Minutes from target meeting held November 30 2007 in 888

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2007/

a) First empty target cell measurement from Thursday November 22 to Sunday 
November 25 at 1.5 K and 1.3 K. All coils working with only small detuning
compared to the TE-calibration period. Kaori: possible residual target material
at the downstream cell. First analysis shows good agreement with Yuris 
line-shape analysis for upstream coils, but for downstream cell the correction
factors are higher. Takumas analysis in good agreement with Kaoris results. 
Coil #9 correction factor too high giving more than 100 % polarization. Other 
coil polarizations are possible. Jaakko: no material was visible inside target 
cells after unloading, but some may have been trapped outside of the cells. 
In addition there was ice on the upstream end of the NMR cables. 

b) Monday November 26 unload the empty target cells. The cells are warmed to
room temperature with air blowers. The caps are used to close the cells. The
cells are cooled rapidly to LN2 temperature and they are loaded inside the 
mixing chamber. Now the amount of ice on the NMR cables is very small. Pump
out air and start to precool with cold helium gas.

c) Tuesday morning restart evaporator rotary pump. Start to condense helium
to mixing chamber. Ramp up the magnetic field 16:00 and start empty cell
calibration at 1.5 K. Kaori: Q-curve of coil #10 missing. Probably the 
soldering to coil broken. Coil #9 tuning shifted due to coupling with #10.
Temperature 1.3 K from Thursday 10:00 to Friday 23:00.

d) Modifications to the polarized target for Drell-Yan physics were discussed.
Two 15 cm long and 3 cm diameter cells are needed. Norihiro: empty volume
could be inserted at the upstream end of aramide epoxy tube. Jaakko: careful
with pressure, should be connected to upstream flange with capillary.