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X5/GIF Test Beam: High Rate Analysis Manuela Cirilli

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Roma, 25 novembre 2002Manuela CirilliX5/2 Detectors * BIS module 0: * 170cm * 30 tubes X 4 layers X 2 ml * parallel gas distribution * 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: * 170cm * 30 tubes X 4 layers X 2 ml * parallel gas distribution * 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 BUNDLE

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Roma, 25 novembre 2002Manuela CirilliX5/3 Glossary * T drift = T max - T 0 * In the TDC spectra, T max and T 0 are in TDC counts * T drift is in ns * T drift is corrected for temperature effect according to H8 2001 results (-2.6 ns/T) * All T drift are @ 19°C * Source intensity is expressed with the absorption factor abs: * abs2 = 1/2 of the full source intensity * abs2 - abs5 corresponds to nominal Atlas flux (100 Hz/cm 2 ) * abs1 corresponds to Atlas X safety factor 5 * T drift = T max - T 0 * In the TDC spectra, T max and T 0 are in TDC counts * T drift is in ns * T drift is corrected for temperature effect according to H8 2001 results (-2.6 ns/T) * All T drift are @ 19°C * Source intensity is expressed with the absorption factor abs: * abs2 = 1/2 of the full source intensity * abs2 - abs5 corresponds to nominal Atlas flux (100 Hz/cm 2 ) * abs1 corresponds to Atlas X safety factor 5

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Roma, 25 novembre 2002Manuela CirilliX5/4 Study of T max 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: * 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: * Lots of bkg on the TDC spectrum: clean it using BIS as an external tracker * At abs1, also distortion of the spectrum: unfolding

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Roma, 25 novembre 2002Manuela CirilliX5/5 New wrt Pavia * Different fitting 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 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

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Roma, 25 novembre 2002Manuela CirilliX5/6 Presented in Pavia Layer 1 Layer 3 Layer 4 Layer 2 * Comparison with BIS: * Use 6 tubes in the beam: m Bundle q BIS ML1 H BIS ML2 * ~40 ns difference between the two between the two chambers chambers * Bundle drift time not constant over the constant over the data taking data taking * Comparison with BIS: * Use 6 tubes in the beam: m Bundle q BIS ML1 H BIS ML2 * ~40 ns difference between the two between the two chambers chambers * Bundle drift time not constant over the constant over the data taking data taking Tube nb T drift (ns)

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Roma, 25 novembre 2002Manuela CirilliX5/7 Hit rejection à la Claudio

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Roma, 25 novembre 2002Manuela CirilliX5/8 Even better for out-of-beam tubes…

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Roma, 25 novembre 2002Manuela CirilliX5/9 Typical T 0 and T max fits * T 0 : Fermi-Dirac + exp * T max : Fermi-Dirac + k

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Roma, 25 novembre 2002Manuela CirilliX5/10 Problems: distortion of the TDC spectra * Already evident without background without background * * If the chambers are really at 0°, then the bias is only in the central part of the TDC spectrum * No bias on T 0 and T max determination T max determination * Already evident without background without background * * If the chambers are really at 0°, then the bias is only in the central part of the TDC spectrum * No bias on T 0 and T max determination T max determination clean spectrum raw spectrum

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Roma, 25 novembre 2002Manuela CirilliX5/11 Bias on T 0 and T max Counts low-statistics tubes * 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 Tmax

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Roma, 25 novembre 2002Manuela CirilliX5/12 Special case: abs1 clean spectrum raw spectrum * The T max of the clean spectrum is shorter * The T max of the clean spectrum is shorter * But spectra at abs1 need unfolding… * But spectra at abs1 need unfolding…

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Roma, 25 novembre 2002Manuela CirilliX5/13 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

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Roma, 25 novembre 2002Manuela CirilliX5/14 Typical T 0 and T max fits at High Rate Abs 2

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Roma, 25 novembre 2002Manuela CirilliX5/15 Results: abs 10 (10-50 Hz/cm 2 ) Clean spectra

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Roma, 25 novembre 2002Manuela CirilliX5/16 Results: abs 5 Clean spectra

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Roma, 25 novembre 2002Manuela CirilliX5/17 Results: abs 5 Clean spectra

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Roma, 25 novembre 2002Manuela CirilliX5/18 Results: abs 5 Clean spectra Raw spectra

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Roma, 25 novembre 2002Manuela CirilliX5/19 Results: abs 2 Clean spectra Runs 8-9 29/05/02 Runs 8-9 29/05/02

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Roma, 25 novembre 2002Manuela CirilliX5/20 Results: abs 2 Clean spectra Run 8 31/05/02 Run 8 31/05/02

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Roma, 25 novembre 2002Manuela CirilliX5/21 Results: abs 2 Raw spectra Clean spectra Run 6 29/05/02 Run 6 29/05/02

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Roma, 25 novembre 2002Manuela CirilliX5/22 Results: abs 2, fitting errors Clean spectra Run 6 29/05/02 Run 6 29/05/02

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Roma, 25 novembre 2002Manuela CirilliX5/23 Another way to look at the data Source off

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Roma, 25 novembre 2002Manuela CirilliX5/24 Another way to look at the data Abs 2 Run 6 29/05/02 Run 6 29/05/02

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Roma, 25 novembre 2002Manuela CirilliX5/25 Another way to look at the data Abs 2 Runs 8-9 29/05/02 Runs 8-9 29/05/02

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Roma, 25 novembre 2002Manuela CirilliX5/26 Provocative: abs 1 Clean spectra

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