[Bteam] BTeam notes, 2011-03-02

Mon Mar 7 11:27:22 EST 2011

BTeam -

Here are notes from last Wednesday's BTeam meeting, partly to facilitate discussion and input for the priorities request I sent out earlier today. In the future I'll be sending separate mails of the meeting notes and meeting agendas so we can share comment/input on the previous week's notes that make it into the next week's agenda.

-Todd

  BTeam 2011-03-02

    2 2011-03-02 Wed 14:00 BTeam Meeting Notes

      2.1 Optics-on-Call Report: Alicia/Reza => Rui/Mike

Tons of failures and recovery efforts made this a rather exciting and frustrating week. Qweak has been down since Friday with a QTor problem, but has known parity quality issues that were discussed in a 2011-02-28 Mon 15:00 meeting. Hall A has bean quality issues as well, in the sense that their beam size is too large.

The A/C split scheduled for Friday was attempted day 2011-02-26 Sat but failed due to regulation problems with, e.g., MAX4T05/MAX4S02. We continue to try to address hall issues in beam studies and take advantage of "free" beam availability, but were sometimes hampered by equipment failures.

      2.2 Beam Studies Report

        2.2.1 BSY/Recombiner measurements: MikeS (~4h) 2011-02-24 Thu PM

ATLis 10810 <http://cebaf.jlab.org/atlis/task/10810>: Multipole measurements in the 6T beamline. Nearly finished up, but will need a little more time for lambertson and calibration data. See e1571680 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1571680>.

    * TODO Final measurements (~4h?) for Lambertson, calibrations (MikeS)

        2.2.2 PZT Resurrection: Arne/Yves 2011-02-24 Thu AM

ATLis 10864 <http://cebaf.jlab.org/atlis/task/10864>: Arne and Yves tried using PZT but only got good results with corrector kicks. See e1570339 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1570339>. Matt Poelker later showed that PZT itself works, see e1572018 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1572018>; is there a problem with PZT Booster software signals, or translation of those signals to hardware? Can this be investigated parasitically? In the meantime decoupling work 
was done with DC kicks.

Injector Fopt data is peculiar. Suspect that an injector Fopt kicker is rotated to produce coupling in the injector Fopt signal. No OPS-PR generated yet, but Yves and/or Jay will generate one for followup.

    * TODO Check parity quality with new decoupling when Hall C returns
    * TODO Generate OPS-PR for suspect rotated injector Fopt kicker (Jay/Yves)

        2.2.3 Three-way A/B/C first pass split: Jay 2011-02-26 Sat day

ATLis 10869 <http://cebaf.jlab.org/atlis/task/10869>: Shunt problems with MAX4T05/MAX4S02 prevented this from working, plus delays from power outage. See e1571186 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1571186>. The multiharps for 0L03/0L08 were taken 2011-02-25 Fri. Replaced 4 shunts but replacements behaved the same way in terms of reduced response. These shunt regulations weren't a problem for G0 at about these relative shunt levels, but they are now. Ron notes test plan in the 
works to diagnose where we may try more kicking with correctors and lower shunt currents.

        2.2.4 DONE Injector/NL rematch at MBL0R04: Jay (2h) 2011-02-26 Sat day

ATLis 10882 <http://cebaf.jlab.org/atlis/task/10882>: Completed, see e1570981 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1570981>. Didn't actually change any injector quads in the longer term; quad changes slightly degraded overall match. Observations indicate emittance growth is not really rooted in this area.

        2.2.5 Injector bunch length measurements: Alicia (3h) 2011-02-26 Sat PM

ATLis 10684 <http://cebaf.jlab.org/atlis/task/10684>: Persistent 0L07 dipole overtemperature prevented completion. See e1571307 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1571307>. This was will have to be repeated from the start for success.

