Minutes from target meeting held June 10 2011 in 892-1-B09

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2011/

a) Thermal equilibrium calibration at 1.3 K started from Saturday morning.
The largest roots switched on Sunday morning for calibration at 1.0 K. 
The TE-calibration finished by Monday noon. Start removing helium-4 from
mixing chamber. The removal of helium stopped due to LHe supply problem
on Tuesday. Finally the mixing chamber empty on Thursday afternoon. Remove
helium-3 from the vapor pressure thermometer. Change the dilution cryostat 
overpressure valves from open mode to closed mode where the gas is recovered 
in case of too high pressure. Condense 1.8 m^3 of gas on Thursday evening.

b) Preliminary Curie constants using proton background from 2010
http://wwwcompass.cern.ch/elog/target_polar/113

c) Norihiro: NMR signals look larger than in 2010 maybe due to better packing
factor. The Yale card that was switched between coil #1 and #2 in 2010 is now
used for coil #10. An external +5 V power supply is used because the one in
the rack is broken.

d) Yuri: optimal microwave frequency is expected to be more far away from the
EPR center due to higher NH2 concentration. First the central cell should be
polarized to see possible microwave leakage. 2010 Curie constants could be 
used in the first polarization tests.

e) Fabrice: diffusion pump water temperature increased up +50 C. Stop the pump
and replace the filter. This maintenance needs to be done every 2 - 3 months
or when the water temperature becomes high. Possible installation of a water 
flow meter or indicator was discussed.