Veto Wall Test Hyupwoo Lee MINERvA/Jupiter Group Meeting Apr, 16, 2008

2 Introduction Timing Test with attenuator (relative hit location in time and the time resolution). - Attenuator vs. 3ch divider. - Hit position. - PMT1, PMT2, and Analog sum of both PMTs. - Cable length. Overall about timing test in this talk. - Attenuator : 6dB (½ for Voltage (also Q) in 50 Ohm system), using this for all data if there were not specifying. - # of events : all data points are got from 2000 events (I use the data which I got during the last two weeks) - TriP-T Gain : apply the lowest value where I can convert ADC to charge with my previous result (not optimal for attenuator!) - Parameters : HV, PMT(1, 2, or sum), hit position(C08, C11, C14), cable length(x1, x2, x3)

3 Parameters (hit position, PMT, cable length) PMT1PMT2 C08C11C14 ~ at center Analog sum Cable length (323 cm) x1, x2, x3 => up to ~10m

4 Setup 1 Trigger hit Trigger input Blue - Positive logic Orange - NIM logic Red - PMT signal Panel hit Trigger hit : Used for reference marker in time analysis Apply an attenuator at the end of signal

5 Setup 2 (TriP-t register setting) Use relatively small threshold value compare with the previous studies, for high efficiency at lower high voltage or where the hit position is far from the PMT. Maintained this setup for all data.

6 Attenuator vs. 3ch divider - Timing Panel hit Trigger hit Time Difference Small value means late coming panel signal The results about timing are almost the same in both ways. I will use mean and sigma values in Gaussian fit as hit location and resolution. 1500V, PMT1, C14, x1

7 Attenuator vs. 3ch divider - Charge ~1 pC >~5.5*3 pC cf. Saturation cutoff 1500V, PMT1, C14, x1 Not ½ almost ~1/20 <= Not 50-Ohm system

8 Hit position Far from the PMT => signal comes lately, roughly resolution increases. x1 only Different day for taking might be reason?

9 PMT1, PMT2, and Analog sum of both PMTs 1600V, x1 Signal sum doesn’t change timing in significantly.

10 Cable length Efficiency drops a lot at 1400V C11, PMT1 Delaying is almost match with cable delay(5.5ns/m). - 1 clock count = ~9.4 ns Longer cable makes signals to smear.

11 Summary TDC with attenuator seems to be overall OK. About ADC… It’s very hard to figure out there will be no problem with attenuator, I’m still uncomfortable with attenuator. However… If we would focus more on the TDC, then attenuator will be a good solution. Using attenuator means sadly for me that I should do all things again from the start. Kevin’s suggestion : Getting a final board from Paul and doing things again with it, not with the old one.