hera_minutes_021023.html

Stable proton was provide for HERA B on Tuesday.
Polarization studies were continued until Thursday (east rotator on, north and south rotators off, solenoids off). The highest polarization was 35%. This was achieved by scanning the beam energy and optimizing some of the harmonic bumps. A second attempt to get high polarization gave 20 to 25%. The beam energy was slightly off.
Thursday to Friday positron files were re-optimized with solenoids turned on.
Stable proton was provide for HERA B on Tuesday.
Several luminosity runs were done over the weekend. The positron files were not optimized, beam dimensions at the IP not correct. After re-tuning the positron files, luminosity could not be obtained at H1.
The proton transfer from PETRA to HERA has been difficult due to problems with the p RF system. This is being repaired today.

Polarization of 35% was measured with the transverse polarimeter. The longitudinal polarimater measured 40%. The LPOL measurement is however difficult at low positron currents.

On Friday the proton background was quite low with the GO/GG beam pipes at 110K. During ep running the background did not improve, which is probably due to the non-optimized positron files.

On Friday the proton background was quite low with the GO/GG beam pipes at 110K. During ep running the background did not improve, which is probably due to the non-optimized positron files.
Sunday morning a radiation monitor, pad sector of the Si vertex detector, was damaged during proton injection. A magnet (BZ) had wrong polarity. This was caused by a hardware failure of a polarity switch. The alarm in the HERA control room was not noticed by the shift crew. A permit server exists, which could in principle prevent such accidents. It is not active.

This evening: get luminosity at H1 again. Continue luminosity studies with polarization tunes.
Friday: stable proton beam for HERAB, 2nd part with positrons for background studies.
Weekend: luminosity studies, including at least one longer fill to study the proton emittance growth. The detectors can be turned on during this fill.
Monday: both north and south rotators will be turned on.
During the Christmas break, 23.12. to 2.01.2003 07:00hrs, access to the tunnel and experiments will not be possible. Power supplies will be kept on in order to re-start beam operation without any delay.
The HERA meeting next week will be Tuesday at 10:00hrs.
H1 is the coordinating experiments.

Uwe Schneekloth