[Rgc] [Rgc_analysis] [EXTERNAL] Fwd: Beam Energy Requirements in Hall B

[Eugene Pasyuk]

The energy increase is not coming for free. It is accompanied by lower availability. You have to put this into the equation when you try to estimate a figure of merit. It is exactly why we were asked this question

-Eugene


From: Rgc <rgc-bounces at jlab.org> On Behalf Of Sebastian Kuhn via Rgc
Sent: Wednesday, August 07, 2024 09:21
To: Kuhn, Sebastian E. via Rgc <rgc at jlab.org>
Subject: [Rgc] Fwd: [Rgc_analysis] [EXTERNAL] Fwd: Beam Energy Requirements in Hall B

In case you haven’t gotten my previous request… =>


Begin forwarded message:

From: "Kuhn, Sebastian E. via Rgc_analysis" <rgc_analysis at jlab.org<mailto:rgc_analysis at jlab.org>>
Subject: [Rgc_analysis] [EXTERNAL] Fwd: Beam Energy Requirements in Hall B
Date: August 5, 2024 at 11:25:37 AM EDT
To: Silvia Niccolai via Rgc_analysis <Rgc_analysis at jlab.org<mailto:Rgc_analysis at jlab.org>>
Reply-To: "Kuhn, Sebastian E." <skuhn at odu.edu<mailto:skuhn at odu.edu>>

Dear all,

I would like to respond to this request by Patrick with a joint statement from RG-C. As you know, we just passed our jeopardy review, and RG-C may be back on the schedule for the remaining 40 PAC days in 2026-27. I personally would very much like to see more than 10.7 GeV for that run - during the jeopardy review, I showed that at least for DIS this would recover the highest x-bin we originally proposed that presently has huge error bars because nearly no events fall inside that bin with the the usual cuts. If we can go to 11 GeV, we would gain a factor 4-5 (2 times smaller error bar) in statistics; with 10.7 GeV, less than a factor of 2 in counts. If you have any similar conclusions for your favorite Physics channel, please try to send an argument my way; alternatively, if you don’t care, please let me know also.

- Sebastian




Begin forwarded message:

From: Patrick Achenbach <patricka at jlab.org<mailto:patricka at jlab.org>>
Subject: Beam Energy Requirements in Hall B
Date: July 23, 2024 at 5:47:27 PM EDT
To: Latifa Elouadrhiri <latifa at jlab.org<mailto:latifa at jlab.org>>, Silvia Niccolai <silvia.niccolai at ijclab.in2p3.fr<mailto:silvia.niccolai at ijclab.in2p3.fr>>, "Sebastian E. Kuhn" <skuhn at odu.edu<mailto:skuhn at odu.edu>>, Raphael Dupre <raphael.dupre at ijclab.in2p3.fr<mailto:raphael.dupre at ijclab.in2p3.fr>>, Hayk Hakobyan <hayk.hakobyan at usm.cl<mailto:hayk.hakobyan at usm.cl>>, Ilya Larin <ilarin at jlab.org<mailto:ilarin at jlab.org>>, "mcontalb at fe.infn.it<mailto:mcontalb at fe.infn.it>" <mcontalb at fe.infn.it<mailto:mcontalb at fe.infn.it>>, William Brooks <william.brooks at usm.cl<mailto:william.brooks at usm.cl>>, Richard G Milner <milner at mit.edu<mailto:milner at mit.edu>>
Cc: Stepan Stepanyan <stepanya at jlab.org<mailto:stepanya at jlab.org>>

EXTERNAL to ODU: This email is not from an ODU account. Do not click links or open attachments unless you recognize the sender and know the content is safe.
Dear contact persons of '11-GeV runs' in Hall-B,

Earlier this year, DOE has performed an Operations Review which was concluded with a list of comments and recommendations. One particular recommendation is to... "Develop a beam energy requirement document for the approved experiments in the experimental halls, complete with physics justifications. This document must be distinctly separate from issues pertaining to reliability."

Physics division will compile, for each experiment still to run, (a) Proposed Energies, (b) Minimum Acceptable Maximum Energy if 12 GeV was proposed, (c) Science Impact of difference from 12 GeV, and (d) any potential mitigation such as run longer.

The focus of this recommendation is a review/justification for a 12-GeV CEBAF beam (equiv. to 11 GeV delivered to Hall B) as compared to a beam with some 100s MeV less energy.

Can you please give me input to the requested table entries (a) to (d)? Feel free to justify running at 11 GeV for Hall B with some extra narrative if the table is not sufficient. I believe, we can give common numbers for experiments in run groups for which the science impact and the potential mitigation is similar. However, I don't think that we can combine all experiments from a run group.

Let me remind you, the scheduled beam energy for the next run is 1060 MeV per linac, equiv. to 10.70 GeV in Hall B. Plans are in place to increase this to 1090 MeV, equiv. to 11 GeV in Hall B for the FY26, but not at all cost.

Physics division is not moving quickly on this, so a reasonable target to have all information compiled is August 20, 2024.

Best regards,
Patrick

_______________________________________________
Rgc_analysis mailing list
Rgc_analysis at jlab.org<mailto:Rgc_analysis at jlab.org>
https://mailman.jlab.org/mailman/listinfo/rgc_analysis

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/rgc/attachments/20240807/1132716f/attachment-0001.html>