[Halla_running] [EXTERNAL] RC Status update

[Caryn Palatchi]

During yesterday DAY shift, injector adjustment to avoid 10percent beam
losses detrimental to PQB and successful beam delivery of 150uA without BLM
trips. During yesterday SWING, injector 5MeVmatch and chicane match, match
into HallA, and getting Hall on design was done, resulting in sufficiently
low Compton rates going straight through. Tuning through Compton chicane
was not completed however, and given that HallC will be taking 1pass beam
imminently, there is no plan to tune through the Compton chicane today.

Production runs were taken over OWL shifts. Some efficiency in running was
lost due to FFB saturation. FFB BPMs had intermittent saturation issues not
always resolved by gain search due to OPS gain search hi limit being set to
the MAX at 3400 and gain tolerance set to 40percent, allowing gains to be
set willy-nilly by FFB without showing OPS a 'gain fail' . Our alarms in
HallA of course accurately reflected when bpms were saturating. DAY shift
crew chief was informed the gain search limits and tolerances needed to be
tightened up and now OPS can properly see a 'gain fail' when bpms saturate.

At start of DAY shift this morning a detector alignment run was performed
and it was clear the left dipole (unregulated, due to NMR being broke)
needed adjustment. Yields in the left arm detectors were observed to be
lower during OWL after a down period yesterday afternoon DAY. Earlier in
the week the lhrs ioc was not communicating for a brief period due to some
software group accidental activity. It may be that this affected the
gaussmeter readback of the left dipole field. The readback of the
gaussmeter was noted by the shift crew to be different from the nominal
field running condition, so the left dipole setpoint current was adjusted
until the gaussmeter read the nominal field value, as per ramping procedure
previously employed. However, this adjustment clearly resulted in a
reduction in the detector rate and in the peak position in a detector
alignment check. Therefore, procedure has been modified such that rather
than trusting the gaussmeter, we trust the current setpoint more, and if
any change is made (or ioc rebooted), detector alignment check will be
performed. Detector yields were found to be very sensitive to such changes
and a good immediate indicator of any change (drift or otherwise) to the
left dipole field.

Production runs will continue through DAY into SWING. Approximately one
slug of data (2C) has been collected since start of DAY yesterday (official
start of PHYSICS) to now.

HallC RC informed us that HallC will lockup mid swing. 5pass beam will be
sent to HallC initially for a short time, during which time Hall A can
continue receiving 1pass beam. Then HallA 1pass beam will be taken away and
HallC will take 1pass beam with the HallC laser and without changing the
HWien angle setting that HallA found as optimal -29.64. If HallC has any
issues, 1pass beam will be returned to HallA while those issues are
resolved. If HallC has no issues with 1pass beam at HWein -29.64, HallA
will not receive further beam and the HWien will be adjusted to the setting
hallC had at 1pass in December around -15. Assuming no issues in HallC,
HallA will stop receiving beam late SWING. Radcon will survey the hall
tomorrow morning and the hall will be placed in controlled access for
Compton laser work Sunday. Monday morning the vacuum group also plan to
come in the hall and examine an iron pump/gauge. The Hall should be locked
up later Monday ready to receive beam. We plan to operate under the
assumption that if HallA 1pass beam is taken Saturday OWL, beam will be
returned 2 days later, no more. So we should plan to lockup the Hall Monday
late DAY-SWING to be ready for Tuesday OWL.

During HallC 1pass running, the hallC laser will be used and so the scripts
used in December for hallC IA Aq feedback should work. We plan to keep a
HallA TO to run Coda, HallC feedback and flipper. A modified flipper should
be used Wich does not increment hallA slug number, or slug number should be
manually set to 1000 while HallC has the beam.
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