1. Luminosity Monitoring For PrimEx Dan Dale PrimEx Collaboration Meeting February 23, 2007

2. E.P. point 14 “Electron counting systematics listed as 0.8%. How did you get this number?” Electron Counting Systematics 0.8% discrepancy between CLOCK and OUT-OF-TIME methods

3. E.P. point 15 “You discuss in the Appendix effects of beam intensity instabilities on rate sampling. You don’t quantify this effect and do not include in final error” 0.8% discrepancy between CLOCK and OUT-OF-TIME methods CLOCK trigger sampling used -> insensitive to beam instabilities

4. Point 11:Clock frequency, window width N e = n e / (W x n trigs ) Live 1 Clock frequency = 195.3125 +-0.020 kHz W = 7 microseconds – integral linearity < 25 ppm differential linearity 100 psec

5. DS point: Different PS dipole settings--run 4339 collimator 0.1 “ off

6. Effect of Collimator Position on Tagging Ratios

7. Effect of Collimator Position on Tagging Ratios – units are inches

8. TAC losses 0.1% interact in vacuum window & Helium – overwhelmingly pair production

9. Point 13: “Section 25 all numbers in two tables identical except last one. Something is not right” Luminosity Error Budget ________________________________________ effect error(%) Uncorrected leakage current0.5 (1.4%/3) TAC statistics0.2 (0.5 per T channel) Electron counting systematics0.8 (clock versus out of time) Electron counting statisticsnegligible TAC reproducibility0.4 HYCAL collimation of TAC 0.25 (worst case, no photon collimator) Beam position/collimator effect0.2 Absorption in TAC runsnot yet evaluated _______________________________________________________________ 1.1%

10. What we can ultimately do. Luminosity Error Budget ________________________________________ effect error(%) Corrected leakage current0.3 (1.4%/3/2) TAC statistics0.2 (0.5 per T channel) electron counting systematics0.8 (clock versus out of time) Electron counting statistics negligible TAC reproducibility0.4 HYCAL collimation of TAC 0.25 (worst case, no photon collimator) Beam position/collimator effect0.2 Absorption in TAC runsnot yet evaluated _______________________________________________________________ 1.0%

11. Points 1,3: “Please define meaning of T- counter and T channel” Point 2, 16: “In section 4 (2002 run analysis) just T counters used. E-T coincides since implemented. Needs to be written up. Point 5: absolute efficiency of TAC – dedicated run????