Difference between revisions of "Fall 2016 LHRS optic plans"
From Hall A Wiki
(→Step L2: Delta Scan with Proton Elastic (without sieve slit)) |
(→Step L2: Delta Scan with Proton Elastic (without sieve slit)) |
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| − | ==== Step L2: Delta Scan with Proton Elastic ( | + | ==== Step L2: Delta Scan with Proton Elastic (with sieve slit)==== |
* Time estimate: 3-4 hours | * Time estimate: 3-4 hours | ||
| − | * | + | * Keep the 1-inch tungsten sieve-slit collimator on the front face of the left HRS. |
* Take runs with the 15 cm liquid hydrogen target for the elastic kinematics in the table. | * Take runs with the 15 cm liquid hydrogen target for the elastic kinematics in the table. | ||
| − | * | + | * Wait until the left 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. | * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. | ||
* Rate estimates only include elastic electrons and does not include rate from inelastic events or from the target endcaps. | * Rate estimates only include elastic electrons and does not include rate from inelastic events or from the target endcaps. | ||
| − | * The Q<sup>2</sup> for these settings is | + | * The Q<sup>2</sup> for these settings is 0.41 GeV<sup>2</sup>. |
<table border="1" style="width:80%"> | <table border="1" style="width:80%"> | ||
Revision as of 18:03, 8 October 2016
Contents
Step L1: Procedure with Sieve-slit
- Time estimate: 1 hour
* Trained personnel will be required to install the 1-inch tungsten sieve-slit collimator onto the front face of the HRS. * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. * Take sieve-slit runs with the multi-foil carbon target (optics) for the inelastic kinematics in the table. * Electron rates assume 9 carbon foils, only 37 out of 155 sieve holes per foil have events (~ 0.41 mSr acceptance), and 8% delta acceptance. * Electron rates assume 15 cm LH2 target, only 45 out of 155 sieve holes have events (~ 0.49 mSr acceptance), and 8% delta acceptance. * Adjust the prescale factors to keep the DAQ deadtime below 10%. * Before moving on to the next target, a GMp expert will determine online how many good electron events have been collected.
| Target | Ebeam [GeV] | P0 [GeV/c] | Raster | θe [deg] | Q2 [GeV2] | W [GeV] | Rate [Hz] at 60 μA | minutes at 60 μA | Good Electrons |
| Optics | 2.217 | 1.0 | Off | 17.5 | 0.20 | 1.72 | 540 | 32 | 1M events |
| 15 cm LH2 | 2.217 | 1.0 | 3x3 mm2 | 17.5 | 0.20 | 1.72 | 4600 | 10.0 | 2.7M events |
Step L2: Delta Scan with Proton Elastic (with sieve slit)
- Time estimate: 3-4 hours
* Keep the 1-inch tungsten sieve-slit collimator on the front face of the left HRS. * Take runs with the 15 cm liquid hydrogen target for the elastic kinematics in the table. * Wait until the left 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. * Rate estimates only include elastic electrons and does not include rate from inelastic events or from the target endcaps. * The Q2 for these settings is 0.41 GeV2.
| Ebeam (GeV) | k' (GeV) | Raster | θe (deg) | ΔP (%) | Rate [Hz] at 10 μA | minutes at 10 μA | Good Electrons |
| 2.217 | 2.078 | 3x3 mm2 | 17.5 | -4 | 650 | 10 | 390k events |
| 2.217 | 2.038 | 3x3 mm2 | 17.5 | -2 | 650 | 10 | 390k events |
| 2.217 | 1.998 | 3x3 mm2 | 17.5 | 0 | 650 | 20 | 780k events |
| 2.217 | 1.958 | 3x3 mm2 | 17.5 | +2 | 650 | 10 | 390k events |
| 2.217 | 1.918 | 3x3 mm2 | 17.5 | +4 | 650 | 10 | 390k events |
Step L3: Dummy Target Runs
- Go back to the ΔP = 0% elastic setting. Make sure the L-HRS P0 = 1.228 GeV.
- Move the target to "15 cm Dummy"
- Take R-HRS run with same setting as previous step.
- Take data with this setting for 1 hour
| Ebeam (GeV) | k' (GeV) | Raster | θe (deg) | ΔP (%) | Rate [Hz] at 40 μA | hours at 40 μA | Good Electrons |
| 2.217 | 1.228 | 3x3 mm2 | 17.5 | 0 | 19.5 | 1 | 70k events |
Step L4: Procedure without Sieve-slit
- Time estimate: 1 hour
* Take a run at the following kinematics without the sieve-slit collimator. * If you need to increase the spectrometer momentum setting, make sure you cycle Q2 and Q3 as per the cycling procedure. * Electron rates assume 9 carbon foils or 1 single carbon foil, 5 mSr acceptance, and 8% delta acceptance. * A GMp expert will check the data quality.
| Target | Ebeam [GeV] | P0 [GeV/c] | Right Q1 Current [A] | θe [deg] | Q2 [GeV2] | W [GeV] | Rate [Hz] at 60 μA | minutes at 60 μA | Good Electrons |
| Optics | 2.217 | 1.0 | 173.808 | 17.5 | 1.51 | 1.287 | 250 | 15 | 220k events |
| Single Carbon | 2.217 | 1.0 | 173.808 | 17.5 | 1.51 | 1.287 | 56 | 15 | 50k events |
