Magnet Quench
RDUDLEY (rdudley@ARSERRC.Gov)
Tue, 20 May 1997 09:01:08 -0500 (EST)
I wrote earlier about our MSL-300 magnet quench. We are back to field and we
know the reason why the magnet quenched. The o-ring groove in the flange had
some corrosion. Water had seeped in behind the o-ring to cause the corrosion.
The water most likely came from the ice melting from the nitrogen ports. On
our 9.4 tesla oxford magnet we have the blaack fins on th nitrogen ports which
eliminate the icing problem. These are not readily available for or 7.05 tesla
Bruker magnet. Instead we have place sponges below th hoses on the nitrogen
ports. (I believe Karen Ann Smith made this recommendation). In addition the
bolts holding the flange together bolt in from the bottom. That means that
water can collect in the holes on top of the flange. These were filled with
RTV (clear silicon sealer)to keep water from collecting in the holes.
Dave Sutton came into our lab to work on the magnet. In five days I learned a
lot about the care and feeding of magnets. Currently the boil off rate and
field drift of the magnet is settling down nicely and should be inside of specs
by the weekend. The magnet shimmed up very nicely and the cryo shims seem to
be very stable. I am very please with the Job. Knock on wood that I won't
have to do this again in the near future.
Bob Dudley