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

[satogata at jlab.org]

Logentry Text:
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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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