Die Präsentation wird geladen. Bitte warten

Die Präsentation wird geladen. Bitte warten

Jochen Markert, IKF Frankfurt Tracking session Jochen Markert, IKF Frankfurt.

Ähnliche Präsentationen


Präsentation zum Thema: "Jochen Markert, IKF Frankfurt Tracking session Jochen Markert, IKF Frankfurt."—  Präsentation transkript:

1 Jochen Markert, IKF Frankfurt Tracking session Jochen Markert, IKF Frankfurt

2 Topics Activities Activities Lepton efficiency estimation Lepton efficiency estimation Implementation of efficiency in digitizer Implementation of efficiency in digitizer Dependency of efficiency on the ionization of the particle track Dependency of efficiency on the ionization of the particle track Number of wires in cluster Number of wires in cluster Estimation of layer efficiency Estimation of layer efficiency Comparison of different tracking code versions Comparison of different tracking code versions Reconstruction of opening angle of lepton pairs Reconstruction of opening angle of lepton pairs Dependency of resolution on the ionization of the particle track Dependency of resolution on the ionization of the particle track PID with MDC: energy loss PID with MDC: energy loss

3 CAL1JochenKhaledYvonne Pulser method for offset calibration Tuning of offsets and second iteration of calibration Tuning of offsets and second iteration of calibrationweeks Done for pp CAL2Jochen New GARFIELD parameters Cathode planes instead of cathode wires short term Cathode planes instead of cathode wires short term Analytical description of xt-correlation and errors DELAYED! Short term Medium term TRACK Segment fitter Vladimir Restructuring of the tracking code Restructuring of the tracking code Improvement of minimization Improvement of minimization Improvement of performance Improvement of performance Tuning of parameters Tuning of parametersDoneDoneDone Medium term ThierryEmilieJean-Lois Investigation on MDCIV Check of geometry Medium term AlignmentAlexander Alignment for inner and outer modules Alignment for inner and outer modules Alignment with photo modeler (MDCs + Magnet) Alignment with photo modeler (MDCs + Magnet) Alignment with cosmics Alignment with cosmics Alignment of META Alignment of METADoneDoneDoneDone Geydar Wire layer offsets Wire layer offsets Layer thickness (MDCIII+IV) Layer thickness (MDCIII+IV) Done but no clear results Activities in MDC analysis

4 Future tasks First priority: Efficiency correction First priority: Efficiency correction Tracking for high multiplicities + CPs, needed for final DSTs of SEP05!!! Tracking for high multiplicities + CPs, needed for final DSTs of SEP05!!! CODE STABILITY!!!!! (we lost weeks for debugging!) CODE STABILITY!!!!! (we lost weeks for debugging!) Second priority: (several weeks) Second priority: (several weeks) Time offsets from pulser method (Khaled) Time offsets from pulser method (Khaled) Development of ideal tracking Development of ideal tracking MDC part ( done by Vladimir) MDC part ( done by Vladimir) Other detectors ? Other detectors ? Development of embedding of simulated tracks in real events Development of embedding of simulated tracks in real events MDC part already existing MDC part already existing Other detectors ? Other detectors ? Investigation of events with very large unphysical multiplicity Investigation of events with very large unphysical multiplicity How many ? Definition of reasonable numbers of tracks (SIM/DATA) How many ? Definition of reasonable numbers of tracks (SIM/DATA) Fixing of geometry of outer MDCs Fixing of geometry of outer MDCs Wire angles, layer thickness (Geydar) Wire angles, layer thickness (Geydar) Wire layer offsets (Geydar + Thierry + Emilie) Wire layer offsets (Geydar + Thierry + Emilie) Measurements on MDCIV (Thierry + Jean-Lois) Measurements on MDCIV (Thierry + Jean-Lois) Optimization of cal2 parameters Optimization of cal2 parameters Smoother values + analytical description (Jochen) Smoother values + analytical description (Jochen) Retrieving parameters for out MDCs from DATA (Thierry + Emilie) Retrieving parameters for out MDCs from DATA (Thierry + Emilie)

