Minutes of the April 8, 2005 Tevatron Dept Meeting

* Ron on Dept News - The 9 o'clock AD operations meetings will change to a 
Monday, Wednesday, Friday schedule.  (Mondays and Wednesdays in the Huddle,
Fridays in One West.)


* Jerry on operations summary - There have been 6 stores in the past week.
Initial luminoisities ranged from 65 to 111 E30 cm^-2 s^-1. All but one was 
ended intentionally.  One store ended prematurely as a result of a 
plate-to-plate spark of A49 vert separator #2 when running at the larger
"110% helix".  The latest two store had 5 pbar transfers from Recycler instead
of the usual 2-3.  Consequently, the effective emittance was ~10-15% lower,
but the lumi lifetime was lower as well.  The high losses between the
last 2 steps of the squeeze continues to cause problems at D0.  We have been
testing flying the E11 wires during HEP store. We have observed occasional 
high losses at E44 during pbar injections.  (See below.)


* Jerry and Vic on losses @ E44 - One shot-setup was delayed by a quench @ E44
that occurred during the first pbar transfer.  Several more instances of
high losses at E44 have been observed.  The losses don't occur on every pbar
shot, but when they do happen, they nearly cause a quench.  No smoking gun has
been identified, but the suspicion is that left-over beam from coalescing 
in the MI is not being kicked cleanly into the Tev.  Vic used the BLT to
look at pbar injections in store 4081.  He saw no differences on transfers
with high losses (#3, #8) and those without.  The investigation will continue.


* Ron on new longitudinal damper monitor - A new OAC automatically checks the
proton longitudinal brightness and longitudinal damper gain during HEP stores.
When the gain should be decreased to prevent driving an instability, an 
audible alarm is posted to the alarm screen to alert the MCR operators. The
digital status bits of the new device T:LNGDMP indicate a suggested gain
setting to be made by the operators.


* Yuri on longitudinal instability study - Yuri summarized the parts of the
study done with coalesced protons.  Several 36x0 stores were done at 150 GeV
with nominal cavity drive frequencies and (up to) 500 Hz lower.  Although some
interesting observations were made, there were no correlations among damping
time and bunch lengths at the different frequencies.  While loading the 36 
proton bunches, 6 of the 8 cavities had increasing temperatures, while the
other 2 had decreasing temperatures.  That may be expected, since it is thought
those two were the pbar cavities that have opposite phase of the proton ones.
(To be verified with the cavity experts.)  Ron noted that there have been no 
proton bunch length blow-ups during pbar injections while running with a lower 
longitudinal damper setting for the past two weeks.  More study and analysis
is expected on this topic that is more and more interesting.


* Mike on BPMs, moving CDF IP - 11 houses now have new BPM electronics
operational.  Another 4-6 houses will be installed today, but they will not
be cabled due to ongoing problems to be solved.  There is a problem with the
turn-by-turn feature that causes improper indexing of data 10-15% of the time.
This problem can adversely affect injection closure.  Another lingering problem
is the occasional of the BPM electronics missing a TCLK event; this hampers
orbit collection up the ramp.  It is important to solve these problems soon.
A proton-only store prior to an HEP store in order to help measure resolution
of the pbar orbit measurements; Mike will prepare a study plan.

CDF would like to have their IP moved down 400 um in one step.  We would prefer
a couple of smaller steps.  In order to do the big change from one store to the
next, we would need ~1 shift of proton-only stores to verify/change orbits,
tunes, coupling, etc, to give us confidence for the subsequent HEP store.


* Study / maintenance priorites for the upcoming week:
  - Proton-only store with seps off to gather orbit data.
  - Continue investigation of high losses during pbar injections.
  - Make periodic wire-flying during HEP operational.  (With D0, CDF blessing.)
  - Move CDF orbit downward.
  - Continued operation with different helix sizes during HEP.