Minutes from target meeting held August 3 2006 in 892-1-B09

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2006/

a) On Saturday July 29 at 7:45 general power failure in CERN. The diesel
and UPS power were available on the target platform around 8:20 and the 
pump room diesel power for 3He roots was recovered soon. The normal network was
recovered around 10:00, but compressed air to control different valves
in the dilution cryostat and magnet was lost. The PV162 from magnet
helium vessel to quench vent line was open and LHe level in magnet dropped
to 75 - 80 %. Later helium gas was used instead of pressurized air to
keep PV162 closed. The pressurized air was recovered only late in afternoon.
Due to the large consumption of LHe the level in buffer dewar dropped to
23 % before the liquefier started to produce new liquid in the evening.
The 3He/4He mixture from the dilution cryostat was recovered to the
tanks.

The demineralized return line water pressure for magnet PSUs went up to
9 bars - next time the inlet and outlet valves should be closed if there is
a problem in demineralized water circuit. The demineralized cooling water
was recovered on Sunday. The magnet was refilled with LHe between Saturday
evening and Sunday morning. The dilution cryostat for precooled to
mixture condensation temperature on Sunday evening. On Monday the dilution
cryostat was filled with 3He/4He mixture. After reaching stable operation,
670 torrs of 3He was put to two tanks to reach temperatures around
50 mK or below. The polarization was restarted on Tuesday 13:00 and
+46.5 %, -44.7 % and 49.8 % polarizations were reached in three days.
About 40 % polarization was reached in 24 hours.

b) The voltage stabilizer used for the mains power of NMR rack was broken and
removed.

c) The second magnet safety system quench back heater unit was off, problem
with the battery charger. There was also a problem with the second electric
flow meter in the magnet.