Minutes of HERA Meeting      27.11.2001

HERA

• During the access last week the magnet bridges in the south hall were moved up by 1.5mm (SL) and 1.2mm (SR).
• The magnet bridges in the north hall were moved in order to check the mechanics and to be prepared for bridge adjustments with stored beam. They were moved back to the old positions.
• Beam operation started with proton beam (first proton beam since the power outage 2 weeks ago). Stable proton beam was delivered to the experiments on Saturday.
• HERA switched to positron beam on Sunday. Beam orbits had to be re-optimized after the bridge movements. The ramp files are still being optimized. Achieving low background conditions is more difficult than before, although the magnet alignment is better now. It is not understood why.
• Understanding of the positron beam optics should be improved. There is a 60% beta beat in the vertical plane.
• The cooling of one RF transmitter station of the electron machine still has to be fixed.

H1

• The forward detector HV was turned on during the stable proton beam on Saturday. The HERA B wire studies did not cause any problems.
• Background monitoring including timing information is being prepared for the synchrotron radiation studies.

HERMES

• Background conditions were acceptable during the stable proton beam running.
• Need a period of 3 hrs without beam or with stable positron beam.

HERA B

• Filters of the magnet power supplies had to be cleaned. During the stable proton running on Saturday the HERA B magnet was on for 9hrs without problems. The beam was lost due to a magnet trip. There were several additional trips. The magnet power supply is being investigated.
• Target operation was successfully tested with proton beam: first single wire movements by hand, followed by automatic wire movements. The maximum interaction rate was 60MHz, which did not cause high background rates in the other experiments. Rate fluctuation were small. Coasting beam was not visible. Summary: established wire operation, ready for for data taking.

ZEUS

• There were several background alarms (MVD diodes) during positron beam studies. An alarm window and beam dump request is now implemented in the luminosity display in the HERA control room. This should include a time when the beam has to be aborted.
• Need 2hrs without beam to turn on the central drift chamber.

Schedule

• Continue improving background conditions during positron ramping (a few shifts).
• Increase positron beam intensity.
• Stable positron beam for experiments.

• ZEUS is the coordinating experiment.

                Uwe Schneekloth