Privacy and Security Notice
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.
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Beam Energy
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4.045 GeV
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Beam position
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< .25 for x and y for 3A and
3B
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Raster size
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1.5x1.5mm
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Beam Current
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» 7-14mA.
Set current to give maximum data rate with deadtime <
60%.
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Target
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15cm Deuterium
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Spectrometer settings
| Spectrometer |
Momentum |
Angle |
Collimator |
| Electron |
3.459 GeV |
16.12° |
6msr |
|
|
|
|
| Proton |
1.202 GeV |
53.06° |
6msr |
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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.
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Data taking
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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.