Minutes of the Tevatron Department meeting, Friday, May 31

1. We have a new Web site http:www-bdnew.fnal.gov/tevatron
Thanks to Ernie and Ron!

2. Bruce reported readiness for the 2 week shutdown: F0 BPMs and striplines 
to be ready in time, vacuum test has shown that another type of microwave 
absorber has much better vacuum properties and will (probably) replace 
the ferrite in the F11 RWM.

3. we are all aware of power outages starting Mon. 7 am

4. in the absence of Jerry, Vladimir reviewed luminosity during the last 
(the worst since January) week:  it was at best 14, at worst 7. We suffer 
from

	a) pbar and p transverse emittance blow up at the ramp; 
	b) larger that usual transverse pbar emittances from MI (25-40 
instead of 20-25 pi); 
	c) the same for protons (25 instead of 20). 

Item a) is due to proton instability on that ramp which leads to small 
emittance growth for protons and significant (2-3 times) emittance growth 
of pbars. Later, pbars are shaved in some 10 seconds by beam-beam interaction 
with protons and their emittances go to normal values at the expense of 
intensity (40% loss in record proton intensity store #1369).

5. reminder: Bruce Hanna is the Tevatron coordinator for 1 
month starting June 1

6. Alvin (+Rick Vidal) compared the total beam current behavior 
with the TEL on and off. He concludes that 2/3 of the total p-losses
is due to vacuum, 1/3 due to leakage from the RF bucket and 5% due to 
luminosity burn-up. Interestingly, losses from between the bunches 
correlate 100% with losses from abort gaps (Valery suggested to FFT them and 

	a) compare with known TeV characteristic frequencies); 
	b) estimate orbit motion which may cause such losses).

7. Tanaji & Co performed EOS (end of store)  measurements of the pbar 
dynamics vs. helix aperture. Observed: 

	a) better luminosity lifetime with 115% helix; 
	b) bad lifetime + pbar emittance growth at 80% helix; 
	c) beam-beam tune shift has right sign (+); 
	d) Tan's Q-meter passed simple tests well; 
	e) after proton removal, pbar tunes were not where they
are supposed to be. 

Conclusion: we need to continue work on bringing the beam-beam model 
predictions to agree with reality.

8. during the same studies - Xl and Dean performed a record fast 
quenchless proton removal - in 1 hour (combination of TEL and collimators)

9. the two Valery's (Balbekov and Lebedev) looked into dancing bunches
(stationary longitudinal instability) at 150 GeV. Dipole frequencies seen in 
the spectrum analyzer for (85 Hz and 75 Hz) agree with the model of the core 
and an intense satellite oscillating with an amplitude of 1.3 rad. 
More questions than answers: why oscillations do not decohere? 
Why quadrupole modes are not seen (and what are their frequencies)?; 
how does that depend on intensity?... Analysis to be continued.

10. Valery L. measured orbit changes at 150 GeV and got
an indication of slow (and small) lattice non-linearity changes in time.

11. Vladimir and Yuri tried to suppress the p-instability on the ramp 
(see item 4) by running with higher chromaticities - sometimes it was 
necessary to add up to 6 units in both planes to keep beam with 
7000-8000 e9 protons stable. The worst thing is that results are not 
always reproducible.  [Even with lower N_p and very large C_v,h the 
instability might pop-up. We did not have serious problems with that 
instability three weeks ago].