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

[Jay Benesch]

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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