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

[Dennis Turner]

I was also confused until I was informed that only B beam is bad, but the others are fine.

Dennis
________________________________
From: BTeam <bteam-bounces at jlab.org> on behalf of Ken Surles-Law via BTeam <bteam at jlab.org>
Sent: Friday, May 23, 2025 12:14
To: Yves Roblin <roblin at jlab.org>; Ken Surles-Law via BTeam <bteam at jlab.org>; Michael Merz <mmerz at jlab.org>; Jay Benesch <benesch at jlab.org>; Matthew Mueller <mmueller at jlab.org>
Subject: Re: [BTeam] B beam is blown. For that matter, the whole machine is blown.

The fopt/CS data demonstrates differently, correct? Reviewing what Kitty posted last night, looks different from data a few weeks ago. Are our tools fooling us then?


Ken

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________________________________
From: Yves Roblin <roblin at jlab.org>
Sent: Friday, May 23, 2025 11:57:07 AM
To: Ken Surles-Law via BTeam <bteam at jlab.org>; Michael Merz <mmerz at jlab.org>; Jay Benesch <benesch at jlab.org>; Matthew Mueller <mmueller at jlab.org>; Ken Surles-Law <law at jlab.org>
Subject: Re: B beam is blown. For that matter, the whole machine is blown.

There is no blown optics. Its within specs in main machine. What's blown is the B beam which is already drastically different at end of injector whereas the other 3 are similar in size. So, matching the INJ won't be able to work for all 4. We matched with A, the high current beam.

Figuring out why B is off from the start will take looking at its behavior in early injector and management wants us to punt on B giving priority to A, D and C.
________________________________
From: BTeam <bteam-bounces at jlab.org> on behalf of Ken Surles-Law via BTeam <bteam at jlab.org>
Sent: Friday, May 23, 2025 11:45 AM
To: Michael Merz <mmerz at jlab.org>; Jay Benesch <benesch at jlab.org>; bteam at jlab.org <bteam at jlab.org>; Matthew Mueller <mmueller at jlab.org>
Subject: Re: [BTeam] B beam is blown. For that matter, the whole machine is blown.

Do we know what the driver is for the blown optics? If memory serves me well, we corrected the optics a week or two ago. We did an injector match after the first wien change (again, if memory serves me well.....I am getting old). Perhaps it's "burt restore integrity"? Recommend, if we're not doing this already, once we have corrected optics in the main machine and in the Halls we establish a "golden allsave" with zero pos, post in PD shift plan under standing orders. Once we return from maintenance we can at least compare present machine with the golden allsave and zero pos, also keeping track of what was changed/repaired/swapped out during maintenance.

Ken

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________________________________
From: BTeam <bteam-bounces at jlab.org> on behalf of Michael Merz via BTeam <bteam at jlab.org>
Sent: Friday, May 23, 2025 8:19:39 AM
To: Jay Benesch <benesch at jlab.org>; bteam at jlab.org <bteam at jlab.org>; Matthew Mueller <mmueller at jlab.org>
Subject: Re: [BTeam] B beam is blown. For that matter, the whole machine is blown.

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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