[BTeam] [New Logentry] Summary of empirical matching work so far

[Arne Freyberger]

Todd,
Thanks for this summary.   The latest fOpt looks  good in general and  
looks very good  through Arc3 as you noted.    This is great! the 
matching process is not resulting in a mess and may actually be 
providing a better setup up.

Today, Inj-group will re-visit the injector.   750MHz team will work on 
their hardware.   If the 750MHz hardware is repaired they will ask for 
beam time.   If we could all meet late in the day (4pm'ish) to discuss 
the path going forward that would be great.   I am OK with the idea of 
just taking the quad-scan data and not rematching except for the hall 
lines, but on the other hand since the process appears to be working 
albeit slower than expected why not push through to the end?

Arne



On 03/02/2015 01:40 AM, satogata at jlab.org wrote:
>
>
>   Summary of empirical matching work so far
>   <https://logbooks.jlab.org/entry/3322725>
>
> Lognumber 3322725 <https://logbooks.jlab.org/entry/3322725>. Submitted 
> by satogata <https://logbooks.jlab.org/user/satogata> on Mon, 
> 03/02/2015 - 01:38.
>
> Last updated on Mon, 03/02/2015 - 01:38
>
> Logbooks: 	ELOG <https://logbooks.jlab.org/book/elog> BTLOG 
> <https://logbooks.jlab.org/book/btlog>
> Entry Makers: 	satogata, roblin
> References: 	3322724 - Fopt to the end 
> <https://logbooks.jlab.org/entry/3322724>
>
> We are matched in the injector (Arne), 1E03 (Mike), and 2E01 (Todd and 
> Yves). The matching process and tools that we have developed worked in 
> all three locations as verified with viewer scans and fopts, including 
> a rather substantial match in 2E where measured Twiss parameters 
> (particularly in vertical) were quite far off design.
>
> After the 2E match and 2R quads were restored to design, there was 
> still an fopt C-S bump in the first horizontal corrector (1E01H) 
> measurement that was quickly corrected with the 2R02 horizontal beta 
> quad without affecting other C-S. This is indicative of a local error 
> in the 2R region; Yves will investigate separately. This appears as a 
> local spike in the 1E01H C-S plot.
>
> Existing C-S/ORFP corrections are still in the machine from 3R 
> onwards, but the upstream machine has been better matched to them by 
> this matching process. We at least should perform harp scans at the 
> remaining xE01 locations to measure emittance through the remainder of 
> the machine, and evaluate any further need for additional optics 
> corrections.
>
> Things that are working well:
> * zigzag scans and tools (no IOCs have needed reboots)
> * qsUtility harp scans
> * qsUtility emittance/Twiss analysis (but see below for fitting needs)
> * qsUtility matching tool
>
> Things that could use further work:
> * zigzag scans cannot be used for emittance/Twiss analysis (though 
> Dennis is actively working on this)
> * harp scan beam size fitting (fitting still needs to be done by hand 
> for some data sets, then added manually to the harp scan sdds file for 
> analysis)
>
> We are not nearly as far as we had anticipated on the white board from 
> Friday planning, but the entire machine has fopts that are excellent 
> at present (see linked elog). We believe we have demonstrated that the 
> process will work, and will work even more efficiently once the two 
> "further work" items above are addressed -- then we'll be able to use 
> zigzag to measure emittance and Twiss parameters quickly in xE01 
> regions, and calculate and install match quads with high confidence. 
> In the meantime we are recommending to the owl shift that they quad 
> center the spreader quads for us so scans and matching can continue on 
> Monday, either before or after injector setup work.
>
> The injector issues are also outstanding, and Yan believes further 
> work on 3-beam setup needs to be done. After that work is done, an 
> injector rematch to design should be all that is needed. This of 
> course is not visible on a traditional fopt since those are launched 
> in the 1S/1E region.
>
>
>
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-- 
Arne Freyberger
Director of Accelerator Operations
Jefferson Lab
12000 Jefferson Avenue      Cell: (757) 876-6289
Postal Suite 19             Email:  freyberg at jlab.org
Newport News, VA 23606

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