Minutes of HERA Meeting
30.10.2001
Summary of HERA Status
There were several technical problems during last week:
- The adjustment of the He flow for the GO/GG magnet in the north IP was fine
tuned. There were however failures at low magnet currents, probably due to
problems with the quench protection. Some electronics cards were exchanged.
- Operation was delayed due to problems with the HERA proton RF system
and the PETRA RF system (last night).
- On Sunday, the cryo OK was missing (computer problems).
Progress on commissioning
- Magnet settings (files) were optimized to improve the background conditions.
- The horizontal coupling of the positron beam was reduced; first with no
solenoids, later with both experimental solenoids turned on. The skew
quadrupole currents are as expected.
- Luminosity beam scans were performed at the north and south IPs.
- Proton and positron (including synchrotron radiation) collimators are
now moved in routinely.
ZEUS
- Successfully tested forward tracker during proton run.
- Did veto run, looked at beam gas background Sunday night.
- F/RCAL was closed with proton beam. The orbit distortion was small
(few tenth of mm).
- The effect of closing of F/RCAL has to be repeated during collisions.
The calorimeter should only be moved after talking to the HERA control
room.
- Would like to take calorimeter calibration runs with GO/GG off and at
full field when there are no beams in HERA.
H1
- Background rates were very high Wednesday evening. Positron beam steering
reduced the rate by a factor of 100.
- Yesterday the proton background reduced by a factor of 2 when the
proton collimators were moved in.
- Muon chambers were turned on during the proton run. The chamber currents
were slightly higher than before because of the reduced iso-butane
concentration.
- The HV of the SPACAL PMTs was optimized to reduce the effect of the
GG stray field.
HERMES
- Continued routine target studies.
- Will try to correlate the beam dump monitor signals with HERA events.
- Haven't turned on detectors yet.
- Requested a 1 h access for work on the target system after Friday.
- Will start operating longitudinal polarimeter.
- Would like stable positron beam in case there is a problem with the
proton machine.
HERA B
- Detector was turned on during proton beam run. Most chambers were at
full HV. Background rates looked reasonably.
- Would like to operate target wires at small rates starting on Monday.
Schedule
- Collide beams with reduced positron beam coupling.
- Repeat luminosity beam scans with reduced positron beam coupling.
- Stable beams to switch on detectors.
- There are several requests for a non-urgent access of about 3 hours
(transverse polarimeter, ZEUS, HERMES, HERA B).
- H1 is the coordinating experiment.
Christmas Break
- M.Bieler showed a schedule of the interlock tests during the Christmas
break, see ps file, which are required
by law. As a consequence the break has to be extended to Tuesday,
15.01.2002.
Uwe Schneekloth