Minutes of the Oct 24, 2008 Tevatron Dept Meeting

http://indico.fnal.gov/conferenceDisplay.py?confId=2183

* News (Ron) – The deadline for PAC 2009 abstract submission is Dec 1, 2008.

* Weekly Operations Summary  (Bruce Hanna) – The Tevatron delivered 51.7 pb^-1 to the experiments this week.  
There have been 9 stores with initial luminosities between 190 and 302 ub^-1/s.  Two stores ended unintentionally: 
store 6500 was aborted after 8.9 hrs on a RF anode trip caused by a spurious crowbar indication and store 6507 was 
aborted after only 2.7 hrs when a CAMAC crate power supply in the C4 electronics room failed.  A CAMAC power supply
in A2 failed during shot-setup causing noisy MDAT signals and problems for ramp cards around the whole ring, 
eventually quenching the D0 low-beta quads; a Kautzky valve at C45 needed to be reseated.  Other work included: 
orbit bumps in the squeeze to reduce losses at D0, deicing of low-beta power leads at B0 and D0, UPS replacement 
at C2 and D3, rougher and turbo pump replacement at A27, correction of a mis-wired motor for the crystal collimator.
The F2 power supply is showing regulation problems again.  We still observe occasional pbar transfers that end up
with large emittances – we continue to try to identify some beamline element that may not be ramping properly.

* Low-Beta Lattice Correction (Alex Valishev) – The source of the increased D0 beta* is local coupling at D0 
equivalent to (as incorporated in the model) the Q3 magnets rolled by 0.5 mrad.  Fortunately, we we were able 
correct that coupling using SQC4 and SQD1 (the independent circuits created when we split SQD0 last year).  After 
testing the correction near the end of an HEP store, it was implemented during store 6503 and increased D0 
luminosity about 4%.  The CDF and D0 luminosities now match to within ~1.5%.  It was also noted that the D0 
low-beta quads have been moving lately, as measured by the tiltmeters and hydrostatic level sensors.

* Beam-Beam Compensation Studies (Seva Kamerdzhiev) – The new modulator for TEL-2 has been exercised successfully 
during 3 end-of-store studies.  The new modulator can be used on single bunches within trains with better than 1% 
variation in output voltage.  It can also be configured to generate the pulsing pattern needed for abort gap 
cleaning, if needed.  When acting on proton bunches were worst lifetime (P3 and P4) during studies, lifetimes did 
not improve suggesting the vertical tune may be too high even without the TEL.  If we lower the tune to help, 
bunches at the ends of the train may then suffer, but TEL-2 could then be used to raise their tunes.  They are 
ready for studies at the beginning of stores.

* Plans for Next Week
   - Deliver luminosity.
   - TEL-2 studies (Seva, Xiaolong, et al., during HEP stores)
   - B0 quad tickling (Jerry, Alex; during shot-setup, proton-only)
   - E48 bumper as abort gap cleaner
   - HEP tune mult calibration (Ron, 2 hrs end-of-store)
   - Crystal Collimator (Dean et al., end-of-store, proton-only)