Difference between revisions of "Spectrometer Optics First pass 48p8d"
From Hall A Wiki
(→Procedure with Sieve-slit) |
(→Procedure with Sieve-slit) |
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* Take a run with the wire target. | * Take a run with the wire target. | ||
* <b>A GMp expert will determine when enough good electron events have been collected.</b> | * <b>A GMp expert will determine when enough good electron events have been collected.</b> | ||
| + | |||
| + | <table border="1" style="width:80%"> | ||
| + | <tr> | ||
| + | <td>Target</td> | ||
| + | <td>E<SUB>beam</SUB> [GeV]</td> | ||
| + | <td>P<sub>0</sub> [GeV/c]</td> | ||
| + | <td>Right Q1 Current [A]</td> | ||
| + | <td>θ<SUB>e</SUB> [deg]</td> | ||
| + | <td>Q<SUP>2</SUP> [GeV<SUP>2</SUP>]</td> | ||
| + | <td>W [GeV]</td> | ||
| + | <td> Rate [Hz] at 20 μA</td> | ||
| + | <td> hours at 20 μA</td> | ||
| + | </tr> | ||
| + | <tr> | ||
| + | <td>200 μm tungsten wire</td> | ||
| + | <td>2.301</td> | ||
| + | <td>0.75</td> | ||
| + | <td>153.36</td> | ||
| + | <td>48.74</td> | ||
| + | <td>1.18</td> | ||
| + | <td>1.617</td> | ||
| + | <td>0.3</td> | ||
| + | <td>1 (for 1k events)</td> | ||
| + | </tr> | ||
| + | </table> | ||
| + | <br> | ||
==== Delta Scan with Proton Elastic ==== | ==== Delta Scan with Proton Elastic ==== | ||
Revision as of 10:16, 25 January 2016
Contents
Procedure without Sieve-slit
- Time estimate: 1 hour
* 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 or 2 Al dummy foils, 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 20 μA | minutes for 50k events at 20 μA |
| Optics | 2.301 | 0.75 | 153.36 | 48.74 | 1.18 | 1.617 | 70.5 | 12 |
| 4 cm Dummy | 2.301 | 0.75 | 153.36 | 48.74 | 1.18 | 1.617 | 37.4 | 22 |
Procedure with Sieve-slit
- Time estimate: 12 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. * Electron rates assume 5 carbon foils, only 37 out of 155 sieve holes per foil have events (~ 0.4 mSr acceptance), and 8% delta acceptance. * Electron rates assume 2 aluminum foils, only 43 out of 155 sieve holes per foil have events (~ 0.47 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. * 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] | Right Q1 Current [A] | θe [deg] | Q2 [GeV2] | W [GeV] | Rate [Hz] at 20 μA | hours at 20 μA |
| Optics | 2.301 | 0.75 | 153.36 | 48.74 | 1.18 | 1.617 | 5.6 | 5 (for 100k events) |
| 4 cm Dummy | 2.301 | 0.75 | 153.36 | 48.74 | 1.18 | 1.617 | 3.5 | 4 (for 50k events) |
| 15 cm LH2 | 2.301 | 0.75 | 153.36 | 48.74 | 1.18 | 1.617 | 20.0 | 1 (for 72k events) |
- Wire Target
* After the above runs are completed, ask for the target group to insert the wire-target (we are not allowed to do it). * Take a run with the wire target. * A GMp expert will determine when enough good electron events have been collected.
| Target | Ebeam [GeV] | P0 [GeV/c] | Right Q1 Current [A] | θe [deg] | Q2 [GeV2] | W [GeV] | Rate [Hz] at 20 μA | hours at 20 μA |
| 200 μm tungsten wire | 2.301 | 0.75 | 153.36 | 48.74 | 1.18 | 1.617 | 0.3 | 1 (for 1k events) |
Delta Scan with Proton Elastic
- Time estimate: 3 hours
* Trained personnel will be required to remove the 1-inch tungsten sieve-slit collimator from 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. * 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 1.96 GeV2.
| Ebeam (GeV) | k' (GeV) | Right Q1 Current [A] | θe (deg) | ΔP (%) | Rate [Hz] at 20 μA | minutes for 220k events at 20 μA |
| 2.301 | 1.304 | 266.64 | 48.74 | -4 | 176 | 21 |
| 2.301 | 1.279 | 261.53 | 48.74 | -2 | 176 | 21 |
| 2.301 | 1.254 | 256.42 | 48.74 | 0 | 176 | 21 |
| 2.301 | 1.229 | 251.3 | 48.74 | +2 | 176 | 21 |
| 2.301 | 1.203 | 245.99 | 48.74 | +4 | 176 | 21 |
Proton Elastic Run and Dummy Target Runs
- Go back to the ΔP = 0% elastic setting. Make sure the R-HRS P0 = 1.254 GeV and Q1 current = 256.42 A.
- Take data with this setting for 1-2 hours
| Ebeam (GeV) | k' (GeV) | θe (deg) | ΔP (%) | Rate [Hz] at 20 μA | minutes for 1M events at 20 μA |
| 2.301 | 1.254 | 48.74 | 0 | 176 | ~ 105 mins |
- Move the target to "Dummy"
- Take R-HRS run with same setting as previous step. We need at least 200 K events.
