[Hallc_running] [New Logentry] Status Update

pooser at jlab.org pooser at jlab.org
Tue Feb 27 12:20:03 EST 2018

Logentry Text:
Beam yesterday was taken away around 12 pm in order for MCC to conduct beam studies.  During this time a number of accesses were made.  Howard conducted some work on the HMS DC’s (https://logbooks.jlab.org/entry/3539015), Jack et. al. inspected the Q2 power supply and replaced the leads on JT8.  The PSS group attempted to install some shielding on the PSS rack behind the green shielding wall which resulted in us being accidentally dropped to restricted access.  Joe inspected the HMS door/shutter breaker box and reported that it was functioning nominally.  At 3:30 pm the Hall was swept, and we were placed in beam permit.  Shortly thereafter the ESR turbine 2 tripped and caused both of Hall-A’s dipoles to  loose there LHe inventory and fast dump.  Fortunately, Hall-C emerged unscathed (https://logbooks.jlab.org/entry/3538994).  While waiting on beam delivery Simona checked the HMS shutter and noticed that it was closed.  As a result a controlled access was made to open it prior to 
 beam delivery into the Hall (https://logbooks.jlab.org/entry/3539048).

At ~5:30 pm beam was delivered into the Hall, and we viewed the beam spot one the YAG (https://logbooks.jlab.org/entry/3539064) and concluded that the beam profile was acceptable.  After a series of SHMS carbon hole runs, and subsequently raising the beam in y by 200 um, the beam was centered on the carbon hole (https://logbooks.jlab.org/entry/3539590).  A “max raster current” run was taken for the purpose of the upcoming polarized 3He ERR (https://logbooks.jlab.org/entry/3539090).  With the raster studies complete, accelerator was able to successfully deliver 60 uA to Hall-C (https://logbooks.jlab.org/entry/3539159) while Hall-A was offline as a result of their dipole trips.  Once Hall-A came back online MCC struggled to deliver anything higher than the usual 40 uA.

At ~8:30 pm we started receiving nice stable beam (https://logbooks.jlab.org/entry/3539200).  Beam remained quite stable for the remainder of the night while we collected a sizable amount of production data.  With the SHMS at -2.0 GeV and 39 degrees, we have collected ~40% of LH2 data, ~31% LD2 data, and ~25% 10 cm Al dummy data.  With the HMS at -1.5 GeV and 59 degrees, we have collected ~89% LH2, 100% of LD2 data, and 100% of 10 cm Al dummy data.

MCC plans to complete the RF recovery no later than 2 pm, at which point we will continue to take data on LH2.  Once the SHMS LH2 data taking is complete we will lower the momentum to -1.6 GeV.  Once the HMS LH2 data collection is complete wi will lower the momentum to -1.35 GeV.  With the new momentum settings, production data collection will commence until complete.  At the moment, MCC has no are no scheduled downs until next Monday at which time beam studies will commence.

Special notices in effect for shift crews:
Trouble shooting HMS Q1 valves JT6 and JT8: https://logbooks.jlab.org/entry/3538239, https://logbooks.jlab.org/entry/3538243, https://logbooks.jlab.org/entry/3538254
Trouble shooting HMS Q2 power supply: https://logbooks.jlab.org/entry/3537306
TO Instructions for LH2 <--> LD2 switches : https://logbooks.jlab.org/entry/3534487

We will meet today in 200C at 1:30 pm (second floor of the counting house)
Link: https://bluejeans.com/543903672
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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/3539605
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