A study of the electromagnetic calorimeter trigger signal for the BELLE experiment

Abstract

We measured the peaking time and the noise level of the fast-shaping signal to be used for the electromagnetic calorimeter trigger of the BELLE experiment performed at the e(+)e(-) collider (KEKB). After this measurement, we chose a shaping time of 200 ns for the fast shaper. For this case, the electronics noise was estimated to be 6030 electron-hole pairs, which corresponds to a 2.0-MeV energy deposit in CsI(Tl) crystal. The corresponding peaking time is 760 ns, which is suitable for the requirement of BELLE global trigger timing latency.