x5/gif test beam: high rate analysis manuela cirilli
TRANSCRIPT
X5/GIF Test Beam:High Rate Analysis
Manuela CirilliManuela Cirilli
Roma, 25 novembre 2002 Manuela Cirilli X5/2
Detectors
BIS module 0:BIS module 0: 170cm 30 tubes X 4 layers X 2 ml parallel gas distribution
Bundle:Bundle: 280cm 6 tubes X 4 layers (1 layer disconnected from gas and HV due to a broken wire) serial gas distribution (6 tubes in series)
BIS module 0:BIS module 0: 170cm 30 tubes X 4 layers X 2 ml parallel gas distribution
Bundle:Bundle: 280cm 6 tubes X 4 layers (1 layer disconnected from gas and HV due to a broken wire) serial gas distribution (6 tubes in series)
BISBIS
BUNDLEBUNDLE
Roma, 25 novembre 2002 Manuela Cirilli X5/3
Glossary
TTdriftdrift = T = Tmaxmax - T - T00
In the TDC spectra, Tmax and T0 are in TDC
counts Tdrift is in ns
Tdrift is corrected for temperature effect
according to H8 2001 results (-2.6 ns/∆T) All Tdrift are @ 19°C
Source intensity is expressed with the absorption Source intensity is expressed with the absorption
factor abs:factor abs: abs2 = 1/2 of the full source intensity abs2 - abs5 corresponds to nominal Atlas flux (100 Hz/cm2) abs1 corresponds to Atlas X safety factor 5
TTdriftdrift = T = Tmaxmax - T - T00
In the TDC spectra, Tmax and T0 are in TDC
counts Tdrift is in ns
Tdrift is corrected for temperature effect
according to H8 2001 results (-2.6 ns/∆T) All Tdrift are @ 19°C
Source intensity is expressed with the absorption Source intensity is expressed with the absorption
factor abs:factor abs: abs2 = 1/2 of the full source intensity abs2 - abs5 corresponds to nominal Atlas flux (100 Hz/cm2) abs1 corresponds to Atlas X safety factor 5
Roma, 25 novembre 2002 Manuela Cirilli X5/4
Study of Tmax vs. Tube in the Bundle
Initial strategy: Initial strategy: Use only source off data taken in nominal conditions of gas pressure, HV, threshold Combine source off runs only when there were no runs with the source on in between Typical run: 500 M Evts 5-6 tubes in a layer have reasonable statistics (>50K evts)
@ high rate:@ high rate: Lots of bkg on the TDC spectrum: clean it using BIS as an external tracker At abs1, also distortion of the spectrum: unfolding
Initial strategy: Initial strategy: Use only source off data taken in nominal conditions of gas pressure, HV, threshold Combine source off runs only when there were no runs with the source on in between Typical run: 500 M Evts 5-6 tubes in a layer have reasonable statistics (>50K evts)
@ high rate:@ high rate: Lots of bkg on the TDC spectrum: clean it using BIS as an external tracker At abs1, also distortion of the spectrum: unfolding
Roma, 25 novembre 2002 Manuela Cirilli X5/5
New wrt Pavia
Different fitting Different fitting procedure:procedure: Fit the rising and falling edge separately (Fermi-Dirac + bkg)
All parameters of the Fermi-Dirac are left free in the fit
More on fitting in my next talk
Different fitting Different fitting procedure:procedure: Fit the rising and falling edge separately (Fermi-Dirac + bkg)
All parameters of the Fermi-Dirac are left free in the fit
More on fitting in my next talk
T0 Tmax
Roma, 25 novembre 2002 Manuela Cirilli X5/6
Presented in Pavia Layer 1
Layer 3 Layer 4
Layer 2 Comparison with Comparison with BIS: BIS:
Use 6 tubes in the beam: Bundle BIS ML1 BIS ML2
~40 ns difference ~40 ns difference between the two between the two chamberschambers Bundle drift time not Bundle drift time not constant over the constant over the data takingdata taking
Comparison with Comparison with BIS: BIS:
