User name Saha
Log entry time 19:13:09 on October 21,1998
Entry number 3240
keyword=procedure for non-invasive beam current calibration
Topic: Non-invasive Beam Current Calibration in Hall A.
Author: A. Saha
Date: Oct 21, 1998
At present the sequencer calibration code may have some bugs in it that is not fully understood and needs more work if it has to be safely and routinely implemented and understood. In the meantime, we are in the mode of just logging the raw data during the current calibration procedure. At present I have a simple algorithm which calculates the calibration coefficients of the two BCMs with respect to the Unser from the raw data. If there are any problems logging the raw data during the calibration procedure, contact A. Saha (x7605) or Kathy McCormick (x5071) at present.
1. Preliminary Set-Up
2. Procedure for the Hall A operators.
- on HAC, open a new terminal
- type "HAC_hp" or "HAC_xt" on this terminal, this will open the Hall A main Control Screen.
- Select the BCMs screen and click on Beam Charge Monitors. The Hall A Current Monitor screen will open up. This screen should be always left open.
- Click on the "Related Screens" button at the bottom left corner and open up the "BCM logging" screen. The "DVM Data Logging" screen will open up.
- Ask MCC to set up the maximum current they can deliver in Hall A. Accuracy of the calibration will be ~ 30%/Imax(microA) for a 5 cycle calibration. After they are ready, make sure there is no beam delivery to the hall.
- On the "DVM Data Logging" screen, push the "Start Logging" button. Data will then be logged into the file in the HAC computer:
- Start a regular data run. Normally, runcontrol willA be already running on another terminal. Push the button "Start Run" to start a run, and note down the Run Number.
- When ready, ask MCC to start the Hall A BCM non-invasive calibration procedure.
- After 5 complete steps (10 up and down cycles of about 1 minute duration each), ask MCC to stop the procedure.
- On the "DVM Data Logging" screen, push the "Stop Logging" button.
- Stop the regular run by pushing the "End Run" button. Note the Run Number.
- In the HAC computer directory:
copy the file bcm.log to bcm.log.run# in the datalog subdirectory by typing:
hac> cp bcm.log ./datalog/bcm.log."run #"
where you put the actual run number in "run #".
- Make a Hall A log entry stating the run number and the data file name you have logged the calibration run and the parameters of the beam conditions and any other pertinent information.