BCM Calibration

(copied from GMP)

BCM Calibrations [2 hours]

Procedure:

The absolute calibration of the bcm is done with the Faraday cup or the unser. In case the Fraday cup is used, you need to request it to the MCC. In this experiment we used the unser as the absolute calibration measurement. The unser calibration is done using the wire, in no production beam time. The Hall A BCM and scalers need to be cross-calibrated to the Faraday cup and a BCM in the accelerator (OLO2) and the Hall A Unser. (If night shift then do NOT bother cross calibrating with the Faraday cup. You can just stay on the line with MCC and request the appropriate beam currents following the rules below.)
Before beginning the procedure, make sure the Hall A BCM logger and the HRS DAQ are started, which will record the signals from all relevant BCM used during the calibration. [Here ] is how to start the logger, choose the BCM logger script (solution 2).
Also start a HRS run to record the scalers during the calibration procedure, if necessary use the clock to take reasonably high data rate (above about 50 Hz at least)
It is useful to have someone over in MCC to help coordinate the calibration with them.
Take data on carbon target with I = 0, 3, 0, 5, 0, 7, 0, 10, 0, 15, 0, 20, 0, 25, 0, 30, 0, 40, 0, 50, 0, 60, 0, 70, 0, 80, 0 μA (or as high a current as available). Each beam period (with or without current) should last 90 s. If you get a trip during a beam up period, take 90s of beam off and restart that beam up period.

In the bcm calibration, the beam needs to be as stable as possible.

The data was taken in the owl shift of December 14/2017.

General comments: the different currents were taken as long as the beam didn't trip.