[Bteam] BTeam notes and agenda, 2011-02-23

[Todd Satogata]

BTeam --

Here are the agenda and notes for this week's BTeam meeting. I'll keep a countdown until the 6 month SAD at the start of the meeting, as we're a little over 10 weeks away and we have quite a few beam studies that should be completed before then. Please nag me to put your ATlis items on the list if they need to be done before then and you do not see them here. I think we have a good plan here for Thursday and we should make a good plan for Tuesday so we can defend that time. Bring all your good 
ideas to the meeting, as always -- cheers!

-Todd


  BTeam-2011-02-23


    1 11.5 weeks remaining before 6-month SAD (run ends 0800 Fri May 13)


    2 2011-02-16 Wed 14:00 BTeam Meeting Agenda


      2.1 Optics-on-Call Report: Todd/Jay => Alicia/Reza

A fairly quiet week for optics on call, dominated by charge asymmetry widths, helicity-correlated position differences, and other HC parity quality issues. Several of these have been or are addressed in beam studies below. Those that are not include dispersion leakage after last HC quad (so horizontal correction is perhaps needed in 0R/1A/3C, vertical in 1S/2S/2T), and IHWP helicity-correlated position difference issues that likely require UVa time on the laser table.


      2.2 Beam Studies Report


        2.2.1 DONE Parity quality from injector coupling: Yves 2011-02-15 Tue

ATLis 8346 <http://cebaf.jlab.org/atlis/task/8346>: Yves has measurements that predict some skew corrections based on a converging 1/4 cryo skew map fit. The 1/4 cryo -- not capture -- seems to dominate coupling.


        2.2.2 DONE BSY/Recombiner measurements: MikeS (~4h) 2011-02-17 Thu PM

ATLis 10810 <http://cebaf.jlab.org/atlis/task/10810>: Multipole measurements in the 6T beamline. Found new quad centers for 6T beamline, minimized corector strengths and used MAU6T04 shunt to set beam at Lambertson. First runs in both (x,x'), (y,y'). Data in support of Mike's thesis work. Want to follow up and repeat some measurements before HA comes out of third pass (see below). See e1568898 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1568898>.


        2.2.3 DONE Minimum beam size possible : Arne (~5h) 2011-02-18 Fri PM

ATLis 10825 <http://cebaf.jlab.org/atlis/task/10825>: HPS experiment requires small beam size at target; how much size comes from beam motion at harps? Required 2-pass beam to HB tagger harp. Demonstrated <30um beam size required for beam test. See e1569137 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1569137>.


        2.2.4 DONE Lower charge asymmetry widths for Qweak: Riad 2011-02-22 PM

New diagnostics from Qweak, asymmetry lowered from 900+ ppm to 450-500 ppm. See e1569770 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1569770>. Later work from Reza improved this at 0I05 to 260-270 ppm; see e1569903 <https://cebaf.jlab.org/elog/elog_item.php?elog_id=1569903>.


      2.3 Beam Studies Planning: Thursday


        2.3.1 TODO BSY/Recombiner measurements: MikeS (~2h invasive) 2011-02-24 Thu

ATLis 10810 <http://cebaf.jlab.org/atlis/task/10810>: Multipole measurements in the 6T beamline. Complete measurements in 6T beamline before HA comes out of third pass.


        2.3.2 TODO PZT Measurement to HC: Jay/Arne/Yves (1h invasive) 2011-02-24 Thu

Motivated by desire to improve helicity-correlated position differences for Qweak. May include coupling corrections from Yves for 1/4 cryo coupling if they are ready.


        2.3.3 TODO HC Rematch using 3C05 Harp: Jay (1h HC) 2011-02-24 Thu

Motivated by unusual beam size at Compton, a compromise position for weekend improvements since no significant injector optics retune is planned before next week.


      2.4 Other Beam Studies Planning


        2.4.1 TODO Raytrace/Multiharp for Qweak: Jay/Ryan/MikeT (3h HC/invasive?)

Investigate optics/transport of response to modulation coils at 3C08/10 and FFB coils at 3C04/06/07. May disrupt beam to other halls depending on where the the measurement is launched.


        2.4.2 TODO LOCO Model Calibration Tests: Yves/Ryan/MikeT (~2h invasive)

ATLis 10700 <http://cebaf.jlab.org/atlis/task/10700>: Measured, but BPM problems in center of arc. Have some analysis upstream and downstream of affected mux, but should restore good BPM behavior and remeasure. Being worked on, will not ask for more time until sorted out. Noisy BPMs were vertical? Tief investigating, noted horizontal noise. ATLis 10746 <http://cebaf.jlab.org/atlis/task/10746> is in place to investigate these BPMs when there is no beam in the east arc.


