Minutes from target meeting held December 3 2010 in 892-1-B09

These minutes are available also from:

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

a) 1.4 K empty cell thermal equilibrium calibration stopped on Saturday 13:00.
Automatic magnet current shift with new baseline taking after five NMR
signals was used. Due to the trim coil heaters this caused extra boil off
of liquid helium. The liquid helium level in the buffer dewar could not be kept
at the 30 % in these conditions. 

b) Restart empty target cell calibration Monday evening. First refill mixing
chamber with helium-4. The gate valve on the helium-3 pumping line now open.
Temperature about 1.1 K. Take NMR data until Wednesday 18:00. Now new Q-meter 
background taken less frequently after 25 NMR signals. After the calibration
start to pump out helium-4. 

c) Start to measure the target material weight on Tuesday. The upstream sock
done on Tuesday and the two central cell socks on Wednesday and Thursday.

d) The second 200 l LN2 dewar for filling the target material storage dewars 
is boiling off LN2 fast probably due to bad isolation vacuum.

e) Kaori: analyze the background TE-calibration data. About 1 - 2 % error 
ignoring the error from the temperature measurement. Coils 1 and 10 have
now 3 calibration points (or temperatures), while the other coils have 5 
calibration points. Some of the signals have a peak noise and the other
activities in the experimental hall on Tuesday and Wednesday were disturbing
the calibration. 

f) Power on the target platform was discussed. The fault current (20 mA)
circuit breaker on the Jura side under the platform switches off when the
magnet is ramped up. Should be replace with something less sensitive. 
The plug-ins on the Saleve side are operating close to the maximum capacity.