5 Influence on the tracking efficiency MDC efficiency (cell efficiency: gas, thresholds, noise). MDC efficiency (cell efficiency: gas, thresholds, noise). MDC hardware problems (missing MBo, …). MDC hardware problems (missing MBo, …). Calibration quality Calibration quality Alignment Alignment Track finder efficiency. Track finder efficiency. Momentum reconstruction efficiency. Momentum reconstruction efficiency. Matching efficiency. Matching efficiency. Cuts efficiency (chi2 cut etc.). Cuts efficiency (chi2 cut etc.). Particle identification efficiency. Particle identification efficiency. …

6 Properties of wire clusters CPR by properties of cluster size and number of wires in cluster Tuned to get good agreement between simulation and experiment

7 Cell efficiency in digitizer Cell efficiency not depending on energy loss of particle in digitizer

8 Mean number of wires in cluster NOV01

9 MDCI

10 MDCII

11 MDCIII

12 MDCIV

13 Detection efficiency of MDC Efficiency of Layer: A particle track has to be detected at least once per efficiency of wire layer better than als 89% (MIPS) Segment theoretical better than 98,4% !????? Good agreement with laboratory measurement Particle Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 Method: MDCI MDCII NOV01

14 Layer efficiency including the wires which have been removed by tukey weights NOV02

15 Layer efficiency from fit accepted wires MDCI MDCIILayMDCIMDCII NOV02

16 MDC I p-blue, - -red MDC II SEP05

17 Ratio fitted segments/all segments of lepton pairs Comparison for Exp URQMD PLUTO Full pair analysis and background rejection applied!

18 Comparison of fitting track fitter for different HYDRA versions Subtitle: long story about nothing

19 Problem description Efficiency of track reconstruction of lepton pairs Efficiency of track reconstruction of lepton pairs Rumors about change in reconstruction efficiency of pairs (10%) observed by Laura between old calculation with HYDRA v7_05b and new v7_07/v7_08 Rumors about change in reconstruction efficiency of pairs (10%) observed by Laura between old calculation with HYDRA v7_05b and new v7_07/v7_08

20 Method Tracking + ideal tracking parallel (HMdcTaskSet/HMdcIdealTracking) Tracking + ideal tracking parallel (HMdcTaskSet/HMdcIdealTracking) Filling of ntuple with HMdcTrackingEff Filling of ntuple with HMdcTrackingEff Efficiency calculation: Efficiency calculation: Input Pluto Sim Nov02 Input Pluto Sim Nov02 Reference sample ideal segments (both inner and outer segments + Meta hits found in GEANT) Reference sample ideal segments (both inner and outer segments + Meta hits found in GEANT) Pairs definition : inner segments cluster/fitted, no condition on outer segments, opening angle cut of 9 degree Pairs definition : inner segments cluster/fitted, no condition on outer segments, opening angle cut of 9 degree Efficiency: found pairs / ideal pairs Efficiency: found pairs / ideal pairs

21 opening angle distribution of lepton pairs Comparison of different code versions of tracking

22 Efficiency of lepton pairs as function of opening angle 1ook events in simulation No significant efficiency between the different versions

23 Opening angle reconstruction Cut on opening angle 9 degree : Difference between GEANT angle accepted reconstructed angle accepted gives 5% more accepted pairs.

24 Reconstruction of invariant Mass

25 Resolution of the drift cells Drift time residuals spatial resolution : Dependence on the primary ionization clearly visual Drift cell resolution better than 150 m Position resolution of the track reconstrution Position resolution of the reconstruction Meets requirements NOV01 Data design value MDCII

26 Energy loss measurement with MDCs ? Contra: MDCs measure drift times not pulse height Low-mass - concept of MDCs not optimized for dE/dx - measurement with high resolution TaT Measurement of energy loss through width of the drift time signal (Time above Threshold, t2-t1) as measure of deposed charge ? 1 1 T. Akesson et al. Nucl. Inst. and Methods, A(474):172–187, 2001.

