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PMD Alignment and Calibration Data Base. Zubayer Ahammed VECC, Kolkata. Outline:. Description of the Objects needed for Detector Align. & Calib. Source of Objects. Procedure to Obtain them. Approx. size of the Objects. Update frequency and Validity Range.
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PMD Alignment and Calibration Data Base Zubayer Ahammed VECC, Kolkata Outline: • Description of the Objects needed for Detector Align. & Calib. • Source of Objects • Procedure to Obtain them • Approx. size of the Objects • Update frequency and Validity Range • Access Pattern and Access Frequency • External data base dependencies • Current Status and Schedule
PMD Alignment Database • (1) For each SM, 4 fudicial markers w.r.t vertexV(0,0,0) . So 16 per plane, Total [32] During the Assembly of SM, 1st cell of each UM will be marked w.r.t the fudicials marks on SM. (2) Cell identification No.(Integer) : (3) Cell co-ordinate(x,y,z) (Float) For 200K channels , apprx. Size would be ~200*4*4=3.2 MB One time entry Depend on survey measurements
Calibration Objects needed for calibration: MEAN, MPV of Landau fit of isolated cell adc. Source of Calibration Objects: Cell
Procedure to Obtain isolated Cell: It is important that the response of each cell be uniform through out the detector. From test beam result we know that charged hadrons typically hit single cell while photons hit more than one cell. We look for hit cell whose surrounding six neighbours are not hit. These isolated cells are assumed to be hadrons. 0 0 isolated cell 0 ADC>0 0 0 0
For each cell, there will be one gain factor, apprx. size~ (for 200k channel) 1.6 MB This gain variation can be SM to SM or UM to UM. In case of SM to SM gain variation, apprx. Size ~64 bytes We might also keep the UM to UM gain variation due to change in operating voltage, apprx. size~384 bytes. Update Frequency: May be once in every run year.
External Database Dependencies Yes ???? Current Status and Schedule Not started yet. For Alignment , end of year 2006. However for Calibration we have to wait till real data comes. At present all gain factors = 1.0 .