Log entry time 14:18:13 on December 11, 1997

Entry number 2785

From:	CEBAF::IN%"benesch@CEBAF.GOV" 11-DEC-1997 10:00:16.62
To:	IN%"machine-ops@CEBAF.GOV"
CC:	
Subj:	8am mtg 12/11/97

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Date: Thu, 11 Dec 1997 10:03:09 -0500
From: benesch@CEBAF.GOV (Jay Benesch)
Subject: 8am mtg 12/11/97
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Hall    Up      Data
A       14.4    13.35
B       17.9    12
C       18.6    17.1
one or more: 19.6 hours up

This may have been our best three-hall day yet.  Hall A fixed their 
collimator motor problem about 1100.  There was one iteration of a new 
procedure to minimize tuning time when A takes an access.  Relatively 
smooth sailing the rest of the time.  

Day shift began with beam in hall C.  A was down with a collimator motor 
failure (radiation damage to electronics) and B was waiting for A to 
come back to avoid the need to resteer the B line.  When it became 
apparent A was going to be quite a bit longer, it was decided to steer 
up B and try to define a procedure for doing so, with Joe B. as Johnson 
and me as Boswell.  First and second drafts were produced, including 
before and after magnet settings to guide subsequent attempts.  Hall A 
fixed their motor about 1100 and began getting beam soon thereafter.  

Swing shift started with beam to all halls.  It was turned off at 1605 
to begin system checks.  SL05-5 dropped the zone due to comm errors, so 
the system checks began at 1615.  Hall B took an access during them.  
Current limiter cards were adjusted in Hall A, C and the injector to 184 
uA max so we could attempt to deliver 180 uA.  The BCM confidence test 
was run.  Hall A requested a current calibration.  They wanted a fast 
cutoff, so injector Faraday cup 1 was usd.  Hall B protection software 
current limit had to be raised to 150 nA from 25 nA because the hall was 
in access working on their Faraday cup electronics and the software kept 
tripping the machine.  6.4 hours of beam to one or more halls, with much 
of the shift spent delivering to all three.  

Owl shift began with beam to all three halls: 90 uA to A at 4045 MeV; 50 
uA to C at 4045 MeV and 1 nA to B at 1645 MeV.  AT 0100, Hall A 
requested 100 uA but the injector current limiter card tripped whenever 
current there exceeded 150 uA.  Hall A elected to continue at 90 uA.  At 
0140, hall A dump ion chambers faulted and couldn't be reset.  D. Dotson 
came in, found the electronics suffering from radiation damaged, and got 
things working again by 0400.  The Hall B tune with Hall A down took 
about 10 minutes.  Unfortunately, it appears the draft procedure wasn't 
consulted because at least one unallowed corrector, 4T09H, was used.  
[Not the crew's fault: it wasn't mentioned in the PD shift plan.]  When 
the magnets were returned to their prior state at 0400, the hall B orbit 
didn't reproduce precisely enough to duplicate the previous PMT counts.  
Abotu 30 minutes were spent tuning the line in CW.  V. Burkert remarked 
at the meeting that the PMT counts were acceptable when the magnet 
values were simply restored, so the tuning may have been unnecessary.  
They weren't as low as when A was off, however.  Even so, B got 6.1 
hours of data.  The shift ended with beam to all halls.  

Hall B will take an access at noon.  I've asked for a harp swipe to be 
taken before or after the access to check for halo.  Nothing else 
sceduled but beam delivery.