【作者】 王亚平； 蔡勖； 周代翠； 殷中宝； 王东；

【Author】 WANG Ya-ping~(1,2),CAI Xu~(1,2),ZHOU Dai-cui~(1,2),WANG Dong~(1,2),YIN Zhong-bao~(1,2) (1.Key Laboratory of Quark and Lepton Physics(Huazhong Normal University,CCNU),Ministry of Education, Wuhan of Hubei Prov.430079,China; 2.Institute of Particle Physics,Huazhong Normal University,Wuhan of Hubei Prov.430079,China)

【机构】 夸克与轻子物理教育部重点实验室(华中师范大学)； 华中师范大学粒子物理研究所；

【摘要】 ALICE实验电磁量能器(PHOS与EMCal)利用雪崩光电二极管(APD)作为光电转换器件,然后经过电荷灵敏前置放大器(CSP)进行电荷-电压信号转换与放大,这些被放大的信号然后送至前端电子学(FEE)板进行整形、模数转换及信号处理。FEE板可同时处理32通道的信号,并达到14比特位的有效测量动态范围,通过该FEE板可以实现的光子能量测量范围为0.005 GeV～80 GeV(PHOS)和0.015～250 GeV(EMCal),并且在室温下噪音水平约为30 MeV(PHOS)和75 MeV(EMCal)。ALICE电磁量能器为ALICE中央触发系统提供两级触发,即L0和L1。触发区域单元(TRU)电子学板在LHC碰撞后600 ns的时间内实现L0触发判选,并且所有TRU将L0触发数据传送到全局触发模块用以在L1时限内实现高横动量光子簇射事件(PHOS)或喷注区域(EMCal)的判选。更多还原

【Abstract】 The ALICE calorimeters PHOS and EMCal are based on Avalanche Photo-Diode(APD) photosensors with Charge Sensitive Preamplifiers(CSP) for readout of the scintillating elements.The amplified signals are read out via 32-channel shaper/digitizer front-end electronics(FEE) with 14-bit effective dynamic range.The signal to noise ratio for MIP at 215 MeV is～7 per channel with a noise level of 30 MeV at room temperature for a dynamic range of 0.005～80 GeV for PHOS,and the fast-OR RMS noise level is about 75 MeV for a dynamic range of 0.015～250 GeV for EMCal.The trigger of the ALICE electromagnetic calorimeters is implemented in 2 hierarchically connected layers of electronics.In the lower layer,level-0 algorithms search shower energy above threshold in locally confined Trigger Region Units(TRU).The top layer is implemented as a single,global trigger unit that receives the trigger data from all TRUs as input to the level-1 algorithm. Local level-0 decisions take less than 600 ns after LHC collisions,upon which all TRU’s transfer their level-0 trigger data to the upstream global trigger module which searches within the remaining level-1 latency for high p_T gamma showers(PHOS) and/or for Jet cone areas(EMCal).更多还原