Minutes from target meeting held on 24th of October 2002 in 892-2-009

a) Yuri reported progress in TE-calibration of coil #1 at 1K. Parabolic 
baseline fit in addition to the linear fit was used. Both baseline fits gave
consistent results, but error of linear baseline fit is much smaller. 
The calibration points were plotted with both left and right baselines in
series {bgr,sig,sig...,bgr} using 100 - 300 points from beginning and end
of the file for baseline fitting. The calibration results with 300 baseline
points were eliminated from the data, since they deviate from the other
probably due to closeness on the NMR-line. In the TE-calibration the 
integrated areas with positive values or outside of twice the average
were eliminated. The data from coil #6 inside the target material has a lot 
of statistical fluctuations and Yuri suggested that it is eliminated from 
the overall average of down stream target cell. Norihiro asked why coil 
inside shows smaller polarisation compared to other. Yuri said that this
could be due to a magnetic skin effect.  

b) Kaori bundled thermometer cables with NMR cables. The frequency shift 
after grounding of thermometers disappeared. Jaakko said that the mutual
inductance to the big groundloop through microwave stopper could be measured
to help to make possible corrections to the polarisation data.
Yuri said that the holes in 3He tube on bottom of Kevlar tube should be
checked for good conductivity. Uneven flow of 3He into mixing chamber could
explain lower polarisation measured in coils #7 and #8. Jaakko said that
the dilution cryostat was designed for high cooling power and not for low 
temperature operation. Jaakko asked what is the reason that in Saturne II 
paper about 40 % polarisation could be reached in 7 hours, while for us
it takes 24 hours. Yuri said that higher microwave power could lead to
electron spin resonance line saturation. Yuri said that there must be 
small variation on scale of the wavelength in the microwave power
distribution inside the cavity. Jaakko said that for amorphous dielectric 
materials (mixing chamber and Kevlar tube) losses at low temperatures
are dramatically decreased compared to room temperature, but they could also
explain some nonuniformity of microwaves.

c) Norihiro prepared multireg packing for sending it to Siemens. He also made
TE temperature estimation at both 1 K and 1.3 K.