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

[Douglas Higinbotham]

Hall B has only run 1st pass and 5th pass it run period.    It was when Hall A was at a lower passes when we seemed to be running Hall B ok.

Douglas


From: BTeam <bteam-bounces at jlab.org> on behalf of Joe Grames via BTeam <bteam at jlab.org>
Date: Friday, May 23, 2025 at 8:36 AM
To: Jay Benesch <benesch at jlab.org>, Dennis Turner <dturner at jlab.org>, BTeam <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.
Jay,

We'll create an estimate, but the B size has been same since startup.

Isn't it true B gets good beam, when on by itself and also at lower passes. Seems that means the present size is not a problem.

I thought B was fine at 3rd pass.  Maybe suggests extraction.

Joe

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________________________________
From: BTeam <bteam-bounces at jlab.org> on behalf of Jay Benesch via BTeam <bteam at jlab.org>
Sent: Friday, May 23, 2025 8:02:33 AM
To: Dennis Turner <dturner at jlab.org>; BTeam <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.

It seems to me that the B spot should be smaller than all the others so
space charge effects are similar at the pre-buncher and buncher, The B
beam is generally over-bunched so the high current beam(s) are under
control.

On 5/23/25 07:31, Dennis Turner wrote:
> I agree with rematching injector to NL. We may find that once we rematch
> the injector we may have to revisit that 7E match.
>
> Dennis
>
> ------------------------------------------------------------------------
> *From:* BTeam <bteam-bounces at jlab.org> on behalf of Jay Benesch via
> BTeam <bteam at jlab.org>
> *Sent:* Friday, May 23, 2025 7:24:53 AM
> *To:* BTeam <bteam at jlab.org>; mmeuller at jlab.org <mmeuller at jlab.org>
> *Subject:* Re: [BTeam] B beam is blown. For that matter, the whole
> machine is blown.
> More recent material
>
> Ops matched at 7E01 https://logbooks.jlab.org/entry/4381741 <https://
> logbooks.jlab.org/entry/4381741>
> harp traces post-match
> https://logbooks.jlab.org/entry/4381745 <https://logbooks.jlab.org/
> entry/4381745> 7E01 A beam
> https://logbooks.jlab.org/entry/4381746 <https://logbooks.jlab.org/
> entry/4381746> 7E01 B beam still big
> https://logbooks.jlab.org/entry/4381751 <https://logbooks.jlab.org/
> entry/4381751> AE01 A beam
> https://logbooks.jlab.org/entry/4381755 <https://logbooks.jlab.org/
> entry/4381755> AE01 B beam still big
> https://logbooks.jlab.org/entry/4381756 <https://logbooks.jlab.org/
> entry/4381756> 2C05 X below design, Y 3x design
> https://logbooks.jlab.org/entry/4381753 <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 <https://logbooks.jlab.org/
> entry/4380694> Yan's summary Wednesday
>> https://logbooks.jlab.org/entry/4381729 <https://logbooks.jlab.org/
> entry/4381729>  IHAAE01 with B beam
>> https://logbooks.jlab.org/entry/4381709 <https://logbooks.jlab.org/
> entry/4381709>  IHAAE01 with A beam
>> https://logbooks.jlab.org/entry/4380687 <https://logbooks.jlab.org/
> entry/4380687>  chopper scans - B beam widest
>> https://logbooks.jlab.org/entry/4380556 <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 <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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