DWC calibration
The delay Wire Chambers should be calibrated before the start of a test beam.
The instruction to perform the calibration are tin the attached pdf file.
Calibration signal
t (ns) |
V (mV) |
0 |
0 |
10 |
Vmax |
30 |
Vmax |
90 |
0 |
Vmax = 40mV according to the manual, but you should probably use Vmax > 100mV because the discriminator thrs is set to 40mV. The pulse frequency should be f < 10kHz. Actually you can use a square pulse of width ~40ns.
Calibration with the DAQ
If you want to use the DAQ for the calibration you'll have to provide a trigger in sync with the calibration pulse. The quantities (up - down) and (right - left) can then be found in one of the online histograms (debug folder). Take one run for each of the three calibration inputs (up-left, center and down-right).
The new macro to compute the calibration is
dwc_calib.cxx. Just change the number of the calibration runs at the bottom of the file.
Manual calibration
Measure the time (up - down) and (right - left) for each of the three calibration inputs (up-left, center and down-right).
The old macro to do the calculation is
calibration_DWC1_Jul2012.cxx, just change the values of this variables
- float ud_left_up
- float ud_right_down
- float ud_center
- float lr_left_up
- float lr_right_down
- float lr_center
with what you measured.
The calibration should be updated in the monitoring software and in the ntuple production program.
--
MicheleCascella - 15-Jul-2012