“End station A setup” data analysis

Josef Uher

Outline

Introduction to setup and analysis

Quartz bar start counter

MA and MCP PMT in the prototype

What was analyzed

quartz bar start counter4 pad MCP - PMT

ADC

ConstantFractionDiscriminator

prototype3x MCP PMT (Burle)

2x MA PMT (Hamamatsu)

light source -pulse laser “Pilas”

LeadingEdgeDiscriminator

TDC

TDC

Tasks for data analysis software

develop a timing strategies for start counters

develop a calibration procedure for the prototype (determine time offsets for each of all modules, determine single electron timing resolutions)

help to tune the setup and find errors

What can affect timing resolution?

fluctuation of avalanche recoil of photoelectrons from MCP

surface charge sharing cross talk electronics noise smear of pulse source (laser) ...

150

170

190

210

230

250

270

290

310

330

350

10 100 1000Frequency [Hz]

Sigm

a [p

s]

The best resolutionMean resolution

Average improvement of the timing resolution

~22%

Timing resolution vs. Pilas trigger frequency

(measured with MA PMT Hamamatsu)

Quartz bar start counter

Quartz bar start counter

quartz bar start counter4 pad MCP - PMT

ADC

LeadingEdgeDiscriminator

TDC

Configuration with ADC gives possibility to correct measured time on pulse height off-line.

=> better control than in case of CFD

ADC correction – how it works?

t1 t2 Time

Am

plitu

de

TDC threshold

TD

C s

pectr

aA

DC

vs.

TD

C

Before correction After correction

1=250 ps 1=100 ps

Time resolution vs. number of electronsQuartz bar start counter

10

100

1000

0.00 50.00 100.00 150.00 200.00 250.00 300.00

ADC signal [photoelectrons]

Nar

row

er S

igm

a [

ps]

Narrower sigma - new data (100x amplification)

Narrower sigma - old data (10x amplification)

Quartz bar start counter timing resolution

Improvement for single photonsfrom ~350 ps to ~138 ps.

Prototype

Burle MCP-PMT, raw TDC spectra

Hamamatsu MA-PMT, raw TDC spectra

MCP and MA PMT timing resolution

SLOT 3 Best resolution Average

resolution

[ps] 194.25 250.5

MA PMT Hamamatsu

SLOT 4 Best resolution Average

resolution

[ps] 156.5 258.75

MCP PMT Burle

(raw data only, single photon mode, no corrections)

±58

±43

Pad timing offset mapsM

A P

MT H

am

am

ats

uWithout TDC link offset

MC

P P

MT B

url

eTDC 1 TDC 2 TDC 3 TDC 4Start

Peak p

osit

ion

Peak p

osit

ion

Peak p

osit

ion

Peak p

osit

ion

Delay ~1ns

Cross talk

Cross talk treatment

Possible sources of “false pulses”: charge sharing recoiled electrons internal PMT cross talk (wiring) cross talk in amplifiers cross talk in CFD photons bouncing in prototype box

Cross talk can appear in any pad of MCP or MA PMT

Cut in certain time after the first pulse

Cross talk treatmentM

CP

or

MA

PM

T

Cross talk treatment

Time [cnt]

Even

ts

[-]

Example of cross talk treatment with time window 15 counts.

MC

P P

MT B

url

e

Cross talk treatment

Time [cnt]

Even

ts

[-]

Example of cross talk treatment with time window 15 counts.

MC

P P

MT B

url

e

Cross talk treatment

The time window changed from 15 to 27 counts

Time [cnt]

Even

ts

[-]

Example of cross talk treatment with time window 27 counts.

MC

P P

MT B

url

e

Time window 15 cnt

Time window 27 cnt

Cross talk only

Cross talk treatment

Time [cnt]

Even

ts

[-]

Cross talk spectra with time window 15 and 27 counts.

MC

P P

MT B

url

e

Time window 15 cnt

Time window 27 cnt

Cross talk treatment

Time [cnt]

Even

ts

[-]

Corrected TDC spectra with time window 15 and 27 counts.

MC

P P

MT B

url

e

Timing resolution as a function of cross talk time window

180

190

200

210

220

230

240

250

260

270

0 10 20 30 40

Cross talk window [cnt]

Sig

ma

[ps]

TDC peak height as a function of cross talk time window

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

0 10 20 30 40

Cross talk window [cnt]

Pea

k h

eig

ht

[-]

Cross talk treatment

Raw TDC spectrum Time window 1 Time window 31

Time [cnt]

Even

ts

[-]

narrow = 190 ps

MCP PMT Burle after cross talk correction

SLOT 4 Best resolution Average

resolution

[ps] 135.12 225.00 improvement 14% 13%

Multiple hits Cross talk “frequency”

Raw data max.: ~7Corrected data: ~5

Conclusion

Influence of Pilas laser on timing resolution discovered. Higher Pilas trigger frequency needed – another Pilas laser will be tested.

Repeated measurement of quartz bar start counter timing resolution – still needs more work

All slots in the prototype will be tested in near future

Effective cross talk treatment was implemented in data analysis code