Muon On-Call: April 2018  

Machine Coordinator: Brian Drendel

Jim Morgan (Noon 4/27/18 - 4/30/18)

 

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MACHINE COORDINATORS:
March 2018 - Dean Still
May 2018 - Jim Morgan

Studies and Work Requests:

Below is a list of work and studies requests.  Work/studies owners will be notified when their requests are approved. Please send additional request and/or changes to Brian Drendel.   Updated 4/2/18 0800.

  1. Work Requests:

    1. Chipmunk Swaps:

      1. MC1 Hall above quad - needs scissors lift  (White). 

    2. Check PWC014 signal connectors - Extraction enclosure (Drendel)

    3. Work on D:Q404 - 30 minutes no beam to experiment (Bernie)

    4. Opportunistic Access

      1. Delivery Ring Access to inspect vac seal on IP303 (Vrbos)

      2. Mid-transport (Still)

  2. Study Requests:

    1.  

    2. M2/M3 Optics Work (Romanov) - Next round TBD.  This is destructive to the beam, so we will try to plan around experimental downtime.

    3. AP0 abort SEMs (Drendel, Morgan) – Initial timing work will take a half shift and will not impact g-2 operations.   Septa changes/moves would take a couple hours and be disruptive to g-2.  This work could be done when the experiment is not taking beam.

    4. Field test suspect ion chamber digitizer (Drendel) -  This will require one ion chamber in the beam for approximately 10 minutes.   This can be done with IC740 during a period when the experiment is not running.

    5. Ap0 chipmunk measurements (Drendel):   Data is being be collected with a set of temporary chipmunks in various configurations.  At this time, this work is completely transparent to operations. 

    6. Delivery Ring Tune Measurement work (Scarpine).   Requires 8 GeV operations.

    7. Dispersion in RR-Target (Nagaslaev, Adamson). Primary 8GeV transport beam line RR-Target. We need to establish a procedure for the dispersion measurement in this line. We will have to do transfers in a slow manner, kind of 20 sec between transfers and run the waterfall display in the RR for each transfer. We will also modify the RF frequency in RR so that the beam will be slightly off momentum. This change doesn't necessarily impact the yield on the target, but may result in increased beam losses, while tuning. This study is opportunistic and requires the presence of myself and Phil Adamson in the MCR at the same time. Time estimate is 2-4 hours.  Will impact the beam delivery to g-2, so needs to be aligned with their planning.

       

  3. Upcoming Non-Destructive Software Upgrades:

    1. Continued work on Wall Current Monitor SA (Budlong)

    2. M57 updates to see multiple pulses (Ahn).

  4. Looking ahead:  The summer shutdown is scheduled to start July 9th.  

 

9am Scheduling meeting summaries:

  1. Monday 4/2/18 Report:

    1. Friday day shift:   We had no beam most of shift due to the MIRF 3-way valve work. 

      1. Bernie changed out C119 PS controller card for D:ICMAG.  

      2. Looked at Abort SEM timing once beam returned.

    2. Weekend:

      1. Ran stable beam to g-2 over the weekend.

      2. Couple of nuisance D:IP906 trips

      3. New beam on target array parameter D:G2POT shows that the <POT> = 0.96E12 for the weekend.

      4. New rate parameter D:TGPRAT showed the  <Rate> = 9.85Hz for the weekend.   (Note: We get 11.4 Hz w/ out SY120, 9.5Hz w/ SY120)

      5. g2 positron decay rate tracked the experiment quad settings, currently sitting around 228.

      6. Started seeing a periodic little fallout in T0 spaced hours apart and lasting half hour or more, but do not see this no the abort ion chamber. 

        1. A closer look after the meeting showed that this feature is logging rate dependent.  At a 15 sec. sampling, we see the periodic fallouts.   At a 1 second sampling, it is a steady feature.  This may simply be the SY120 cycle with a beat frequency tied to the logging rate.  We ill look further before asking to put in further diagnostics.