Use 6 tubes in the beam: Bundle BIS ML1 BIS ML2
~40 ns difference ~40 ns difference between the two between the two chamberschambers Bundle drift time not Bundle drift time not constant over the constant over the data takingdata takingTube nb
Td
rift(n
s)
Roma, 25 novembre 2002 Manuela Cirilli X5/7
Hit rejection à la Claudio
Roma, 25 novembre 2002 Manuela Cirilli X5/8
Even better for out-of-beam tubes…
Roma, 25 novembre 2002 Manuela Cirilli X5/9
Typical T0 and Tmax fits
T0: Fermi-Dirac + exp T0: Fermi-Dirac + exp
Tmax: Fermi-Dirac + k Tmax: Fermi-Dirac + k
Roma, 25 novembre 2002 Manuela Cirilli X5/10
Problems: distortion of the TDC spectra
Already evident Already evident
without backgroundwithout background
If the chambers are really at 0°, then the bias is only in the central part of the TDC spectrum No bias on TNo bias on T00 and and
TTmaxmax determination determination
Already evident Already evident
without backgroundwithout background
If the chambers are really at 0°, then the bias is only in the central part of the TDC spectrum No bias on TNo bias on T00 and and
TTmaxmax determination determination
clean spectrumraw spectrum
Roma, 25 novembre 2002 Manuela Cirilli X5/11
Bias on T0 and Tmax
Counts Counts
Counts Counts
low-statisticstubes
Mean = 0.16 counts RMS = 0.29 counts Mean = 0.16 counts RMS = 0.29 counts
Mean = -1.49 counts RMS = 2.1 counts Mean = -1.49 counts RMS = 2.1 counts
T0 T0
Tmax Tmax
Roma, 25 novembre 2002 Manuela Cirilli X5/12
Special case: abs1
clean spectrumraw spectrum
The Tmax of the clean spectrum is shorter
The Tmax of the clean spectrum is shorter
But spectra at abs1 need unfolding… But spectra at abs1 need unfolding…
Roma, 25 novembre 2002 Manuela Cirilli X5/13
Problem: loss of statistics
It is problematic for out-of-beam tubes (already low stat) It could be overcome if we could combine different runs together…
It is problematic for out-of-beam tubes (already low stat) It could be overcome if we could combine different runs together…
Source off Source off
Roma, 25 novembre 2002 Manuela Cirilli X5/14
Typical T0 and Tmax fits at High Rate
Abs 2 Abs 2
Roma, 25 novembre 2002 Manuela Cirilli X5/15
Results: abs 10 (10-50 Hz/cm2)
Clean spectra Clean spectra
Roma, 25 novembre 2002 Manuela Cirilli X5/16
Results: abs 5Clean spectra Clean spectra
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Results: abs 5Clean spectra Clean spectra
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Results: abs 5Clean spectra Clean spectra Raw spectra Raw spectra
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Results: abs 2
Clean spectra Clean spectra
Runs 8-929/05/02 Runs 8-929/05/02
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Results: abs 2
Clean spectra Clean spectra
Run 831/05/02 Run 831/05/02
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Results: abs 2Raw spectra Raw spectra Clean spectra Clean spectra
Run 629/05/02 Run 629/05/02
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Results: abs 2, fitting errorsClean spectra Clean spectra
Run 629/05/02 Run 629/05/02
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Another way to look at the data
Source off Source off
Roma, 25 novembre 2002 Manuela Cirilli X5/24
Another way to look at the data
Abs 2 Abs 2
Run 629/05/02 Run 629/05/02
Roma, 25 novembre 2002 Manuela Cirilli X5/25
Another way to look at the data
Abs 2 Abs 2
Runs 8-929/05/02 Runs 8-929/05/02
Roma, 25 novembre 2002 Manuela Cirilli X5/26
Provocative: abs 1
Clean spectra Clean spectra