Difference between revisions of "Spectrometer Optics"
From Hall A Wiki
(→Delta Scan with Hydrogen Elastic) |
(→Elastic from Hydrogen) |
||
| Line 132: | Line 132: | ||
<td>Q<SUP>2</SUP> (GeV<SUP>2</SUP>)</td> | <td>Q<SUP>2</SUP> (GeV<SUP>2</SUP>)</td> | ||
<td> Rate [Hz] at 20 μA</td> | <td> Rate [Hz] at 20 μA</td> | ||
| − | <td> minutes for | + | <td> minutes for 20.6k events at 20 μA</td> |
</tr> | </tr> | ||
<tr> | <tr> | ||
| − | <td> | + | <td>3.8</td> |
| − | <td> | + | <td>2.29832</td> |
<td>33.0</td> | <td>33.0</td> | ||
| − | <td> | + | <td>2.82</td> |
| − | <td> | + | <td>6</td> |
| − | <td> | + | <td>60</td> |
</tr> | </tr> | ||
</table> | </table> | ||
Revision as of 15:12, 10 February 2015
Contents
Procedure without Sieve-slit
- Time estimate: 4 hours
* Take a run at the following kinematics without the sieve-slit collimator on the multi-foil optics target. * 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, 6 mSr acceptance, and 9% 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 300k events at 20 μA |
| 3.8 | 1.002 | 33.0 | 1.23 | 2.214 | 316 | 16 |
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 90k events at 20 μA |
| 3.8 | 1.002 | 33.0 | 1.23 | 2.214 | 17 | 90 |
Delta Scan with Hydrogen 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 10k events at 20 μA |
| 3.8 | 2.39025 | 33.0 | -4 | 6 | 30 |
| 3.8 | 2.34429 | 33.0 | -2 | 6 | 30 |
| 3.8 | 2.29832 | 33.0 | 0 | 6 | 30 |
| 3.8 | 2.25235 | 33.0 | +2 | 6 | 30 |
| 3.8 | 2.20639 | 33.0 | +4 | 6 | 30 |
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 20.6k events at 20 μA |
| 3.8 | 2.29832 | 33.0 | 2.82 | 6 | 60 |