27 Normalization of signal width Drift cell Impact angle, distance from wire Drift chamber Gas amplification (HV) Track segment Mean over all cells Impact angle

28 Protons and pions can be separated Electrons and pions overlay deuterons and protons overlay Normalized and averaged Signal width

29 Resolution of signal width measurement resolution for protons 6-9 % resolution for pions 10-12% Data Resolution comparable with dE/dx measurement through pulse height! % p 7.6 % d 7.2 % %

30 Correlation of signal width with dE/dx Fitted with F(dE/dx Bethe-Bloch ) Correlation of signal width measurement with dE/dx property of signal shape and readout electronic 1 Good agreement for protons and pions 1 L. Ratti et al., WCC 2004, Vienna, Vortrag 2004.

31

32 The drift cell Dimension of the drift cells 5x5 - 10x14 mm 2 Dimension of the drift cells 5x5 - 10x14 mm 2 Gas mixture He/i-Butan (60/40) Simulation of the drift cells with GARFIELD - Geometry, Field, Drift MAGBOLZ - Gas properties HEED - Primary ionization Field wire Cathode wires Amplification area Sense wire

33 Simulation with GARFIELD x [cm] y [cm] Simulation : Inhomogeneous electric Field inside the drift cell V Drift depending on electric field Inhomogeneous distribution of V Drift inside drift cell drift

34 Time distance For track reconstruction space points are needed, but MDCs measure drift times Relation between drift time and minimal distance of the particle track from sense wire has to be known

35 x-t- correlation 2-dimensional drift cell model : Simulation of the drift signals using GARFIELD Parameterization through impac angle and minimum distance from wire Implementation into track reconstruction and GEANT - Simulation

36 Normalization of signal width (t2-t1) MDCII Data Nov01 Normalization with one curve per impact angle step (5°) MDCI/II normalized to the same value Deviation for higher momenta

37 Normalization of signal width Normalization: Impact angle ( ), minimal distance from wire All chamber types normalized to common value Normalization point at 450 MeV/c Inner segment (MDCI/II) : Good agreement at small momenta Deviation at higher momenta MDCIII/IV show different behavior as MDCI/II (statistic/geometry/working point?) Data Nov01 Nomalization

38 Comparison of dE/dx resolution with other experiments dE/dx resolution for gas mixtures with large fraction of hydrocarbon (Quencher) better as predicted Empiric formula for calculation of dE/dx resolution (MIPS): A. H. Walenta et al. Nucl. Instr. Methods, 161(45), 1979

39 The drift time measurement The drift time measurement started by the induced signal at the sense wire The signal gets amplified, shaped and discriminated The TDC measures the time between the edges of the logic signal and an external signal (common stop (CMS))

40 Calibration of drift times

41 Track reconstruction Track fitting:

42 Energy loss measurement with MDCs Energy loss calculation with GARFIELD Protons above 1GeV nearly minimal ionizing Protons at 100 MeV have 4 times larger dE/dx compared to,e,

43 Simulation with GARFIELD

44 Impact of a asymmetrical cathode voltage Cathode voltage -1000V instead t -1750V (MDCI in NOV01) Cathode voltage -1000V instead t -1750V (MDCI in NOV01) Electric field deformed near the cathode Electric field deformed near the cathode y [cm] x [cm]

45 Relative error of the drift time measurement compared to normal working conditions is large Relative error of the drift time measurement compared to normal working conditions is large Affected wire layers should nor be used in analysis Affected wire layers should nor be used in analysis Impact of a asymmetrical cathode voltage

46 Analysis of the GARFIELD Signals Leading- and trailing edge –times are calculated at a give threshold Distribution of drift times of 100 tracks for a given parameter set (minimal distance, angle) are accumulated and the mean and sigma of the time measurement calculated