    * TODO Revisit backphase bunch length measurements at later date (Alicia)

        2.2.6 Improve match to halls: Jay 2011-03-01 Tue AM

ATLis 10892 <http://cebaf.jlab.org/atlis/task/10892>: Some progress with C-S tuning in 1S/1E. Jay performed hall A multiharps and several fopts, improved emittances by factor 4, mostly by improvements in vertical, see e1572043 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1572043>. Don't have clean numbers in horizontal; would be nice to get new data at 2S10 and 3C04 with tune beam to dumplette.

    * TODO: Get better match data at 2S10, 3C04 with tune beam to dumplette (Jay)

      2.3 Beam Studies Planning

        2.3.1 TODO Improve match to halls: Jay/Todd 2011-03-03 Thu?

ATLis 10892 <http://cebaf.jlab.org/atlis/task/10892>: Continue to improve match into hall C? Revisit based on QTor status. Jay will revisit procedure with Todd. Can reperform measurement to dumplette; will plan to stay out of hall until we can get high current and good statistics on parity DAQ. Can still use injector DAQ in coordination with hall with high current beam to Hall A in meantime. (Data taken opportunistically swing 2011-03-02 Weds; see e1572364 
<https://cebaf.jlab.org/elog/elog_item.php?elog_id=1572364> and e1572365 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1572365>.)

        2.3.2 TODO: 5 MeV helicity magnet parity correction? Riad 2011-03-03 Thu?

Yves has checked this and it appears to be working, but injector folks have not checked it out fully in MCC recently. Poelker has done basic checks yesterday only on PZT. Driven by square wave at 980Hz reversal frequency? Consulted with Joe Grames/Riad Suleiman on 2011-03-03 Thu; Riad will likely prepare a test plan. These magnets have not been used operationally in the past because they were not needed and because of concerns about introduction of extra spin-correlated systematics.

        2.3.3 TODO Parity quality from injector coupling: Yves/Arne/Riad...

ATLis 8346 <http://cebaf.jlab.org/atlis/task/8346>: Need to revisit with working PZT, other ideas to improve Qweak parity quality.

        2.3.4 TODO BSY/Recombiner measurements: MikeS (~2h invasive)

ATLis 10810 <http://cebaf.jlab.org/atlis/task/10810>: Complete measurements with Lambertson and calibration data. Requires at least 3-pass beam.

      2.4 Other Beam Studies Planning

        2.4.1 TODO Assemble list of priorities before summer SAD (Todd)

Strategic suggestions during the meeting included establish a baseline of 6 GeV CEBAF at the end of the current run, and investigating Arne's improved optics.

We have a ~1d possible maintenance/studies availability on Mon 2011-03-07. How can we leverage this time most effectively? What maintenance should be done to address issues found during beam studies in the past week? NOTE that we stay in one-pass until Tue2011-03-08. Hall A now wants to run Mon 2011-03-07, and will likely be off Tue 2011-03-08. We may be able to run beam to Hall C by Tue 2011-03-08, so maintenance/beam studies for Tue 2011-03-08 look more feasible.

There was a great deal of discussion of near-term facility planning for various contingencies for Mar 7-9. My recommendation for future meetings is that we focus on beam studies prioritizations, benefits, and requirements, and make schedule recommendations based on personnel availability. This will give the PD the maximum flexibility to arrange their schedule.

        2.4.2 Comments on Maintenance: SteveS

    * Driver should be studies between now and 6 month SAD.
    * Shunt regulation? But not necessary if we aren't doing the split.
    * 0L07 magnet spectrometer is important for backphase bunch length msmt, probably also will be needed with little lead time in ops sometime.
    * TODO 0L07 magnet spectrometer checkout (and possible repair) (Ron/SteveS)

      2.5 APEL Hall Liason Comments

        2.5.1 Hall A: Yves

        2.5.2 Hall B: Tief

        2.5.3 Hall C: Jay

      2.6 AOB?

        2.6.1 TODO Injector configuration documentation: Reza

Document proper operational injector configuration (6.3 MeV energy, crested within 5 degrees, etc): Reza et al

Author: Todd Satogata <satogata at Todd-Satogatas-MacBook-Pro.local> <mailto:satogata at Todd-Satogatas-MacBook-Pro.local>

Date: 2011/03/07 11:20:58

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