This page is a summary of Veto counter efficiency analysis. The list below contains the items of the analysis which are completed.
Timing calibrations of the TDCs.
Function for the TDC timewalk corrections added to Primex software but not applied or committed to CVS. I need to determine the fit constants for all counters and add them to a database.
Veto reconstruction added to the Primex software in the VETOHIT bank.
Cuts applied in efficiency calculation
Lower ADC cut set just below the minimum ionization peak.
Time difference between top and bottom pmts of each counter within a 25ns window.
Exclude out-of-time hits with average time between top and bottom pmts.
Matching between x-position of hit in HYCAL and Veto.
Matching between y-position of hit in HYCAL and Veto.
Below are ADC spectra for counter #3(x=-25cm) from a pair production run(4865) and from a photon calibration run(5353). The black histogram is the raw spectrum, and the red is with requiring a TDC hit in the top and bottom pmts of the counter. From the left plot, an ADC cut was placed at channel 600.
For these two plots, I am showing the HYCAL x vs y (left) and the HYCAL x vs Veto y (right) for run 5353. For more info on y-matching, check out this link.
In the graph below, I am showing results of HYCAL-VETO y matching and ADC cuts.
Black - No ADC or y matching cuts.
Red - ADC cut
Green - y matching cut
Blue - ADC cut and y matching cut
Each graph below is the efficiency vs y for a particular Veto counter.
Pair production efficiency. The black line is with no extra cuts, and the red line is with y-matching between HYCAL and the Veto. No ADC cuts have been applied.
Items left to do:
Apply the timewalk corrections.
Implement a y-matching algorithm for production data.
Analyze the Pb glass calibration data to obtain the efficiencies for the Veto counters farthest from the beamline.
Calculate a realistic global efficiency for the Veto.
