Spectrometer Optics First pass 48p75d
From Hall A Wiki
If you have questions call Vince Sulkosky or Kalyan Allada, Numbers are on white board
Integration with LHRS plan
|LHRS step||RHRS step||Approximate beam time||Goals||Status|
|L1 (sieve)||R1 (sieve)||3h||60 uA DIS with sieve slit on optics foils and LH2|
|L2 (sieve)||1-2h||Elastic Delta Scan on LH2, 10 uA||Completed|
|R2 (no sieve)||3-4h||Elastic Delta Scan on LH2, 60 uA||Completed|
|L3 (sieve)||R3 (no sieve)||1h||Elastic dummy|
|L4 (no sieve)||R4 (no sieve)||1h|| LHRS: elastic LH2, 60 uA
RHRS: DIS on single carbon and optics, 60 uA
Step R1: Procedure with Sieve-slit
- Time estimate: 3 hours
* 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. * 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]||RQ1||Raster||θe [deg]||Q2 [GeV2]||W [GeV]||Rate [Hz] at 60 μA||hours at 60 μA||Good Electrons|
|15 cm LH2||2.217||1.0||200.41||2 x 2 mm2||48.75||1.51||1.287||40.0||1.0||144k events|
Step R2: Delta Scan with Proton Elastic (without sieve slit)
- Time estimate: 3-4 hours
* Trained personnel will be required to remove the 1-inch tungsten sieve-slit collimator from the front face of the HRS. * Take runs with the 15 cm liquid hydrogen target for the elastic kinematics in the table. * There will be about a 40 minute 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 1.86 GeV2.
|Ebeam (GeV)||k' (GeV)||RQ1||Raster||θe (deg)||ΔP (%)||Rate [Hz] at 60 μA||minutes at 60 μA||Good Electrons|
|2.217||1.277||255.93||2 x 2 mm2||48.75||-4||650||10||390k events|
|2.217||1.253||251.11||2 x 2 mm2||48.75||-2||650||10||390k events|
|2.217||1.228||246.10||2 x 2 mm2||48.75||0||650||20||780k events|
|2.217||1.204||241.29||2 x 2 mm2||48.75||+2||650||10||390k events|
|2.217||1.179||236.28||2 x 2 mm2||48.75||+4||650||10||390k events|
Step R3: Dummy Target Runs
- Go back to the ΔP = 0% elastic setting. Make sure the R-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)||RQ1||Raster||θe (deg)||ΔP (%)||Rate [Hz] at 40 μA||hours at 40 μA||Good Electrons|
|2.217||1.228||246.10||2 x 2 mm2||48.75||0||19.5||1||70k events|
Step R4: 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|
|Single Carbon||2.217||1.0||200.41||48.75||1.51||1.287||56||15||50k events|