hera_minutes_051004.html

F.Willeke summarized HERA operation of last week ( transparency)

HERA delivered 6.1pb-1 in 13 fills last week. Initial currents were 36mA for electrons and up to 93mA for protons. Due to some problems with the proton RF on Friday, the proton current was reduced to about 76mA. The operational efficiency was 57%.
There were technical problems with the cryogenic distributions system, proton 208MHz RF system, the electron RF system and a dump switch. One of the four 208MHz systems (system B) is defective, which was the reason for reducing the proton current. System B will be repaired during the maintenance day tomorrow.
Background conditions were in general fine, although there were some runs with spiky proton background, which could have been caused by power supply controllers for some proton magnet, which had to be reset.
After some bump tuning electron polarization reached 50% for non-colliding and 30-40% for colliding bunches.
After the maintenance day HERA will go back to full proton intensity. The goal is to increase the electron current above 40mA.

J.Olsson summarized the H1 status ( transparencies)

The detector is in good shape. The main problem was bursts of proton background spikes. The overall HV efficiency was only 60%. It improved to 70% over the weekend. The slope of the gated luminosity (with HV on) has decreased a bit.
The drift chamber gain was increased by 17%. The trip thresholds were raised accordingly.
The VFPS was repaired during an access on Friday.
Some electronics for the FPS will be exchanged tomorrow.

Y.Yamazaki summarized the ZEUS status ( transparencies)

At the beginning of the week ZEUS was still recovering from the power glitch. Background conditions were somewhat spiky during the week. They become much better during the weekend.
The CTD baseline current is very good. The vacuum recovered very quickly from the leak.
The detector will be opened tomorrow, mainly for maintenance work on the calorimeter.

In general good data taking. For some period the triggers had to be pre-scaled due high proton background.
The increase in polarization is very welcome.

Luminosity operation until tomorrow at 06:00hrs.
Tomorrow access to the tunnel will be possible until 14:00hrs. All interlocks should be set by 22:00hrs.
The NEG pumps in the north and souths IRs will not be regenerated.
There will be no machines studies after the maintenance day.
The present plan is to cancel the maintenance day in November.

H1 is the coordinating experiment.

Uwe Schneekloth