铅-闪烁光纤夹层电磁量能器高能γ触发方案的研究

Studies on High Energy γ Trigger of Lead-Scintillating Fiber Electromagnetic Calorimeter

在电磁量能器探测高能γ射线的实验中 ,主要本底来源于高通量的宇宙线质子事例 .为了有效排除质子本底 ,本文利用蒙特卡洛方法研究了γ事例在铅 -闪烁光纤夹层电磁量能器中的触发方案 ,并且使用束流测试数据对判选条件进行检验 .通过分析质子和γ事例在量能器中的能量沉积和纵向发展的特征 ,提出了一种有效的触发方法 ,使得质子的事例率被限制在 1 0 0Hz以内 ,同时能量高于 1 0GeV的γ事例获得了 99%的触发效率 .

The high flux of cosmic ray proton forms the main background of γ ray detection experiments using a lead scintillating fiber sandwiched electromagnetic calorimeter. The trigger scheme is studied to efficiently detect high energy γ rays and reject most of the proton events. Efficient cuts are derived from the Monte Carlo analysis of electromagnetic shower shape in the calorimeter. Photons with energy above 10GeV are triggered at the level of 99%. The requirement of proton rate less than 100 Hz is also satisfied. The accuracy of the simulations is testified with the beam test.