bcm calibration

BCM calibration results 01/26/05

Numbers from N.Fomin - global fit 11.23.4
http://hallcweb.jlab.org/xmptlog/0412_archive/041203162113.html
Runs 50180,50288,50306,50442,50536,50611,50734,50905,50980,51068,51237,51334,51438,51574,51691,51817
gbcm1_gain = 0.00032889              ; microA/Hz
gbcm2_gain = 0.00038301              ; microA/Hz
gbcm1_offset = 250507.              ; Hz
gbcm2_offset = 250517.              ; Hz

Numbers from Dec 04 (this work)
gbcm1_gain = 0.00032385              ; microA/Hz
gbcm2_gain = 0.00037682              ; microA/Hz
gbcm1_offset = 248515.              ; Hz
gbcm2_offset = 248614.              ; Hz

Sept 07, 2004. Dave Gaskell changed the gain settings on BCM 1 and 2.
http://hallcweb.jlab.org/hclog/0409_archive/040907160808.html

Numbers from D. Mack - global fit for summer 04
http://hallcweb.jlab.org/hclog/0407_archive/040726132942.html
gbcm1_gain = 0.00108747              ; microA/Hz
gbcm2_gain = 0.00126986              ; microA/Hz
gbcm1_offset = 250250.               ; Hz
gbcm2_offset = 250163.               ; Hz

Numbers from D. Mack, 6.22.4
gbcm1_gain = 0.00108902              ; microA/Hz
gbcm2_gain = 0.00127300              ; microA/Hz
gbcm1_offset = 250346.              ; Hz
gbcm2_offset = 250258.              ; Hz

BCM calibration 01/11/05

Dave Mack walked me through the procedure of calibrating the BCM's. The results for run52368 are shown below.

The output from the calibration script was run52368.cal, and the gscalers file was updated (gscalers.param.52368). Note, these calibrations coefficients are very different to the July running period (gscalers.param.49955).

Here is my attempt at some instructions.

1) Move Dave Mack's physica script, bcmcal_summer04.pcm, to a convenient directory. Note- physica, which is required later, seems to work better on jlabs1 rather than on the ifarm Linux machines. You should make the directory accessible from jlabs1. Also, we experienced some problems in copying this file as an attachment. It can be copied directly from ~clasie/work/replay/BCM/bcmcal_summer04.pcm.
2) Replay the BCM run and move the scalers/charge#.txt to the same directory.
3) ssh to jlabs1, move to the directory with the physica script and charge#.txt, and type in "setup physica"
4) physica
5) exe bcmcal_summer04.pcm
6) 52368 (ie. the run number) NB. after this a plot will be shown with the beam off and on periods
7) return
8) Use the mouse and hover it over the furthest beam off position to the left. Press r (for record).
9) Without pressing any mouse buttons, move the mouse to the right, along the first beam off interval, and hit r again.
10) Repeat 8) and 9) with all of the other beam off intervals. When you are done, keep the mouse inside the window and press q. NB there will be two points per interval.
11) Next, do the same with all of the stable beam on periods.
12) After pressing q in step 11, it will ask you if you would like I=0 removed from the fit. Press enter.
13) Hit enter again to fit the offset.
14) A plot of the unser residuals will be shown. Press enter again.
15) A plot of the BCM residuals will be shown. Press enter again.
16) The original BCM plot will be shown. Press enter again.
17) A plot of the calibrated currents will be shown. The BCM current should overlap the unser current. Press enter again.
18) At "see the plots again", press n. This will write the output file run52368.cal and the physica script will end.
19) exit. This will end physica. A compete text copy of the physica session can be found here.
20) Copy the calibration constants in the output file run52368.cal
            gain factors for three cavity monitors
          gbcm1_gain = 0.00032385              ; microA/Hz
            gbcm2_gain = 0.00037682              ; microA/Hz
            gunser_gain = 0.00024980              ; microA/Hz
            zero offsets for BCM s
            gbcm1_offset = 248515.              ; Hz
            gbcm2_offset = 248614.              ; Hz
            gunser_offset = 513902.              ; Hz
to the file PARAM/online04/gscalers.param. Make sure to comment out the old calibration constants and the information text "gain factors for the three cavity monitors" and "zero offsets for BCM s".