Difference between revisions of "BCM calibration (d2n)"
From Hall A Wiki
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* <math>\sigma_b = 0.0104</math> | * <math>\sigma_b = 0.0104</math> | ||
| − | Combining these equations gives the overall real current from the BCM readings: | + | Combining these equations gives the overall real current (in <math>\mu</math>A) from the BCM readings: |
<math>\mu</math> = 48.24 * BCM1 + 0.0987 | <math>\mu</math> = 48.24 * BCM1 + 0.0987 | ||
Revision as of 18:17, 7 December 2009
Contents
Strategy
- Use special run to calibrate OL02 cavity against Faraday cup
- Calibrate EPICS bcm variable by calibrating BCMs against OL02
- Calibrate BB/LHRS scalers against OL02
Key for BcmLog files
Column headings for BCM log file (from Vince via Kalyan):
- Entry #
- BCM 1 voltage (upstream BCM)
- BCM 2 voltage (downstream BCM)
- Unser (not used)
- Faraday Cup (if extracted = 0)
- 0L02 (injector reading)
- 0R07 (not used)
Results for BCM calibration
Using scripts in Diana's ifarm account, /u/home/dseymour/d2n_analysis/bcm_calibration
From MakeBCMPlotHists, calibrating BCM1 & 2 to OLO2 for each current set point:
BCM1 = 0.020673 * OLO2 - 0.001692
- <math>\sigma_m = 0.000035</math>
- <math>\sigma_b = 0.000243</math>
BCM2 = 0.020990 * OLO2 - 0.001710
- <math>\sigma_m = 0.000037</math>
- <math>\sigma_b = 0.000276</math>
From MakeBCMPlotError, calibrating OLO2 to Faraday cup from linear fit to entire run (minus 12 outlier points). Data points given arbitrary error bars of 0.1 in x and y.
FARA = 0.9971 * OLO2 + 0.0171
- <math>\sigma_m = 0.0003</math>
- <math>\sigma_b = 0.0104</math>
Combining these equations gives the overall real current (in <math>\mu</math>A) from the BCM readings:
<math>\mu</math> = 48.24 * BCM1 + 0.0987
- <math>\sigma_m = 0.0829</math>
- <math>\sigma_b = 0.0157</math>
<math>\mu</math> = 47.51 * BCM2 + 0.0983
- <math>\sigma_m = 0.0849</math>
- <math>\sigma_b = 0.0167</math>
Results for Beam Charge calibration
yet to be done
Relevant HALOG entries
- Feb 17 BCM cal data:
Useful Documents
- Explanatory page from PVDIS experiment
- Vince Sulkosky's tech note
- Mark Jones's tech note: Media:Jones_bcm.pdf
