Minutes from target meeting held November 24 2006 in 888

These minutes are available also from:

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

a) Yuri showed calculations on the local field inside polarized target 
material. For 6LiD the field is expected to shift +-30 ppm due to 
polarization while for ammonia the shift is an order of magnitude larger.

b) The physics data taking stopped on Monday November 20 at 16:30. The 
polarization was then measured at 2.5 T. No clear EPR line was seen with
the thermometers while sweeping the frequency of the IMPATT diode microwave
generator. 

c) The influence of the NMR measurement on the polarization relaxation was
tested with continuous frequency sweeping. The relaxation was about three
times faster compared to the normal data taking.

d) On Tuesday morning the transverse mode with 0.62 T dipole field was tested.
NMR signals from the polarized 6LiD could be measured with the central coils 
while at extreme ends of the target no signal was seen. After the transverse
mode the polarization at 2.5 T was checked again. 

e) The target polarization was destroyed by going to zero field on Tuesday 
afternoon. The energy stored in the spin system is released and the mixing
chamber warms up momentarily.

f) The 3He/4He mixture was pumped out from the dilution cryostat and stored
to the tanks in the pump room. After this pure 4He was condensed into the
mixing chamber. The TE-calibration at 1.0 K temperature in 2.5 T field was 
started on Thursday. The calibration was finished when the pressurized air to
target platform was lost 9:00 Friday morning. Kaori: the new 1.0 K point is 
in good agreement with the July and September TE-calibrations.