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BOS Testbeam Results in 2001. 1. Drift time spectra 2. RT-relation 3. Resolution - HV & threshold dependance -Comparison with the 1999 data 4. Summary. MPI & LMU, Munich.
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BOS Testbeam Results in 2001 1. Drift time spectra 2. RT-relation 3. Resolution -HV & threshold dependance -Comparison with the 1999 data 4. Summary MPI & LMU, Munich ________________________________________________________________________________________ Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Teststand & Program 3 sections scanned, 10 cm each ML2 Chamber: 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 V Angular scans (900-1000, 1100-1300) => still to be analised… ML1 ______________________________________________________________________________________ 1 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Drift Time Spectra 2001: 60 mV threshold, trise=(10.6±0.3) ns 1999: 25e threshold, trise=(8.4±0.4) ns 3080 V 77 mV 60 mV 77 mV 98 mV 2980 V 3080 V 3180 V _____________________________________________________________________________________ 2 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Fine Time Oscillations Channel 2 Channel 16 Fine time spectra Fine time spectra Uncorrected Drift Time Uncorrected Drift Time Corrected Drift Time Corrected Drift Time trise=12.8 ns trise=11.6 ns Excluded from the analysis! _____________________________________________________________________________________ 3 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Maximum drift time & Rise time trise=4T0 Dt=t0-tmax • Dt 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 ______________________________________________________________________________________ 4 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
RT-relation residuals 1. 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 r=4.5mm r=10.5 mm _____________________________________________________________________________________ 5 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
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: • smeas=s(rextrapolated-rmeasured) Correcting for the fit error-> tube resolution: • sreal= sqrt (s2measured-s2corr), • Where s2corr=s2(m)*z2+s2(b), • track is given by : y=z*m+b _____________________________________________________________________________________ 6 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Tube Resolution - Results Preliminary! Preliminary! • Similar resolution curves • obtained for all layers. - Good reproducibility! _____________________________________________________________________________________ 7 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Tube Resolution – Threshold & HV dependence Preliminary! Preliminary! • degradation of the resolution with the rising threshold • resolution improves with higer HV (at lower radii) _____________________________________________________________________________________ 8 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Comparison with the 1999 data 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 a slight degradation in the resolution with respect to the 1999 testbeam (same chamber type and gas as in 1999) Electronis? Preliminary! _____________________________________________________________________________________ 9 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
BOS <-> BIL2001 testbeam results BOS BIL • BOS resolution curve rises somewhat more slowly • similar resolution at large r _____________________________________________________________________________________ 10 Sandra Horvat 10.12.2000, Testbeam meeting, CERN
Summary Drift time spectra : • low noise • larger rise time compared with 1999. • dependence on threshold & HV • fine time oscillations in some channels 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 Many, many special thanks to the ROME group, for the constant help, support & encouragement !!! _____________________________________________________________________________________ 11 Sandra Horvat 10.12.2000, Testbeam meeting,CERN