Design of Sc-ECAL Prototype for CEPC and Performance of First Two Layers

As a future Higgs or Z factory, construction of the circular electron positron collider (CEPC) has been proposed to precisely measure Higgs bosons. A particle flow-oriented electromagnetic calorimeter (ECAL) and a hadronic calorimeter (HCAL) comprise a baseline design for the CEPC calorimetry system. The scintillator-tungsten ECAL (Sc-ECAL) prototype is being developed within the CEPC calorimetry working group. The Sc-ECAL is a sampling calorimeter consisting of alternating absorber layers and high granularity active layers. Each component of the active layer has been studied and optimized from a variety of aspects to meet the design requirements. The complete technological Sc-ECAL prototype will contain 30 layers of ECAL-based unit (EBU) boards alternating with 30 layers of the absorber. The first two layers of the prototype have been developed, and primary commissioning has been performed to validate their performance.