Veto Wall Test

Hyupwoo Lee

MINERvA/Jupiter Group MeetingJuly 18, 2007

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.

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Previous result of timing test

C02 C08 C14n 25 25 25

ave 75.936 64.548 65.928std 9.460923 9.226643 10.86476

error 1.931203 1.883381 2.217759n 80 80 31

ave 75.85625 66.86088 55.73316std 9.621555 11.59667 14.60623

error 1.08251 1.304727 2.66672

C02 C08 C14n 25 25 25

ave 70.712 61.964 53.416std 9.457463 10.13044 9.473282

error 1.930496 2.067867 1.933726

C02 C08 C14n 25 25 25

ave 76.368 65.028 52.248std 8.921637 12.35993 9.2787

error 1.821121 2.522961 1.894007

scope cal.

waveform

waveform

Timing - 200fC (ns)

waveform

Timing - 10% charge (ns)

Timing - 10% peak (ns)

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

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Timing test without FEB

Standard deviation of timing (signal’s falling edge to trigger’s falling edge) is ~4ns

Distribution of Timing

0

2

4

6

8

10

12

14

16

1 3 5 7 9 11 13 15 17 19 21 23 25

Timing (ns)

Fre

qu

en

cy

N 100Average 10.60885Stdev 4.046468Error 0.406685

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Setup with FEB - 1

Trigger hit

Trigger input

Blue - Positive logic Orange - NIM logic Red - PMT signal

Panel hit

kHz

1Mohm, 1Mohm

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Setup with FEB - 2

Register # Trip Register Trip01 IBP 1002 IBBNFoll 1203 IFF 04 IBPPIFF1REF 1605 IBPOPAMP 1386 IBPFol2 247 IFFP2 428 IBCOMP 89 VREF 160

10 VTH 10011 GAIN 1111 PIPEDELAY 712 IRSEL 313 IWSEL 3

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

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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

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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.

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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 res

ult => Something goes wrong with trigger hit and it shows more clear evident

~20ns ~40ns

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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

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

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Attenuator - 2

The signal looks like to be a little distorted and delayed

Delayed

Distorted

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Plan for Future Now Bob carries the master FEB to Fermila

b 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