Brief status reports
Update of shutdown activities
Startup with e-
Date of next meeting
Presentation:
Lumi production improved steadily until mid June, reaching beam currents
of 100*45 mA2 and 1 pb/day.
The peak luminosity was 3.8 1031 /cm^2 s,
the highest specific lumi was
1.5 1031 / cm2 s mA2.
The average duty cycle was 40%.
The North IR was vented on June 19, requiring exchange of seals and
rewelding of a beam pipe connection at NR11m.
After one week of bakeout with
e+ at 12 and 27.6 GeV, lumi production commenced with
50*30 mA2 in 120 bunches.
A new design for the e and p beam pipes between ABS4 and the GM magnet at NR11m and SR11m avoiding flanges but with in-situ welding is being worked out.
Extrapolating the delivered lumi until mid Aug 2004 about 90 pb-1 are now expected for the run since 29.12.2003.
Polarization had reached 40-50% in the backward helicity state. The spin rotators were switched to forward helicity on 22.6.2004. Since then the polarization is only 30-40%. This is not understood. Energy and harmonic bump scans and calculations continue.
The shutdown dates and plans are unchanged.
A tentative schedule for the restart and e-p lumi operation until Christmas 2004 was presented.
The idea is to proceed stepwise, starting with p and e+, then change magnet polarity to e- and finally move GI, GJ an GO magnets around H1 and ZEUS for e-p collisions.
Discussion:
The personpower situation is tight but does not affect the e- startup procedure.
There was no objection to the proposed sequence of switching to e-.
The decision about the installation of modified ABS4 and beam pipes should take place in a separate meeting. The recent vacuum incidents (NR11, SR165m, WR) should be reviewed.
Any changes to the e- optics should be checked in the synchrotron radiation simulation.
Presentation:
Good data taking, improved backgrounds up to the vacuum leak NR11m on 19.6.2004. Recovery with 20 days time constant since 2.7., factor 5 neeeded.
Discussion:
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Discussion:
There will be a HERA end of run discussion on Fri 13.8.2004.
The date of the next coordination meeting is Tuesday, Oct 5, 2004, at 10:00 in building 30b room 459.
Daniel Pitzl