Main INDEX
Monthly INDEX
PREV
NEXT
#### User name M Jones

#### Log entry time 12:35:11 on February15,2002

#### Entry number 82797

#### This entry is a followup to: 82781

keyword=revised estimate of calibration time for Ac measurement

revised estimate of calibration time for Ac measurement

----------------------------------------

Bogdan pointed out that the beam energy was wrong.

Assume

current = 100uA

beam helicity = .75

beam energy = 3.481

Q^2 = 4.13

Combined efficiency of carbon and CH2 = 0.55

Effective analyzing power of carbon and CH2 = 0.09

The expected focal plane Px = -0.05779 Py = -0.01500

The sqrt(2/N/eff) = 0.00068 in 24 hours of running. The would give

about a 2% error since extracting Ac depends mainly on Px.

The N is calculated from rate of 92 Hz for proton assuming that the

calorimeter is position to match the hadron HRS acceptance.

At these kinematics the ratio is 5.6 . The rate ignores radiation correction,

deadtime and tracking efficiency so to be conservative the rate probably

should be lower by 60%. Using that the error would go up to 2.6%.

Please double check the results.