Pulsed current supply apparatus and method for a superconducting coil.

摘要

A pulsed electrical current supply apparatus or method is provided to energise a superconducting coil. A power supply PSU is arranged to generate, when in use, at the superconducting coil, a pulsed output current signal. A bidirectional diode pack may be connected across the output from the current leads to protect a cryogenic switch. The cryogenic switch may be operated using one or more heating elements disposed adjacent a coil of superconductive material to provide a response-delayed selective conductive device. A threshold-dependent conduction switching device, such as a Field Effect Transistor FET, is coupled in parallel to the cryogenic switch. The FET and cryogenic switch may be controlled by one or more processing elements involved in the system. The current leads may be fixed or demountable. A maximum operating current of the current leads is judged from a number of factors. The pulsed current supply signal is then controlled to ensure that the maximum current in the leads is not exceeded. During operation the FET may be activated to maintain current flow while the cryogenic switch is in a non-superconductive mode and deactivated when the desired current level in the coil is attained and the cryogenic switch is cooled to its superconducting mode.