        2.4.3 TODO RayTrace in ARC3: Ryan/MikeT (~30min)

ATLis 10708 <http://cebaf.jlab.org/atlis/task/10708>: See above, should redo with LOCO model remeasurement. RayTrace analysis also needs to close loop on optics correction.


        2.4.4 TODO Injector bunch length measurements: Alicia/Reza (invasive inj)

ATLis 10684 <http://cebaf.jlab.org/atlis/task/10684>: Need to check harp status before measurement. Both 130 kV normal and backphase bunch length measurements should be performed and procedures checked before 6 month SAD.


        2.4.5 TODO Injector transmission vs current: MattP (2-4h) (invasive inj)

ATLis 10838 <http://cebaf.jlab.org/atlis/task/10838>: Desired before 6 month SAD. Probably workable behind arc or linac maintenance/repair, when halls are down, or behind a(nother) CHL trip.


        2.4.6 ???? IHWP helicity-correlated position differences? (invasive inj)

UVa time on laser table to investigate IHWP issues for Qweak.


      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 Plan 1-pass A/C split, B offline for 2011-02-25 Fri (Jay/Yves)

What resources/beam time do we need to be prepared?


        2.6.2 TODO Injector configuration documentation: Reza

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

======================================================================


    3 2011-02-16 Wed 14:00 BTeam Meeting Agenda


      3.1 Optics-on-Call Report: Shahid/Geoff => Todd/Jay

At last at least a moderately quiet week, though with some position parity issues to be worked out for Hall C/Qweak. This included an investigation of injector match through the injector chicane into NL, which seems to still be questionable. Also assisted separator work on Fri 2011-02-11. Majority of separator/injector match work was motivated by Hall C Compton backgrounds. Final resolution was to move to crest in in injector/NL/SL by retuning injector on Fri 2011-02-11. Hall C reports that 
Compton rates were good after Fri but were not very stable over time. Spot move improved this, consistent with previous hypothesis/sensitivity when QE degrades. At what point in QE does this become problematic? Should we change our criteria for a spot move?


        3.1.1 DONE Check quad ranges/procedure for injector match multiharp

Arne questioned last week: Does multiharp have good quad ranges for match? Need to collect multiharp data and return to injector match procedure. This includes getting hardware for harps back in working order. RonL notes that harp repair wants an injector access. This was checked and adjusted during below Tue 2011-02-15 studies by Jay. After rematch, beam bigger in H in Hall B, but results really inconclusive -- product of beta*emit same before/after match. Spots looked equally good before/after 
on viewers. Current settings should be close to design at present. Files are good in 0L03/08 in terms of quad ranges for multiharp scans.


        3.1.2 DONE Check injector skew quad scaling and setup

Yves noted last week that we should check skew quads, particularly whether they were scaled properly for 6.3 MeV and lemi work. This was likely done as part of check and measurement to 100 keV during 2011-02-15 Tue beam studies by Yves. These are several fopt runs to 100 keV, NOT PZT measurements as listed below. Data remains to be analyzed to get matrices and correct with skews.


      3.2 Beam Studies Report


        3.2.1 DONE Multiharp, injector optics match into NL: Jay

ATLis 10556 <http://cebaf.jlab.org/atlis/task/10556>: Some data acquired 2011-02-15 Tue. Do we need more Data and attempt at rematch acquired 2011-02-15 Tue, but rematch seemed to not make conditions worse or better. (see above) Hall C reports that charge asymmetry did seem to be worse with "matched" settings.

    * TODO Reevaluate match procedures during, e.g., summer SAD.


        3.2.2 DONE Measure injector transport across capture, 1/4: Yves

ATLis 9622 <http://cebaf.jlab.org/atlis/task/9622>: Some data acquired 2011-02-15 Tue. Do we need more data for the downstream section of the injector? (almost certainly) Reza: Steering done on A2 after HWien on/off during this study. Why? Clyde: Comment about ~400Hz IF amplitude instability/modulation. Warm/cold may react differently because of analog/digital differences.


