Minutes of the HERA Meeting 7.2.2006

F. Willeke:
HERA restart underway.
An e quad QC OR14 had a winding fault, shorting one half quadrant.
It was exchanged last Thu eve and night.
e startup then proceeded as planned, but 2 days of vacuum bakeout
had to be skipped. On Mon 28 mA were filled, and 20 mA were ramped
to 27.6 GeV.
p startup: fast cycling of PETRA caused trips of DORIS magnets.
One main 10 kV transformer station is still under repair.
Slow ramp is possible and protons were stored in HERA in Mon night,
ahead of schedule.
Diagnostic systems are taken into operation: p BPMs, tune controller,
new long feedback cavity. Tunnel access might be necessary today.

J.Stewart, Hermes:
Observed 390K in target cell with 28 mA at 12 GeV, cooling down
at 27.6 GeV: HOM heating.
The target cell beam RF shield is now 50 um Al instead of 75 um last
year, and the cell is operated at 18 deg C instead at 100 K.
Want to install more temp monitors. The cell was baked out at 500K
during production. HOM calculations were done, but the cooling
contacts depend on manufacturing tolerances.

ZEUS:
U.Schneekloth takes over as Technical Coordinator from W.Zeuner.
Interested in background studies with e at 27.6 GeV (CTD on) and
calibration at 12 GeV.

G.Eckerlin, H1:
Vacuum near H1 is 10^-9 mbar with 20 mA at 27.6 GeV, a factor 2 to 5
above the situation from June 2005, after the leak NR14m.
GO/GG positions: all within 0.5 mm as in 2005, except for GG vertical
at tunnel end: 1.2 mm low.
F.Willeke: not critical, GG is only used as dipole.
BP temp monitoring is connected to beam dump: 90 C.
NEG pump regeneration after some more beam operation.
Radiation Monitor is a new device: one scintillator disk around the beam
pipe at z=32cm (was at -35cm last year), with SiPM readout.
Acceptance and efficiency expected to be similar to last year, but
bias and thresold adjustment still underway (32 channel segmentation).

F.Willeke, Plan:
Continue with startup as scheduled with about 1 day delay:
http://adweb.desy.de/mpy/hera/MachineStudies/welcome.html
- test p BPMs in the IRs
- test p long feedback
- e BBA in the IRs
- test new optics with smaller beta*
- test lumi

H1 is coordinating experiment (sequence North-East-South).

  Daniel Pitzl