Minutes of the 14 Dec 2007 Tevatron Dept Meeting

http://indico.fnal.gov/conferenceDisplay.py?confId=1441

* News (Ron) - Winter weather is upon us again - if you find slippery
sidewalks near the building entrances, please spread a bit of salt from the
bag near the doors.

* Weekly Operations Summary (Jerry Annala) - The Tevatron has delivered over
44 pb^-1 to CDF and D0 over the past 2 weeks.  There have been 10 HEP stores
with initial luminosities between 120 and 188 ub^-1/s.  All 10 were terminated
intentionally, but we did lose 2 other shots before reaching HEP.  Shot 5772
was lost when a CAMAC power supply failed pulling a spurious abort (but no
quench); shot 5776 was lost during scraping due to higher than normal proton
losses as the tunes landed badly from much lower pbar intensity.  A normally
unused collimator at D17 developed a vacuum leak in its bellows, requiring
several hours of access to fix.  The B0Q2 CAMAC card failed during store 5780,
but in a such a manner that allowed the power supply to continue outputting the
correct current.  Alpha bumps @ D0 were made during store 5770 to adjust
the horz and vert beta* position; D0 luminosity improved ~4%.  There were 6
hours of crystal collimator studies at the end of store 5780.  The HF46 BPM
seems to be reporting bad positions recently.  One consequence is that the 
orbit stabilization application was introducing orbit errors due to that bad 
BPM.  Manually smoothing orbits without the HF46 BPM worked well, so that BPM
is no longer used in orbit stabilization.  Our current operational issue is
the poor proton lifetime and high losses early in stores.

* Collimating in the Squeeze (Dean Still) - Dean proposed using the E01H
collimator (unused, intended for proton removal) to help shield CDF and D0 from
proton losses in the squeeze during the transition to the collision helix.
E01H moves in from the radial outside, and the protons are on that side for
both the injection and collision helix. If it works, perhaps we can avoid 
chasing losses around the ring with various orbit bumps.  The idea is to have 
E01H start moving toward the beam at the start of the squeeze so that it is 
"close" (10 sigma?) when the helix transition occurs; then it would be 
retracted prior to the normal halo removal sequence.  Dean will create the
new collimator state and test it with proton-only studies.

* E17 Schottky Gains (Ron) - The E17 Schottky tune readings, particular for
protons, are frequently "noisy" early in HEP stores.  Recently, the baseband
gain setting controls were found to be broken and stuck in the highest (40 dB)
setting.  After repair, those gains were changed to observe the effect on the
signals.  The noise floor dropped as expected, and there was no effect on the
various measurements, including tunes.  Nevertheless, the same noisy structure
was observed early in stores, even with 36 dB less gain.  The suspicion is the
preamplifiers in the tunnel may have too much gain and saturating later stages.
Ralph Pasquinelli will order new preamps for us.

* Plan for Next Week

   - Deliver luminosity.
   - Request higher beam intensities.
   - Continue work on timing the E17 pinger (Dan)
   - Make TBT measurements of low-beta lattice (Yuri, when pinger OK)
   - Request larger pbar emittances, or blow them up ourselves to help
     improve proton lifetime, losses early in HEP.
   - TEL studies (Seva, during shot setup)