Minutes of the 08/02/02 Tevatron Dept Meeting


1. Bruce presented the status of the new Schottky detectors to be
installed at E17: location is good for 36x36 as dT between arrival of p
and pbar bunches is 125 ns (for 132ns spacing it'll be 9 ns), the
detectors (2=V+H) probably be ready by Oct.1, there are doubts about
vacuum properties of the ferrite in them and we (Dan+Mech) will
investigate possibilities to do vacuum test, we(Crisp?) have to measure
impedances before we put them into the TEV (Ralph says it's about 16kOhms
at 1.5(?)GHz), another concern is that some electronics may be installed
in the tunnel - we(Dan, Bruce) will place either TLD or thin Al foils
there and measure doses.

2. Vladimir has requested place shot-stetup summaries into the TEv E-log
after each shot: general or specific comments on intensities nad
emittances; Schottky/instabilities/bunch length; what's different from
previous store(s), what's new in Tev; anything unusual in other machines,
etc. To be done by any person present at the shot: Tev coord, on-call
person, anybody from Tev who feels that (s)he understands what's going
on.

3. XLZhang reported record L=26.4 in store 1583 and good lumis 2
stores afterward except 1613 when there were problems with pbar injection
+ small stack (L=13.4). All stores had quite poor proton lifetime
early in stores (40 hrs vs usual 150-350 hrs). Vladimir suggested that we
have some eort of longitudinal shaving because he sees that sigma_s does
not change at all during the first 1-2 hrs. We have decided to oblige Tev
on-call people to attend this weekend's store(s) and take part in lifetime
optimization (vary tunes, coupling, C_v,h, orbits-??). Following Stephen's
comment (that we fly FWs 50 times during shot set-up) Valery told that
it's insignificant contribution to the emittance growth at 150 GeV, but
Paul had different opinion (later today Valery recalculated and got
dEmittance=3pi, very close to Paul's experimental evidence reported last
week! - so we'd better do only few(e.g., 3) flights during p-injection).

4. Ron investigated large orbit changes at IPs after recent orbit
smoothing (D0 H+600, V+1250um; CDF H-500, V-300um). Tev Collision point
monitors agree with detector monitors (except sign in the B0 X-position).
(Sign difference now understood - Ron 08/05/02) 
D0 wants their IP to be moved down by 1mm and inward by 0.6mm. Mike
Martens will do that next week after one more round of talks with D0
guys. Ron also mentioned that detectors worry about large (50-100 micron)
movements of their IPs during regular HEP stores.

5. Mike M. summarized orbit smoothing on 7/30: smoothing done 3 weeks ago
had incorrect BPM profile timing - tha was fixed, orbits look not good in
arcs, but IP positions need more work (e.g. D0 requested position change
in the direction opposite to what Mike though is right). Still there are
some problems: some correctors run hard, once he obsereved that the orbit
drifts by 1 mm over few hours (vertical); he thinks that we have to
implement "operational smoothing" (faster procedures and more frequent);
we probably do not need A0 and F0 bumps at flat top - to be removed next
week.

6. CYTan reported successful demonstration of the longitudinal
bunch-by-bunch damper effectiveness at 980 GeV : over some 7 stores when
the damper was ON there were no bunch length blowup, then in the only
store with damper OFF the blowup took place and again, there were no
blowups in the following stores with the damper ON. Congratulations! Now
he is looking for positive effects of the damper at 150 GEV. The first
observations show that coalesced bunches do not "dance" that much with the
damper ON at 150 GeV.

7. Yuri summarized studies of beam stability at 980 GeV (36x0, low-beta?):
a) tunes are the same on p and pbar helices, measured C_h=20, C_v=12; b)
stability (Schottky power)  depends on V and H position at F0 (closer to
the center of RF cavities - the better, futher from the Lambertson notch
the better); c) there were some strange 10 sec oscillations observed in
Schottky power - external noise?; d) very high order modes (eg 5 or 6
Q_s) become unstable. Vladimir/Valery suggested to build a monitor to see
these head-tail modes.

8. Valery told that the first attempt to fix A1 line was not successful -
not much of emittance improvement, though he expects to elimitate some 60%
emittance dilution in H and 30% in V plane (and requested 5 shifts over
the next month).

9. Alvin asked for end of store studies with reduced RF voltage and wants
to install scintillator paddle on/near proton target collimator @ D49 to 
calibrate CDF loss counters.