        3.2.3 New injector optics review: Alex

Alex will briefly review the high points (including dispersion through the chicane, and modified optics for diagnostics) of the injector optics installed 2011-02-03 Thu. Alex presented optics that produce 1.5m or 3m of dispersion at the injector SLM, but at the cost of losing match so this is not an online diagnostic. Much discussion about what would be required to have this online, including zigzag chicane (ha). Geoff notes that Kevin Jordan had a transition foil at a high dispersion point, but 
there were historically problems with that as well. Could also throw away isochronous condition in match into NL, possibly gaining another handle on bunch length in the process.


        3.2.4 DONE Injector model: Arne

Elegant baseline should now match machine settings. Jay: Are these values consistent with those used by matchElengant? Are there new optics in the arcs that we should investigate?

    * TODO Check consistency. If not, make consistent and achieve consensus.
      Model is consistent with Alex's setup, match points are consistent now too. Have noticed some very strong sensitivities to some quad settings in the model for this setup though: robustness? We should evaluate how sensitive these optics are and communicate sensitivity. Tief recalls that match from injector to injector chicane has a small waist, a signature of sensitivity to upstream errors. Geoff questions the 6.3 MeV setting; Reza notes this is based on GSETs and not a spectrometer
      measurement. Yet. Some concern about the changed quad settings and their impact on the consistency of this setup. Yves's data should help resolve this optics/scaling. Should perhaps measure again at 2-5% level; much discussion. Have to do this for 5 MeV Mott measurements anyway (Matt/Joe/Riad).


      3.3 APEL Hall Liason Comments

Deferred to next week.


      3.4 Beam Studies Planning and Discussion


        3.4.1 TODO BSY/Recombiner measurements: MikeS (4h) 2011-02-17 Thu

ATLis 10810 <http://cebaf.jlab.org/atlis/task/10810>: Multipole measurements in the 6T beamline. Air-core correctors were checked out 01-22-2011 Sat. Data in support of Mike's thesis work. Third pass beam, invasive. Part is setting up beamline (setup, rechecking quad centers, first set of cal checks, first measurement to chew on offline, backout). Want to follow up and repeat some measurements before Hall A comes out of third pass.

Clyde notes that capture is starting to fail and might need some maintenance tomorrow. Has been showing degredation ~4d. 1h to replace, then rephase etc. Total 3-4h of planned time.


        3.4.2 TODO Minimum beam size possible : Arne (~4h) 2011-02-18 Fri AM

ATLis ?: Second pass hall B. Hall B wants torus flip during day as well, being up at 2nd pass between 0800-1200. Parasitic to other halls.

Beam unlikely in HallC 2011-02-17 Thu AM or for several days due to vacuum failure. May try to fit in RayTrace before repair if feasible.


        3.4.3 TODO Raytrace/Multiharp in HallC/Qweak: Jay/Ryan/MikeT (3h?)

Investigate optics/transport of response to modulation coils at 3C08/10 and FFB coils at 3C04/06/07. Requires beam to hall C and may disrupt beam to other halls depending on where the the measurement is launched.


        3.4.4 TODO Bunch length measurement: Alicia/Reza

Need to check harp status before measurement. Both 130 kV normal and backphase bunch length measurements should be performed before 6 month SAD. 4D00 spectrometer PS was reinstalled 2011-02-10 Thu.


        3.4.5 TODO Parity quality improvements from injector coupling: Yves

ATLis 8346 <http://cebaf.jlab.org/atlis/task/8346>: Some concern that parity quality is marginal for Qweak. A measurement and retune, such as this ATLis from Yves, is fairly invasive. Can be checked in ~10min with 30Hz PZT; this is a backup plan in case PZT/other injector measurements are inconclusive.


        3.4.6 TODO LOCO Model Calibration Tests: Yves/Ryan/MikeT (~2h)

ATLis 10700 <http://cebaf.jlab.org/atlis/task/10700>: Measured, but BPM problems in center of arc. Have some analysis upstream and downstream of affected mux, but should restore good BPM behavior and remeasure. Being worked on, will not ask for more time until sorted out. Noisy BPMs were vertical? Tief investigating, noted horizontal noise.


        3.4.7 TODO RayTrace in ARC3: Ryan/MikeT (~30min)

ATLis 10708 <http://cebaf.jlab.org/atlis/task/10708>: See above, should redo with LOCO model remeasurement.


      3.5 AOB?


        3.5.1 TODO Injector configuration documentation: Reza

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


        3.5.2 TODO Plan 1-pass A/C split, B offline (probably) for Feb 25 (Yves/Jay)

What resources/beam time do we need to be prepared?

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

Date: 2011/02/22 18:54:30

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/bteam/attachments/20110222/c7796c58/attachment-0002.html>