Minutes of HERA Meeting      23.10.2001

Summary of HERA Status

• First collisions in the south IP were finally achieved Saturday afternoon. The beams had been separated vertically by 3mm. Collisions were restored on Sunday without problems.
• The positron beam only period on Thursday, requested for commissioning of the ZEUS luminosity monitor, was used for response matrix measurements in order to check for distortions of the optics.
• Beam scans were performed at the north and south IPs. A preliminary value for the specific luminosity measured at the north IP is 1.2*10**30 cm-2 s-1 mA-2.
• Proton ramp files were improved.
• The transport beam lines are now ramped down routinely.
• There are still technical problems with the GO/GG magnets. The cooling and ventilation of the current leads is very critical.
• The proton collimators were tested last night (same procedure as last year).
• The plan is to increase the beam currents to check for multi-bunch instabilities and to continue studying the coupling of the positron beam.

H1

• Calibration of the luminosity monitor was improved.
• Started shifts in the H1 control room.

ZEUS

• The timing of the luminosity monitor was optimized during the positron beam only period. Calibration runs were taken.
• A clear signal was observed during collisions.
• Shifts moved to the ZEUS control room.
• The effect of closing F/RCAL should be studied with proton beam.
• Need a 3 hour access to repair a defective pump in case of a break.
• A hot spot on the proton beam pipe between the GN25 and BN27 magnets was measured during the access.
• U.Koetz talked about synchrotron radiation originating from the BHL63 and BNL41 magnets. Synchrotron radiation collimators should now be closed as part of the standard procedure.

HERMES

• The effect of the transverse target magnet on the positron beam is very small (0.1mm beam displacement). Magnet was turned on several times.
• The broken glass tube was repaired during the access.

HERA B

• Commissioned target system.
• Information in netmex has to be updated. Need rates of other experiments.

Schedule

• Several short stable proton runs: a few hours of stable proton beam before positrons are injected. Experiments will set injection vetos.
• HERA will increase beam currents. Continue studying beam coupling.
• The transverse polarimeter group needs a 3 hour access in case of a break.
• ZEUS is the coordinating experiment.

                Uwe Schneekloth