Spectrometer Optics First pass 48p8d

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)	14h	20 uA DIS with sieve slit on optics foils, single carbon and LH2	Completed
L2 (sieve)		3h	Delta Elastic on LH2, 1 uA	In Progress
L3 (no sieve)		3h	Elastic on carbon (Needs A. Camsonne as sieve operator)
L1 (sieve)	R1 (sieve)	4h	20 uA DIS with sieve slit on 4 cm dummy (Needs A. Camsonne as sieve operator)
	R2 (no sieve)	3h	Delta Elastic on LH2, 20 uA
	R3 (no sieve)	1h	Elastic dummy
	R4 (no sieve)	1h	DIS on dummy and optics
L4 (sieve)	R5 (no sieve)	1h	Tungsten wire (Needs D. Mekins as wire operator) (Needs A. Camsonne as sieve operator)

See Left HRS Optics Run Plan

Step R1: 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.
* 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 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]	Raster	θe [deg]	Q2 [GeV2]	W [GeV]	Rate [Hz] at 20 μA	hours at 20 μA	Good Electrons
Optics	2.301	0.75	Off	48.74	1.18	1.617	2.5	10	100k events
Carbon single foil	2.301	0.75	Off	48.74	1.18	1.617	2.2	1.3	10.3k events
15 cm LH2	2.301	0.75	2x2 mm2	48.74	1.18	1.617	20.0	1.3	96k events
4 cm Dummy	2.301	0.75	1x1 mm2	48.74	1.18	1.617	1.8	4	25k 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 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)	Raster	θe (deg)	ΔP (%)	Rate [Hz] at 20 μA	minutes at 20 μA	Good Electrons
2.301	1.304	2x2 mm2	48.74	-4	176	20	210k events
2.301	1.279	2x2 mm2	48.74	-2	176	20	210k events
2.301	1.254	2x2 mm2	48.74	0	176	50	500k events
2.301	1.229	2x2 mm2	48.74	+2	176	20	210k events
2.301	1.203	2x2 mm2	48.74	+4	176	20	210k events

Step R3: Dummy Target Runs

• Go back to the ΔP = 0% elastic setting. Make sure the R-HRS P0 = 1.254 GeV.
• Move the target to "15 cm Dummy"
• Take R-HRS run with same setting as previous step. We need at least 100 k events.
• Take data with this setting for 1 hour

Ebeam (GeV)	k' (GeV)	Raster	θe (deg)	ΔP (%)	Rate [Hz] at 20 μA	hours at 20 μA	Good Electrons
2.301	1.254	2x2 mm2	48.74	0	13.2	1	50k 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 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 at 20 μA	Good Electrons
Optics	2.301	0.75	153.36	48.74	1.18	1.617	70.5	12	50k events
4 cm Dummy	2.301	0.75	153.36	48.74	1.18	1.617	37.4	22	50k events

Step R5: Cross-wire Target Run

• Time estimate: 5 hours (includes access to install wire target and left HRS Sieve-slit)

* After the above runs are completed, ask for the target group (call Dave Meekins) to insert the cross-wire target (we are not allowed to do it).
* Target expert will need to go to the Hall and manually move the target in position, so ask for controlled access before starting this step  
* At the same time have the Techs or A. Camsonne install the left HRS sieve-slit.  The right HRS sieve-slit remains off.
* Take a run with the cross-wire target with 2x2 mm2 rastered beam, and verify that the beam is centered on the cross-wire target using spot++.
* If the beam in not centered, then ask MCC to move the beam until the rastered beam spot is centered on the wires.
* Once beam is centered on the cross-wire target, have MCC turn off the raster.  Make sure the spectrometers still have rates above cosmics by checking 
the scaler rates.
* Take a run with the with raster off for both LHRS and RHRS.
* Electron rates assume 200 μm of tungsten. For LHRS, the rate is 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.

Spectrometer	Target	Sieve Slit	Raster	Ebeam [GeV]	P0 [GeV/c]	θe [deg]	Q2 [GeV2]	W [GeV]	Rate [Hz] at 1 μA	minutes at 1 μA	Good Electrons
Right HRS	200 μm tungsten wire	OUT	Off	2.301	0.75	48.74	1.18	1.617	3.28	30	5.9k events
Left HRS	200 μm tungsten wire	IN	Off	2.301	1.0	16.63	0.19	1.769	1.3	30	2.3k events

• After finishing this step ask for Controlled access and call the target expert to move the wire-target out of the way. Also call Hall-A Tech on-call to remove the R-HRS sieve-slit.