Minutes of the Jan 7, 2005 Tevatron Dept Meeting

1. Dept news: Jean-Paul Carneiro joined Tev Dept as Research Associate
- welcome!

2. CYTan - operations summary: 14 stores since Dec.15, max L=80e30, one
store lost due to kicker prefire, two due to high proton losses in squeeze
(only in presence of pbars); squeeze efficiency improved after parsing,
correction of chromaticities (C_v was above 20 after seq=9!) and vertical
tune adjustments; we ran with 10% reduced helix size (so max separator
voltage is only 100kV), there was only one spark over three weeks; 2 days
shutdown after ComEd power outage last Monday was used to fix vacuum leak
at A49 separator and to move CDF LB quads; noisy MUX boxes removed from
the 1.7GHz Schottky (Andreas/Ralph) that made tune measurements better;
21MHz Schottky's were saturated after the LB quad moves - seem to be
fixed now; strange background spikes took place during store #3906 - no
explanation yet.

3. Petr Ivanov, Yuri and Jerry had two periods of octupole studies,
observed superb proton lifetime on 150 GeV helix (1000 hrs for IBEAM, 45
for PNG) with octupole currents OD=6A, OF=-4.5A; some 4 hrs studies are
needed to be ready to try octupoles at 150 Gev in real HEP store.

4. Tan analyzed changes in CDF and D0 luminosity after recent RF trips and
concluded that beta^*'s are the same in both IPs: 36+-8cm at B0 and
34+-1cm at D0.

5. Jerry and Jim Volk presented the work done on CDF LB quads - 4 quads
moved (by max of 0.9 mm H and 0.3 mm vert) and 0.8 mrad roll of B1Q3 and
B1Q4 removed; the latter resulted in significant coupling changes (esp in
squeeze); at the end, currents in dipole correctors were reduced, CDF is
absolutely happy about IP positions and angles; the very next store had
remarkably low CDF/D0 luminosity ratio of 1.09 thought to be related to
the unroll (though in the store after that, #3909, the ratio was high
again R=1.16); separator scans at the end of #3906 did not reveal gross
separations at IPs, luminosities after optimization changed by about 1%.

6. Yuri checked helix closure after CDF LB quad moves and concluded that
voltages in D48H and A17H separators are some 20kV off optimal - to be
adjusted later. He pointed out that beam-beam effects may introduce
significant (40 urad) crossing angle and corresponding optimization scans
should be done at the beginning of store.

7. Mike Martens reported that SD and SF chromaticity correctors appear to
be 10% weaker than they used to be a year ago and that explains observed
chromaticity drifts of the order of 5 units; same for tune correctors
(tune drift is 0.002 at 150 GeV). The reason is not known yet (per TD guys
- not reshimming) but proper coefficient adjustments should be introduced
in the drift compensation algorithms.

8. Nathan Eddy flew one wire at the end of #3906 and CDF HV PSs did not
trip (the only effect was on CDF Roman Pots) and spikes of LOSTP were
tolerable (few kHz). That makes us to believe that we can fly new (thin, 7
micron) FWs regularly in the stores (though additional tests needed at the
start of HEP).

9. Vahid perfected his analysis of head-tail motion in proton bunches at
150 GeV and thinks that he can extract impedance information from slice
decoherence data. His model prediction resembles observations, though the
impedance estimates are orders of magnitude below what (we think) real
transverse impedance is - to be followed up.


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