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Comparison of algorithms for hit reconstruction in the DTs:

Test of calibration code and v drift parametrization on TB2004 data. S.Bolognesi , G.Cerminara. Test of calibration procedures for t trig and drift velocity on Test Beam data. Comparison of algorithms for hit reconstruction in the DTs:. digi (time). recHit (distance).

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Comparison of algorithms for hit reconstruction in the DTs:

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  1. Test of calibration code and vdrift parametrization on TB2004 data S.Bolognesi, G.Cerminara • Test of calibration procedures for ttrig and drift velocity on Test Beam data • Comparison of algorithms for hit reconstruction in the DTs: digi (time) recHit (distance) • constant drift velocity • parametrized drift velocity * * CMS IN 2005/037 J.Puerta-Pelayo, M.C.Fouz, P.Garcia-Abia S.Bolognesi, G.Cerminara Muon week (08 February 2006)

  2. TB data run 2551 2701 2230 2618 2699 • TB2004 0 -10 -15 -20 -30 f (deg) y MB1 MB3 beam theta phi z x • Preliminar cut: requested at least 12 hits for each segment no vertex constraint we want to study the performances of the hit reconstruction algorithms independently from performances of the chambers and the track fitting algorithm S.Bolognesi, G.Cerminara 1 Muon week (08 February 2006)

  3. Calibration • Residual on distance = |x measured (xRecHit)| – |x extrapolated (xextr)| ttrig effect In the residual distribution is impossible to disentangle the effects of miscalibration of ttrig and vdrift • Meantimers to calibrate vdriftstrongly depend on the ttrig S.Bolognesi, G.Cerminara 2 Muon week (08 February 2006)

  4. Constant vdrift: calibration procedure • ttrig, s(ttrig) tm = t0pulses + t.o.f. + tprop + toffset + tdrift • fit of the rising edge of the time boxes with the integral of a gaussian (by SL) ttrig = tflex – k×s(ttrig) • calibration = k factor optimization (by SL): 1)residual distribution on position for different k factors 2) fit of (m1-m2)/2(s1+s2) vs k (vdrift = 54.3 mm/ns) xextr > 0 xextr < 0 xm-xextr m1 m2 • vdrift • fit of the meantimer distributions (by SL) • re-calibrate the k factor S.Bolognesi, G.Cerminara 3 Muon week (08 February 2006)

  5. f = 0° (SL1) BEFORE CALIBRATION AFTER CALIBRATION Constant vdrift: calibration results (1) Re-fitting the segment without the recHit itself s(residual) increases of about 100mm The calibration software in ORCA works for all the considered angles because it implements different meantimer formulas for different track patterns S.Bolognesi, G.Cerminara 4 Muon week (08 February 2006)

  6. BEFORE CALIBRATION AFTER CALIBRATION Constant vdrift: calibration results (2) f = -20° (SL1) S.Bolognesi, G.Cerminara 5 Muon week (08 February 2006)

  7. Parametrized vdrift: calibration • ttrig and s(ttrig) calibrated with the same strategy • the parametrization of the vdrift doesn’t provide any parameter for calibration f = -20° (SL1) ttrig miscalibration effects • shift on the mean (like for the constant vdrift) • increase of the width (s) because the non linearities are also shifted NOTE: the ttrig for the parametrized vdrift is different from the one for the constant vdrift because the parametrization has its own intrinsic offset S.Bolognesi, G.Cerminara 6 Muon week (08 February 2006)

  8. Conclusions and plans on calibration Conclusions • we have applied a preliminary calibration procedure on the TB data and we have obtained good results • all the code necessary for the calibration is already implemented in ORCA (Muon/MBCalibration*) • these algorithms will be ported in CMSSW as soon as all the segment reconstruction software will be in place * see G.Cerminara PRS/MU (10 Jan ’06) ToDo • ttrig-k×sigma(ttrig) is the best recipe? k is not the same for different chambers/SL • we have to check the robustness of the calibration strategy we have used: start from a big miscalibration on vdrift to verify the convergence of the procedure S.Bolognesi, G.Cerminara 7 Muon week (08 February 2006)

  9. Constant vdrift VS parametrized vdrift There are two hit reconstruction algorithms available in ORCA • constant drift velocity • parametrized drift velocity Parametrization based on cell simulation obtained with GARFIELD x = x(t,a, Bwire, Bnorm) GOAL OF THIS STUDY: • on real data test these two algorithms • for different angles S.Bolognesi, G.Cerminara 8 Muon week (08 February 2006)

  10. Residual on distance from wire AFTER CALIBRATION f = -10° (SL1) CONSTANT vdrift PARAMETRIZED vdrift • a central peak (s1 resolution) Fit with the sum of two gaussians • large gaussian for the tails with the constant drift velocity we have a worse resolution and bigger tails due to non linearity effects S.Bolognesi, G.Cerminara 9 Muon week (08 February 2006)

  11. Residual on distance from wire VS distance AFTER CALIBRATION f = -10° (SL1) CONSTANT vdrift PARAMETRIZED vdrift non linearity effects cause the larger tails in the residual distribution non linearity effects reduced to 100 mm (200 mm very close to the anode wire) S.Bolognesi, G.Cerminara 10 Muon week (08 February 2006)

  12. Residuals VS f angle SL3 We get the best results using the parametrized vdrift but for a more precise comparison we need to develop a more sophisticated calibration strategy ToDo • Introduce the possibility of calibrate parametrization on the data (at least the mean value of the drift velocity) S.Bolognesi, G.Cerminara 11 Muon week (08 February 2006)

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