Minutes from target meeting held February 22 2007 in 892-1-B09

These minutes are available also from:

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

a) LN2 trap in the 3He circulation was opened. The activated carbon was very
clean. The trap was closed again with the same carbon and leak checked at
room temperature.

b) The oil was changed to the 3He Pfeiffer roots blowers, 4He Alcatel roots
blower, 4He Busch rotary and to the isolation vacuum Alcatel rotary pump.
The 3He roots blowers were started on Thursday after replacing PTC resistor
motor protection relay MSR220Z for pump #13. In two motors the PTCs embedded
into the windings show too high value and the security is deactivated.

c) The 4He return line from the platform to the liquefier was washed with 
water on Wednesday. It will be dried with nitrogen gas flow heated to 60 C.

d) Tapio from meeting with Moranne, Laetitia, Fabrice, Norihiro: activated 
carbon does not remove oil mist efficiently and coalescing type filter should
be used instead (these are typically made from borosilicate micro-fiber). 
The filters need to be drained regularly.

e) Maintenance of the pump system was discussed. The 3He roots blowers were 
refurbished before the COMPASS started in 1999. Two of the roots blowers have 
been sent for a repair to Pfeiffer and were reinstalled after they came
back. The Busch rotary pump was refurbished at CERN by a Busch technician.
Before the run the pump oil is drained and changed to new oil. The pumps
are started and leak checked. For the 3He roots the pumps are purged by
pumping dry nitrogen to remove any water vapor from the 3He circulation.

f) Norihiro: from the magnet system one 4 - 20 mA signal can be received for
alarms to the PLC. These include fast and slow discharge of solenoid and 
dipole, cryogenic system alarm and opening of quench vent valve. It is 
planned to use PLC pt100 modules to monitor the pump motor temperatures.

g) Kaori: problem with new VXI driver for the NMR DAQ. The driver does not 
allow to use full memory and only 24 signals instead of 32 can be averaged 
at each frequency point when NMR signals are recorded.