Minutes from target meeting held October 20 2006 in 892-1-B09

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2006/

a) On Friday October 13 a field rotation at 2.5 T was done from
negative solenoid current to positive. Then the field was reduced to 1.0 T.
Frozen spin mode was kept until Tuesday October 17 morning. During the
accelerator machine development the polarization was started at 09:00 in 
2.5 T field with positive current. The initial polarization values were 
-48.6 %, +54.5 % and -48.9 %. On Wednesday at 14:00 polarizations -49.2 %,
+54.8 % and -49.9 % were reached. The magnet was then ramped to 1.0 T.

b) Jaakko analyzed the TE-calibration data from July and September using
robust statistics to determine the Curie constants and spin temperatures
during the calibration. The results are in good agreement with Kaori's
analysis, but would give a little higher polarization with about +3 % in the 
difference between positive and negative polarizations. Check and error 
estimate for this analysis needs to be still done. 

c) The field map of the magnet has changed a little between the July and 
September calibrations due to retuning of the trim currents. During the 
polarization October 17 - 18 no shift of deuteron NMR frequency on coil #1
was seen. On coil #10 there is however 1 kHz decay or about 60 ppm in magnetic
field. Stable value is reached in about 10 hours. The spectrometer magnet SM1 
was kept switched off during this period. Fabrice: the decay is due to induced 
current to the shorted trim coil G2 when the SM1 field is changed.

d) Kaori produced first offline data for 2006 with +|-|+ polarizations
before the microwave reversal of September 27.

e) Norihiro showed temperature of the two calibrated ruthenium oxide 
thermometers TTH4 and TTH5. When the microwaves are on they show very close
the same value. After switching off the microwaves there is a 10 mK difference
in frozen spin mode. TTH4 is at the upstream end of the mixing chamber and
TTH5 at the downstream half of the middle target cell.

f) The Spin 2006 talk from Fabrice is available on the web from
http://wwwcompass.cern.ch/compass/publications/talks/t2006