1. Veto Wall Test Hyupwoo Lee MINERvA/Jupiter Group Meeting July 18, 2007

2. 2 From the last presentation to now Timing test with NIM modules and scope : in order to reduce errors from DAQ board ( 24ns for one clock count ) Have been troubled with lots of problem in using the FEB. ( about electronics, DAQ software, setting, and etc.) A few days ago, I could get first reasonable data. Wrote a program for data analysis with PAW.

3. 3 Previous result of timing test Standard deviation of timing (signal’s falling edge to trigger’s falling edge) is ~10ns Time characteristics are almost the same with analysis method : just use scope calculation

4. 4 Timing test without FEB Standard deviation of timing (signal’s falling edge to trigger’s falling edge) is ~4ns

5. 5 Setup with FEB - 1 Trigger hit Trigger input Blue - Positive logic Orange - NIM logic Red - PMT signal Panel hit kHz 1Mohm, 1Mohm

6. 6 Setup with FEB - 2 Trip register setting I followed Paul’s suggestion and Jesse’s note only but VTH. I set relatively very high threshold for big signal and big noise but it should be calibrated and cut more down in later time. Trigger hit Panel hit Large cross talk

7. 7 Using trigger hit for timing test Two kind of time information in output data file - Board clock counts for the fastest hit between the channels (It has random reference position in time dimension. One count matches with ~9.4ns) - Time difference from above time to the time of firing discriminator in ¼ clock count units for each channels (If there were no fire, it shows 0. The minimum quantized value is ~2.5ns) There are no information about timing for trigger input in data output file! Use trigger hit signal as an indicator of reference position in time dimension. (I have lots of unused channel!) More over, it can give a good cut condition for event selection. (During a triggered gate, 4 events can be taken. If there were only one real event, the rooms for the others are filled with meaningless data. 3.9*9.4ns = ~40ns ~3.5ns

8. 8 Problem with trigger hit -1 Actual time difference( panel hit to trigger hit) is ~20ns but output data tells ~40ns (?) I used NIM logic (need 50 ohm termination) for trigger hit signal but the input impedance of the FEB is not 50 ohm. ( So, impedance mismatching can make reflections, interferences, oscillations, and long discharging tail. ) I need one more pulse generator in order to solve this problem. However, I will assume that the signal patterns of trigger hit with the NIM logic are the same and I will do rough analysis for timing resolution.

9. 9 Problem with trigger hit - 2 During I tried to change VREF( Trip register ), I got a data set that the cross talk( of trigger hit ) fires discriminator. The data show that cross talk seems to be an early walker than trigger hit. The time difference from panel hit to cross talk is roughly matched with scope result => Something goes wrong with trigger hit and it shows more clear evident ~20ns ~40ns

10. 10 Timing resolution summary With DAQ board ( being used for PARTICLE program) and scope : ~10ns With NIM modules and scope : ~4ns With FEB : ~4ns ( rough result with an assumption ) The last two are roughly matched with

11. 11 Attenuator - 1 I tried to use an attenuator( ~6db ) for panel hit

12. 12 Attenuator - 2 The signal looks like to be a little distorted and delayed Delayed Distorted

13. 13 Plan for Future Now Bob carries the master FEB to Fermilab for modifying input AC coupling to use directly for big signal. => Need ADC calibration and check linearity after change Determine the proper threshold setup of FEB for veto wall Use both side PMTs to do hit position related study