Luminosity Monitoring For PrimEx

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
  dont quantify this effect and do not include in
  final error

0.8 discrepancy between CLOCK and OUT-OF-TIME
methods CLOCK trigger sampling used -gt
insensitive to beam instabilities
4
Point 11Clock frequency, window width

• Ne ne / (W x ntrigs) Live1
• Clock frequency 195.3125 -0.020 kHz
• W 7 microseconds
• integral linearity lt 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 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 negligible
• TAC reproducibility 0.4
• HYCAL collimation of TAC 0.25 (worst case, no
  photon collimator)
• Beam position/collimator effect 0.2
• Absorption in TAC runs not yet evaluated
• __________________________________________________
  _____________
• 1.1

10
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 negligible
• TAC reproducibility 0.4
• HYCAL collimation of TAC 0.25 (worst case, no
  photon collimator)
• Beam position/collimator effect 0.2
• Absorption in TAC runs not 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????