Luminosity Monitoring For PrimEx Dan Dale PrimEx Collaboration Meeting December 16, 2006.

Luminosity Monitoring For PrimEx

Dan DalePrimEx Collaboration Meeting

December 16, 2006

Conclusion 1: What we have nowLuminosity Error Budget

________________________________________effect error(%)Uncorrected leakage current 0.5 (1.4%/3) TAC statistics 0.2 (0.5 per T channel)Electron counting systematics 0.8 (clock versus out of time)Electron counting statistics negligibleTAC reproducibility 0.4HYCAL collimation of TAC 0.25 (worst case, no photon collimator)Beam position/collimator effect 0.2Absorption in TAC runs not yet evaluated_______________________________________________________________

1.1%

Beam leakage from other Halls

If not corrected: ~1.4% effect on 1/3 of runs = 0.5% error

TAC Statistics

• +- 0.5% per T channel

• If we combine all 0.2%

Electron Counting Systematics

0.8% discrepancy between CLOCK and OUT-OF-TIME methods

Electron Counting Statistics

Negligible.

Dependence of Tagging Ratios on Beam Intensity

Dependence of Tagging Ratios on Beam Intensity

Effect of Photon Beam Collimator

Effect of Photon Beam Collimator

Effect of Collimator Position on Tagging Ratios

Effect of Collimator Position on Tagging Ratios

Effect of Beam Missteering on Tagging Ratios

Run 4338: centeredRun 4340: 5mm upRun 4341: 5.7 mm X 0.22mm YRun 4342: 8.62 X Run 4343: 6 mm X

Short Term Stability of Tagging Ratios – Consecutive Runs

Short Term Stability of Tagging Ratios – Consecutive Runs

Long Term Stability of Tagging Ratios

Long Term Stability of Tagging Ratios

Dependence of Relative Tagging Ratios on Rate

Conclusion 2: What we can ultimately do.

Luminosity Error Budget________________________________________effect error(%)Corrected leakage current 0.3 (1.4%/3/2) TAC statistics 0.2 (0.5 per T channel)electron counting systematics 0.8 (clock versus out of time)Electron counting statistics negligibleTAC reproducibility 0.4HYCAL collimation of TAC 0.25 (worst case, no photon collimator)Beam position/collimator effect 0.2Absorption in TAC runs not yet evaluated_______________________________________________________________

1.0%