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User name brads
Log entry time 18:35:39 on March 15, 2012
Entry number 366582
Followups:
keyword=GEp/G2p status update -- Thursday
We had significant problems getting beam steered into our Hall last night
(Thursday OWL).
ELOG
1699235
has a brief summary of the issues encountered. The big problem began around
midnight and extended through to the morning. We are still not sure what
the
underlying problem is, but executed several diagnostic plans during a
Controlled Access that ran through DAY shift. These include:
- Run a radiological survey of the beamline.
- Found some hot-spots on the line, notably at the septa exit flange.
See
Halog
366549,
Halog
366552.
- Verify operation of the chicane magnets power supply
- Corrected the (minor) magnet cycling problem by lowering upper cycle
current, and verified current at the magnet using clamp-on ammeter.
ELOG
1699333
- Verified
- Verify chicane magnet fields
- Magnet group came to the Hall to take some direct field
measurements of
the FZ fields, but no report yet. Working on it...
- Relocate the Lumi ion chamber and add a new ion chamber to be above and
below the dump entrance
(ELOG
1699336).
The hope is that this will give the Optics experts a better handle on the
beam location in that region (where they are otherwise running blind).
The other significant item addressed was an opportunistic replacement of the
faulty control valve on the target buffer dewar
(Halog
366548).
The target group is wrapping this work up now.
We will be locking the Hall as soon as the Target group is ready. Should be
mid-SWING. Items in the queue once beam returns include (roughly in
order of
priority). A detailed runplan (as of this time) is attached to this Halog.
- BCM calorimeter run (Alex/Pengia)
- BPM/Harp runs (Alex/Pengia)
- TE measurement (if we can do this in parallel with 1, 2)
- Carbon, empty target dilution runs
- G2p production
Note that we may drop or reorder as needed to make sure that we have time to
polarize and start production running before midnight.
Shift crew need to pay close attention to the following:
- Do a bleedthrough
check every 4--5 hours.
- Hall C will be flipping the IHWP every 4 hours. You
should be notified, but please pay attention! Stop and restart
our runs and make a Halog whenever the IHWP is flipped.
A copy of this log entry has been emailed to: brads,g2p