Difference between revisions of "Spectrometer Optics 2pass 48p8d"

Revision as of 18:29, 22 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 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.

Procedure with Sieve-slit

• Time estimate: 23+ 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.
* Repeat the above with the beam position shifted so that you see a vertical shift by one row.
* Electron rates assume 5 carbon foils, only 25 out of 63 sieve holes have events (~ 0.265 mSr acceptance), and 8% delta acceptance.

We want to take a full statistics run at a Q1 current setting -4%(153.36 A).

We want to take short runs with the following Q1 currents:

1. +5%: 167.7375 A
2. Off: 0 A

Delta Scan with Proton Elastic

• Time estimate: 3-4 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.
* Rate estimates only include elastic electrons and does not include inelastic rate or rate from the target endcaps. 
* The Q2 for these settings is 1.65 GeV2.

For each ΔP (%) setting, we want to take 3 runs with different Q1 currents:

For ΔP = -4%, we want the following Q1 currents:

1. -5%: 247.6764 A
2. -4%: 250.2835 A
3. +5%: 273.7476 A

For ΔP = -2%, we want the following Q1 currents:

1. -5%: 243.0224 A
2. -4%: 245.5805 A
3. +5%: 268.6037 A

For ΔP = 0%, we want the following Q1 currents:

1. -5%: 238.1660 A
2. -4%: 240.6730 A
3. +5%: 263.2361 A

For ΔP = +2%, we want the following Q1 currents:

1. -5%: 233.5119 A
2. -4%: 235.9699 A
3. +5%: 258.0921 A

For ΔP = +4%, we want the following Q1 currents:

1. -5%: 228.8579 A
2. -4%: 231.2669 A
3. +5%: 252.9482 A

Hall A Gmp Luminosity Scan

Set Left HRS to P = 1.0 GeV, θ= 25, 2mmx2mm raster. Take 10 minute runs with the targets and beam currents listed below. Set prescale factor to keep livetimes approximately constant for each current with a given target.

Proton Elastic Run and Dummy Target Runs

• Go back to the ΔP = 0% elastic setting. Make sure the L-HRS P0 = 1.177 GeV and Q1 current = 240.6730 A (-4%)
• Take data with this setting for 1 hour

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