Minutes from target meeting held May 6 2011 in 892-2-009

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2011/

a) Reinstall all the helium-3 roots water cooled heat exchangers Monday -
Thursday. Pump vacuum into the helium volume from roots inlet pipe. One 
helium leak located on DN10 flange of roots #10 and fixed on Friday.

b) Reconnect electricity to the helium-3 roots control cabinet on Friday
morning. One wiring error found after the previous change of thermal 
protection relays. Start all the roots for a few minutes without cooling
water and test the motor thermal protection by disconnecting the PTC resistor 
cables one by one. 

c) Plans in case of heat exchanger water or helium leak during the
run were discussed. Small intervention should be possible by filling the
dilution cryostat with helium first to avoid any air entering.

d) Shift organization was discussed. Alarms from the target system are
important if less expert shifters are present. In addition to the target
week coordinator taking care of the routines like field rotation, 
a target on call person is available to solve more serious problems.

e) Werner: new ammonia has about 8 - 9 minutes relaxation time at 1 K and
2.5 T. The material is now stored into glass containers in LN2. The
density of NH2 radicals was determined to be about 3.8 10^19/ccm. This value
is changing during the storage however. Fast build up of the polarization
in the COMPASS dilution cryostat is expected.

f) Yuri: the hermetic rotary pump 2033H for helium-3 recovery should be 
tested.

g) Fabrice: new 200 l LN2 dewar received. Needs to be registered at CERN. 

h) Norihiro: helium-4 pumps and the pumping line were leak tested.