BOS BOS Testbeam ResultsTestbeam Results

in 2001 in 2001

BOS BOS Testbeam ResultsTestbeam Results

in 2001 in 2001

MPI & LMU, Munich 1. Drift time spectra 2. RT-relation 3. Resolution -HV & threshold dependance -Comparison with the 1999 data 4. Summary

1. Drift time spectra 2. RT-relation 3. Resolution -HV & threshold dependance -Comparison with the 1999 data 4. Summary

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Sandra Horvat 10.12.2000, Testbeam meeting, CERN

Teststand & ProgramChamber: BOS-0Chamber: BOS-0- same chamber type as in the 1999 testbeam, (differrent electronics!)

- runs with 2 or 4 mezzanine cards- flowing nitrogen in ML2, to avoid high HV currents

Threshold scan: 60 mV 77 mV 90 mV 98 mV HV scan: 2980 V 3080 V 3180 VAngular scans (900-1000, 1100-1300) => still to be analised…

ML1

ML2

______________________________________________________________________________________ 1 Sandra Horvat

10.12.2000, Testbeam meeting, CERN

3 sections scanned, 10 cm each

Drift Time Spectra

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10.12.2000, Testbeam meeting, CERN

3080 V 77 mV

60 mV77 mV98 mV

2980 V3080 V3180 V

2001:60 mV threshold,trise=(10.6±0.3) ns

1999:25e threshold,

trise=(8.4±0.4) ns

Fine Time Oscillations

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10.12.2000, Testbeam meeting, CERN

Channel 2 Channel 16

Fine time spectra Fine time spectra

Uncorrected Drift Time

Corrected Drift Time

Uncorrected Drift Time

Corrected Drift Time

trise=11.6 ns trise=12.8 ns

Excluded from the analysis!

Maximum drift time & Rise time

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10.12.2000, Testbeam meeting, CERN

t=t0-tmaxtrise=4T0

t decreases with : threshold (due to the change in t0) HV (due to t0 & tmax)- trise degradation at higher threshols and lower HV => implies degradation in the tube resolution

RT-relation1. step: applying the rt-relation from 1999 testbeam (determined by a silicon tracker) and tracking through the 6 layers (using LMU analysis software)

2. step:Autocalibration – correcting the rt-relation using residuals from the track, 15 bins of 1 mm

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10.12.2000, Testbeam meeting, CERN

residuals

r=4.5mm r=10.5 mm

Tube Resolution

Method:- tracking through the 5 layers,- track interpolation to the tube in the excluded layer (excluding layers 1, 3, 4 & 6)-histograming the distance of the real hit from the track, rextrapolated-rmeasured

Measured resolution:meas=(rextrapolated-rmeasured)

Correcting for the fit error-> tube resolution:tube resolution:real= sqrt (2

measured-corr),

Where corr=2(m)*z2+2(b),

track is given by : y=z*m+b

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10.12.2000, Testbeam meeting, CERN

Tube Resolution - Results

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10.12.2000, Testbeam meeting, CERN

-Similar resolution curves obtained for all layers.

- Good reproducibility!

Preliminary! Preliminary!

Tube Resolution – Threshold & HV dependence

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10.12.2000, Testbeam meeting, CERN

Preliminary! Preliminary!

- degradation of the resolution with the rising threshold- resolution improves with higer HV (at lower radii)

Comparison with the 1999 data

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10.12.2000, Testbeam meeting, CERN

Resolution curve for the 1999 testbeam: obtained using the same analysis method as for 2001 testbeam data

This is compared to the single tube resolution,obtained by a silicon tracker => 5-hit tracking method gives similar results as silicon tracker (differences for large radii)

2001 testbeam results show aslight degradation in the resolutionwith respect to the 1999 testbeam(same chamber type and gas as in 1999) Electronis?

Preliminary!

BOS <-> BIL2001 testbeam results

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10.12.2000, Testbeam meeting, CERN

BOS BIL

- BOS resolution curve rises somewhat more slowly- similar resolution at large r

Summary Drift time spectra :Drift time spectra :• low noise• larger rise time compared with 1999.• dependence on threshold & HV• fine time oscillations in some channels

Tube Resolution:Tube Resolution: • calculated by tracking through 5 layers (LMU software)• similar resolution for all layers, reproducible results• dependence on threshold & HV• degradation with respect to the 1999. data (both silicon tracker and tracking through 5 layers give similar result for 1999.)• BOS 2001. comparable to BIL 2001. testbeam results

_____________________________________________________________________________________ 11 Sandra Horvat

10.12.2000, Testbeam meeting,CERN

Many, many special thanks to the Many, many special thanks to the ROME group, for the constant ROME group, for the constant help, support & help, support & encouragement !!!encouragement !!!

Many, many special thanks to the Many, many special thanks to the ROME group, for the constant ROME group, for the constant help, support & help, support & encouragement !!!encouragement !!!