Development of cosmic-ray detector for the new reactor-neutrino oscillation experiment KASKA

(1)研究了典型的液体和固体除湿器的基本特性。人们发现他们有足够的光线。(2)研究了多阳极光电倍增管的增益均匀性和通道间串扰等基本性能。他们被认为是足够好的实验需要。(3)一个原型宇宙跟踪器是用挤压塑料闪烁器制成的，它带有在闪烁器棒中间通过的波长移动光纤读出器。2005年11月在KEK质子同步加速器测试光束线进行了光束测试。测量了光产额和定时分辨率的位置依赖性，以及通过从两端读出的标记效率和位置分辨率。(4)使用1.4Ge V/c π介子束，光产额在4.2和7.2个光电子之间。当光束位置离光纤1cm时，光输出下降10%。(5)在-15mV阈值下，当需要两端信号的AND时，效率为96%，当需要OR时，效率为99%。(6)利用两端信号的位置分辨力，在定时时为36.9cm，在光量时大于100cm。因此，有必要将探测器放置在两个维度上，以便具有几厘米的分辨率。(7)获得了多像素光子计数器（MPPC）的样品，并测量了其增益、噪声、温度特性等基本特性。(8)研究了封闭气体正比计数管的电压曲线、效率、位置依赖性、长期稳定性等基本性能。

(1) Basic characters of typical liquid and solid scintillators were investigated. It was found that they have enough light yoeld.(2) Basic performances of multi-anode PMT were studied, such as gain uniformity or cross-talk between neighboring channels. They were found to be good enough for the experimental needs.(3) A prototype cosmic tracker was constructed using extruded plastic scintillators with wave-length shifting fiber readout that passed in the middle of the scintillator bar. A beam test was performed at KEK Proton Synchrotron test beamline in November 2005. Position dependence of light yield and timing resolution were measured, as well as tagging efficiency and position resolution by readout from both ends.(4) With a beam of 1.4Ge V/c pions, the light yield was between 4.2 and 7.2 photoelectrons. When the beam position was 1cm away from the fiber, a 10% decrease of light yield was observed.(5) The efficiency, as defined at-15mV threshold, was 96% when AND of signals at both ends was required, and 99% when OR was required.(6) The position resolution using signals from both ends was 36.9cm when using the timing, and was more then 100cm when using the light amount. Thus it is necessary to place the detector in two dimensions in order to have a few cm resolution.(7) Samples of multi-pixel photon counter, MPPC, was obtained as an alternative candidate for PMTs, and its basic characteristics such as gain, noise, temperature dependence were measured.(8) Enclosed-gas proportional counters were obtained as an alternative candidate for scintillators, and basic performances such as voltage curve, efficiency, position dependence, long-term stability were studied.