Minutes from target meeting held on 17th of October 2002 in 892-2-009

a) Kaori checked the shift of NMR baseline frequencies in different Q-meters
after grounding of the thermometers. With grounding of TTH1 about 10 kHz 
shift was observed. The shift was to opposite direction after grounding
of TTH2. The upstream and downstream NMR-cables were routed together 
to remove possible ground loops. Yuri suggested to route also the thermometer
cables along with the NMR-cables. Norihiro said that after removing the
target cells from the Kevlar tube there was no influence from grounding
of TTH6. Jaakko said that in the long SMC paper influence of field rotation
to the polarisation was reported. Yuri said that in the SMC experiment
there was never influence from the thermometers. Jaakko found a ground loop
which can explain different behaviour between upstream and downstream target
halves:
                                         ___ ___
SMA ====================================|       |===================
|       |               |               |       |  |
|       |_______        |______         |       |  |_____
|       |coil   |       |coil  |        |       |  |coil |
|       |_______|       |______|        |       |  |_____|
|                                       |       |
|                                       |       |
========================================|__   __|===================
3He filling tube                        microwave 
                                        stopper

There is a loop through the 3He filling tube, microwave stopper and 
NMR-cables in upstream part. Similar loop on downstream half does not exist.
The coils #1 and #3 have an axis in parallel with this loop, while for coils
#2 and #4 the angle is 90 degrees. This explains also bigger effect on
the coils #1 and #3.

b) Yuri made the first TE-calibration for coil #1 using linear residual
baseline fit. At temperature of about 1 K the area was 9296+-67 giving
an error of +-0.7 %. The error bars in Kaoris calibration data were discussed.

c) Norihiro checked the temperature during the TE-calibration. Baratron
and TTH4 now in the downstream end agree very well with each other.
Last year these two were very close to each other. Thus there was a good
homogeneity of temperature in the mixing chamber during the calibration.
There is a small but clear dependence on the magnetic field seen
after ramping down the magnetic field from 2.5 T to 0 T. Norihiro 
recalibrated TTH6 and compared its value to the baratron data during the
calibration. Good agreement was found. The TTH6 was used to determine
the temperature at 1 K TE-calibration, when the baratron was not yet
available due to a broken valve in the system. In the beginning of the
the calibration at 1.3 in one data set rather big temperature drift was
observed from 1.30 K to 1.33 K. Jaakko said that the TE-calibration was
done only in positive field direction with SM1 off. Only TTH2 and TTH6
were connected during the calibration.

d) The request from Gerhard M. about help from different target institutes
in the Oxford-Danfysik magnet project was discussed. This would include
system integration to present setup, design/specification tasks, production
quality check, tests at CERN, installation to COMPASS and 
operation/maintenance. Yuri said that he could calculate the field map
of the magnet and help in measuring the field map. Generally for the moment
CERN target group feels that it is too busy with the present system.
Naoki would be a good candidate for this work.

e) Fabrice tested a new driver to communicate with the Siemens multireg.
After a long operation no failure was observed. A spare Sun system for
the magnet control is being tested.