Minutes of the Jan 19, 2007 Tevatron Dept Meeting

https://indico.fnal.gov/conferenceDisplay.py?confId=525

* Operations Summary (Dan Bollinger) - The accelerator complex has continued 
running remarkably well.  The Tevatron delivered 45.8 pb^-1 to CDF and D0
over the Friday-to-Friday period.  There have been 8 stores over that period
with initial luminosites between 196 and a another new record 277 E30 cm^-2 
s^-1!  Four of those stores are in the top 5 for initial luminosities.  Only 1
store was lost unintentionally - store 5179 was aborted after 8 hrs when the
A2 potential transformer blew a fuse.  The new pbar cogging for the ramp
remains in place with no ill effects.  Dean implemented some improvements in
collimator moves that have reduced the halo removal time by a few minutes.
The E2 wet engine flywheel was replaced between stores.  TRF1 tripped off
during one HEP store.  The B17 roughing and turbo pumps trips have faulted off;
an access will be needed to replace them.

* Planning for Long Shutdown (Jim Volk) - Jim will be our shutdown coordinator
for the summer shutdown - assumed to be 8 weeks long beginning in early July.
There are several jobs already on the list (TEL maintenance, vacuum work @ A17
and C0, unrolling ~40 worst magnets, upgrade of low-beta hydrostatic level
sensors), and several others still being considered.  If there's a tunnel job
you need or want to do, let Jim know...the sooner the better!

* Long-Term Lattice Quad Tilts (Todd Johnson) - Todd looked at his tiltmeter
over the long-term.  Over the past 3 years, the B26 quad has a seasonal 
variation that seems to be growing (now ~1.5 mrad peak-to-peak in roll).  Since
in-store orbit stabilization was implemented, the VB11 dipole corrector current
follows the slow and fast changes of the B26 quad roll rather well (15 amp
changes over the 6 months).  The hydrostatic level system sees some of the 
general tiltmeter motion.  Todd also noticed that some quads, in particular
B25 and B38, that used to show very little roll changes, now have larger roll
features, including on the ramp.  He doesn't believe they are instrumental 
effects. Those magnet stands were considered good when last checked, but they 
will examined at the next opportunity.

* Electron Cloud Studies (Xiaolong Zhang) - Xiaolong and Bruce looked for 
vacuum bursts caused by electron cloud cacades when injecting high-intensity,
uncoalesced protons (30 consecutive bunces, ~1 ns bunch length).  They saw 
big bursts (~10^-6 torr) in the A0 and C0 warm straights when the beam
beam intensity reached ~ 10^12.  However, they didn't observe pressure rise
at B48 where an electron pick-up (retarding field analyzer) was installed 
during the last shutdown.  They did see small signals on the RFA when the
neighboring ion pump was turned off; the signals were consistent ~0.5 nA 
electron current predicted by simulation.  They wish to repeat the study with
higher beam intensity and/or longer bunch train and perhaps degrade the B48
vacuum a bit with heater tapes.  Simulations will continue as well.

* Observing Pbars in the IPM (Andreas Jansson) - The timing problem in the horz
IPM was resolved.  Pbars have been observed in both the horz and vert IPM @ 980
GeV.  After fixing a triggering problem, the vertical IPM can see pbars at 
injection.  Now Andreas can begin analyzing turn-by-turn data to look at
optics mismatches between the A1-line and the Tevatron.  A quick look shows
oscillations in both beam position and beam size at injection - more data
and analysis is needed, but at least we can do it now!

* Plan for Next Week

  - Continue delivering lots of lumiosity to CDF and D0.
  - Implement IP position change requested by D0.
  - Try different pbar cogging while waiting between pbar transfers (to
    look for better proton lifetime) (Ron - shot-setup)
  - Resume proton scraping @ 150 GeV (Dean - shot-setup)
  - Digital tune meter testing (Seva - during HEP)
  - Crystal collimator alignment (Dean - end-of-HEP stores)
  - ...couple of other studies