The Research On Simulation Of EEMC On BESâ…¢

BESâ…¢(BEijing Spectrometerâ…¢) is a large-scale particle detector which is going to run on the upgraded Beijing Electron Positron Collider (BEPCâ…¡). It can record the tracking information, like trjactories and energies of particles in the detector. As one of its sub-detectors, the electromagnetic calorimeter (EMC) made of CsI crystals, is mainly used to measure the energies and positions of electrons and photons coming out from interactions. The end-cap EMC has been recently designed as a supplement to the previous barrel part in order to increase the acceptance.Aiming at the basic configuration of BESIII electromagnetic calorimeter(EMC), the simulation system of BESIII is annalyzed in detail. Based on the software GEANT4, a full simulation on the complex end-cap electromagnetic calorimeter(EEMC) has been carried out. The detector description is accomplished by using programm language. After discussion and annalysis of the unsymmetrical crystal, the geometry description is completed and the simulation of the result has been done. Then, it confirms the geometry descprition of unsymmetrical quadrangular crystal and pentagonal crystal. At the same time, this paper annaylses the particle-detector interaction and the detector response. The behaviors of electrons, photons and hadrons in EEMC are studied and they are also compared with the rusults in barrel electromagnetic calorimeter(BEMC). Also, the calculation and realization method of standard electromagnetic interaction is compared with the low electromagnetic interaction.Preliminary results indicate that the Standard and Low electromagnetic interaction packages in GEANT4 give almost identical simulation on EMC, the detector performance, such as energy/position resolution, satisfies requirements of physics design. Different behaviors of hadrons and electrons in EMC will be helpful for particle discrimination, such as e /Ï€discrimination. The complete and perfect offline simulation software will play an important role in physics study at BESâ…¢.