Minutes of the 22 Nov 2002 Tevatron Dept Meeting


1. Vladimir reviewed 28 possible Tev-related presentations for PAC'03. All
primary authors OK'd to send papers. Tanaji added B0/D0 decoupling report
(Bela as primary). MMartens has reservations on orbit smoothing paper he's
supposed to submit.

2. Ray Stefanski summarized survey work done during 2 shift access -
mostly as founds at C0 + two suspects remeasured at A(?) Still there some
Q's remain - e.g. mess in where magnets should be longitudinally.
Though shutdown list finalized, tHere are still some unresolved issues with scope 
of alighment work at A-E during Jan shutdown - will we move any A,E,F sector dipoles or not?

3. Lucano Piccoli (CD) described new PC/Java software tool available in
MCR which allows to change settings of ACNET devices and get readings of
other devices. People are welcome to try. Aimin+MM+Valery will try to set
it for automatic ring-wide aperture scan msmnts.

4. Jerry summarized stores last week : there were only few successful
ones due to access and 12 hrs after access recovery, then one store was
lost due to quench in squeeze (with record pbar intensity in it). Squeeze
was parsed thru dangerous steps and losses dropped significantly. It's
not 100% clear, but seems that higher pbar intensities aggravate proton
losses in squeeze. Pbar lifetime at 150 is consistently good because of
differential chromaticities (much lower on pbar helix).

5. Dave Johnson reported no success with 5-bunch coalescing -
ramp efficiency was the same as for 7. He mentioned slight long blowup at
the beginning of flat top - sigma_s blowups are back?

6. Vahid Ranjbar analysed TBT data and extracted tunes and coupling at
injection of pbar and p bunches: he observes some scallop like variation
of pbar hor tune of about 0.001-0.004 (varies store to store), vert tune
is too low, coupling in some stores was huge for pbars (dQmin about
0.01!). Situation with protons is closer to our ordinary understanding.
Next on list - a) correlate pbar tune variations with lifetime; b) make
sense of the variations, talk to Tanaji and Meiqin on what we should have
at inj.

7. Peter Ivanov presented progress in understanding head-tail: a) beams
are elliptical at 150 due to large dispersive size, so it plays role in SC
forces and that makes vertical plane much less stable than hor plane; b)
OZF and OZD should have opposite polarities to stabilize HTI (before they
thought polarities must be the same); c) octupoles help to stabilize
instability because they introduce nonlinear chramaticity rather than
because of betatron tune spread.

8. Vladimir on studies with Schottky: a) vert tune varied in collisions
#1968 by 0.004 with about 20 min period (not regular); b) we need
Maraffino/Lebrun software analysis!; c) at injection and in stores
Schottky power P proportional to beam intensity P propto N; d) Markus H
and Brian F tuned Pbar vert Schottky and it started to show some pbar like
signals (see below).

9. Frank Z summarized EoS pbar tune and pbar removal studies: a) TEL was
tuned by XLZ to be a noise tickler for selected pbar bunches, TEL
parameters adjusted to have decent lifetime; b) for bunch A24 V tune is
0.003 lower and hor tune is 0.004 higher than proton; c) as for pbar
removal we realized that there is significant discrepancy between FBIANG
and SBDAIS at low intensity; d) there is difference about 2 in pbar beam
sizes btw SL and FW; e) surprizingly, after scraping (5% of the beam left)
remaining beam had significvant emittance (say 1/4 of intial one).

10. Finally, Alvin reconsidered distribution of losses in between the
bunches and found similar pictures as Morris Binkley presented week ago.
Alvin has also checked that longitudinally bunches are spaced equally,
though beam loading makes the distance shorter than usual 18.9ns and
thus, abort gaps are (a very little bit) shorter than for low-intensity
bunches.