Minutes of the HERA Meeting 1.11.2005

F.Willeke reported on HERA performance in week 43 of 2005:
in 12 lumi fills (24.-31.10.) HERA produced 9.9 pb^-1 - the best week
ever. During Oct HERA produced 35 pb^-1 - the best month ever.
Peak lumi reached 5 10^31/cm^2/s. Duty cycle was 68%. There were no
interruptions due to technical failures.
Proton current incrased towards 100 mA, Ie filling reached 42 mA, lumi
tuning started just under 40 mA.
Polarisation is unchanged, increasing from 25 to 40% during a lumi fill.

Yuji Yamazaki, ZEUS:
the HV efficiency varied from fill to fill, with marked improvement over
the weekend, with low backgrounds and small scatter, correlated with good
proton beam lifetime around 400 h.
F.Willeke: BG tuning involves about 40 knobs and requires experienced
operators.
The lumi at the ZEUS IP is observed to decay faster than at H1 during a
lumi fill. This is not understood. Maintaining high lumi may require
steering which causes increased background and occasional chamber trips.
The offline lumi corrections in ZEUS and H1 are similar: -3 to -4%.

Paul Laycock, H1:
H1 collected 8.9 pb^-1 during the week, 5.7 pb^-1 with all HV on.
Lumi 2005, HV efficiency, lumi tuning,