[BTeam] B beam is blown. For that matter, the whole machine is blown.

[Michael Merz]

Please keep me (crew chief) posted on the plan to address optics today.
________________________________
From: Jay Benesch <benesch at jlab.org>
Sent: Friday, May 23, 2025 07:27
To: Michael Merz <mmerz at jlab.org>
Subject: Fwd: B beam is blown. For that matter, the whole machine is blown.




-------- Forwarded Message --------
Subject: Re: B beam is blown. For that matter, the whole machine is blown.
Date: Fri, 23 May 2025 07:24:53 -0400
From: Jay Benesch <benesch at jlab.org>
To: BTeam <bteam at jlab.org>, mmeuller at jlab.org

More recent material

Ops matched at 7E01 https://logbooks.jlab.org/entry/4381741
harp traces post-match
https://logbooks.jlab.org/entry/4381745 7E01 A beam
https://logbooks.jlab.org/entry/4381746 7E01 B beam still big
https://logbooks.jlab.org/entry/4381751 AE01 A beam
https://logbooks.jlab.org/entry/4381755 AE01 B beam still big
https://logbooks.jlab.org/entry/4381756 2C05 X below design, Y 3x design
https://logbooks.jlab.org/entry/4381753 Hall B now makes it to the
dumplette without tripping ILM7S/9S01!

My recommendation to reduce the B laser spot to ~1.3 mm round still
holds.  I also recommend rematching Injector to NL  YMMV

On 5/23/25 07:16, Jay Benesch wrote:
> Colleagues,
>
> A selection of elogs.  Scan the logbook for a fuller picture.
>
> https://logbooks.jlab.org/entry/4380694 Yan's summary Wednesday
> https://logbooks.jlab.org/entry/4381729  IHAAE01 with B beam
> https://logbooks.jlab.org/entry/4381709  IHAAE01 with A beam
> https://logbooks.jlab.org/entry/4380687  chopper scans - B beam widest
> https://logbooks.jlab.org/entry/4380556 laser size measurements in pdf
>
> All values 4 sigma from pdf
> A laser X 1.60 mm Y 1.61 mm
> B laser X 1.92 mm Y 2.00 mm
> C laser X 1.22 mm Y 1.27 mm
> D laser X 1.27 mm Y 1.42 mm
>
> Joe told me that they allow a larger spot for B because of the narrow
> slit.  The slit constains the beam in the longitudinal dimension, not
> transversely.
>
> I suggest the B laser spot be adjusted to match C and D, ~1.3 mm in both
> planes, this morning.
>
> https://logbooks.jlab.org/entry/4381707 fopt results with half-kick.
> Scraping in AL and BL.  No response on the first kick in either plane
> implies to me that the injector-NL match is blown.  The sensitivity to
> MBL0R03 suggests the beta functions there are far larger than the design
> (x,y) (19.1, 13.3) m.
>
> Jay


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