LDX Project Status

Helium Vessel Ability has finished machining the bottom half of the torus which will locate the 10 winding-support frames and machined the smooth transitions to the toroidal weld-preps. Floating Coil Cryostat Ability has ordered the spun stainless-steel half-tori that will form the outer vacuum vessel of the cryostat. MIT has completed prototyping the support bumpers, and MIT has been working with Ability to coordinate the layout of the support and refrigeration components within the cryostat.

Floating Coil Winding The winding of the floating coil was re-started on February 22nd after the excessive-strain interlock-protection system was thoroughly tested. Presently, the pancake winding (46 turns) and the inner 17 layers (211 turns) have been completed. When the winding is completed, we will have approximately 44 layers and 710 turns.) Overall, the winding is proceeding as planned. The coil should be ready for vacuum epoxy impregnation within approximately 12 working days. Some photos are shown below

Step 1: Make pancake winding and first layer winding. Step 2: Solder copper protection strips on top of first protection layer. Step 3: Inspect copper protection sheet joint. Step 4: Continue winding layers over copper protection sheet. Step 4: Continue layer winding outward... Notice transition at steps?

Charging Coil The STC "SINTEZ" of Efremov (Russia) is preparing the design the charging coil. Three options of the winding are under the stress analysis, and preliminary results have been obtained. These include detailed analysis of conductor stress, quench protection circuitry, and options for the current leads.

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. A conductor sample probe is being modified to test the performance of short samples of this conductor in a dipole magnet over a field range of 0-2.5 T and from 20-77 K. Testing should be completed before the design of the L-Coil is frozen. MIT's LEVITATOR code was improved to include arbitrary arrangements of pancakes and layers, to calculate DC losses in the joints and imperfect (finite n-value) superconductor, and to evaluate the ability of the power supply to crowbar the L-coil to zero current in the event of a control instability. Several design options have been investigated which allow reduced cost and elimination of the requirement for interior joints in the winding pack. The design is currently being evaluated by the American Superconductor Corporation. The down-select between the disk and conventional solenoid options should be completed within the next month.