Minutes of HERA Meeting
15.10.2002
HERA
The program for last week was polarization studies and two stable proton
fills for HERA B.
- HERA was able to reach the polarization tunes. The resonances are
relatively strong. Polarization tuning started Saturday morning
(East rotator on, North and South rotators off, H1 and ZEUS solenoids off).
The highest polarization was 12%. Both measurements, transverse and
longitudinal polarimeters, were in good agreement.
During the energy scan this morning the polarization increased
to 20% (transv. polarimeter) - 32% (long. polarimeter). It is
not yet clear why the polarimeters measure different values. The
polarimeter position has to be checked.
The North rotator has not been turned on yet.
- During maintenance of the cooling system on Thursday, the main
water pumps were turned off accidentally. It took all day to
recover. Since then background conditions at H1 and HERMES
are much worse than before.
- Stable proton beam was provided for HERA B on Tuesday and Friday.
- The temperature of the GO/GG magnet beam pipe was increased
from 50 to 110K in order to avoid freezing of methane.
HERMES
- Both polarimeters had problems with the HERA timing system.
A HERA HIT crate system in the west hall was defective. In the
east hall the bunch current information was not correct.
- Both polarimeter measurements were in good agreement until this
morning.
HERA B
- The dedicated proton fills (15 hours long) were very efficient.
HERA B is now running with the final trigger configuration. The
rate of J/Psi's and dead-time is now being optimized.
- A run with the HERA B magnet turned off is necessary for alignment
studies. The fill on Friday will start with magnet off. It will
be ramped up later during the run.
ZEUS
- During the proton fill on Friday, the detector HV was turned for
background studies.
- The calorimeter trigger is still not working properly after the power
failure last Thursday.
H1
- The detector was not turned on during the proton fill as the solenoid
was off for the polarization studies.
Schedule
- Starting this afternoon stable proton beam for HERAB.
- Tomorrow morning continue with polarization studies.
- Friday: stable proton beam for HERA B and background studies.
First part HERA B magnet off, second part magnet on. Fill positrons.
- Weekend continue with polarization studies.
- HERMES is the coordinating experiments.
Uwe Schneekloth