        2. If there is a problem, we will ask to put IC902 in for part of a shift to determine if the problem is upstream or downstream of the start of the M4 line.  We would then also want to put in IC025. 

    3. Requests

      1.  Momentum collimation studies:  Details are in the link.  5 to 6 hours - need a healthy ring and DAQ.  Study involves selecting different momentum slices of beam with the DR momentum scrapers and determine the momentum distribution of the injected muon beam into the g-2 storage ring.  Also measure the dispersion in the M4/M5 line.  We will coordinate with the g-2 experiment, and will prefer weekday days or evening shift.

    4. Info from the meeting

      1. g-2 Trolly run will be 4am Tuesday morning.

      2. Friday/Saturday there will be radiography of the Mu2e building.  Access will be limited.

      3. There may be more accelerator downtime later in the week to address the RF three way valve issue.

  2. Wednesday 4/4/18 report 

    1. Overall

      1. Delivered beam to the experiment.

      2. <POT> = 0.99E12

      3. <Rate> = 9.10 Hz

    2. Monday: 

      1. Upgrade of all muon campus ion chamber electronics is complete.  This upgrade replaces the 200ms time constant digitizer with a faster 100ms version.   The faster digitizer allows us to measure beam intensity in 16 pulse operation without clipping the end of the charge integration.

      2.  The periodic drooping of the T0 signal seen in our lumberjack was determined to be an artifact of the sampling and not a problem.  At a 15 sec. sampling, we see the periodic fallouts.   At a 1 second sampling, it is a steady feature.  This may simply be the SY120 cycle with a beat frequency tied to the logging rate.  We ill look further before asking to put in further diagnostics.

    3. Tuesday:

      1. Jim Morgan tuned up the beam lines and Delivery Ring.   A solid 5% to 10% gain of beam delivered to the experiment.

        1. IC025 up from 1.58E8 to 1.67E8.

      2. Controls has better parameter for protons on target using Tor107 and TCLK $82 event.

        1. D:G2POT[0:16] - 0 = sum, 1-16 = inivudal bunches

        2. D:POTAVE = average of the 16

        3. D:POTMIN - protons on target integrated over a minute updated once per minute

        4. D:POTHR - protons on target for the last hour updated once per minute

        5. D:POTDAY = protons on target for the day updated once per hour.

        6. At 16:32 the FE was rebooted to sample on the $82.   You can see a bump up from the correct sampling.

      3. We had one AP0 dump external interlock trip on return flow low (D:DPWM1).  Lumberjack shows it is in it's normal operating range and reset right away. 

      4. New set of temporary chipmunks delivered to AP0 to continue shielding assessment studies.  They are due for calibration end of April.

    4. Studies

      1. Coordinating 5-6 hour  Momentum collimation studies with g-2.

        1. The target time for this work is likely Friday morning.   If the g-2 quads have trouble earlier, we may move the study up.

    5. Downtime

      1. As of right now, we don't have enough to justify an access during the downtime.  If we do go in, we would inspect vac seal on IP303 (Vrbos)

