Minutes of the HERA Meeting 21.2.2006

HERA (F. Willeke):

Machine startup concluded last week with collisions in H1 on Thu and
in ZEUS on Fri (long scan from bad starting point).
Lspec fine at 2.1 10^30/cm^2/s/mA^2 in 10x10 bunches.
Pol 40% without tuning, loading 2005 corrections.
e injection efficiency reached 70%, requires asym. vert. bump at Hermes.
Electron current limited by RF: coupler cooling problem at sc. cavity,
cavity tuning ongoing.
60 bunch operation over the weekend. Went to 120 bunches on Mon, as
proposed by the experiments.
A few e beam losses on ramp above 25 mA, needs further study.

The SynRad monitor at South gives no signal - under investigation.
Helpful for orbit monitoring during ramp and lumi tuning.

Hermes solenoid has strong effect on orbit: 0.6 mrad tilt? asym. fringe
field? Needs further studies.


H1 (G. Eckerlin):

Taking data since Fri.
Chambers operated at 10*20 mA^2 with 50 uA, a factor of 2 above the best
value, consistent with dynamic beam pipe pressure.
Room for 120 bunches
Radiation Monitor gains and thresholds equalized on Mon (32 channels summed).
Limit unchanged: warning at 50 kHz, Alarm at 250 kHz.


ZEUS:

Taking data since Fri. High e background on Sat, tuned away on Sun, chamber
operation since then, spikes causing trips on Tue morning with 6*60 mA^2.


Hermes (E. Aschenauer):

operational since Sun, spectrometer and recoil with Si, SciFi and calo.
Solenoid off. Backgrounds are low.
Lpol operation started Mon.

Requests:
2h with e only to set up trigger, at end of fill, but more than 6 mA.
>20 mA at 12 GeV for 1h to study target cell heating.
Ramp solenoid at 27.6 GeV.


Plan:
continue lumi operation with 120 bunches, 60*25 mA^2.
End of fill after 8 hours or when Ie drops below 5 mA.

Maintenance day Wed 1.3.2006:
GO/GG warmup N and S, NEG regeneration.
Please send access requests to M. Bieler and P. Hopf.

ZEUS is coordinating experiment.


Daniel Pitzl