LDX Project Status

July 16, 2001

Floating Coil Helium Vessel and Cryostat

Ability Engineering Technology completed the high-pressure helium testing of the floating coil helium vessel. This test completes all requirements of the ASME Boiler and Pressure Vessel Code, and the vessel has been stamped safe for operation to 126 atmospheres. Ability also completed detailed measurements of the outside dimensions of the vessel, and fabricated the tooling jigs needed to machine the toroidal mold for the fiberglass radiation shield.

Charging Coil

The dummy coil with three joints was successfully tested in liquid helium by cycling current: 300 cycles from zero to 560 A at the current rate of 20 A/s. The high voltage test was performed after three thermal shocks, created by immersing the dummy coil to liquid nitrogen and then in hot water. The coil survived the designed voltage to the ground of 7 kV. A breakdown of the ground insulation at the inner hole of the coil was observed at 7.2 kV. After the test the coil was cut into two halves in order to determine the modulus of elasticity of the dummy winding and the coefficient of thermal contraction. Additionally, the compression of the coil samples will be performed by a 60 ton press to obtain the required pre-loading forces on the coil clamps. The new modified set of aluminum coil clamps is being manufactured.

The latest version of the Interface Control Document has been accepted by MIT. MIT also received a description and drawings of the quench detection and quench protection systems of the charging-coil.

The full package of manufacturing drawings for the charging- coil project has been completed by SINTEZ and sent to vendors for quotations.

The Cable Institute in Moscow continues the production of conductor for C-coil. They estimate the full amount of conductor will be ready less than 2 weeks.

Levitation Coil

A sub-contract between American Superconductor Corporation (ASC) and MIT-PSFC for work on the SBIR Phase II contract, "Advanced Plasma Fusion Magnets with High Temperature Superconductors" was signed during the week of June 23, 2001. This sub-contract will be used to support the fabrication of the high-temperature-superconductor levitation coil (L-coil) for LDX. Requisitions have been submitted to the MIT purchasing office for the purchase from ASC of the high temperature superconductor tape needed for the L-coil, for the fabrication at Everson Electric Company of the L-coil, and for the fabrication at Everson Electric of the L-coil cryostat.


Hollis Line Machine has completed the parts for the launcher system. The detailed design for the suspension fixture to be used in the supported mode of operation is complete; drawings for final manufacturing are underway.


The ECRH heating system for LDX requires multiple frequencies to achieve pressure profile control. Progress during the past month includes:

6 GHz: The klystron cabinet has been fully tested and it is ready to be moved into the test cell. The design for a launching structure has begun.

10 GHz: The high voltage/filament supply has been ordered.

18 GHz: We have made an inventory of components and have initiated requests for a new magnet supply, a repaired high-voltage supply, and a microwave isolator.

28 GHz: We have begun to inspect the gyrotrons, and we have located components, like the mode-preserving, corrugated 90-degree bends, originally used for the Tara experiment.

Diagnostics and Controls

The real-time levitation control computer was tested successfully with the scale, permanent-magnet, levitation model.