| The absolute photon energy calibration in EMC of BESâ…¢ detector is detaileddiscussed in this paper. The procedures of absolute photon energy calibration are asfollows. Firstly, for Monte Carlo (MC) simulated data, we use MC simulated singlephoton events to calibrate the absolute energy of photons. Secondly, we will dofurther calibration for real data based on MC calibration by using the inclusiveprocess: X0.The energy of Time-of-Flight counters (TOF) has been reconstructed andmatched with the energy of the electromagnetic calorimeter (EMC) to reconstruct theenergy of photons. The matching between TOF energy and EMC energy will improvethe reconstruction efficiency for photons, especially for the high-energy photons.This paper will give two kinds of absolute energy calibration parameters of photonsby using TOF energy or not.After the improvement of absolute energy calibration, we check the MCsimulated data with the single photon MC events. The results show that themeasurement precision of the energy of MC photon is about0.08﹪, the resolution forthe energy of reconstruction photons has been improved when matching the TOFenergy with the EMC energy. For real data, we check the results of the absoluteenergy calibration by the processâ†'γ c1,2. The results show that themeasurement precision for the photons with low energy is about0.5﹪. Thereconstruction efficiency has been improved when matching the TOF energy with theEMC energy. |
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