B.Holzer summarized HERA operation of last week,
see transparency
HERA delivered 10 luminosity fills last week. Some runs were relatively
short due to technical problems. The specific luminosity was degrading
during the fills. The positron current was limited to 40mA because
of background conditions and RF transmitter problems. (Work is in
progress to improve the klystron protection system.)
Some runs had a strange background behavior (long time background
spikes).
Technical problems were
positron losses during injection,
3 trips of the proton 208MHz system (defective electronics), power supply
trips and several alarms of the quench protection system this morning.
The cooling system was running at the limit due to the hot weather
conditions.
Polarization was tuned several times. The maximum was 42% measured
by the LPOL.
The proton orbit feedback was tested successfully. The tune controller
was tested. The goal is to do automatic tune control during the
proton ramp.
The proton beam was moved 3-5mm at the H1 VFPS.
A fire alarm occurred yesterday between hall west and the tunnel.
Nothing was found when the technical emergency entered the tunnel,
power was turned off. The magnets were then set to nominal current for
30 minutes. The alarm did not reappear.
ZEUS
Successful data taking. Background conditions were usually fine, with
some HV trips.
The normalized CTD current was shown as a function of time,
see transparency
Another gas burst occurred yesterday evening
(plot) . The pressure close to the
IP increased up to 10**-4 mbar causing very high background and
a beam dump. It happened when HERA went to proton luminosity optics.
If possible, the beam will be moved today to study the source.
Chamber operation will be stopped on Thursday.
HERMES
HERMES had several technical problems: the glass tube broke again,
cooling failure (the target magnet went down),
a broken HV crate and problems with the DAQ system.
HERMES is now running with unpolarized target. In case of a
3 hour break, a new glass tube will be installed.
A lumi scan was performed. The energy scan for the LPOL
calibration will not be done.
Schedule
Luminosity operation will stop Thursday 07:00hrs.
Machine studies will be performed from Thursday 07:00hrs
to Monday 07:00hrs, see updated schedule .
The H1 and ZEUS solenoid and luminosity monitors should be on
(lumi monitors only for some shifts).
On Monday the tunnel will remain closed until the radiation
safety group has complete their round (about 09:00hrs).
