Minutes of the HERA-Experiments Coordination Meeting 9.9.2003

Agenda

• Brief status reports: machine and experiments
• Discussion of schedule:
  • Further vacuum conditioning
  • Polarization studies
  • Background studies
  • Luminosity startup
• Date of next meeting
• AoB

F.Willeke: HERA status

• 12 GeV bakeout accumulated 9 Ah in 2.5 weeks until Mon 8.9.03. e+ lifetime improved to from 4h at 30 mA to 7h at 40 mA, indicating an overall vacuum improvement.
• However the regions most critical for proton-gas background like NR3.6m shows only small improvement. The pressure peaks are similar to Jan. 2003.
• The gas load released on the 3rd GO/GG warmup on 10.9. will be used to decide on the further conditioning procedure.
• e+ injection has been optimized, but appears to have a narrow working range.

W.Zeuner: ZEUS status

• ZEUS is ready for data taking.
• 5800 CTD postamps have been modified to increase gain, to compensate for reduced HV to avoid aging.
• Radiqtion dose during 12 GeV bakeout is about 0.15 krad/day. The average for a year should not exceed 0.1 krad/day.
• One RadFET showed a 2krad step during repeated injections on 5.9.03, correlated with diode spikes up to 300 nA. Injection problems should be studied with lowest possible currents.
• The cooling for the central beam pipe stays on. The temperature should not exceed 50C.
• The lumi pair spectrometer is ready, providing beam angle information.

D.Pitzl: H1 status

• H1 will be ready for data taking with flammable tracker gases from 22.9.03.
• Beam pipe temperature reaches 80C limit at C4A collimator, limiting the bakeout current to about 42 mA.

P. di Nezza: Hermes status, dose 1, and dose 2

• Radiaion dose at 12 GeV improved a lot after orbit and collimator optimization on 22.8.03.
• LPOL needs 2 fills at 27.5 GeV with at least 10 mA to prepare.
• Lumi detector needs 3 fills for timing adjustment and beam angle scan for acceptance calibration.

Discussion of schedule

• 3rd GO/GG warmup on 10.9.03.
• HERA background meeting on 12.9. will decide on further procedure. (note added: the 12 GeV bakeout showed some saturation in gas loads and pressure peaks. It was decided to go to 27.5 GeV operation.)
• Establish lumi files and collisions in H1 and ZEUS with low currents.
• Interlock test for the transmitter SR: Tue 16.9.03. With then 6 RF stations about 20 mA at 27.5 GeV should be possible.
• Set up TPOL and LPOL: 17. and 18.9.03.
• Polarization studies and 27.5 GeV conditioning until Open Day and maintenance day 28. and 29.9.03.
• Background studies: backscattered SynRad in H1 and ZEUS drift chambers with an isolated e+ bunch after 22.9.03.
• Set up for polarized lumi run from 30.9.03.
• All 3 spin rotators are set for right-handed e+.
• HERA prefers to change all 3 simultaneously, once before Christmas.

Tentative date of the next coordination meeting: Mon 20.10.03 at 10:00.