Minutes of the December 16, 2005 Tevatron Dept Meeting

* Weekly Summary (Jerry Annala) - The Tevatron was turned on and beam operation
resumed after nearly 3 weeks of down time started by the failure of the B17
spool piece during a quench on Nov 21.  In addition, dipoles at B17-4 (low 
quench current) and B11-2 (failed hipot) were replaced.  A high voltage 
feedthrough the B11H #2 separator developed a vacuum leak and was replaced
during the shutdown.   There were 3 shots were pbars were injected into the
Tevatron; 2 made it to HEP.  The first had a lumi of 38 E30 cm^-2 s^-1 and
ended in a quench 2 hours later due to an instability exacerbated by the 
very small pbar intensities.  The other ended with a quench induced by a 
spark in the B11H #1 separator.  As a result, we spent 3 shifts reconditioning
the B11 separartors in both polarities.  One shot attempt ended in a quench
during scraping; it was later found that one face of the F17-2 collimator
is damaged.  The best guess is that the damage occured during a multi-house
quench in June, but beam somehow avoided that small part of the collimator
until now.  The collimator will not be used for now, and it will be borescoped
at a convenient time to decide a future course of action.

* Status of IPM (Andreas Jansson) - During the 3 week shutdown, the vertical
Ionization Profile Monitor detectors was installed at E0.  The vacuum is 
~10^-7 torr, about an order of magnitude higher than expected.  (That's 
without the controlled leak valved into the system.) Some component may be 
outgassing more than expected, but this behavior was not seen on the bench.
While testing electronics without beam, noise was observed around 2.7 MHz.
However, there is still additional filter components and grounding to be 
completed.  The high voltage section still needs to be tested.  The OTR was 
also installed, but the foil can not be removed from the beam line remotely;
the motor seems unable to overcome vacuum forces.  Some cable adjustments may
be needed to solve the problem.  The foil was manually moved out of the way 
and locked out until an opportunity arises to implement and verify a solution.

* Electron Cloud Studies (Xiaolong Zhang) - Xiaolong tried to identify the 
locations most likely to suffer from electron cloud problems in preparation
for future studies and installation of new hardware.  He ramped 1 E12 protons
in a single uncoalesced batch and saw vacuum in the C0 straight increase by
2 orders of magnitude.  The Schottky power indicated some weak instabilities
that gradually damped without intervention.  There was no obvious pattern
of bunch lifetime or lengthening along the train.  The 2"x4" beam tube in the
(Main Injector) dipoles in C0 is the likely source of the problem.  Xiaolong
will try using the 1.7 GHz Schottky system to measure bunch-by-bunch tunes
and try to look at the bunch-by-bunch flying wire emittances.  Xiaolong and 
Bruce Hanna have a proposal to install a section of MI-style beam pipe during 
the long shutdown (in parallel with the separator installation there), along 
with electron detectors and a weak solenoid.

* TEL-1 Work (Vladimir Shiltsev) - Vladimir summarized recent TEL-1 work and
studies.  The spare modulator was installed and tested.  The TEL BPMs were
calibrated (there is a big dependence on the bunch length).  A new RF gun was
also installed.  It provides a wider & flatter electron profile than the old 
gun, so it is easier to align the e-beam to the protons (or pbars).  They did
some proton-only studies with the new RF gun.  They tried tune-shifting a
single coalesced proton bunch and compared to 2 other untouched bunches.
The max horz tune shift of 0.0044 was in good agreement with theory.  The
lifetime of the bunch being shifted was ~140 hr, while the other bunches
had ~280 hr.  They are ready to try tune-shifting a pbar bunch in an
end-of-store study, and to resume lifetime vs working point studies.  They
will also attempt to tune-shift pbars and clean the abort gap simultaneously.

* Plan for the next week

   - Return to normal Tevatron operations prior to the holidays.
   - There are a few studies to do if time permits...
     - Eliana's coupling adjustment application @ 150 GeV.
     - Tan's chromaticity tracker.
     - 36x0 proton-only store to measure lifetime from IBS.
     - Crystal collimator (end-of-store)
     - HEP tune mult calibration (end-of-store)
     - TEL studies