Spectrometer Optics 2pass
From Hall A Wiki
H | 10μA | 20μA | 30μA | 40μA | 50μA | 60μA |
Run No. |
Procedure without Sieve-slit
- Time estimate: 2 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. * Electron 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 5 μA | minutes for 23k events at 5 μA |
2.0 | 0.75 | 52.5 | 1.17 | 1.433 | 15.5 | 25 |
We want to take runs with the following Q1 currents:
- 0%: 159.75 A
- -6%: 150.165 A
- -5%: 151.7625 A
- -4%: 153.36 A
- -3%: 154.9575 A μA
- +5%: 167.7375 A
Procedure with Sieve-slit
- Time estimate: 34 hours
* Trained personnel will be required to install the 1-inch tungsten 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 8% delta acceptance.
Ebeam [GeV] | P0 [GeV/c] | θe [deg] | Q2 [GeV2] | W [GeV] | Rate [Hz] at 5 μA | hours for 100k events at 5 μA |
2.0 | 0.75 | 52.5 | 1.17 | 1.443 | 0.8 | 34 |
We want to take a full statistics run at a Q1 current setting -5%(151.7625 A).
We want to take short runs with the following Q1 currents:
- +5%: 167.7375 A
- Off: 0 A
Delta Scan with Proton Elastic
- Time estimate: 2-3 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 145k events at 20 μA |
2.0 | 1.134 | 52.5 | -4 | 243 | 10 |
2.0 | 1.112 | 52.5 | -2 | 243 | 10 |
2.0 | 1.091 | 52.5 | 0 | 243 | 10 |
2.0 | 1.069 | 52.5 | +2 | 243 | 10 |
2.0 | 1.047 | 52.5 | +4 | 243 | 10 |
For each ΔP (%) setting, we want to take 3 runs with different Q1 currents:
For ΔP = -4%, we want the following Q1 currents:
- -5%: 229.4649 A
- +5%: 253.6191 A
- TBD
For ΔP = -2%, we want the following Q1 currents:
- -5%: 225.0132 A
- +5%: 248.6988 A
- TBD
For ΔP = 0%, we want the following Q1 currents:
- -5%: 220.76385 A
- +5%: 244.00215 A
- TBD
For ΔP = +2%, we want the following Q1 currents:
- -5%: 216.31215 A
- +5%: 239.08185 A
- TBD
For ΔP = +4%, we want the following Q1 currents:
- -5%: 211.86045 A
- +5%: 234.16155 A
- TBD