      2. Close M5 beam valves during experiment downtime (Vrbos)

  3. Friday 4/16/18 Report

    1. Wednesday

      1. Field tested problematic ion chamber digitzer card

    2. Downday.

        1. MC-1 Hall:  
          1. Chipmunks (White):   The chipmunk at the center of the ring was changed out, but the one above the quads was not.  A scissors jack will be moved over to allow this chipmunk to be changed out during the next access period.
          2. PWC/IC purge pumps (Vander/Budlong):   Purge pumps and timers were installed on PWC021 and PWC025/IC025.   They will purge for 15 minutes every hour.   Air samples were taken of the purged air from the antivacuum chamber.  It should be noted that a vacuum spike occurred when moving a ladder in the vicinity of the beam pipe, but it started pumping down immediataly.
        2. AP0: 
          1. Target Air Blower Maintenance (Ford)
          2. Old target module was moved out of the alcove (Ford).  Ralph Ford will further document this work in the Target Station Web.
          3. Li Lens and PMAG resistor change (Quinn): Installed voltage dividers in Lens & PMAG power supplies for maintaining pulse cap banks 'topped off' during long idle periods. This modification is expected to prevent the charging choke over-current trips occurring on first pulse when g-2 events are returned to the timeline.
        3. Power Supply Work
          1. D:QA04 firing module swap (Wisner)
        4. Motion Control
          1. AP30 PLC firmware (Peterson):  The AP30 Motion Control PLC firmware was successfully updated this morning for both units.  Motion with both systems was verified.
        5. Chipmunks:
          1. Chipmunk outside the M4 gate was changed out (White)
          2. Two chipmunks at AP30 were changed out (White)
        6. M4 Vacuum investigation
          1. M4 vacuum valves were closed during the downtime so experts could examine the borderline vacuum.
        7. Turn on issues:
          1. D:V003 regulation - needed a little assistance to get up to current.
            1. Have to run up manually by hand
          2. M4 vacuum took a while to recover as the ion pumps all tripped off after the valves were closed.
            1. Looking at the time when the three vacuum valves were closed (BV900, BV001, and BV015), there was a significant jump in the pressure at IP906, and a small bump up at IP904, but the pressure at IP902 actually started to drop.

              At 08:40:12, IP906 tripped off (probably due to the supply timing out on the pressure being too high after the beam valves were closed). IP904 pressure jumped about half a decade at that time and IP902 showed a small increase. The pressure on IP904 started a steady climb up and rolled over at about 09:38 before starting to go down. At 10:08:38 it also tripped off, probably due to that supply timing out on the pressure being too high because of IP906 having tripped off. When IP904 tripped, the pressure just ran away and IP902 followed. This looks to me like a simple vacuum avalanche.

              Because the M5 vacuum is in general pretty poor right now, we are more sensitive to this kind of problem.
          3. D:Q105 lost control power - lost 480V at the panel breaker.  Experts swapping to a spare breaker.
            1. Panel Breaker failure.  Moved to spare.

         

  4. Monday,  4/9/18 report

    1. Friday

      1. 9:13am - Lithium Lens failure

        1. Return conductivity pegged followed by system conductivity two minutes later.

      2. Lens/Transformer Changeout

        1. Procedure:  BDDP-ME-000131

        2. Web - https://web.fnal.gov/experiment/MuonG2/g-2_target_hall/SitePages/Lens-Transformer%20Change-out%202018%20April.aspx

  5. Friday, 4/13/18 Report

    1. Muon Campus Update (see link)

  6. Monday, April 16 Report

    1. Weekend

      1. Friday Tuning

        1. After g-2 kicker HV work, we tuned up muon campus

        2. Went to 16 turns

        3. RRRF bunch length tuning

        4. Jim had tuned up beam to the experiment: Steering, target cord length and M2 quads.

      2. Notes on cooling for new lens

        1. Lens is running cooler

        2. Transformer temp a little higher, but still normal.

      3. Performance

        1. Friday and Saturday running average 1E12 on target

        2. Target pulse rate averaged only 5.8Hz due to the weekend downtime

        3. We have a new parameter D:G2TPWR (target power). 

          1. Ran about 12.5KW on Saturday w/ SY120 in the TLG

          2. Ran about 14 KW overnight without SY120.

  7. Wednesday, April 18 Report

    1. Monday completed momentum collimation studies.  Provided beam when requested.

    2. Momentum collimation studies

      1. Average POT was up to 1e12 (Monday evening into Tuesday days).  Down to about 0.97e12 overnight.

      2. Average target rate 9.85Hz.   Up with SY down, down due to downtime.

      3. Target power peaked about 15KW.  Overnight was 14.5KW and 12.25KW.

 

 

 

 

 

 

 

 

 

 

 

 

 

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