Minutes from target meeting held March 13 2015 in 892-1-B09

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2015/

a) On Monday - Tuesday drill 2.3 mm holes for the target cell longitudinal 
aramid epoxy supports and 6.3 mm holes for the helium-3 filling tube.
Special drilling table was produced from wood for the drilling to keep
the plastic cell part in place and to align the holes symmetrically. Never 
the less two of the fans for the helium-3 filling tube were broken during
the drilling and the alignment of the Kevlar epoxy support is not perfect. 

Drill the same holes to the two copper microwave stoppers in the center 
of the target holder with two additional holes for feeding the NMR and 
thermometer cables.

b) The plastic cells are 555 mm long, they have inner diameter of 40.1 mm
and out diameter of 41.6 mm. The fans for aramid epoxy supports and
helium-3 tube have an outer diameter of about 69 mm. The cell walls have
a 2.0 x 2.0 mm grid of diameter 1.2 mm holes. In liquid nitrogen the
cells are expected to shrink to the nominal 550 mm length. 

c) Bring the helium-3 roots pump WKP4000 internal heat exchanger to the
workshop on Tuesday. The heat exchanger was still touching the internal
opening wall at the last 1 - 2 mm and could not be centered in transverse
direction. 

Assemble the heat exchanger with the bottom plate on Thursday morning. Leak 
test the water circuit with helium leak detector. Insert the heat exchanger
into the pump on Thursday afternoon and start pumping vacuum to the roots
pumps for leak testing. Pump out helium from mixing chamber to reduce 
background signal from possible leak through the gate valve. On Friday 
afternoon at level ~10^-3 mbar l/s no helium leaks could be observed.

d) Christophe: list of the magnet parameters is already visible from 
the DIP server, but the values can not yet be read.

e) Fabrice: test magnet protection system. First attempt to do fast discharge 
test at 50 A by firing the coil heaters did work due to small stored energy
in the magnet. Powering up the magnet solenoid and dipole to the nominal 
field is planned for next week.

f) Norihiro: thin coaxial cable for the NMR coils on the target cells was
received.