First results from 8-stage PMTs

1. ADC spectra

2. Efficiency

PMT high voltage was set at the nominal value (1750 and 1500 for 10-stage and 8-stage tubes respectively). Trigger is based on 4 PMTs in two short trigger paddles (TOF tubes are not in the trigger). Discriminator threshold was set at 30mV. Linear fan-in/fan-out was used to split the signal between ADC and TDC. The table below shows the percentage of triggered events with good hits in TOF PMTs.
Left Right
10-stage PMT 97.2% 98.3%
8-stage PMT 79.8% 79.9%

3. Timing resolution

In progress....