47 Shape of the signals Broad arrival time distribution near sense wire slow electrons from the edge of the drift cell

48 Anzahl der Cluster pro cm als Funktion der Teilchenenergie Nimmt mit steigender Energie ab Unterschiede zwischen Teilchenspezies ver- schwinden bei hohen Energien

49 Anzahl der Cluster pro cm als Funktion der Gasmischung Ändert sich mit der Zusammensetzung des Zählgases Nimmt mit steigendem i-Butan Anteil zu

50 Signalbreite versus Teilchenimpuls Messung einzelner Driftzellen (oberer Reihe) Normalisierte Signalbreite für ein Segment (unten) Data Nov01 Segment Single cell

51 Korrelation der Signalbreite mit dE/dx Freie Anpassung mit Korrelation der Signalbreitenmessung gegenüber dE/dx Eigenschaft der Ausleseelektronik 1 Gute Übereinstimmung fürProtonen und Pionen 1 L. Ratti et al., WCC 2004, Vienna, Vortrag Data

52 Zeitauflösung als Funktion des Schwellenwertes Zeitauflösung verschlechtert sich mit steigender Schwelle Der Effekt ist nahe am Auslesedraht und in den Randbereichen der Driftzelle stärker ausgeprägt DUBNA

53 Zeitauflösung als Funktion der Teilchenenergie Zeitauflösung verschlechtert sich mit steigender Energie Der Effekt ist nahe dem Auslesdraht und in den Randbereichen der Driftzelle stärker ausgeprägt DUBNA

54 Zeitauflösung als Funktion der Teilchenenergie Zeitauflösung verschlechtert sich mit steigender Energie Data Nov01 impact 90°

55 Zeitauflösung als Funktion der Schwelle Änderungen in der Zeitauflösung führen zu einer Verschiebung der Driftzeitmessung mit steigender Energie resolution in the middle of the cell DUBNA

56 Verschiebung in der Driftzeitmessung xt – Relation für 100/1000 MeV Protonen Effekt ist nahe dem Auslesedraht und in den Randbereichen der Driftzelle stärker ausgeprägt DUBNA

57 Verschiebung in der Driftzeitmessung Änderungen in der Zeitauflösung (verursacht durch Änderungen der Ionisation) führt zu einer Verschiebung der Driftzeitmessung mit zunehmender Energie Timing shift in the middle of the cell DUBNA

58 V D als Funktion der Gasmischung Driftgeschwindigkeit in der Mitte der Driftzelle i-Butan verringert die Driftgeschwindigkeit

59 Relativer Fehler der Driftzeitmessung

60 V D als Funktion des Gasdruckes Driftgeschwindigkeit in der Mitte der Driftzelle Driftgeschwindigkeit verringert sich mit steigendem Druck

61 Relativer Fehler der Driftzeitmessung

62 V D als Funktion der Gastemperatur Driftgeschwindigkeit in der Mitte der Driftzelle Driftgeschwindigkeit steigt mit steigender Temperatur

63 Relativer Fehler der Driftzeitmessung

64 V D als Funktion der O 2 und N 2 Konzentration Driftgeschwindigkeit in der Mitte der Driftzelle Effekt vernachlässigbar

65 V D als Funktion der H 2 O Konzentration Driftgeschwindigkeit in der Mitte der Driftzelle Driftgeschwindigkeit nimmt mit steigender H 2 O-Kozentration ab

66 Relativer Fehler der Driftzeitmessung

67 Townsend Koeffizient Nimmt mit steigendem i-Butananteil zu

68 Attachment Koeffizient

69 Diffusionskoeffizienten

70


Herunterladen ppt "Jochen Markert, IKF Frankfurt Tracking session Jochen Markert, IKF Frankfurt."

Ähnliche Präsentationen


Google-Anzeigen