Electronics setup

The analog signals from the 2 $\times$ 12 segments $\times$ 2 layers, totally 48 PMT's were first led to the patch panel behind the HKS hut. The signals were splitted after upstairs patch panel into TDC line and ADC line. Since analog signal height is large enough by usage of the wave length shifter, and also the length of the signal delay cable is long enough, any signal attenuator is not required. 1/2 of the signal pulse height from each PMT was recorded as ADC signal. The remaining 1/2 were first discriminated and splitted into 2 lines again. The threshold of each discriminator was set to survive kaon as much as possible. 1/2 were recorded as TDC and scaler information, the rest were sent to grouping logic for PID.

The HVs of the PMTs were gain matched so that the one photo-electron peaks were aligned at about the same ADC channels after pedestal subtraction in the ADC spectra.