Minutes of the Sep 16, 2005 Tevatron Dept Meeting

* News - Vladimir remarked briefly on his recent trip to CERN for LARP.  He
described how turbulent flow of LHe through a line meant to cool a synchrotron
radiation screen in the LHC magnets could cause increased emittance growth in 
the beams.  He will pursue how to measure the effects via vibrations or
magnetic field changes.


* Weekly Summary (Ron) - There have been 6 stores put in since the last 
meeting.  Initial luminosities ranged from 62 to 107 E30 cm^-2 s^-1; the lower
luminosities were caused by fewer available pbars.  Only store 4378 was lost
unintentionally - a ComEd power glitch killed the store as well as the pbars
in the Accumulator and the Recycler.  Tan's Tune Tracker has been put into
operation for the ramp and squeeze of HEP shots; the sequencer turns it on/off.


* Tune Tracker (Tan) - The Tune Tracker has been used successfully on the ramp
and squeeze for 3 consecutive stores.  The reported horz tune seems to drift 
upward ~0.002 after reaching flattop, but before the squeeze...we can't see
the tunes clearly at that time without the tracker, so it's not clear if the
drift is real or just an instrumental effect.  We'll continue to use the
tracker for HEP shots to check the reproducibility of the measurements and gain
more operational experience.


* HEP Tune Mults (Ron) - During an end-of-store study, the pbar horz+vert tune
mult for 35 cm beta* was verified to be still well-calibrated.  After changing
to the 28 cm beta* lattice, 2 iterations of measuring and tweaking the proton
and pbar horz+vert tune mults were done.  The present 28 cm beta* mults are
deemed good enough for the first HEP stores with the smaller beta*.


* Studies for Next Week (all)

   The emphasis will be on making the 28 cm beta* lattice operational.  We need
up to 1 shift of proton-only stores to implement and verify the changes and 
tune up the squeeze.  The first 28 cm HEP store will have slightly reduced
proton and pbar intensities just for a bit of caution.  We will defer moving
the proton tunes above the 7/12 resonance for maybe a week or so, just so we 
can decouple the 28 cm beta* from the new proton working point.  Moreover, the
TEL pulsing scheme needs to be changed (to every 3 turns) so that the TEL can 
clean the abort gap efficiently at the higher proton tunes.  Changing the 
polarity of the B0 low-beta trims will also be delayed until we achieve stable
operations with 28 cm beta*

   Other studies on the horizon...

   - Try orbit stabilization at end of HEP store (when Vahid returns)
   - Try bent-crystal collimation at end of HEP store (Dean)
   - Measure chromatic beta functions near 1/2 integer (Alex, proton-only)**
   - Measure beam-beam induced beta-beating (Andreas, end-of-store)**
   - Investigate bend field drift @ 150 GeV (Bruce, proton-only)
   - Try octupoles to reduce chromaticity @ low-beta (Yuri, end-of-store)**

   ** = written plan has been submitted



Minutes recorded by R. Moore