Settings for fpp_scat_3
Measure d(e,ep) quasi-elastic scattering at kinematics for elastic ep at Q2 = 1.1 GeV2. Want to measure instrumental asymmetries to 0.0015 level. Estimated time for measurement is 2.0 hours.
Beam Energy
4.045 GeV
Beam position
< .25 for x and y for 3A and 3B
Raster size
1.5x1.5mm
Beam Current
» 7-14mA. Set current to give maximum data rate with deadtime < 60%.
Target
15cm Deuterium
Spectrometer settings
Spectrometer  Momentum  Angle  Collimator 
Electron  3.459 GeV  16.12°  6msr 
Proton  1.202 GeV  53.06°  6msr
 
Magnet settings
Spectrometer  Dipole  Q1  Q2  Q3 
Electron  1.36131 T  2587.94 A  1481.20 A  1369.49 A 
Proton  0.4434 T  898.511 A  514.260 A  475.574 A
 

The electron quads are all set to negative polarity. The hadron Q1 and Q3 are set to positive polarity, but Q2 is set to negative polarity. For a first guess at current for electron dipole either scale from earlier run or use 909 A/T. Suggest that the electron dipole be set to 10-3 level and then quads scaled to match.

Data taking
The T5 prescale should be one. The prescales for T1,T2,T3 and T4 should be set to give less than 5 Hz trigger rate for each. The T8 prescale should be set to maximum.

The trigger setup should be proton_1170-1700.settings .

Would like about 9x106 coincidence triggers.