Riccardo Farinelli Charge Centroid Feasibility
Outline Prototype and TB setup Data set studied Analysis approch Results Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 2
Test chambers Conversion gap To understand the detector behavior two 10x10 cm 2 triple-gem prototypes have been tested with a muon beam inside a magnetic field. For the purpose of this analysis the main difference between them is the conversion gap. In this way we can test simultaney different geometry: 3 and 5 mm. Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 3
TB setup Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 4
TB data set HV scan @ B=0T in ArCO2 HV scan @ B=1T in ArCO2 B scan in ArCO2 Drift field scan @ B=0/1T in ArCO2 Induction f.scan @ B=1T in ArCO2 Incident angle scan in ArCO2 HV scan @ B=0T in ArIso HV scan @ B=1T in ArIso B scan in ArIso Drift field scan @ B=0/1T in ArIso Induction f.scan @ B=1T in ArIso Incident angle scan in ArIso Drift f. scan @ 45 in ArIso Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 5
TB data set HV scan @ B=0T in ArCO2 HV scan @ B=1T in ArCO2 B scan in ArCO2 Drift field scan @ B=0/1T in ArCO2 Induction f.scan @ B=1T in ArCO2 Incident angle scan in ArCO2 HV scan @ B=0T in ArIso HV scan @ B=1T in ArIso B scan in ArIso Drift field scan @ B=0/1T in ArIso Induction f.scan @ B=1T in ArIso Incident angle scan in ArIso Drift f. scan @ 45 in ArIso Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 6
Preliminary analysis data set The drift field scan allows to access to different behaviour of the prototype and to measure its functional limits. The analyzed data are: ArCO2 @ B=0T and drift f. [0.5;2,5] ArCO2 @ B=1T and drift f. [1;2.5] ArIso @ B=0T and drift f. [0.5;2.5] ArIso @ B=1T and drift f. [0.5;2.5] Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 7
Electron avalanche behaviours C G1 G2 G3 A B = 0 T B = 1 T C G1 G2 G3 A B = 0 T B = 1 T B = 1 T Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 8
Preliminary cuts Charge (ADC ch.) Several configuration have been studied to apply a preliminary cut on the charge and time sample of the hit. Trackers have worked in unchanged condition, test chambers changed with the gas mixture Tracker: Q_cut = 50 & 8 < t_sample < 14 Test ArCo2: Q_cut = 50 & 9 < t_sample < 18 Test ArIso: Q_cut = 50 & 12 < t_sample < 22 Time sample Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 9
Tracking approch A preliminary aligment of the chambers (tests and trackers) is perform @ B=0T. A straight line is used to fit the particle track. Meanwhile in magnetic field the tracks are bended and because a.t.m. no alghoritm has been developed to recontruct bended tracks then a second aligment is perform to adjust the shift introduced by the magnetic field. Tracker backward B=0T B=1T Tracker forward Test chamber Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 10
Analysis After the aligment the tracks are reconstructed by a straight line. Only events with 1 cluster per plane are considered The residual, the difference between the position measured by the test chamber and the position extrapolated by the tracking telescope, is calculated for each event. The Gaussian fitting the residual distribution allows to measure the resolution of the chamber. Only the Y coordinate has been studied for this preliminary analysis. Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 11
Y coordinate The Y coordinate is the one that it is perpendicular to the magnetic field. It is the coordinate that it is affected by the magnetic field. Magnetic field Beam direction Electron avalanche direction or Y coordinate Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 12
Efficiency @ B=0T Higher efficiency plateaux is reached by ArIso ArCO2, due lower primary electron production, is less efficent than ArIso at low drift field ArIso shows a flat behaviour Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 13
Resolution @ B=0T ArIso is flat ArCO2 has an higher resolution for low drift filed. Plateaux efficency values are comparable. ArCO2 seems to work better because has lower diffusion. Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 14
Efficiency @ B=1T in ArCO2 Efficiency plateux is about 92%. Geometry shows differences at low drift field. Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 15
Efficiency @ B=1T in ArIso Higher efficiency level is reached in magnetic field No difference gave by the geometry. Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 16
Resolution @ B=1T in ArCO2 The resolution in magnetic field goes from 250 to 320 µm Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 17
Resolution @ B=1T in ArIso Strong dependence of the resolution to the drfit field. The lower values is reached at 2,5kV/cm with a value of 209µm Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 18
Cluster size vs Resolution @ B=1T & 5mm conversion gap Two different behaviour are given by the mixtures. Resolution and cluster size are linear in ArIso Cluster size in ArCO2 is limited and it seems to confine the resolution below that 300µm Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 19
Summary and Conclusion Without magnetic field, ArCO2 gas mixture shows a lower resolution. No significan differents are given by the geometry. With magnetic field, ArCO2 doesn`t show big differences between low and high drift field. It increase the resolution from 250 to 330 microns With magnetic field, ArIso shows a huge dependence by the drift field. At low field the charge centroid gives 1(0,7)mm of resolution and at high field 249(209) microns with 5(3)mm conversion gap. We are far away for the resolution goal with orthogonal tracks, non orthrogonal can be only worst. Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 20
Charge Centroid Feasibility Ferrara July 07, 2015 R.Farinelli 21