Minutes of the July 6, 2007 Tevatron Dept Meeting

https://indico.fnal.gov/conferenceDisplay.py?confId=989

* News (Ron) - Please complete your yearly accomplishment report by July 15;
the appropriate form can be downloaded from the URL 
http://wdrs.fnal.gov/elr/perform_rev.html.

* Last 2 Weeks Operations Summary (Xiaolong Zhang and C-Y Tan) - Almost 
62 pb^-1 was delivered to CDF and D0 over the past two weeks.  There have been
11 HEP stores with initial luminosity betwen 140 and 218 ub^-1/s; all have been
terminated intentionally.  Two HEP shots were lost @ LBSEQ 17 due to quenches
at D11.  Those shots had the "brightest" pbars (intensity/transverse emittance)
since all of our work on the new sextupoles and orbits - we had solved our
pbar emittance growth at injection by lowering the pbar vertical tune which
had become too close to the 3/5 resonance.  The smaller emittance pbars led to
stronger beam-beam effects and larger proton loss @ LBSEQ 17 when we have 
minimal separation during the transition to the collision helix.  We requested
lower pbar intensities as we investigated the situation. We believe the beam 
normally lost at this point hit D11 as a result of various angle bumps to 
reduce losses at the experiments.  Relaxing those orbit bumps has reduced
the loss at D11, so we have asked for higher pbar intensities again.  We still
have problems with beam loss and likely emittance growth during the transition
from LBSEQ 24 -> 25 when the changes for the new sextupoles are played out.
Upon request, IP adjustments were made this week: +100 urad D0 horz angle and
+500 um CDF vert position.  Those bumps were inadvertently once when an orbit
smooth was sent out.  The CDF vert bump was removed a second time when an
incorrect dipole corrector settings file was restored after replacing the 
VA18 ramp card.  The VA18 card was replaced because it was thought to be the
cause of a quench beam studies; later it was found the MCR console was sending
out incorrect values to the card.  The new electronics for the E17 Schottky 
system are ready for operation; an access is desired to swap in new amplifiers.
A set of differential orbit measurements were taken to help investigate the 
low-beta lattice with the new sextupoles; unfortunately, the measurements will
need to be repeated because the D0 low-beta quads were moving around at that
time, and the resulting orbit changes rendered the data useless.  CDF will
likely have a 2-shift access on Tuesday or Wednesday of next week to address
a leak in their silicon cooling system.

* CDF Diamond Loss Monitor Review (Dean Still) - Dean was part of a committee
that reviewed the CDF diamond-based loss monitor system.  They are preparing
to enable those devices as inputs to the Tevatron abort system.  (They will
replace the existing ionization chamber BLMs.)  These detectors are thin
film diamonds produced by chemical vapor deposition.  The proponents have
been evaluating their performance since October.  The diamonds are located very
close to the beam line and can provide turn-by-turn loss measurements using
the new Tevatron BLM electronics.  With their proposed threshholds, the new
system would not have pulled any aborts on events where the Tevatron system
did not either.  There were 3 occasions that the diamond system would have
pulled the abort faster than the Tevatron system did - that could allow better
protection capability.  The review committee supported the use of the diamonds
in the Tevatron abort system.  After tying up some procedural issues, they hope
to implement the new system for a couple of weeks before the long shutdown
begins on Aug 6.

* Plans for Next Week (All)

   - Integrate plenty of luminosity for the experiments.
   - Lattice measurements at low-beta (Alex, Eliana - proton-only 4 hrs)
   - Lattice measurements around LBSEQ 17 (Alex, Eliana, Yuri - proton-only
     4 hrs)
   - Pbar-only store (Yuri - check collision helix closure + other possible
     studies to be determined)
   - Transfer line measurements with IPM (Andreas - proton-only or shot-setup)
   - Chromaticity tracker (Tan - proton only - 2 hrs)
   - Try E38 kicker as abort gap cleaner (Jim, Elmie - proton-only)
   - AC dipole measurements (Ryoichi - proton-only)