[Lad_hallc] [EXTERNAL] Re: Runplan final draft

[Holly Szumila-Vance]

Hi Axel,

Here are the explanations which we will incorporate into the run plan:

- I notice that the GEMs are off for the (e,e') study. Would it be possible to already start the (e,e'p) checkout of with the GEMs and LAD reference bar at the same time as the (e,e') elastics?

We can’t run the GEMs at the rates that would be useful to take data for the spectrometer optics. So it’s crucial they are off. They also will not be in the acceptance of the elastically-scattered proton. So they should remain off until we have an idea of the reference bar timing with protons from SHMS and HMS electron triggers. This shift will be used to adjust the GEM latency which is known to the reference bar using cosmics.

- Your overview plan goes from low-energy (e,e') to low energy (e,e'p) and then to GEM optics. Your detailed plan has GEM optics before LAD timing. I think GEM and LAD timing should happen before optics because it has the GEMs in the forward position, no?

Spectrometer optics is separate. Yes, we need to do the LAD timing before GEM alignment.

- When we move the GEMs from forward angle to their final backward angle position, when will we do a survey? Same for after the SHMS move from 17 to 13.5.?

This will be done at the end of the run.

- What is the meaning of a prescale factor of -1?

We are not using that trigger.


From: Lad_hallc <lad_hallc-bounces at jlab.org> on behalf of Axel Schmidt <axelschmidt at gwu.edu>
Date: Wednesday, March 19, 2025 at 11:04 AM
To: lad_hallc at jlab.org <lad_hallc at jlab.org>
Subject: [Lad_hallc] [EXTERNAL] Re: Runplan final draft
Thanks for sending. Here are things I notice, which I'm sure you are well-aware of, but just in case.


- I notice that the GEMs are off for the (e,e') study. Would it be possible to already start the (e,e'p) checkout of with the GEMs and LAD reference bar at the same time as the (e,e') elastics?

- Your overview plan goes from low-energy (e,e') to low energy (e,e'p) and then to GEM optics. Your detailed plan has GEM optics before LAD timing. I think GEM and LAD timing should happen before optics because it has the GEMs in the forward position, no?

- When we move the GEMs from forward angle to their final backward angle position, when will we do a survey? Same for after the SHMS move from 17 to 13.5.?

- What is the meaning of a prescale factor of -1?

Thanks,
Axel

________________


On Mar 19, 2025, at 10:32, Florian Hauenstein <hauenst at jlab.org> wrote:

Dear all,

please find attached the final draft  from Dien, Holly and me of the run plan.
The amount of production running in each setting is not fully set in stone since it depends on the observed statistics.
Please let us know your comments as soon as possible.

Best,
Florian
<LAD_Runplan-5.pdf>_______________________________________________
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