LDX December 2000
Helium Vessel, Cryostat and Charging Station
Ability Engineering Technology has shown steady progress in the manufacture of the F-coil cryostat and charging station. On the He vessel, the interior structural supports were fitted and final positioned to within 1/64" of center. The heat exchange finned tubing has been fitted, welded and leak checked. Final welding of the vessel will commence early February.
The support structure for the outer cryostat has been cut and the support structure assembly fixture has been assembled. Once the He vessel has been pressure tested, fitting of the support structure will commence.
Aspects of the charging station conceptual design has undergone a revision to reduce cost and complexity. Detailed design is now underway.
Two prototype bumper supports have been tested for mechanical stability under non axial hit loads. Following these tests the shape of bumper coin was finalized. MIT has provided Ability with the spring-pre-loaded modified bumper design. The 0.004" thick tape material that will be used for stamping out the bumper coins is under final consideration. The material must be strong, hard and ductile with a minimum magnetization in the large temperature range (from 300 to 5 K). The combination of these requirements requires a very careful material selection.
The design of the revised cryostat anti- rotation device has been finished. After the final selection of materials for the belleville washers necessary tests will be performed.
Bumper stack before and after test.
Bumper stack test
The Efremov Institute (Russia) will perform a trial (dummy) winding of the charging coil conductor to determine the real winding density and to finalize the winding and vacuum impregnation technology. Efremov finished all preparations for the dummy winding and obtained necessary materials from their subcontractor. The first three bobbins with the C-coil conductor were received from the Moscow Cable Institute. One bobbin will be used for the dummy winding. The materials passed the incoming quality control and the cable has been sent out for the anti- bonding treatment. A winding machine has been prepared for the dummy winding. The welded cryostat vacuum vessel design with reinforcing ribs has been finalized along with the design of the removable helium vessel transport supports. The new design resulted in some additional reduction of the cryostat mass. Efremov Institute has begun to produce the final 3D assembly drawings.
The manufacturing of the highly reflective aluminized stainless steel tapes for a cryostat thermal shielding has been begun by a subcontractor. The electronic elements of the quench protection and quench detection systems are being assembled. Resistors for the quench protection system have been received and are being tested. A special high voltage breaker for the quench protection system has been ordered (from a Swiss firm). High RRR copper tubes that will be used for the current leads have been received from Finland.
An integrated design concept for the L-coil and it support system has now been completed and drawings are are now beingcompleted which largely follow this design concept. The drawings will be incorporated in the fabriction specifications that will be put out for competitive bid--one for the winding and one for the cryostat. The conductor has not yet been delivered from ASC. It is nearly ready for delivery, but is awaiting final contractual agreement between the MIT and the ASC legal counsels. We anticipate this will be resolved shortly.
We are in the process of obtaining the full description of the work from the selected vendor and we are finishing the preliminary drawings of temporary fixture.