Minutes of the Apr 29, 2005 Tevatron Dept Meeting

1. Dept news: a) 105 days without a recordable injury in AD!; b) May 11
is deadline for PAC05 paper submission.

2. Jerry on operations: 6 stores, L from 70 to 123e30, two records L=119
in #4116 and 123 in #4118, both with >50% of pbars from RR; we are
enjoying record low losses of pbars (~1%) and protons (~2-3%) at 150 GeV;
good lumi lifetime; one store had only 24 pbar bunches and corresponding
data analysis shows that parasitic collisions do not affect proton
lifetime at all; E44 losses at pbar injections are gone; but D0 losses at
seq 24 are still present, although a sharp peak in the losses is gone after
parsing work and chromaticity adjustment.

3. Ron reported that pbar non-luminous loss rates depend on the helix size
as 1/d^3 (i.e. 30% effect for 10% helix size change); they also
depend on pbar emittances as emm^2. Helix size variations at an EoS
study show that there is no crossing angle (<5 urad) at CDF and D0.

4. Vladimir summarized Tev inefficiencies due to beam beam effects: a) now
the hit on integrated luminosity is about 25%; b) all sources of the
losses are now properly parametrized; c) if we are to increase pbar
intensity by factor of 3 (under corrent conditions) then the beam-beam hit
on luminosity (losses before collisions and reduction of luminosity
lifetime) will be about 45% - see beams-doc-1799.

5. Andreas investigated what happened after last week's FWs calibration
constants update: a) both vert (-) and hor (+) emittances changed but with
no effect on effective emittance; b) discrepancy with SL has become
larger, but it varies store-to-store (pbar SL mirror position effect?)

6. Elliott explained what was behind the FWs change (desire to use same
beta-functions in all applications): beta_y changed from 58 to 80 m, D_x
from 2.7 to 2.0 m; his comments sparked a discussion on how to measure
beta-functions at FWs and SL routinely/automatically.

7. Jean-Paul and Vic excited beam by VTICK at the end of a store and
detected single bunch tunelines by using digital scope. They believe that
employment of a better digitizer will allow them to achieve the same or
smaller noise level than current 21 MHz Schottky (advantage - tunes can be
measured for individual bunches). J-P & Vic also see smaller than expected
synchrotron tunes at 150 GeV (62-74 Hz vs 85-90Hz) - to be investigated
because new BPMs show expected f_s.

8. Vaia on CDF/D0 luminosity meeting: a) D0 fixed lumi-monitor and now it
reports baseline- and deadtime-corrected luminosity... still overreport by
4-6% due to recent reduction in their solenoid field - all corrections and
new DAQ to be operational in Aug-Sep; b) since the corrections, AC part of
the CDF/D0 luminosity ratio is reduced to 2%, while DC part is increased
to 9%+(4-6%); c) a part of the 9% discrepancy can be due to the fact that
CDF beta-functions seem to be smaller than the D0 ones: (Y/X)=29/34 vs
33/36 +- 1 cm.


Minutes recorded by V. Shiltsev; edited by R. Moore