Minutes of the TeV Dept Meeting, May 3, 2002

1. TeV work request list for the 2-week shutdown (June) was presented by
Bruce. It includes running cables for future C0 magnet replacement, fix
known vacuum problems(including F11), open aperture at F0, and replace TEl
e-gun.

2. Vladimir: a) results of the CDF silicon ladder rad test show that few
Mrad/sec loda experienced on during March 30 abort should not be a
problem; b) C0 IR plans are back - Peter Garbincius will lead the design.

3. Jerry on recent stores: record peak luminosity 18.3e30 in store 1280.
Bunch length blow-up (2 --> 3.2 ns rms) in the same store - no
explanation, 40% luminosity drop at the end of store 1253 due to HV
separator failure. Tanaji/Vladimir estimate the b-b separation induced by
that to be some 58micron=1.4 sigma with 28 pi mm mrad emittance. IP orbit
motion was also detected by BPMs. The most recent store 1283 was lost due
to (p) loss at the ramp.

4. Harry Cheung on SyncLite monitor: proton light is still blocked, orbit
bump studies show different scales in X and Y (and both are not equal to
1 - bump amplitude to be checked again by Valery/Aimin), SL optics is
tilted by no more than 1.5 deg, while pbar image ellipse is tilted by 15
deg.

5. Both Harry and Stephen (i.e. SyncLite and Flying Wires monitors) report
that scraping 75% of the beam led to ONLY 25% reduction of the
transverse beam size. Why was that?

6. Valery and Ron did retracted V and later H collimators by about 0.5 mm
during recent stores and observed very little reduction in the CDF halo
counter rates (<2%). That suggests that single large angle scattering is
basic process determining the CDF background (contrary to
previously thought to be slow diffusion). Too many questions, studies to
continue.

7. Mike Martens: V and H tunes early at the ramp are aligned with extra
break point, coupling found to play major role in previous tune wobbling,
energy mismatch fixed by changing E_inj from 149.95 to 150.02 GeV, beam
goes thru centers of quads... but synchrotron oscillations are still seen
(frequency mismatch?).

8. Yuri did reduce chromaticity by 4 units by introducing current in
octupoles. As the result, p-lifetime seems to be improved by factor of
3-4. That was tried successfully in store 1280 but - due to unknown reasons
- did not work in the next store 1283.

9. Double success for Tan's pbar-tune meter: a) got "stamp of approval"
from McGinnis and b) got nice/clean pbar spectra with 1000 averages. There
is some "regular noise" in the spectra which needs to be understood.

10. Bela Erdeli's simulations show very little effect on DA=dynamic
aperture due to (measured---> incorporated into tracking code)
nonlinearities of C0 Lambertson and C-magnets.

11. Meiqin tried to understand how cogging affects DA at 150 GeV due to
B-Beam and non-linearities. There are 4 stages of cogging, stage 0 was
found slightly worse than others but still DA is some 4-5 sigma that is
1-2 sigma larger than apparent physical aperture.