[Halla_running] [New Logentry] RC update and plan for swing/owl

[Paul King]

Subject: [New Logentry] RC update and plan for swing/owl

RC update and plan for swing/owl<https://logbooks.jlab.org/entry/3924773>

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Lognumber 3924773<https://logbooks.jlab.org/entry/3924773>. Submitted by pking<https://logbooks.jlab.org/user/pking> on Thu, 10/14/2021 - 19:25<https://logbooks.jlab.org/entries?start_date=1634250328&end_date=1634257528&book=HALOG>.

Last updated on Thu, 10/14/2021 - 19:29

Logbooks:       HALOG<https://logbooks.jlab.org/book/halog>

The accelerator is currently recovering from a cryo trip in the North Linac.

Jack has done the first set of full current tests, and are able to have OPS operate the SBS magnet. The first time we bring SBS up in each configuration, OPS has a procedure to set the correctors to ensure beam transports to the dump. In the RC meeting we had discussed doing the SBS setup at the time we were ready to turn on BigBite, but after talking with Brian, we will delay doing that to try to ensure we get the LH2 running to checkout HCal.

We plan to have an escorted access in the morning to remove the sieve from the spectrometers, assuming we are able to complete the optics running.

Run plan for swing/owl
---------------------------------
1) Start with SBS and BigBite turned off. Establish the beam on the carbon hole with positions (-0.8, 0.4) on both 1H04A and 1H04E, and a raster setting of height=0.8, width=2.0. The limitations were supposed to have been adjusted to let us have this height value, but a height of 0.9 is fine if the adjustment didn't happen. Check spot to verify that the steering is still generally good; I don't think resteering is needed unless the hole is drastically off center. Call Paul or David Flay if needed.

2) Move to the 0.5% carbon target. The swing crew chief indicated that he thought we would not need to do an ion chamber calibraiton. Collect low-current (1 uA) data for straight-through alignment of the GEMs with respect to the BigBite magnet. Use a relatively high threshold on BigBite for this purpose. Run for about an hour, or collect about 5M events.

3) Turn BigBite on at 750A : https://sbs.jlab.org/wiki/index.php/HOW_TOs#Procedure_for_Ramping_the_Bi...<https://sbs.jlab.org/wiki/index.php/HOW_TOs#Procedure_for_Ramping_the_BigBite_Magnet>

4) Move to the 4-foil optics target. The crew chief thought we would not need to do an ion chamber calibration on this target. Complete the GEM HV tests with 1 uA beam. Time estimate for this was 1.5 hrs. Settings to be specified by experts, but earlier today anticipated settings were:
>> -UVa U-V GEMs: test at 3700 and 3725
>> -UVa X-Y GEM: test all modules at 3700. Decide to go up to 3725 for modules
>> 9-11 -INFN GEMs: J2 middle higher? Do we want to take points at 4100V and 4150V? Will converge on this today.

5) Take approximately 1-2 hours of data on the 4-foil optics target under similar trigger and beam conditions (5uA beam, magnet on, sieve). This may require additional IC calibrations by MCC (I would say not to spend more than an hour on this IC calibration….then 1.5h of data).

6) Take LH2 data with the sieve slit in, for at least 1-2 hours (actual time TBD depending on SBS magnet and HCAL status after day shift). We may want to use a higher threshold and/or beam current closer to the elastic peak for this running.

7) (optional, time permitting) Take a small amount (no more than ~1 hour) of single-foil carbon data with the sieve slit in and magnet on