Study of Phoswich Detector and Possible Application to Super Belle Experiment

Abstract

The Super KEKB e+e- collider project is currently being prepared at KEK in Japan to probe of the Beyond Standard Model physics from B meson and Tau/Charm weak decays. For the upgrade of the Belle detector running at the collider, very harsh background environment is anticipated due to a high beam current. In particular forward and backward endcap electromagnetic calorimeters currently composed of CsI(Tl) counters will suffer several problems such as radiation damage of the crystals, pileup noise of the counters and fake photons. To overcome these problems, we have studied the feasibility of pure-CsI:CsI(Tl) phoswich detector as an alternative in Super Belle endcap calorimeter. Transmittance and X-ray luminescence are studied with prototype phoswich crystal. The scintillation properties of the phoswich detector coupled with Photomultiplier are studied using various gamma ray and alpha radioactive sources. The properties of energy resolution and effectiveness of pulse shaper discrimination have been investigated.