Difference between revisions of "Spectrometer Optics 1pass"
From Hall A Wiki
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* Start with initial right HRS spectrometer tune with the SOS quad in place of right Q1. | * Start with initial right HRS spectrometer tune with the SOS quad in place of right Q1. | ||
* If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. | * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. | ||
| − | * Rates assume 5 carbon foils, | + | * Rates assume 5 carbon foils, 5 mSr acceptance, and 8% delta acceptance. |
* <b>A GMp expert will check the data quality and decide, if the right HRS tune needs to be adjusted to change the size of the acceptance.</b> | * <b>A GMp expert will check the data quality and decide, if the right HRS tune needs to be adjusted to change the size of the acceptance.</b> | ||
* This process will be repeated until the spectrometer tune is satisfactory.<br> | * This process will be repeated until the spectrometer tune is satisfactory.<br> | ||
Revision as of 10:59, 17 March 2015
Contents
Procedure without Sieve-slit
- Time estimate: 4 hours
* Take a run at the following kinematics without the sieve-slit collimator. * Start with initial right HRS spectrometer tune with the SOS quad in place of right Q1. * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. * Rates assume 5 carbon foils, 5 mSr acceptance, and 8% delta acceptance. * A GMp expert will check the data quality and decide, if the right HRS tune needs to be adjusted to change the size of the acceptance. * This process will be repeated until the spectrometer tune is satisfactory.
| Ebeam [GeV] | P0 [GeV/c] | θe [deg] | Q2 [GeV2] | W [GeV] | Rate [Hz] at 20 μA | minutes for 745k events at 20 μA |
| 2.0 | 0.95 | 33.0 | 0.61 | 1.496 | 1240 | 10 |
Procedure with Sieve-slit
- Time estimate: 1-2 hours
* Trained personnel will be required to install the 1-inch lead sieve-slit collimator onto the front face of the HRS. * Take a sieve slit run with the multi-foil carbon target for the inelastic kinematics in the table. * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. * Repeat the above with the beam position shifted so that you see a vertical shift by one row. * Rates assume 5 carbon foils, only 25 out of 63 sieve holes have events (~ 0.265 mSr acceptance), and 9% delta acceptance. * Note: if the right HRS minimum angle is 35 degrees instead of 33 degrees, then the rate will be ~ 50 Hz instead.
| Ebeam [GeV] | P0 [GeV/c] | θe [deg] | Q2 [GeV2] | W [GeV] | Rate [Hz] at 20 μA | minutes for 100k events at 20 μA |
| 2.0 | 0.95 | 33.0 | 0.61 | 1.496 | 66 | 25 |
Delta Scan with Hydrogen Elastic
- Time estimate: 1-2 hours
* Trained personnel will be required to remove the 1-inch lead sieve-slit collimator onto the front face of the HRS. * Take a run with the 15 cm liquid hydrogen target for the elastic kinematics in the table. * There will be a time lapse between settings until the right dipole reaches the desired momentum and is stable. * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure.
| Ebeam (GeV) | k' (GeV) | θe (deg) | ΔP (%) | Rate [Hz] at 20 μA | minutes for 10k events at 20 μA |
| 2.0 | 1.5478 | 33.0 | -4 | 12 | 14 |
| 2.0 | 1.518 | 33.0 | -2 | 12 | 14 |
| 2.0 | 1.4882 | 33.0 | 0 | 12 | 14 |
| 2.0 | 1.4585 | 33.0 | +2 | 12 | 14 |
| 2.0 | 1.4287 | 33.0 | +4 | 12 | 14 |
Elastic from Hydrogen
- Time estimate: 1-2 hours
* If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. * Elastic electron-proton measurement. Assuming a 15 cm LH2 target, a spectrometer acceptance of 5 msr and elastic from Eric's rate program
to compute the cross-section.
| Ebeam (GeV) | k' (GeV) | θe (deg) | Q2 (GeV2) | Rate [Hz] at 20 μA | minutes for 40k events at 20 μA |
| 2.0 | 1.488 | 33.0 | 0.96 | 12 | 55 |
