BCM calibration E06007
Wiki Entry
https://hallaweb.jlab.org/wiki/index.php/BCM_calibration_E04-018
PVDIS entry
http://hallaweb.jlab.org/experiment/E08-011/documents/bcm/AboutBCMcalibrations.html
BCM LOGS
http://hallaweb.jlab.org/experiment/E08-011/documents/bcm/bcmLogs
Previous SCALERS CALIBRATION used in end of run information
http://www.jlab.org/~adaq/halog/html/0705_archive/070530235058.html
I-scan runs in E06007 http://spreadsheets.google.com/ccc?key=0AomwfAy24yA3dEpFQ3k0QnhUQzJ2VEFKei0xaVdIY1E&hl=en
Carbon (1179-1183) | Pb (1184-1188) | Bi (1349-1354) | |||
---|---|---|---|---|---|
I (µA) | T1 / T3 (Hz) | I (µA) | T1 / T3 (Hz) | I (µA) | T1 / T3 (Hz) |
5.3 | 256 / 243 | 4.9 | 1.64k / 605 | 1.0 | 192 / 202 |
10 | 443 / 414 | 9.1 | 3.11k / 1.14k | 2.1 | 420 / 420 |
21 | 884 / 826 | 19.5 | 6.64k / 2.43k | 5 | 1.1k / 1.0k |
40 | 1.77k / 1.65k | 39.2 | 13.4k / 4.91k | 10 | 2.0k / 2.0k |
53 | 2.24k / 2.08k | 42.8 | 14.7k / 5.40k | 25 | 4.9k / 4.0k |
40 | 8.0k / 7.2k |
Steps for BCM calibration
The Run faraday cup vs I0L02 is in [BcmLog125]
Faraday vs Injector current - From BCMLOg-125 - 20Feb07
Faraday_Current = (0.28+-0.03) + (0.994+-0.001) * IBC0L02_Current
Faraday / Injector = 1.0027 +- 0.0006 , for Current >5uA
Ratio Faraday vs I0L02 (All range) | Ratio Faraday vs I0L02 (Current > 5uA) | |
---|---|---|
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Check of the Average Beam Current used in E06007 -- Only initial optics calibration runs used low currents -
A complete list of run information can be found in the link in the initial page: https://hallaweb.jlab.org/wiki/index.php/E06-007
EPICS calibration from bcmlog-127 (Offsets without current in Hall from bcmlog-125)
Note that the constants differ significantly from the ones used in the Start of Run info. The values obtained in CSR are: 43.399±0.558 and 42.913±0.358, which are similar (within error bars) to the ones obtained here.
Upstream | Downstream | |
---|---|---|
Offset | 0.0009191 +/- 1e-07 | 0.00028730 +/- 5e-08 |
Constant | 43.16 +/- 0.05 | 42.45 +/- 0.06 |
Constant (I>5uA) | 43.25 +/- 0.02 | 42.60 +/- 0.02 |
Constant in Start of Run | 45.218 | 45.532 |
Start of Run info: Upstream Cavity Coefficient : 45.218 Downstream Cavity Coefficient : 45.532
Production Runs without Current in Hall C --> Run 1326, 1327, 1328 (Bi,80uA)
Sample of Cosmics Runs for Scalers Offset along the experiment--> Run 1335, 1488, 1752, 2006
They can be used to check offset variations as showed in Vince's Tech note.
http://hallaweb.jlab.org/experiment/E97-110/tech/bcm_info.pdf
--> "hac_bcm_average hac_bcm_dvm1_read hac_bcm_dvm2_read hac_bcm_dvm1_current hac_bcm_dvm2_current hac_unser_current IPM2C24A.IENG IBC0R07CRCUR1 IBC1H04CRCUR2 FCupsCORRECTED.VAL EHAR_LIXWidth EHAR_LIYWidth EHAR_ENABLE EHAR_IXPEAK EHAR_IYPEAK"
--> hac_bcm_average = 0.5*(hac_bcm_dvm1_current + hac_bcm_dvm2_current) [dvm1-->upstream, dvm2-->downstream]
--> hac_bcm_dvm1_current = (hac_bcm_dvm1_read - offset)*Calibration_constant
Instead of hac_bcm_average (that uses the uncalibrated end of run constant), using hac_bcm_dvm(1,2)_read and the calibrated constant from bcmlog_127 a value closer to the Injector Current IOLO2 is obtained:
The ratio can be also obtained for each BCM. It can be seen that the upstream seems to perform better. Nevertheless the range around 40uA (where most of the production data were acquired) is very close to 1.0.
BCM Scalers offset calibration from Run 1335 (Without Current).
METHOD 1: Linear fit from the plot of number of counts vs time: T->Draw("left_bcmd10cnt:left_clkcount/1024","abs(IBCxxxxCRCUR1)<1");
METHOD 2: Average of counts (Fit with zeroth order pol.) T->Draw("left_bcm_d10:left_clkcount/1024","abs(IBCxxxxCRCUR1)<1");
Scaler | Offset (Hz) LINEAR FIT | Offset (Hz) AVERAGE |
---|---|---|
u1 | 352.913 | 353.959 |
u3 | 448.114 | 449.124 |
u10 | 768.792 | 769.504 |
d1 | 160.086 | 161.289 |
d3 | 131.773 | 133.073 |
d10 | 325.993 | 326.945 |
BCM Scalers Calibration from I-scan runs (1179-1188) I obtained it from a macro that I have created. It can be found at:
http://jlab.org/~juaky/scaler_calib.C
Current | U1 | U3 | U10 | D1 | D3 | D10 |
---|---|---|---|---|---|---|
5.62 | 2368.87 | 7288.25 | 28010.50 | 2333.33 | 7233.49 | 22848.08 |
9.77 | 2367.87 | 7284.67 | 26507.30 | 2337.04 | 7242.17 | 22877.50 |
19.91 | 2366.45 | 7279.48 | 25761.77 | 2337.90 | 7242.01 | 22879.11 |
40.26 | 2366.19 | 7277.08 | 26787.56 | 2339.68 | 7244.73 | 22740.94 |
4.86 | 2369.84 | 7291.41 | 28384.30 | 2336.07 | 7242.90 | 22877.60 |
19.83 | 2367.49 | 7282.48 | 26275.95 | 2338.95 | 7245.49 | 22890.23 |
39.94 | 2365.37 | 7274.34 | 25031.78 | 2341.17 | 7249.47 | 22782.08 |
50.36 | 2365.30 | 7273.11 | 22919.79 | 2341.55 | 7249.50 | 20712.17 |
MEAN = | 2367.17 | 7281.35 | 26209.87 | 2338.21 | 7243.72 | 22575.96 |
ERROR = | 0.58 | 2.31 | 609.60 | 0.97 | 1.80 | 266.93 |
In the CSR, the constant obtained for U3 was: 7294 +- 7 , so compared to our 7281 +- 2 there is a good agreement.
http://www.jlab.org/%7Exyan/CSR/Meeting/BcmCalib.pdf
In order to get the charge from a file:
Q = (scaler_bcm - offset(Hz) * time(s) ) / calib_constant
Q(C) = 1e-6 *( right_bcmu3cnt - 449.124 * (right_clkcount/1024) ) / 7281.35