Minutes of the Jan 17, 2003 Tevatron Dept Meeting

1. Jim Steimel summarized Tev BPM meeting held last week: requirements
have been reconsidered, there were number of suggestions how to proced
with design (e.g., Andreas is in favor of LHC design), Yuri Alexahin was
asked to outline reasons why we need turn-by-turn option for all BPMs. Jim
still sees modification(fix) of existing BPMs as an option (if not
expensive).

2. Jim Volk reported shutdown progress: 50% of C0 has been done, 33% of
E17 Schottky project and CDF shielding has been done. Pinger (vert kicker
magnet) at E17 was found 1" horizontally OFF the place it is supposed to
be.

3. Other shutdown projects: a) Bruce is still waiting for 10 out 16 ion
pumps to improve F0 vacuum; he observed that A1 and P1 lines significantly
deteriorate F0 vacuum if valves are open; b) XL says that TEL gun
replacement was successful vacuum-wise, gun test will start as soon as LCW
is back; c) Vladimir said that sinking of the B0 lowbeta quads will be
monitored by two water levels while shielding blocks are being installed;
d) Andreas and Dean will calibrate mechanical movements of some Tev
collimators; e) Jim S said that TD guys (Gennady and Temir) will try to
measure vibrations of RF cavities and correlate them with RF phase noise;
f) Mike Martens made a point that PSD box removal in the arcs obly will
not slow after-shutdown recovery, it was decided to remove them.

4. Bruce reported results of Tev aperture scans he and Dan did the last
week before shutdown: yes, C0 still was the tightest vert aperture, in all
other places apertures were not significantly different from what we
measured in Feb'02. Bruce does not see any beam evidence of significant
magnet misalignment at B16 - opposite to survey data.

5. Yuri analyzed helix options after C0 magnet replacement and found that
it would not be optimal to go back to "old injection helix" with only 2
separators. Instead, he thinks with 3 separators (B11H, B17H, C17V) helix
would be better, allowing almost 1 sigma larger beam-beam separation. He
continues to work on helices on ramp and during the squeeze where he feels
we still need and have possibilities [like - use B11H] to separate beams
more.

6. Tanaji analyzed old data on luminosity drop in store #1253 when failure
of one of H-separators occured. His model describes all observed phenomena
(lumi drop, lifetime, even beam lifetime) very well. He pointed out that
one can determine effective emittance from lumi vs (separator voltage) -
and result will be beta^* independent.

7. Vladimir have found that effective emittance reported in the Tev store
spreadsheet is overestimated because the hourglass factor in the formula
is 0.75 instead of 0.6. That has to be corrected by the next Tev
coordinator.  With that correction effective emittance for store #1953 is
equal to 16.5 pi, while eff-emittance from FW measurements is 21pi -->
either FW scaling is wrong for p or/and pbars and emittances are actually
smaller or beta-function is smaller. The latter does not look probable as
estimated beta^* at CDF and D0 is even larger than the design beta^* (42
cm vs 35cm). The issues should be resolved by - a) FW calibration V/H for
p/pbars - that requires better knowledge of beta-functions; b) using
lumi(separator voltage); c) ???

8. Alvin got time to look into losses during record luminosity store #1953
and found that the losses also were unusual - there was high p-loss rate
at the beginning of store due to some "beam dynamics" reason. We don't
have those large losses anymore (since early November when tunes were
slightly corrected). He also observed some saturation effect in E0TOT
counter - again early in the store when losses were high. At the end of
the store RF bucket losses dominated.


Minutes recorded by V. Shiltsev; edited by R. Moore