Minutes from target meeting held June 25 2004 in 888

a) Physics data taking with transverse polarization is going to be started 
around July 14. 

b) Second TE-calibration June 10 - 14 was in good agreement with the 
TE-calibration done in May 5 - 12. Both were done with positive solenoid 
current. Isabel is finalizing the TE data. 

c) Aoibhinn and Jaakko tested the Yamagata mixing chamber. No problem with 
+ 1 bar pressure inside. Small diffusive leak 10^-4 mbar l/s at room 
temperature. Cooled down with LN2 heat exchanger and helium gas flow to 220 K.
No leaks. Further cool down with cold N2 gas to 120 K. Leak detected during
cool down. New test at room temperature shows similar 10^-4 mbar l/s leak like
in the beginning. The mixing chamber removed from the test vessel and
inspected from the surface. Only very tiny crack seen on the surface. 
Can probably be fixed by gluing.

d) Target polarization with IMPATT diode system was tested. Buildup time 
comparable to the EIO tubes. In the beginning the frequency was drifting
during the first half day. 

e) Polarization relaxation was measured at low field. Jacques reminded that
the relaxation time at 0.42 T with negative polarization was 2.5 10^3 h and 
with positive polarization 1.5 10^3 h. The beam does not have effect on the 
relaxation. At 0.1 T with waiting time from 10 minutes to 60 minutes positive 
polarization relaxation time was seen to be much longer than the relaxation
time of the negative polarization. Preliminary analysis also showed that 
the relaxation time depends on the value of the polarization. This result
needs to be rechecked. 

f) EPR spectrum was measured with IMPATT diode system by sweeping the magnetic
field. The resistive speer thermometers inside the mixing chamber were used as 
microwave bolometers. Sweeping the field up or down gave reproducible spectra 
with speer resistor TTH1 or TTH2 about 4 kohm. Later EPR spectra with speer
resistor 1 kohm was taken with no significant polarization loss.

g) After one week of use unstable power from the IMPATT diode system was 
observed. The problem needs to be investigated.