1. Veto Wall Test Hyupwoo Lee MINERvA/Jupiter Group Meeting Oct, 24, 2007

2. 2 Pedestal Use two different way for taking pedestal data - Pedestal Mode : without hit (Jesse’s note) - Discriminator Mode : with trigger hit (random trigger) Pedestal - (board offset) + (board noise) + (PMT noise) Open channel : without PMT signal => only about board PMT channel : with PMT signal (with 3-ch wire divider) => board and PMT

3. 3 Setup – 1 (TriP-t register setting) Pedestal Mode - Without hit - Without firing discri. - Same condition for real data? Discriminator Mode - Need trigger hit - Use random trigger - Almost same condition for real data - Need more time for all channel - I will choose this mode for future pedestal data taking

4. 4 Setup – 2

5. 5 Open & PMT 1 (same channel – discri. mode) Gaussian fit with selected interval Gaussian fit with whole interval

6. 6 Open & PMT 2 (same channel – discri. mode) In log scale for the previous plots

7. 7 Overall - graph With PMT Only for ch 1, 3, 5 Error bar 1-sigma

8. 8 Overall - table Sigma of board pedestal is ~1.3 ADC counts for both mode Sigma of total pedestal is ~2 ADC counts for discri. mode About open channel pedestals, there is ~1.5 ADC counts difference between both mode PMT pedestal has roughly the same mean but different sigma about both mode # of Events - Ped-open : 33933 - Ped-PMT : 34511 - Discr-open : 30402, 34750 - Discr-PMT : 34750

9. 9 Stability Need to test the pedestals frequently for making sure of their stability - Struggle with very low writing rate of DAQ program ( < 1 Hz even though I used 50 kHz random trigger rate) Check stability only at this time for a ~10 hr data set ( Discr. mode with PMT signal – 34750 events) - Divide it into ~1 hr sub data sets (3000 events) and see the history of pedestal change - The result seems roughly good - Need warming-up time for electronics?

10. 10 Stability Need Warming-up?

11. 11 Conclusion Overall, Pedestal seems to be no problem with that. Need to find charge/ADC counts ratio for more about pedestals. I will keep going on veto wall.