Minutes of the Apr 2, 2004 Tevatron Dept Meeting

1) Ron on HEP store summary.  There have been 5 stores after the recent shutdown with initial luminosities 
ranging from 40 to 55 E30.  Three were ended unintentionally: 3328 - DQ9 quad tripped off in one (no quench), 
3337 - pbar abort kicker AAK1 prefire (multi-house quench), 3341 - cause yet unknown (another multi-house 
quench).  All 5 stores suffered from higher than usual 8-10% proton loss early in the ramp (causing rad trips of 
the D0 utility room) and poor pbar lifetime during scraping (4-7% pbars lost during the 10 min of scraping).  The 
belief is that is machine is not yet tuned up well.  Changes to feeddowns circuits are muddying the  problem.  
Tune adjustments are likely needed up the ramp and at collisions.   Separators scans were done at the end of 
store 3335, but there were only minor changes.  CDF has been suffering from high and/or spiky proton losses 
again.  Dean checked alignment of the secondary collimators during store 3335; 4 of them were misaligned by 
> 40 mils.  After alignment in store 3335, losses seemed much better.  However, the next 2 HEP stores still had 
spiky losses.  The problem is not yet understood.  On a different note, the usual Tevatron store summary 
spreadsheet now uses the SDA Supertable as its input.  That should save the machine  coordinates time and 
effort.

2) Nathan Eddy on Flying Wire status.  Nathan described recent work on the flying wire system.  The E11 horz
flying wire was replaced during the shutdown.  An additional attenuating filter has been added to all 4 loss 
monitors.  The gate timing for proton and pbars has been checked and improved.  A new DAQ FIFO may have 
eliminated the "jumping emittances" problem (larger than desired emittance measurement differences between 
opposite direction wire flies).  More analysis is needed before declaring victory.

3) Alex Valishev on Synch Light status.  During the shutdown, a beam splitter was installed into the proton synch
light box.  This splitter diverts half of the proton synch light to the abort gap monitor PMT (to be installed by end
of April?).  There has been some difficulty with the elctronics that provide the abort gap timing gate.  A CCD TV 
camera mounted inside the proton box allows one to see the correctly aimed light destined for the abort gap 
monitor.  (It's actually very interesting to see that display...lots of  "sparkles" from lost particles passing through 
the box.)  Progress on the abort gap monitor DAQ system is proceeding fine.  Overall, the synch light system 
is running well since the shutdown.

4) Tanaji Sen on tune vs collision helix.  Tanaji provided an update on this analysis.  Using the correct sextupole 
and feeddown currents, Tanaji's model now correctly predicts the horizontal and vertical tune changes observed 
by the 21 MHz tune fitter when varying the collision helix amplitude (uncoalesced protons on the proton helix).
The predicted chromaticity values seemed correct, but accurately measuring the chromaticity from the raw 
Schottly data proved difficult.  One of the DSAs used for the 21 MHz tune fitter has died. Jim Steimel will try to 
get it fixed, but support for those rather old devices may be difficult to find.

5) Valeri Lebedev on measuring tunes with BLT.  Valeri has analyzed part of BLT data sample obtained with 
coalesced bunches at 980 GeV.  He obtains beam position measurements with 2 micron RMS.  He believes he 
will be able to extract the tunes, but he needs to process additional data.  If it works, it will be great to have an 
additional method to measure the tunes during HEP stores.


Minuted recorded and edited by R. Moore.