Minutes of the Nov 15, 2002 Tevatron Dept Meeting


1. On Nov.1 Jim Volk transferred to Tev Dept to supervise enginnering
aspects of all hardware projects in the Tevatron tunnel. Welcome!

2. Vladimir on last week kicker prefire investigation: a) Dean/Jerry have
moved A11 collimator 100 mils closer to the beam; b) Bruce and Chris
Jensen considered measures to train the thyratrons and report submitted to
Mike Church; c) Nikolai Mokhov & Co to simulate how additional A48
collimator may help in future.

3. Jerry on b2-Workshop in TD last Friday: Td division is performing
magnetic measurements of persistent current effects in MTF, so far 2
magnets measured and sextupole fields behavior in them is quite
individual; because of the magnet "individualism", the TD team is
reluctant to install reference magnets in the Tev tunnel, also the
rotating coil msmt system does not seem to be a reliable solution.
Vladimir is proponent of the system and his arguments are a) it's not only
b2 that we want to monitor but also quadrupole and dipole field
components; b) rotating coil is not the only method, array of NMRs, Halls,
wires can be used as well. Alvin called for better understanding of
history effect in b2 and its better modeling.

4. Jean summarized SL/FW meeting: a) dispersive beam size is about or
larger betatron beam size in FWs; b) FW emittances are jumping because of
improper dp/p determination (dp/p is jumping while SBD bunch length is
not); c) scaling/difference in emittances btw FWs and SL should be
resolved; d) SL emittancs are intensity dependent. Jerry asked SL and FW
report in ACNET the same way as other devices (index 1-36 for bunches 1-36
and index 0 or no index - for average values. Valery was asked to provide
measured values of D_x, D_y in locations of FWs and SL.

5. Vladimir reminded that abstract submission deadline for PAC'03 is
Dec'03,2002. He asked people to think about what they want to present and
talk to him and Valery.

6. Dean described 4 stores last week with L=32.4-36.6e30. One store
(#1863) had record (+15% to previous record) pbar intensity but was lost
during squeeze. Dean mentioned that reduction of chromaticity at the
beginning of the ramp leads to smaller losses of pbars.  Calculated values
of p-lifetime at 150 GeV helix are not that bad compared toprevious month
but total p-loss at 150 is somewhat larger than it used to be (20% vs 15%
before).

7. Alexei Burov reported instability studies made 2 wks ago by peter
Ivanov and him. Measured impedance is about 3MOhm/m and thought to be
dominated by 44 separator plates. Alexei's macroparticle simulation code
(water bag model) describes results well.  He asked for additional studies
of minimum (threshold) C_v,h. Vladimir pointed that his model should also
include and demonstrate dependence of the instability on tunes and
coupling. Bruce passed results of the separator impedance measurements
to Alexei and Valery for further analysis.

8. Ron re-analyzed MI/Tev proton bunch length at injection, confirmed
effects of the long damper (5-10% blowup of P1-P12 length while loading
P13-24).

9. Alvin on pbar and p intensity calibration: the SBD intensities can be
easily calibrated wrt IBEAM (DC beam current). His analysis still points
that we probably have 4-5% less pbars than we think, on the other hand
there are some troubles with proton intensity calibration using the same
technique and that should be fixed before we can finally conclude on pbar
calibration.

10. Tanaji presented analysis of coupling studies around D0 at 150 GeV -
seems that there is either quad roll or some other source of coupling at
D0 but measurements are not understood well: e.g. first turn differential
orbit changes before the corrector which had been used.

11. Another puzzle: Morris Binkley reports that according to his new
counter at E0 losses from bunches anticorrelate with abort gap
losses: e.g. in recent stores if E0LABT is higher then E0LTOT is lower and
vice versa.