闪烁条。MPPCs耦合到另一侧镜像的波长移动光纤，并通过在0.96×0.96×200 cm条中间挤出的孔。研究表明，尽管存在较大的串扰和后脉冲，但MPPC性能在暗噪声率、增益、增益波动和量子效率方面满足FGD规范。束流测试结果表明，在后脉冲概率小于10%的偏置电压下，最小电离粒子通过FGD棒时至少产生10个光电子。后脉冲是MPPCs的主要限制，它随偏置电压迅速上升，并表现出大约20和100 ns的两个时间常数。mppc由新设计的AFTER ASIC读出。它是一个72通道的波形整形/数字化仪，工作在120 ns的峰值时间和50 MHz的采样频率；ASIC提供10微秒连续采样。我们发现，与MPPC耦合的AFTER ASIC为MIP提供了非常好的能量分辨率和约3.5 ns的定时分辨率，同时通过检测米歇尔正电子的后续发射，提供了一种有效的方法来识别π在闪烁体条中停止。
Multi-Pixel Photon Counters from Hamamatsu Photonics will be used to read out the 8448 scintillator bars of T2K Near Detector Fine Grain Detector (FGD). The MPPCs are coupled to wavelength shifting fibers that are mirrored on the other side and go through a hole extruded in the middle of the 0.96×0.96×200 cm bars. We show that the MPPC performance meets the FGD specifications for dark noise rate, gain, gain fluctuation, and quantum efficiency despite fairly large cross-talk and after-pulsing. Beam test measurements show that minimum ionizing particles produce at least 10 photo-electrons when going through a FGD bar at a bias voltage where the after-pulsing probability is less than 10%. After-pulsing has been found to be the main limitations of MPPCs as it rises quickly with bias voltage and exhibits two time constant of roughly 20 and 100 ns. MPPCs are read out by the newly designed AFTER ASIC. It is a 72 channel waveform shaper/digitizer, which is operated with a 120 ns peaking time and a 50 MHz sampling frequency; the ASIC provides 10 microsecond continuous sampling. We show that the AFTER ASIC coupled to a MPPC provides very good energy resolution and about 3.5 ns timing resolution for MIP, while providing an efficient mean of identifying π stopping in the scintillator bars by detecting the subsequent emission of Michel positrons.