||LDX Project Status
Work towards the "final fitup" milestone for the floating coil cryostat is proceeding at Ability Engineering, South Holland, IL. These included careful assembly, measurement, and shimming of the Helium pressure vessel into the space frame using dummy supports. The space frame was also fitted into the vacuum shell and checked for tightness. Work continues on the final setting of the glass ball supports for the lead shield. Dr. Darren Garnier made several trips to oversee these activities.
Ability completed the second heads for the Inconel rods of the anti-rotation devices. The rod assemblies were tested at MIT, and the rod assemblies are now ready to be installed into the cryostat.
An additional set of tests of the helium transfer line (made by Quality Cryogenics) demonstrated an unacceptable high heat leak. The vender has agreed to remake the transfer line upon mutual technical solution of the problem with MIT.
Intensive additional tests of the bayonet inlet into a test cryostat were completed at MIT. The tests with the bayonet, plug, and transfer line while transferring LN2 and liquid helium demonstrated reliable operation and yielded necessary temperature data on the o-ring seals. (The o-ring seals were designed to work and were tested in both the surrounding atmosphere and in vacuum.) The guard tube vacuum seal was also successfully tested. As a result of these tests, the inlet and outlet F-coil bayonets were ordered for manufacturing.
Two stacks of the laminated metal supports that provide low heat-leak supports for the helium vessel were successfully tested at MIT to determine their compression load versus deflection characteristic.
Both the nitrogen cans and copper section of the cryostat shield have been fully polished. The helium vessel bottom, outer cylinder, and mushroom bottom with all coil and transport supports have been assembled and welded. The nitrogen support ring has been fully assembled, welded, polished, and tested for leaks. The cryostat top and bottom have been fully welded and polished, and are ready for assembly. The inner cryostat cylinder has been rolled and welded and special tools are being utilized to adjust it to the precise dimensions that the design requires.
One current lead insulator appeared to be leaking. It was replaced for a new one, which was thermal cycled and then leak tested. The current leads were connected with insulators and then impregnated with epoxy resin and cured. In the next step they will be tested by a high voltage.
Two assembly problems have caused some delay in the project schedule:
During the adjustment on the coil of the upper bandage, it wasdetermined that the existing bandage design required redesign using strengthened fiberglass parts. The additional steel tools for assembly and bonding were machined. The first of the new bandages is presently being epoxied to the coil.
During the preparation for the assembly of the helium vessel with its support ring it was discovered that two of the 12 threaded rods that had been installed as transport supports were cold welded to the helium vessel mushroom and all attempts to remove these rods failed. This problem required that the two 42 mm rods be drilled out and a new set of transport supports will be made of carbon steel 45 to avoid possible bonding. Furthermore the cryostat
design will be revised to eliminate possible occurrences of this problem through the use of special anti-bonding spray in such places.
SINTEZ has developed a preliminary test procedure document. Many changes were made in the test procedure as a result of discussions with the MIT engineers. Several problems regarding the test at the SINTEZ stand are still under investigation. SINTEZ has begun the preparation of the stand for installation and testing of the C-coil.
Dr. Alex Zhukovsky is going to visit SINTEZ in a first week of October to inspect the final stage of cryostat assembly and for the preparation for the final testing of the coil.
The fabrication of the levitation coil is now complete. The coil was returned to Everson Electric for installation into the cryostat on Sept. 4. The machining of cryostat pieces has begun. The top cover and liquid nitrogen reservoir should be complete this week. The factory test of the power supply at Dynapower was postponed until Sept. 19 by a Dynapower request. MIT has received a complete set of drawings for the cryostat. Dr. Phil Michael will discuss the drawings during a visit to Everson on Sept. 23.
FACILITY AND LAUNCHER
Work on a catwalk to provide safe access to the top ports of LDX was finished by Dynavac. The mounting hardware and surface preparation work for the launcher system is continuing. The gas helium recovery piping outside of the building is finished and is being leak tested by a high pressure.