LDX Project Status

Floating Coil Helium Vessel Ability has adjusted the welding positioner to operate at low speed using new motor, gear reducer and speed control. Using the new positioner Ability has successfully finished practice of the outer equatorial weld using the dummy Inconel elbows. The weld quality was good. The lower half of the vessel was weighed and has a weight of 182 lbs. This corresponds to a full weight for the helium vessel of about 162 kg which corresponds to an average wall thickness of about 9.8 mm. Ability will make measurements of the shape and wall thickness of the vessel halves and consider the possibility of machining the outer surface to reduce the weight of the vessel.

Floating Coil Cryostat . Ability has tried to manufacture the thin stainless steel disks that will serve as supports for the helium vessel using water jet cutting machine. The result were unsuccessful and an external vendor shall be found to make the 7000 disks that will be used in the low thermal conductance supports.

Floating Coil Winding/Impregnation Everson completed the winding of the floating coil on March 31, 2000. The completed coil currently has a total of 714 turns in 44 layers. This is equal to the full number of turns planned for the coil. Everson is now completing the tasks associated with the protective copper sheets at the coil OD, arrangement of the coil leads, and vacuum impregnation. These tasks are expected to take 2-3 weeks, and we are planning for the coil should arrive at MIT by the end of April for testing at full current Closeup of projection outer copper sheets and conductor joint region in the center. Completion of winding. Coil is now ready to impregnate. Test of impregnation method. The coil must be completely impregnated with epoxy keeping the leads and joint region clear.

Launcher/Catcher The drafting for the final design of the launcher-catcher continued including modifications to accommodate size changes in the charging and levitation coils. The technical requirements document was revised. The final design review at PPPL was postponed until April so that the manufacturing drawings can be completed.

Charging Station The tolerances for the position of the floating coil during charging were found to be acceptable, and we have determined two design options for adjusting the coils, both horizontally and vertically, to within 2 millimeters. In design A, the floating coil rests on three rollers secured at the bottom of the charging station. Its horizontal position is fixed by three retractable tapered rods which slide into grooves on the outer reinforcing ring of the floating coil. In design B, the reinforcing outer ring of the floating coil will rest on a cylinder which can rotate on ball bearings. The rotating cylinder will react both the horizontal and vertical forces on the floating coil. This design frees up space at the bottom of the charging station but may be harder to manufacture within the specifications. The design option selection will be finalized in collaboration with Ability Engineering.

Charging Coil After detailed comparison of design options with high temperature super conducting (HTS) current leads and copper current leads the STC "Sintez" of Efremov (Russia) convinced us that the copper current leads is the best option in the particular application to the LDX C-coil. Several options of the magnet winding were analyzed for stresses by "Sintez". The layer winding was chosen. The Sintez group has proposed the use of a new type of a cabled conductor in order to reduce the manufacturing time. The first 10 m of this conductor was made in Moscow and mechanically tested by "Sintez". Measurements of the critical current of this cable are being made.

Levitation Coil Design work continued on the LDX high-temperature superconducting L-Coil. Three batches of conductor samples have been received from the American Superconductor Corporation and 2 of the batches were tested over the range of temperatures (20-77K) and fields (0-2T). The first batch gave results that were consistent with expectations, the second batch gave poor results and it is believed that the sample was overcompressed by the mounting fixture. Testing should be completed before the design of the L-Coil is frozen. We are presently optimizing the cross-section shape of the coil.