Minutes of the Nov 4, 2005 Tevatron Dept Meeting

* Controls Linux Port (Roger Tokarek) - Porting the AD controls from VMS to 
Linux is in full swing.  Users are encouraged to use the so-called duplex 
consoles when launching ACNet consoles from their office PC.  Application 
keepers should also begin trying to build their applications under the Linux 
build system to identify porting problems.  (Known problems include fileshares
and different floating point representation.)

* Weekly Summary (Andreas) - There were 6 HEP stores in the past week with
initial luminosities ranging from 138 E30 to (new record) 164 E30 cm^-2 s^-1.
Two stores had delivered lumi per experiment (averaged) over 5.5 pb^-1.  TRF1
has tripped off three times this week; the PA was replaced once already, so
RF experts are scrambling to understand the problem.  One store was lost when
TRF2 tripped off after TRF1 had done so earlier.  The RF trips also dumped 
lots of beam into the abort gaps, and Xiaolong needed to assist cleaning it
up a couple of times.  The F2 wet engine chewed up its bearings, but it lasted
long enough to have the store terminated intentionally.

* A48 & Crystal Collimator Shutdown Readiness (Jim Volk) - CDF will remove
their pot detectors at A48 so we can install a longer collimator.  T&M will
fill the floor holes so the collimator stands can be placed where desired.
The collimator is ready, but new spool pieces need to be made.  A new crystal
collimator (specific for Tev) will be replace the one at E0.  We hope to remove
the existing crystal assembly during a short (~1 shift) shutdown to replace the
innards at NWA.  The assembly could then be reinstalled more readily during 
the long shutdown.

* Trying Octupoles during HEP (Yuri) - During an end-of-store study, the
octupole circuits were powered to investigate if they would help stabilize
coherent oscillations for lower chromaticities.  We would like to lower 
chromaticity to try to improve beam lifetime.  The O2 circuit did lower the 
pbar vertical chromaticity, but less than expected.  Proton lifetime fell when
the OF circuit was turned on, no other tuning helped it.  The pbar lifetime
improved slightly as the chromaticities were lowered close to 0, but the proton
lifetime remained bad until OF was turned off.  The 1.7 GHz Schottky proton
horz chromaticity reported higher than expected (7 vs 2 units).  Analysis will
continue on understanding the results and developing new ideas (rewiring
octupole or sextupole circuits?) to allow lower chromaticity.

* Measuring Pbar Tune Spread due to TEL (Xiaolong) - Xiaolong et al. wanted
to compress the tune spread of a single pbar bunch (A12) during an end-of-store
study.  They had trouble centering the electron orbit on the pbars since
pbar losses were quite low and the tune shift was hard to detect since the
signal/noise for a single-bunch tune measurement is low.  The electrons
excited coherent motion on the pbar bunch as they were attempting to move the 
e-beam.  In addition, abort gap cleaning efficiency dropped when the electrons
were moved away from the proton orbit, so we can't (easily) tune-shift pbars
and clean the abort gap with a single TEL simultaneously.  They would like to 
repeat this study and improve how to center electrons on the pbar orbit.

* Joint AD/CDF/D0 Luminosity Meeting (Vaia) - Vaia summarized talks from 
Wednesday's AD/CDF/D0 meeting.  Both experiments summarized luminosity checks
and beam width measurements since the Tev implemented the 28 cm beta*.  Both
experiments see improvements in their beam width/beta* measurements.  D0 made
their new VME-based lumi electronics operational, and the linearity should be
much better; they are still finalizing the absolute scale.  CDF compared their
lumi measurements to currents in the outer tracker superlayer wires; the
linearity is very good.  Having more uniform bunch-to-bunch luminosities would
be useful - factor of 4 difference is too much...request passed on to the 
Recycler for more uniform pbar intensities - they're working on it.  Both
experiments want AD to keep pushing peak luminosity since they are uncovering
new problems and they need to learn how to run at those luminosities routinely
in the future.

* BPMs and D0 IP (Mike) - Mike showed that we can correct the D0 IP that has
been slowing moving (few 100 microns both planes) over the past several weeks.
He would like to implement the changes during an end-of-store study.  A bug
in the BPM front-ends that affected fast time plots has been fixed.  The proton
and pbar positions (relative to central orbit) @ 150 GeV over the past 90
stores has been very consistent.  That demonstrates long-term stability of the 
BPM system (and separators).  The RMS variations are ~50 microns which is about
the same size as motion within the beam, so that's about the best measurement
one can do.  One can identify a few BPMs with problems from this study, too.

* Enlarging the Collision Helix (Alex/Ron) - Alex and Ron did an end-of-store
study in which they enlarged the collision helix horizontally by 5%.  The tune
changes were hardly visible.  The beam lifetimes maybe decreased a little, but
the collimators were not retracted, so there was some shaving.  We should be
able to implement these changes for operations without worrying about big
tune changes.

* Studies/Maintenance for Next Week

   - Change helix at LBSEQ 24 (D0 losses)
   - Move tunes above 7/12 @ 150 GeV (Yuri - proton-only, shot-setup)
   - Bunch-by-bunch tunes with new tune monitor (Jean-Paul, mid/end-of-store)
   - Crystal collimator (Dean, end-of-store)
   - Calibrate HEP tune mults (Ron, end-of-store)
   - Pbar tune spread (Xiaolong, end-of-store)
   - TBT calibration @ 150 GeV (Eliana, proton-only)
   - several other studies if time permits