Speakers
Description
The future Circular Electron-Positron Collider (CEPC) is a large-scale experimental facility, which aims to accurately measure the Higgs boson, electroweak physics and avor physics. For the detec- tor system in CEPC, a highly granular crystal electromagnetic calorimeter is proposed to achieve an EM energy resolution of less than 3%. It is a homogenous structure with long crystal scintilla- tor bar as active material. e energy deposition range in one crystal bar is about 500keV ̃10GeV. SiPM, as the preferred photon detector in crystal bar ECAL, should cover a dynamic range of at least 50000 photons. e response calibration for SiPMs with such a large dynamic range is chal- lenging. We have developed an experiment which used laser and PMT as light source and scaler respectively. By adjusting the bias voltage, we expanded the linear region of the PMT to cover the whole response range of SiPMs. e nal response curves are reasonable. We have also built a simulation model to describe them. Improvements to this experiment are still ongoing, including design of large dynamic range PMT, optimization of SiPM electronics and light source.
