Summary of meeting on 4/6/00.

 Present: Cester, Mandelkern, Schultz, Gollwitzer, Marchetto, Kasper,
          Garzoglio, Boca, Stancari (M), Seo, Graham, Rumerio, Obertino,
          Hu, Pordes

 Current Beam Status: (at ~ 5 pm ) about 15 mA and stacking at 2.75 mA/hr.
 We have asked to go to 30 mA. The pbar staff experts are concerned that 
 there may be beam instability (ie not what Stephen would call a wall across
 the road but a massive hole in the road) above 20 mA. We are prepared to
 accept this possibility (unless there is some known remedy which is in 
 preparation). 
 Rosanna mentioned the importance of good diagnostics. We really need
 stacks of >30 mA to run efficiently so we have to face this issue.
 Rosanna said that she had replied to kam's e-mail about the choice
 of energy.

 Stephen asked people to report on the status/achievements of the last stack.

 Michelle described the work on the timing of the charged veto for the neutral
 trigger. Scope traces showed that the minbias strobe on EToT events has
 very little jitter (<5 ns) and that the veto pulse is about 10 ns longer than
 needed. Histograms of the timing of the vetoing pulse (events which satisfy
 the neutral energy threshold but have a pulse from the h1.h2p 'or' which
 vetoes the event from being a neutral trigger) show a tiny cut-off at early
 times, suggesting that the veto may be a tiny bit (1 ns or so) late.
 The width of the veto from h1.h2p has been reduced; the veto from the
 forward hodoscope has yet to be done.

Matt reported that there now seem to be 4 thoroughly dead (a la parrot)
 channels in the FCal (3 medium, 1 small) and 2 dead shaper channels. Michelle
 volunteered to help fix the shapers; Matt said that given there are 4 dead
 blocks, he has spare shaper channels. Stephen wondered if the shaper deaths 
 are due to sparking in the bases.

 Paolo said that one of the two DAQ problems - the only-odd VSN's for the
 Fiber TDC's - had been fixed (see report of 4/5 evening shift). Experts from
 CD had come to look at the 2nd DAQ issue (hanging of DYC3 in Fiber ADC
 crate) this morning but he had not been able to reproduce the problem - even 
 with the Fibers generating large amounts of noise data.

 Flavio said that he, Wander and Keith had implemented the phi-phi and phi-phi
 gamma filters in Prude (the online filter), using the <13 block in the CCAL
 flavor. (See previous minutes for Federica's description of the cuts). The 
 rejection (from a sample of 1000 events) seems to be 10; this is not quite 
 as large a rejection as anticipated (15) but still gives an acceptable rate 
 to tape (200 Hz at 2.5*10^31).

 Margherita said that plots of the invariant mass for events taken with 
 running on the psi' peak (or near it) are in the "Interesting Plots" area 
 of our home page. There were 209 events with ELW>0.1 from the first running; 
 the luminosity quoted in the previous minutes is wrong because the center 
 detector was in the wrong place and its data (nil) is averaged in with the
 left and right detectors; the actual luminosity is probably 30% to 
 50% higher than the 45 nb-1 quoted by Stephen previously.

  Martin described the problems we had with the beam on the evening shift.
 A "travelling wave tube" power supply tripped reducing the cooling power
 available. As a result the beam energy began to drop to the point where much 
 of the beam was no longer within the cooling plates. (That there was 
 something drastically wrong with the energy could be seen on the beam 
 revolution frequency spectrum where a new peak at high frequency was larger 
 than the peak at the nominal frequency.)
 Giulio recovered the situation. He asked us to turn off the jet, bunched 
 (captured?) the beam at the appropriate frequency and nudged it back (close) 
 to the psi' energy.  Last night, the problem with the "tube" was diagnosed 
 as a "diode" in the tunnel. It turned out in fact that a special technique 
 was needed to reset the power supply.

 Gianluigi reported on the work he is doing on the CCaL monte-carlo to 
 understand the phi-phi and phi-phi-gamma filters. The electromagnetic 
 performance is fine - the hadron performance "is not great and will probably 
 not get greater".

 Stephen