analysis of psi beam test r.sawada 09/feb/2004 meg collaboration meeting @psi r.sawada 09/feb/2004...
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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)
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.
18
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)
7160 events(4223 events Qsum>25000)
7160 events(4223 events Qsum>25000)
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)
3077 events(2059 events Qsum>25000)
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