Production and test of sPHENIX W/SciFiber electromagnetic calorimeter blocks in China

The sPHENIX experiment is a new generation of large acceptance detectors at the relativistic heavy ion collider at Brookhaven National Laboratory,with scientific goals focusing on probing the strongly interacting Quark–Gluon plasma with hard probes of jets,open heavy flavor particles,andγproduction.The EMCal detector,which covers the pseudo-rapidity region of|η|≤1.1,is an essential subsystem of sPHENIX.In this study,we focused on producing and testing EMCal blocks covering a pseudo-rapidity of|η|∈[0.8,1.1].These,in conjunction with the central pseudo-rapidity EMCal blocks,significantly enhance the sPHENIX physics capability of the jet andγparticle measurements.In this paper,the detector module production and testing of sPHENIX W-powder/scintillating fiber(W/ScFi)electromagnetic calorimeter blocks are presented.The selection of the tungsten powder,mold fabrication,QA procedures,and cosmic ray test results are discussed.

Improvement of cosmic-ray protonmeasurement with the electromagnetic calorimeter of the Alpha Magnetic Spectrometer

Purpose The energy response of protons measured by electromagnetic calorimeter(ECAL)of Alpha Magnetic Spectrometer(AMS-02)shows disagreement between Monte Carlo(MC)simulation and data.Therefore,using the response matrix from MC to apply the energy unfolding,which is crucial for cosmic-ray proton spectrum measurement,is unreliable.As a result,cosmic-ray proton spectrum measured by ECAL based on raw MC would be different from the published results(based on the momentum measurement)by AMS-02.The purpose is tuning the response matrix to agree with data.Methods The independent energy measurement by AMS-02 magnetic spectrometer provides in-flight calibration for ECAL.The distributions of proton energy measured by ECAL in MC are corrected after the calibration.Results The proton spectrum based on the tuned response matrix is consistent with the published one.Conclusions The matrix tuning is effective for the energy unfolding for cosmic-ray proton spectrum measurement.

Cosmic-ray helium nuclei measurement with the calorimeter of the Alpha Magnetic Spectrometer

Purpose The distributions of energy responses of helium measured by the electromagnetic calorimeter(ECAL)of Alpha Magnetic Spectrometer(AMS-02)in Monte-Carlo do not agree with those in real data,thus using energy response matrix obtained from Monte-Carlo to measure the cosmic ray helium spectrum is not correct.Therefore,the spectrum measured with ECAL based on raw Monte-Carlo would be different from the real one.The purpose is to correct the response matrix to measure helium spectrum with ECAL.Methods The energy measured by ECAL of AMS-02 provides in-flight correction for the energy response matrix in Monte-Carlo.Results The spectrum based on corrected response matrix is consistent with the AMS collaboration published result.Conclusions It is feasible to measure helium spectrum with ECAL with corrected energy response matrix.

BESIII电磁量能器宇宙线测试与刻度

通过对北京谱仪Ⅲ(BESⅢ)电磁量能器(EMC)进行宇宙线测试来检验EMC各个探测单元的电子学系统工作是否正常,电缆连接是否正确。利用实验室测量得到的晶体相对光产额(RLY)系数对无磁场的宇宙线数据进行刻度,然后与蒙特卡洛(MC)宇宙线样本进行比较,得出每个晶体探测单元的宇宙线能量刻度常数,以此作为EMC的初始能量刻度常数。