[Sbs] [Revised Logentry] Hall A RC Update [10/2/21]

[flay at jlab.org]

Logentry Text:
--
All teams are doing great work to get ready to take beam some time next week, special thanks to Jessie, Jack, and their teams with all their big efforts to get us installed and ready to go.  We're almost there, and a lot is happening in the hall.  The details are as follows:  

Announcements
- All shifts are cancelled up to and including Wednesday Owl (https://misportal.jlab.org/mis/physics/shiftSchedule/?experimentRunId=GMn-2021)
- From Silviu Covrig Dusa: There will be an online LH2 target training on Monday Oct 4 
  starting at 1pm. The training should not last more than 90 min and will be conducted 
  via bluejeans. This training is required of people who'd like to take target operator 
  shifts and who have not yet been LH2 target trained in the 12 GeV era. The link to the 
  bj meeting is below. https://bluejeans.com/127830759/1614?src=calendarLink
- Yellow book documentation (COO, ESAD, RSAD) will be placed in the counting house 
  once we receive the run certificate from Patrizia (expected early Monday).  
  All shifters must read and sign this documentation prior to sitting for shifts.  
  Note that you can read most of this documentation on the GMn website (https://hallaweb.jlab.org/experiment/SBS/GMn/GMn_Website.html#gmnsafety).   

Overview
- The Hall is in Restricted Access 
- All subsystems are close to ready for beam 
- HCAL and BB CAL groups working on smaller issues (noisy channels)
- Analysis and online monitoring software is mature and continual improvements ongoing 
- Beam is not expected before Wednesday, Oct 6; see further notes below 

DAQ
- Ongoing testing running the full DAQ
- Replaced the CPU on ROC17 that has alleviated some of the issues seen this past week. 
- The team is now folding in the readout of the SBS beam line signal crate (sbsvme29)  

Beam Line
- Upstream beam line is under vacuum 
- Target chamber and downstream/exit beam line are at atmosphere 

Target 
- Chamber was not pumped down to vacuum on Friday 
  due to the installation of lead shielding just downstream of the target chamber 
  on the beam-left side.  This additionally required disassembly of part of the 
  pumping equipment for the DP volume.  Vacuum pumpdown scheduled for Monday 10/4
- If all goes well, cool down on Tuesday. Once complete, the target group 
  will condense H2 and L2 the following day (Wednesday) 
- Ion chamber location identified; fixture will be installed Sunday 
  prior to IC installation on Monday 

BigBite Arm
- Sieve is installed (attachment 1) 
- Lead shielding installed on BigBite side of beam line late Friday evening (attachment 2).  Considering 
  safety precautions, the vacuum pump down on the target was not started.  
- BigBite Magnet 
  - New hoses installed (attachment 3).  Pressurized and inspected for 30 mins with successful operation, 
    and then turned off.  Will monitor over the weekend. 
  - Survey team is scheduled for Monday.  

GEMs 
- Better shielding installed between aluminized Mylar (on J2 middle region) 
  and Faraday shielding on the J2 middle chamber.
- Tested HV overnight, and the current is much more stable compared to previous trials.  
  No trips observed at the required operating voltage 
- Will continue to operate opportunistically for cosmics to prepare for beam
- Will start with J2 top module turned off; continuing to make plans for swapping this out for 
  a full operational one (need a tie off ladder point in the Hall to do this work). 

Late Afternoon Work
- Low power testing on both the BB and SBS magnets  

Next Week 
- Monday
  - BB side downstream lead shielding installation 
  - Installing guards on SBS corrector magnets  
  - Ion chamber installation 
  - Target chamber/downstream beam line vacuum pumpdown 
  - BigBite magnet survey   
- Tuesday (depends on success of Monday) 
  - Target cooldown 
  - Clean up the hall 
  - Power BB and SBS magnets to full power, establish 5 Gauss lines 

Safety 
- Cleaning up the hall! A lot of cleaning effort was done end of this week; 
  we should all circle back early next week and make sure extra tools and supplies are removed 
  or put away appropriately. 
- Signage: If you have a specific sign for your system, be sure it matches the 
  JLab safety specifications.  Check with Jessie if need be. 


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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3916641
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