Minutes of the Nov 9, 2007 Tevatron Dept Meeting

http://indico.fnal.gov/conferenceDisplay.py?confId=1367

* News (Ron) - Next Wednesday, 14 Nov, there will be a speical seminar on 
optical stochastic cooling in Curia II from 10:00-12:00.  There will be a
follow-up discussion from 13:00-15:00 on possible uses in the Tevatron
(location to be determined).

* Weekly Operations Summary (Jerry Annala) - Tevatron post-shutdown 
commissioning continues.  There have been 5 HEP shot attempts in the last week.
The first three stores, with initial luminosities between 90 and 97 ub^-1/s,
were terminated intentionally, but the last aborted in the
squeeze during the transition to the collision helix.  We have been keeping
beam intensities low intentionally as we try to fix the transition to the new
collision helix.  Unfortunately, we have been unable to fix the helix, so we
are reverting to the old helix.  The CDF low-beta quads needed to be moved
since we were unable to move the interaction point to their desired position 
within the current limits of our dipole correctors.  Two separators were
found to be producing less kick than expected; a bad surge resistor was
found and replaced at both the D48H and C17V separator locations.  After the 
CDF low-beta quad moves, the low-beta optics were remeasured and found to be 
close to desired; any corrections will wait until at least the next HEP store 
so we can see if the CDF IP position is OK.

* Measuring Separator Responses (Yuri Alexahin) - Only the aforementioned D48H
and C17V separator problems were identified in this study.  Yuri has been
using this data to design new helices more reliably.  A bad BPM (already fixed)
was causing confusion when working on the new helix, but it is now understood.

* New Idea for Old Helix Transition (Ron Moore) - The problem with the
transition from the injection helix to the collision during the squeeze is the
need for the B17H separator to ramp to 0 and change polarity - horz beam
separation becomes reduced.  There are 4 separators at B17 all powered by a 
single power supply set.  If we could power the 2 pairs independently, it would
be possible to leave one set on while the other switches polarity.  It's not
clear if that would be beneficial.  Issues include depleting our spare
supplies, polarity switches, and controls cards.  Removing old Main Ring
power supplies would be needed to create floor space in the B1 service
building for the additional separator infrastructure.  The plan will be 
investigated in more detail after regular HEP operation resumes.

* Plan

   - Continue recommissioning after moving CDF low-beta quads and reverting
to old helix.
   - Set tunes, feeddowns, etc. on proton and pbar helix up the ramp and
through the squeeze.
   - Verify CDF IP with a 36x36 store.
   - Iterate, if needed.
   - Get back to normal running.