analysis of psi beam test r.sawada 09/feb/2004 meg collaboration meeting @psi r.sawada 09/feb/2004...

Analysis of PSI beam

test

Analysis of PSI beam

testR.Sawada

09/Feb/2004MEG collaboration

meeting@PSI

R.Sawada09/Feb/2004

MEG collaboration meeting

@PSI

Energy ResolutionEnergy Resolution

3

Data Condition

#6628-#6671 with paraffin shield

Collimator sizeXenon 9.5 cmNaI 11.5 cm

FSH52 DAC value(beam intensity)

125

PMT gain 1e6

4

Event Selection and Q.E. correction

Q.E. estimated from liquid data was used for each PMT.Q.E. estimated from liquid data was used for each PMT.

& (NaI sum)<105

This cut is not important , because resolution doesn’t change with this cut.

5

5th step (depth correction)

3077 events(2059 events Qsum>25000)


FWHM = 4.5 ± 0.4 %FWHM = 4.5 ± 0.4 %

6

Masking effect

➀ without masking➀ without masking

➁ mask: edge of front➁ mask: edge of front

➂ mask: edge of front top,bottom➂ mask: edge of front top,bottom

➃ mask: edge of front top,bottom right,left

➃ mask: edge of front top,bottom right,left

gammagamma

Some PMTs are masked to simulate the curved shape of the final detector. Curved shape is corresponding between ➀ and ➂ (it depends on how to put PMTs).

Some PMTs are masked to simulate the curved shape of the final detector. Curved shape is corresponding between ➀ and ➂ (it depends on how to put PMTs).

FWHMsigma(right)FWHMsigma(right)

7

Masking effect 2

mask ➄mask ➄

mask ➅mask ➅

mask➄mask➄

mask➅mask➅Is symmetry important?Is symmetry important?

8

Energy resolution (83,129 MeV)

#689[6-7], trigger:S1*Xe#689[6-7], trigger:S1*Xe

FWHM: 4.5 ± 1.8 %σ(right): 1.0 ± 0.2 %FWHM: 4.5 ± 1.8 %σ(right): 1.0 ± 0.2 %

FWHM: 5.0 ± 0.6 % σ(right): 1.16 ± 0.06 %

FWHM: 5.0 ± 0.6 % σ(right): 1.16 ± 0.06 %

What are these 2 events?What are these 2 events?

83MeV83MeV 129MeV

129MeV

9

High energy events

Cosmic Ray?Cosmic Ray?

Miss reconstructed

position ?(due to using

simple average)

Miss reconstructed

position ?(due to using

simple average)http://www.icepp.s.u-tokyo.ac.jp/~sawada/files/eventdisplay/http://www.icepp.s.u-tokyo.ac.jp/~sawada/files/eventdisplay/

10

Energy and Resolution

PSI 2003TERAS 2003alpha

PSI 2003TERAS 2003alpha

Resolution(right) becomes better as a function of gamma energy.

Resolution(right) becomes better as a function of gamma energy.

* Error bar shows only fitting error.* Error bar shows only fitting error.

Timing Resolution

Timing Resolution

12

Data Condition

#699[4-6],7045 without Amplifier

Collimator sizeXenon 9.5 cmNaI 11.5 cm

FSH52 DAC value(beam intensity)

125

PMT gain ~5e6

addedadded

13

Algorithm

Timing correction of each PMT ☀ time walk

☀vertex (x_average,y_average,sigma2)

Timing correction of each PMT ☀ time walk

☀vertex (x_average,y_average,sigma2)

Timing of each PMT is shifted so that mean become 0.

Timing of each PMT is shifted so that mean become 0.

Taking the average with☀ software threshold : 50 nphe☀ weight : sqrt(ADC)☀ masked if (TDC - mean) > 10nsec

Taking the average with☀ software threshold : 50 nphe☀ weight : sqrt(ADC)☀ masked if (TDC - mean) > 10nsec

TDC’(i) = TDC(i) - TDC(TC)TDC’(i) = TDC(i) - TDC(TC)

addedadded

14

Timing resolution (right - left)

Resolution is 65 ± 2 psec (5e6 gain)Resolution is 65 ± 2 psec (5e6 gain)

☀ Depth cut : Nfpmt(0.5)>4

☀ No impinging point cut is applied.☀ Xe energy cut for selecting 55MeV gamma is applied.

☀ Depth cut : Nfpmt(0.5)>4

☀ No impinging point cut is applied.☀ Xe energy cut for selecting 55MeV gamma is applied.

# of events resolution (σ)

55 MeVw/ depth cut

1049 65 psec

55 MeV w/o depth cut

2794 73 psec

83 MeVw/ depth cut

956 55 psec

83 MeVw/o depth cut

1805 59 psec

15

Timing resolution (Xe - TC)

3:003:00 9:009:00 4:004:00 12:0012:00cut # of events resolution (σ)

w/ Nfpmt(0.5>4w/ sigma2<90

930 133 psec

w/ Nfpmt(0.5)>4

1048 137 psec

w/o depth cut 2792 147 psec

Resolution includes ☀resolution of TC ~ 60psec☀target size ~ 60 psec

but it is still worse than “r-l analysis”.

