Minutes of the HERA Meeting 11.10.2005

HERA (F. Willeke):

There were 11 lumi fills from Tue 4.10. until Tue 11.10.05.
HERA produced 8.0 pb^-1 at H1 - a very good week, despite the
maintenance day on Wed 5.10. The machine duty cycle was 70%.
Some problems still caused interruptions: on Sat a Sedac problem
occured in the Kryo system, which disappeared after a few hours
without being solved (probably a contact problem).
On Mon a power supply controler for the GA 08 magnets in the South
had to be investigated.
On Tue a power switch problem in Hall South caused the ZEUS solenoid
to ramp down.
Ie was increased towards 40 mA, Ip varies between 76 and 92 mA
depending on preaccelerators.

Average polarization per fill was around 35%, still some 5% points
lower than in the other helicity states. Harmonic bump scanning
continues and special rotator scans around H1 are still to
be done.

On the maintenance day a driver tube of the proton 208 MHz RF
system was exchanged, which had limited the p current over the
previous holiday weekend.

ZEUS (E. Gallo):

Good data taking with 80-85% efficiency, mainly limited by CTD trips
due to background spikes.

On Fri 8.10. evening a fire in the horse stables next to Hall
South led to smoke in the ventilation system and the Hall was
evacuated. No data were taken that night.

On Tue morning a power cable for the Toroid magnet burned out
and was exchanged by MKK.
The solenoid ramp down required a full calo calibration after ramp up.

H1 (P. van Mechelen):

H1 took data with 95.7% DAQ efficiency, 9.0 % deadtime and 62% HV
efficiency for 4.1 pb^-1 with HV on.
HV losses are due to spikes and include the lumi tuning period
as well.

Hermes reported steady data taking.

Plan:
Continue lumi production, slowly increase Ie above 40 mA.
Rescan 1st order harmonic bumps for polarization, tune rotator
magnets in the North.

Hermes is coordinating experiment.

Daniel Pitzl