DCH calibrations 2013 Gordon Lim, UCI

DCH calibrations Wire & pad time offsets Effective wire lengths Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions DCH calibrations Wire & pad time offsets Effective wire lengths Wire & pad gain corrections Foil bowing corrections TIC-DCH time offset

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions DCH calibrations Input: Reconstructed Michel tracks from 800 unbiassed runs (202600-203500) Starting point: All calibration constants = 0 Acronyms used in this presentation: UA (DA) = upstream (downstream) anode UH (DH) = upstream (downstream) hood UC (DC) = upstream (downstream) cathode DH UH UA DA DC UC

Wire time offsets Goal: Alignment of all anode waveforms Procedure: Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Wire time offsets Goal: Alignment of all anode waveforms Procedure: Use hits on reconstructed Michel tracks to determine the time offset of the (hit time – track time) distribution of each wire-end. Time offsets are calculated via 3rd order polynomial fits to the corresponding “reverse-cumulative” distributions, e.g.: Reprocess raw data with new time offsets. Repeat steps 1-2 for a number of iterations (typically 5). ΔT0 between successive iterations should converge. Administer persisting time offsets among two ends of the same wire symmetrically across the two ends. time offset hit time – track time [ns] hit time – track time [ns]

Wire time offsets 1st iteration: Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Wire time offsets 1st iteration:

Wire time offsets 6th iteration: Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Wire time offsets 6th iteration: outliers due to bad fits – corrected by hand outliers due to bad fits – corrected by hand

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Pad time offsets Goal: Alignment of pad and anode waveforms Waveform alignment is done by taking into account the upstream-downstream time difference of hits on each pad (UH-DH and UC-DC) and the time differences of hits on each upstream/downstream wire-pad pair (UA-UH, UA-UC, DA-DH and DA-DC) e.g.:

Hood time offsets (UH-DH) Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Hood time offsets (UH-DH) before calib after calib outliers due to bad fits – corrected by hand

Hood time offsets (UA-UH) Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Hood time offsets (UA-UH) before calib after calib outliers due to bad fits – corrected by hand

Hood time offsets (DA-DH) Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Hood time offsets (DA-DH) before calib after calib outliers due to bad fits – corrected by hand

Cathode time offsets (UC-DC) Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Cathode time offsets (UC-DC) before calib after calib outliers due to bad fits – corrected by hand

Cathode time offsets (UA-UC) Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Cathode time offsets (UA-UC) before calib after calib outliers due to bad fits – corrected by hand

Cathode time offsets (DA-DC) Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Cathode time offsets (DA-DC) before calib after calib outliers due to bad fits – corrected by hand

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Comparison between the anode time offsets from this time calibration and the preliminary CRC time calibration (DCHCellT0 ID #50) this calib CRC calib time difference

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Comparison between the hood time offsets from this time calibration and the preliminary CRC time calibration (DCHCellT0 ID #50) this calib CRC calib time difference

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Comparison between the cathode time offsets from this time calibration and the preliminary CRC time calibration (DCHCellT0 ID #50) this calib CRC calib time difference

Effective wire lengths, wire & pad gain corrections Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Effective wire lengths, wire & pad gain corrections Goal: Improve z-coordinate determination Plot pad charge asymmetry vs. z-anode, and fit the profile with the following function: where It can be shown that: l effective wire length d anode gain ratio h pad gain ratio Pad gain calibration (h) can be improved by doing the above exercise using z-track

outliers due to bad fits – corrected by hand Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Effective wire length before calib after calib outliers due to bad fits – corrected by hand

outliers due to bad fits – corrected by hand Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Wire gain corrections before calib after calib outliers due to bad fits – corrected by hand

outliers due to bad fits – corrected by hand Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Hood gain corrections before calib after calib outliers due to bad fits – corrected by hand

Cathode gain corrections Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Cathode gain corrections before calib after calib outliers due to bad fits – corrected by hand

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Foil bowing effect Goal: Correct bowing of hood foils due to pressure difference with surroundings Procedure: Plot the pad charge ratio as a function of z for each cell and fit with 3rd order polynomial Calculate correction factor for hood charge of each cell according to fit results Plot the pad charge asymmetry amplitude ratio as a function of the pad total charge ratio for all cells and values of z, and fit with 1st order polynomial before calib / after calib

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions TIC-DCH time offset The relative time difference between the TIC and DCH is determined by using tracks that have a matching TIC cluster:

Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions DCH status 2013 20 cells with a dead wire: 9-11, 29, 98, 107, 124, 125, 152, 162-166, 196, 213-215, 218, 254 9 cells with a dead pad: 44, 67, 68, 160, 175, 221, 272, 274, 278 20 cells with a “semi-dead” pad: 88, 120, 131, 252-269 (DC14) 4 cells with a weak pad: 97, 117, 216, 229 new in 2013

Conclusions Database: To do: Introduction Wire timing Pad timing Wire lengths Wire gains Pad gains Foil bowing TIC-DCH time Conclusions Conclusions Database: The DCHConfig table for 2013 data (ID #24) has been updated with the following IDs: Wire & pad time offsets: DCHCellT0 ID #51 Eff. wire lengths & dead channels: DCHCellParam ID #31 Wire & pad gain corrections: DCHCellGain ID #37 Foil bowing corrections: DCHHoodAsymRescale ID #8 TIC-DCH time offset: MEGTimeDifference ID #42 Wire positions: DCHWirePosition ID #91 To do: Reprocess a larger data sample and check the DCH performance optical survey 2013