Resolution includes ☀resolution of TC ~ 60psec☀target size ~ 60 psec

but it is still worse than “r-l analysis”.

due to temperature of delay cable ?

due to temperature of delay cable ?

Time difference is shifting.Time difference is shifting.corrected with linear function.corrected with linear function.

16

Masking effect (Timing)

gammagamma

# of photo-electrons

w/ depth cut

(R-L)

w/o depth cut

(R-L)

w/o mask 30,000 65 psec 73 psec

mask: L,R 18,830 75 psec 86 psec

mask: L,R,T,BT

7,728 117 psec 152 psec

mask:ADC#>127

23,024 73 psec 80 psec

SummarySummary

Energy resolution of 83,129MeV gamma is estimated. Resolution becomes better as a function of gamma energy.

Timing resolution is estimated with more statistics.

Depth cut which I applied is strict. I will search optimum depth cut for sensitivity.

Energy resolution of 83,129MeV gamma is estimated. Resolution becomes better as a function of gamma energy.

Timing resolution is estimated with more statistics.

Depth cut which I applied is strict. I will search optimum depth cut for sensitivity.

19

Number of Events

# of events(Qsum>25000)

FWHM [%]

all 367k

step1Mainly,removal pedestal events.

267k

step2 removal 83 MeV 82k(34k) 8.5 ± 0.3

step3 x-y selection 7160(4223) 7.9 ± 0.9

step4 depth cut 3077(2059) 4.9 ± 0.4

step5 depth correction same 4.5 ± 0.4

20

cut & correction

Nfpmt(0.5) is used as depth parameter for correction and cut.

Nfpmt : number of PMTs which occupy the half of Qfront.

sigma2<90 is also applied to remove very deep events.

MCMC

Nfpmt(0.5)>4Nfpmt(0.5)>4

rejected

accepted

21

Position dependence of resolution4.3±1.0

4.8±0.4

4.6±0.7

4.5±0.6

4.5±0.3

4.5±0.6

4.1±0.9

5.0±0.5

5.0±1.6

center ofF15

FWHM [%]

There is no positioin dependence of resolution.

There is no positioin dependence of resolution.

22FWHM is constant if depth > ~4cmFWHM is constant if depth > ~4cm

Resolution is estimated with slicing with depth parameter. Correspondence of depth parameter and the depth is calculated from MC.

Resolution is estimated with slicing with depth parameter. Correspondence of depth parameter and the depth is calculated from MC.

23

Timing Counter (TC)

Timing resolution of the timing counter

is 60 psec

Timing resolution of the timing counter

is 60 psec

☀ Time walk correction.☀ virtex correction with Nphe(light)/Nphe(right)☀ Time walk correction.☀ virtex correction with Nphe(light)/Nphe(right)

☀ 2 × 5cm × 5cm × 1cm BC404☀ 4 × 1-inch finemesh type PMTs☀ 5cm × 5cm × 0.6 cm lead target

☀ 2 × 5cm × 5cm × 1cm BC404☀ 4 × 1-inch finemesh type PMTs☀ 5cm × 5cm × 0.6 cm lead target

24

Timing resolution with 1e6 gain + Amplifier

gainbeam

intensity(FSH52 DAC)

time resolution

(right - left) [psec]

time resolution (Xenon - tc)

[psec]

w/o Amp 1e6 350 391 ± 11 426.8 ± 11

w/ Yuri’s Amp 1e6 125 251 ± 6 295 ± 6

w/ Lecce Amp 1e6 125 246 ± 6 300 ± 7

w/o Amp 5e6 125 197 ± 6 256 ± 7

Time resolution using 8 PMTs which is applied amplifiers.Time resolution using 8 PMTs which is applied amplifiers.

Amplifier improve the resolution at 1e6 gain.Amplifier improve the resolution at 1e6 gain.

25

1st Step (remove pedestal events)

367k events367k events 267k events267k events

Mainly, subtraction of pedestal events.Mainly, subtraction of pedestal events.

26

2nd Step (83 MeV gamma rejection)

82k events(34k events Qsum>25000)

82k events(34k events Qsum>25000)

FWHM = 8.5 ± 0.3 %FWHM = 8.5 ± 0.3 %

& (NaI sum)<105& (NaI sum)<105

27

3rd step (position selection)



FWHM = 7.9 ± 0.9 %FWHM = 7.9 ± 0.9 %

28

4th step (depth selection)

FWHM = 4.9 ± 0.4 %FWHM = 4.9 ± 0.4 %3077 events(2059 events Qsum>25000)


analysis of psi beam test r.sawada 09/feb/2004 meg collaboration meeting @psi r.sawada 09/feb/2004...

Documents

optimum depth

psec 5e6 gain depth

resolution of tc

mev gamma

cut correctionnfpmt0

function of gamma energy

masking mask

xe energy