Minutes of the Oct 28, 2005 Tevatron Dept Meeting

* Weekly Summary (Bruce) -  We had another good week in terms of initial 
luminosity.  Three of the 5 stores had initial luminosity > 140 E30 cm^-2 s^-1,
including the new record store #4473 with 158 E30 cm^-2 s^-1.  All stores
have had pbars from the Recycler only.  Two stores aborted unintentionally 
(without quenches): 4462 ended when a second RF station tripped off (TRF1 and 
TRF2), while in store 4468, the B2 VCB opened up and caused a ramp dump.  There
was a long (2 shift) access for D0 to replace calorimeter power supplies.  No
major work was done in the Tev, but several safety system tests were completed.
D0 has been hit hard again with losses at the end of the squeeze, but then we
made progress on solving the problem (see more below). Most of the CDF IP 
waist correction was implemented for store 4473.  

* Addressing D0 Losses at End of Squeeze (Jerry and Ron):  We believe we 
finally understand the root of the problem.  There were significant differences
in the arc orbits between low beta and collisions.  Ideally, the only changes
should be near the IPs as nearby separators ramp to remove the beam offsets
that prevent collisions.  However, the low beta separator settings were 
different and caused the arc orbit changes and smaller than desired beam
separations.  Separator settings at low beta were modified to fix the mismatch.
In addition, the sequencer was modified to start collisions automatically after
reaching low beta in HEP shots - this eliminated a needless delay of human
intervention.  Both changes were implemented for store 4473.  The losses 
while sitting at low beta were reduced greatly! There is still a loss spike
at sequence 24, so we will make similar separator changes there.

* IPM Shutdown Readiness (Jim Volk) - The IPM seems to be on track for
installation in the long shutdown, pending available tech labor.  One detector
is ready now.  The controlled vacuum leak was just installed into the tunnel.
The availability of spare vacuum pumps needs clarification.  The OTR is ready
to install, but we need to obtain the offset numbers for alignment.  On a side
note, the flying wire cans at E11 and E17 could be replaced if labor is
available.  Next week's meeting will cover the new crystal collimator and the
longer collimater for A48.

* Bunch-by-Bunch Tunes from Digital Tune Monitor (Jean-Paul) - Jean-Paul showed
results from 2 end-of-store studies in which they tried using the horz or vert
striplines to get bunch-by-bunch tune measurements.  They were able to see
single bunch tunes when using the vertical tickler VTICK!  The measurements
seem to be consistent with the (average) tune measurement from the 1.7 GHz 
Schottky system.  They will repeat the measurements using VTICK and HTICK, and
compare to bunch-by-bunch measurements from the 1.7 GHz Schottky.

* Chromaticity from BBQ + Head-Tail (Vahid) - Vahid and Tan made a first
attempt at using the Base-Band Tune system to make chromaticity measurements
using the head/tail method.  Sometimes the peak in phase decoherence occurs
60 turns or so later than expected.  The chromaticities seem consistent with
the usual head/tail method.

* Studies/Maintenance Plans for Next Week

   - Fix helix at LBSEQ 24 for D0 losses (several people, proton-only)
   - Using octupoles @ low beta (Yuri, Alex, end-of-store)
   - Increase helix size for HEP (several people, end-of-store first)
   - TBT application calibration (Eliana, proton-only @ 150 GeV)
   - several other studies if time...