Minutes of HERA Meeting 8.11.2005
HERA
B.Holzer summarized HERA operation of last week
( transparency)
- Beam operation was quite efficient last week. There were 10 luminosity
runs with initial beam currents of 87-99mA (protons) and 38-43mA
for electrons. The injection and transfer efficiencies were excellent.
Refilling times were short.
- Technical problems were: power supply error (GA 08 magnet), defective
temperature measurement of cooling water (GJ 08), wrong polarity
switch (BJ magnet), wrong setting of temperature thresholds and
transmitter problems.
- The electron beam was lost a few times when the tune was changed,
going from tune step 3 to 4.
- Polarization was close to 40% at the end of a fill.
ZEUS
Y.Yamazaki summarized the ZEUS status ( transparencies)
- The overall data taking efficiency was 75%, same as last week. Just
below 7pb-1 were written to tape.
- Background conditions varied. There were good (first half of the week)
and bad fills (Thursday/Friday).
- The total delivered luminosity reached 200pb-1,
149pb-1 have been recorded so far (both online values). The offline
correction is about -3%.
H1
Th.Kluge summarized the H1 status ( transparencies)
- The normalized fast tack trigger rate continues to be very good. In
general, the background conditions were good, although there were a few
bad fills. The HV efficiency was around 90%.
- The total delivered luminosity is 210pb-1, 114pb-1 have been recorded
with HV on. (The offline correction is also about -3%).
HERMES
C.Riedl summarized the HERMES status, transparencies:
( vacuum pressure,
ps2 pressure,
location of leak)
- Increased proton background was still observed during the fills.
B.Holzer remarked that the upstream proton orbit was changed
without any improvement of the background. It is not clear whether
the proton collimator settings are optimal for HERMES.
- The depolarization attempt was not successful. Another test is
encouraged.
- A leak occurred at the exit window of the target optical monitor.
It was fixed by MVA using glue. The TOM will be removed during the
shutdown.
Schedule
- Continue luminosity operation until Friday morning.
- Machine studies from Friday to Monday 07:00hrs.
The luminosity monitors will be needed for the machine studies.
- Shutdown starting Monday 07:00hrs.
ZEUS is the coordinating experiment.
Uwe Schneekloth