Minutes of HERA Meeting
03.12.2002
HERA
F.Willeke summarized HERA operation of last week, see transparencies
- The positron fill was lost after the power failure on Wednesday. The
proton fill was kept. It took some time until positrons were available
again (power station A had a short to ground.)
- Luminosity was delivered on Friday and over the weekend. Accelerating
the positron beam was difficult on Saturday. There was a problem with the
file system. The specific luminosity was lower than before. Background
spike are still occurring, although less frequent. They are correlated to
vertical orbit changes. The origin is not known. The QS magnets were checked
and are fine.
- Some conditioning of the proton vacuum system was done by injecting high
proton currents (close to 100mA). The pressure increase is improving
slightly.
- The H1 solenoid was ramped down during luminosity operation on Friday.
The reason was to check whether there was any background due to
ions trapped by the solenoidal field. In this case, the background should
decrease when the magnet is ramped down.
The chamber current did not decrease, it increased.
HERMES
- Got 4 fills last week. In general, the beam conditions and rate of data
taking was good except yesterday when the background was high.
- Once the collimators were not closed properly.
HERA B
- Beam conditions were good. The target was in operation for 40% of the week.
Very long runs (>10h) were taken on the weekend. The J/Psi rate is okay
(3234 J/Psi events/day)
- Yesterday morning the proton collimator WR was too close to the beam.
HERA B could not take data for about 2 hours.
- The tungsten wire broke. It is being replaced during the access today.
ZEUS
- It was a mixed week. There were some good runs. The background has improved
again. The CTD current is now as expected from the extrapolation.
- Once the F/RCAL was opened without notifying the HERA control room.
- The luminosity measurement is being studied. Beam tilt scans are
still required to check the acceptance.
H1
- In November the total integrated luminosity was 2pb-1 (H1 active). The
luminosity with drift chamber HV on was 0.8pb-1.
- The rate of the radiation monitor was affected by reprogramming of FGPAs.
- The positron beam was dumped twice.
Schedule
- Today: access
- After access two shifts of positron injection studies.
- Tomorrow: positron beam tilt scans and high current positron fill.
- Tomorrow evening: 1-2 hrs proton beam only, HERA B magnet turned off.
- Continue luminosity operation.
- Friday, 20.12.2002 to Monday morning, 23.12.2002: machine studies
- Monday, 23.12.2002: install residual gas analyzer North IP.
- Christmas break
- 2.01.2003 early morning: close H1 detector. Continue luminosity operation.
- HERA B is the coordinating experiments.
Uwe Schneekloth