Minutes of the March 7, 2008 Tevatron Dept Meeting

http://indico.fnal.gov/conferenceDisplay.py?confId=1616

(Note - this was our first meeting in 3 weeks, but we only focussed on last
week's activities.)

* News - CDF recently surpassed 3 fb^-1 integrated luminosity to tape - they 
invite us to a celebration today at 5 pm at the Users' Center.

* Weekly Operations Summary (Andreas Jansson) - Over the past 3 weeks, the
Tevatron delivered over 76 pb^-1 to CDF and D0.  There were only 12 HEP stores
with initial luminosities were in the range 100 to 281 ub^-1/s.  No pbars were
the big problem this week due to a failure of a lithium lens and difficulties
with spare lenses, so there were no pbars available for HEP stores for 3 days.
There was ample time for maintenance and proton-only studies which included:
tests of a modified orbit stabilization program, studies of P1 line and
low-beta optics, chromaticity tracker, splitting the SQD0 circuit, timing
of the E17 pinger trigger, and AC dipole studies.  CDF's 360 kW heater in their
HVAC system is functional again after replacing a failed 800 amp breaker;
temperatures and the low-beta quadrupoles are stabilizing.  Vic Scarpine
recently noted small energy offsets for proton and pbar injections.  We also
noticed some odd orbit changes in the last part of the squeeze; part of it
may be caused by the ramping of feeddown sextupole circuits that are slew-rate
limited, but additional investigation is needed.

* Status of BPM Mode-Switching Investigation (Brian Hendricks and Luciano
Piccoli) - There are still reports of some missed state transitions, but the
effect is mitigated by stronger checking and forcing the correct BPM DAQ mode
when a mismatch is detected.  A network sniffer has been installed to look
for dropped packets.  There have been firmware updates in network switches
that are expected to help.

* E17 Pinger Timing (Dan Bollinger) - A failed thyratron was the source
of the pinger problems.  After Dan replaced the tube, he and Ryoichi made
timing scans.  The pinger system is now operational, but Eliana requested
additional timing scans for use in her TBT applications.

* Split SQD0 Circuits (Ron) - The skew quad elements in the C49 and D11 spools
are now controlled independently via the devices T:SQC4 and T:SQD1.  The 
C49 application has been modified accordingly.  The currents are presently set
to the nominal values they had when in series in the old SQD0 circuit.  We 
need to plan studies to study the effect of running the elements with 
different currents.

* Low-Beta Optics Change Results (Alex Valishev) - The low-beta optics
corrections to reduce dispersion at D0 were implemented for store 5891.
Subsequent optics measurements obtained by the orbit response method are
consistent with the predicted values for beta* and dispersion.

* Plan for Upcoming Week

   - Now that pbar production has resumed, deliver lots of luminosity.
   - E17 pinger timing scans (Dan/Ryoichi, proton-only)
   - Investigate SQC4 and SQD1 circuits on coupling (Alex, proton-only)
   - E48 Bumper Magnet as Abort Gap Cleaner (Bruce, Jim, proton-only)