X5/GIF Test Beam: High Rate Analysis Manuela Cirilli.

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


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


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


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


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)


Hit rejection à la Claudio


Even better for out-of-beam tubes…


Typical T0 and Tmax fits

T0: Fermi-Dirac + exp T0: Fermi-Dirac + exp

Tmax: Fermi-Dirac + k Tmax: Fermi-Dirac + k


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


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


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…


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


Typical T0 and Tmax fits at High Rate

Abs 2 Abs 2


Results: abs 10 (10-50 Hz/cm2)

Clean spectra Clean spectra


Results: abs 5Clean spectra Clean spectra


Results: abs 5Clean spectra Clean spectra Raw spectra Raw spectra


Results: abs 2


Runs 8-929/05/02 Runs 8-929/05/02


Results: abs 2


Run 831/05/02 Run 831/05/02


Results: abs 2Raw spectra Raw spectra Clean spectra Clean spectra

Run 629/05/02 Run 629/05/02


Results: abs 2, fitting errorsClean spectra Clean spectra

Run 629/05/02 Run 629/05/02


Another way to look at the data

Source off Source off



Abs 2 Abs 2

Run 629/05/02 Run 629/05/02



Abs 2 Abs 2

Runs 8-929/05/02 Runs 8-929/05/02


Provocative: abs 1


X5/GIF Test Beam: High Rate Analysis Manuela Cirilli.

Documents

Transcript of X5/GIF Test Beam: High Rate Analysis Manuela Cirilli.