Energy loss correction for a crystal calorimeter

Material effect of inner-detectors on the performances of the BESIII Electromagnetic Calorimeter (EMC) is investigated. The BESIII Time-Of-Flight counters (TOF) have been utilized to improve the energy resolution and detection efficiency for photons after a careful energy calibration. A matching algorithm between TOF and EMC energy deposits is developed, and the effects of beam-related background are discussed. The energy resolution is improved and the photon detection efficiency can be increased by the combined measurement of EMC and TOF detectors.