Optimization of the CEPC-AHCAL scintillator detector cells

Abstract

The Circular Electron Positron Collider (CEPC) project was proposed to measure precisely the properties of the Higgs bosons. A superb Hadronic Calorimetry (HCAL) will be a crucial component of the CEPC. Among many choices, an analog read-out HCAL is under development, which consists of stainless steel as absorber and scintillator as active medium. A detector cell consists of a scintillator tile and Silicon photomultipliers (SiPMs). A new cavity shape design for scintillator tiles of 40× 40× 3 mm^3 by injection molding technique is developed. The simulation and measurements results show the light output uniformity deviation is within 10% in a tile with the new design. In this paper, performance of SiPMs from Hamamatsu (13360-1325PE) and Novel Device Laboratory (NDL 22-1313-15S) are compared for the CEPC-AHCAL detector cells. From the measurements of MIP response, the average light output of a detector cell consisting of the injection molding tiles and the NDL-SiPMs can reach about 40 photoelectrons (p.e.), which is reasonable, considering that the light yield of a scintillator will be reduced by about 40% after 10 years running. The energy resolution of the CEPC-AHCAL prototype will degrade less than 2% for each tile with a non-uniformity of less than 10%, which is acceptable. This kind of detector cells could be massively produced.