Minutes of the Jan 3, 2003 Tevatron Dept Meeting


1. Welcome to Andreas Jansson! - he joined the Tev group starting Jan 1
and will work on the Tev diagnostics. As a Peoples Fellow, he may use up to
50% of his time for self-directed research. Andreas thinks it'll be during
his sleep time :-)

2. Vladimir announced that Jerry Annala is going to arrange a few-week
long MCR training for new Tev Dept members (Amin, Vahid, Andreas?). Goal
is to make tham more familiar with Tevatron and eventaully be able to do
the Tevatron Coordinator job.

3. Vladimir explained why and how the BBCompensation team is going to
replace the TEL e-gun during the shutdown. New "Gaussian" gun has been
design, built and tested. It produces smooth e-beam edges and supposed to
improve p/pbar lifetime with the TEL.  Valery asked whether smooth edges
will deteriorate TEL ability to clean the DC beam, but Vladimir responded
that they should not.

4. CYTan store summary: luminosity was not that great last week (5 stores
with L between 22 and 31.6, only two stores >30e30). Intensities,
emittances and lifetimes were kind of usual. There was a 12 (out of 24)
house quench last week, Dec.28 (E48 Kicker prefire thought to be the
reason, but no hard evidences). Tan gradually (store-by-store) lowered
chromaticities on the ramp to straight lines (8 at 150 to 14 at 980) and
that led to smaller pbar losses on ramp (about 12% now vs 18-20% a week
ago). He also mentioned significant orbit wandering only 3 weeks after
smoothing.

5. XLZhang presented preliminary results of EoS studies when TEL was used
as noise source to blow up some pbar bunches - emittance growth rate
depends quadratically on the e-current fluctuation amplitude (as
expected). Pbar tunes were observed during this studies quite well (e.g.
for A12 Q_x is 0.004 above the proton tune)

6. Aimin has successfully tried to use new software which allows to vary
several ACNET channels while tracking others - she made hor orbit aperture
scan with HE42 and HE44 correctors while tracking changes in IBEAM. It did
work (till beam lost due to instability). Next step - make it work
for a fast straight section aperture scans.

7. Jerry smoothed orbits at flat top down to 0.3 mm rms (before that the
rms orbit-"silver orbit" was 1 mm or 3.5 mm peak-to-peak). That
immidiately improved tune behavior during squeeze. He also
returned coupling corrections back to where they were 3 weeks ago that
helped to decouple the Tev.

8. Todd presented plots suggesting that some of the orbit diffusion over
last week might be due to quench(es). E.g., roll of some magnets after
Dec.28 quench jumped by some 20 microrad. Some magnets recovered back
after few days, some (E35-1) did not. Valery raised the question should
we try to wrench alignment bolts of the Tev magnet support stands. Todd
presented a picture of one really ugly rusted support. During the
shutdown Todd will make pictures of all(!) Tev magnet stands. He is also
purchasing 10 more tiltmeters to track magnet motion.

9. Valery explained famous sqrt(time) beam loss at injection in a simple
scraping model. The scraping/shaving might be in transverse on in
longitudinal plane, on hard aperture (e.g. C0) or soft collimator (e.g.
beam-beam on protons). It's important to know distribution function at the
tails. Alvin will look into dynamics of the Tevatron bunch profile at 150
GeV to get an idea of what's going on in the tails. Andreas was asked to
look into raw 2D data from SL and see particle distrubution in the
(transverse) tails.

10. Paul made tune tracker working better, tune variations on ramp are
seen quite well (need to be compared with expert analysis of VSA color
tune spectrogram), synchrotron tune variation on the ramp is reported as
well, tune variation during stores is found to be some 0.002 peak-to-peak.


Minutes taken by V. Shiltsev, edited by R. Moore.