Switch for fine adjustment of persistent current loops in superconductive circuits

Abstract

A small portion of a lead for a superconducting coil is made to function as a controllable resistor with a low resistance value and fast thermal response so as to be capable of rapidly being switched between the superconducting and resistive states. The device is thus capable of fine adjustment of the current flowing in a superconducting loop. The switch includes lengths of parallel conductor so that the resulting section of superconductive material is cryostable. The superconducting oil lead is disposed on a substrate so as to permit ready access for helium or other cryogenic coolant to most lead surfaces. The small mass and close contact with the coolant produce rapid turn-on and turn-off response characteristics. Furthermore, the low overall resistance causes the coil current to decay slowly, thus preventing precise control of the superconducting current.

Dependencies are inferred from the claim text.