Minutes of the June 6, 2008 Tevatron Dept Meeting

http://indico.fnal.gov/conferenceDisplay.py?confId=1864

* Weekly Operations Summary (Xiaolong Zhang) - The Tevatron delivered > 46
pb^-1 to the experiments over the past 7 days.  There have been 10 HEP stores 
with initial luminosities between 224 and 295 ub^-1/s.  (Store 6200 was the 
second highest initial lumi ever.)  Three stores were terminated "abnormally".
Store 6179 quenched @ E1 when one of the C49 vertical separator power supplies
lost regulation and cuased an orbit distortion and high losses in E1.
(The power supply was replaced.)  Store 6191 needed to be terminated after
only 5.7 hr to fix a frozen power lead on the BQ0 magnet caused by a cracked
nut.  There was a quench @ E1 during a brief end-of-store study (more later).
Just prior to the scheduled end of store 6195, a technician preparing to work
on the D3 power supply closed an incorrect LCW valve and caused an abort. The
PBJ "on-time" was lengthened from 40 to 60 sec to blow-up the pbar emittances
a bit more.  In store 6179, the VB12 dipole corrector tripped off - orbit
stabilization compensated just fine.  TRF7 tripped off during store 6191, and
TRF8 tripped off during store 6185.  Some minor orbit corrections were made
this week to reduce losses in the squeeze.

* Separating Beams for CDF End-of-Store Study (Jerry Annala) - CDF requested
special beam conditions for special silicon vertex detector calibration run -
up to 30 min of running with both beams in the Tev but no collisions.  We 
did a test run of retracting collimators a bit and separating the beams as they
would be at low-beta prior to initiating collisions.  In our first test of the
process at the end of store 6191, there was a quench at E1 - the best guess
for now is that the proton beam because unstable.  For the next attempt, the
tunes will be adjusted, orbit stabilization turned off, pull out collimators
a bit more, and perhaps raise chromaticity.

* Yet Another Tune Monitor (Alex Valishev) - Alex described the YATuM (get it?)
that Alex, Seva, and Fedor are using to look for coherent motion among the beam
bunches.  They use the vertical B11 BPM and a fast, deep-memory oscilloscope to
record turn-by-turn measurements of the sum and difference signals of the BPM
pickups.  The 60 Hz noise and "slow" orbit motion of a few 10s of um is 
evident.  An external noise source is needed to see tunes of individual
bunches, and there are interesting peaks in the spectra soon after the noise
source is turned off - one of the peaks is at the "bare" (unshifted) pbar tune,
but they are currently measuring only protons!  Future work will include
looking at pbars, improving sensitivity, and explaining the observations.

* Plan for Next Week

   - Keep on delivering luminosity.
   - P1 line matching (Alex, Jerry, proton-only)
   - Low-beta lattice measurments (Alex, proton-only)
   - Chromaticity tracker (Tan, proton-only)
   - Beam separation for CDF (Jerry, end-of-store)
   - Test new firmware for 460 dipole corrector cards (Dean, Jerry, controls)
   - Adjust fast abort parameters in low-beta QPMs (EE support)
   - Start propagating new BLM electronics around ring (Dean, Marv, et al.)