Minutes from target meeting held March 12 2010 in 892-2-009

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2010/

a) All spare SMA feed-throughs for target holder leaking. Produce two new 
feed-throughs from UT85 coax and 2 mm CuNi tube. Stycast 2850 curing time 
at room temperature about 24 hours.

b) Hiroki: test Ka-band attenuator with IMPATT diode using 500 mW power. About
25 dB loss with blade depth of 3.5 mm at 70.30 GHz. Insertion loss about
0.21 dB. Use old thermocouple power meter. The shape of the blade important
to eliminate frequency dependence of attenuation. SiC blade can be machined
to optimum round shape. 

c) Fabrice: magnet filled with LHe. Successful test of field rotation at 1 T 
and 2.5 T. Helium recovery pressure high probably due to new Unicos controlling
system settings for the helium liquefier and balloon control valves. Also
parallel helium-4 evaporator pump testing was increasing the pressure.
There is a risk of quench due to lack of current lead cooling if the recovery
pressure stays high for long time. Magnet now ready for 2010 run.

d) Start filling helium-4 evaporator with LHe on Thursday morning. Test the new
helium-4 pumps in afternoon with half of the maximum pumping speed or at 
1000 m^3/h. The pump inlet pressure was regulated at 4 mbar setting. The flow 
was about 100 mmol/s and TPO4 reached 10 kohm. Stable operation achieved 
although the recovery line pressure was high about 1150 mbar during the test.

e) Yuri: install an attenuator also at the central cell microwave feed-through.

f) PXI crate shelve received from Bochum.