Minutes of the May 4, 2007 Tevatron Dept Meeting

https://indico.fnal.gov/conferenceDisplay.py?confId=833

* Weekly Operations Summary (Dean Still) - We delivered 33.6 pb^-1 to CDF and
D0 over the past week.  There were 6 HEP stores with initial luminosities
between 165 and 245 ub^-1/s.  Only 1 store was lost prematurely - store 5384
was lost after 6 hrs when a thunderstorm rolled through and lightning caused
a glitch that caused a spurious D0 SMT abort.  After that abort, we began a
lengthy effort to implement the new sextupole configuration (see next topic
below).  Various problems include: the A1 QPM not communicating via ACNET for
a couple of hours - a temporary work-around is in place; the TCHROM OAC not
loading the proper time ramp for the b2 unwind for acceleration; the E48 pbar
injection kicker requiring a top-off of SF6.  The A1 BLMs were switched over
to the new electronics to move forward on commissioning; there has been good 
progress on the software, but there is too much noise on the readbacks from
the new system.

* Summary of New Sextupoles (Jerry Annala + comments from many others) - The
point of the current effort is to turn OFF the new sextupole circuits.  We 
spent over 4 shifts this week to do an HEP shot in the new configuration.
The big problem is high proton losses at the C49 separators at 150 GeV and 
early in the ramp.  After spending > 18 hours on studies Monday-Tuesday owl
shifts (implementing orbit corrections, general tune-up), we reverted back to
the old configuration because of the unresolved high losses at C49.  On
Thursday, we revisited the situation, identifying coupling and chromaticity
as problems early in the ramp.  After satisfying ourselves we could ramp
a 36x36 store, we went into shot-setup but encountered some more problems.
The chromaticities after coming back down to 150 GeV have been inconsistent.
There were still high losses at C49 while injecting pbars, and the proton
lifetime was rather poor. We believe additional adjustments (tune, coupling,
chromaticity) are needed on the proton helix, and the helix itself may need
some tweaking to reduce beam-beam effects that seem to be worse now @ 150 GeV.

* Plans for Next Week (All)

   - Continue improvements after implementing the new sextupole configuration.
   - Deliver luminosity to CDF and D0.
   - the usual list of desired studies should the time arise