Minutes of the May 2, 2008 Tevatron Dept Meeting

http://indico.fnal.gov/conferenceDisplay.py?confId=1790

* Weekly Operations Summary (C-Y Tan) - The Tevatron delivered 33 pb^-1 to
CDF and D0 over the past week.  There have been 7 HEP stores with initial
luminosities between 163 and 245 ub^-1/s.  Two other shots were lost during
the squeeze; shot 6083 was lost when the electrical safety system dropped when
high winds rattled open an interlocked door (adjustment made), while shot 6104
was lost due to another unexplained quench in the B0 low-beta magnets.  (Is
there an ice ball in the B0 straight section from an outside air leak?)  CDF 
made a change to their HVAC system last week that caused a ~10 deg drop in the
collision hall temperature; consequently, the resulting low-beta quad motion
caused large (several mm) orbit deviations.  CDF reverted from the HVAC
change and the quads and orbits returned to nominal.  Some orbit smoothing was
needed and a new reference orbit file was made.  While both experiments needed
long access, there was an opportunity for Tevatron access and maintenance: 
turbos were installed/replaced at A45 and E47, fluorinert topped off in the F17
kickers, A49 spool 2-phase Kautzky valve replaced.  The AAK1 pbar abort kicker
thyratron tripped off during store 6102 - it was reset and turned back on
without incident; experts replaced a circuit breaker and installed some
diagnostics after the store ended.  One mystery has likely been solved; the
drifting of the vertical orbit for a few seconds after reaching low-beta is
being caused by the C:VA48 corrector which has a higher inductance and lower
slew-rate limit than other typical correctors; we may lengthen the duration
of that last time slot or try to reduce the requested currect chagne there.

* AC Dipole Optics Measurements (Ryoichi Miyamoto) - From a recent
suite of measurements at 150 GeV, Ryoichi presented new results.  In addition
to extracting the beta functions around the ring, he can also measure the phase
advances.  He observed the expected closed orbit changes and higher order
frequency modes when changing the current in a single sextupole element.  He
was able to reconstruct the location of that known source from the AC dipole
data, but several people pointed out that the real test would be to identify
*unknown* sources.

* Plan for Next Week

   - Deliver luminosity.
   - Vacuum tests and additional aperture scans to try to understand the 
     recent quenches around B0 in the squeeze.
   - HEP tune mult calibration (Ron, 1-2 hr end-of-store)
   - AC dipole (Ryoichi, proton-only)
   - Chromaticity tracker (Tan, proton-only)
   - Low-beta lattice measurements (Alex, proton-only)