Difference between revisions of "Spectrometer Optics First pass 48p8d"

Revision as of 10:19, 25 January 2016

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.

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. 

• 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.
* Electron rates assume 200 μm of tungsten, only for the central hole of the sieve slit (~ 0.023 mSr acceptance), and 8% delta acceptance.
* A GMp expert will determine when enough good electron events have been collected.

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.

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

• Move the target to "Dummy"
• Take R-HRS run with same setting as previous step. We need at least 200 K events.