Minutes of the March 16, 2007 Tevatron Dept Meeting

https://indico.fnal.gov/conferenceDisplay.py?confId=702

* News (Ron) - If you are interested in attending the next US Particle
Accelerator School (Jun 4-15), please let me know.

* Operations Summary (C.Y. Tan) - Over the previous two weeks, 39.8 and 34.8
pb^-1 were delivered to CDF and D0.  There have been 6 stores spinning in the
Tevatron over the past week with initial luminosities in the range 151 to 264
ub^-1 s^-1 (note the switch to the popular new luminosity units).  All stores
were terminated normally.  One shot attempt was lost early in the ramp - the
TCHROM Open Access Client may have had difficulty with the time change, and it
was restarted after protons were loaded.  The b2 unwind table was corrupted
and caused the sextupole currents to have a discontinuity on acceleration
causing the quench.  Store 5283 had larger than normal pbar emittances because
pbar injection closure in the Tevatron was not performed for some reason.  A
CDF IP adjustment was removed after it was found that the position bump caused
larger than desired orbit distortion in the arcs.  Orbits were smoothed in
all slots.  During an access on Monday: the crystal collimator was found to be
misaligned horizontally by 14 mrad - only a 7 mrad adjustement could be made
in-situ in the allowed time; some new IPM electronics were installed; the A25
and A35 spools were verified to have proper wiring; various turbo and rougher
pump maintenance.  The discrepancy between the low-beta vertical tune readings
from the 1.7 GHz Schottky and Tan's tune tracker is understood - for some
reason, the tune tracker phase needs to be altered between flattop and
low-beta; manually changing the phase gives agreement, but work needs to be
done to automate the change.

* Status of New Sextupole Studies (Alex Valishev) - We ramped and squeezed on 
the proton helix with the new sextupoles at zero.  The tunes, chromaticity,
and coupling were measured on the central orbit, proton helix, and pbar helix
(simulated with dipole correctors).  As expected, the changes were not large,
so it should not be difficult to tune up to run HEP stores in this
configuration.  Next to do: smooth central orbit up ramp and through the
squeeze, do a full tune-up, and verify with wet squeezes.

* Status of AC Dipole Studies (Ryoichi Miyamoto) - Ryoichi found that he gets
better measurements using a two-mode driven oscillation model (nu_d and 1-nu_d
where nu_d is the AC dipole frequency).  Previously, just using nu_d could, for
example, show what looked like a significant beta-wave around the ring.  Using
the updated model, Ryoichi was able to extract beta* measurments (@ 150 GeV)
that matched measurements made by Alex using the differential orbit technique
during the same study period.  A new switch was installed on the E17 kicker to
allow easy change-over between pinger and AC dipole operation.

* Status of Digital Tune Meter (Seva Kamerdshiev) - Seva and Alexei can get
reliable tune measurements of single proton bunches using the B11 vertical
BPM pick-up and using the E0 vertical tickler.  While tickling, the Schottky
power increases 6/9 dB (horz/vert).  They would like to install the tune
meter in the B1 service building and install coaxial relays at B1 and E0 so
that they can "take over" the B11 vertical BPM and the stipline when a tune
measurement is done.  There may be some minor issues to address before making
routing measurements during HEP, e.g. possible interference with orbit
stabilization on the BPMs.  For now, there will only be the unit for proton
vertical tune measurements.

* IPM Status (Andreas Jansson) - Two data boards previously removed from the 
tunnel because they were misbehaving likely were just affected by single-event
upsets - powercycling should fix, so they are adding functionality to remotely
powercycle the electronics crates.  Forty channels on each IPM are now working.
The first batch hard-programmed FPGAs have arrived, so the first production
boards should be ready "soon".

* Plans for Next Week

   - Deliver quality luminosity.
   - New sextupole studies (Alex et al., proton-only)
   - Transfer line matching (Andreas, during shot-setup)
   - E48 bumper to clean abort gap (Jim, Elmie, proton-only)
   - Chromaticity Tracker (Tan, proton-only)
   - AC Dipole @ Low-Beta (Ryoichi, proton-only)
   - ...