Precision triggering circuit for a high magnetic field pulse generator

The authors detail the SCR control circuit for a superconducting magnetic pulse generator. Two different designs for the generator´s coil were studied. Both used liquid nitrogen as a coolant. The first design employs a high T_c superconducting thin film in the coil. A twenty-five milli Tesla pulse could be generated at a frequency of ≈100 Hz using a coil current of 25 A. The second design utilizes aluminium material for the coil and generates a pulse of 1.01 Tesla at 250 Hz from a coil current of 1340 A. The electrical and thermal responses of both designs were studied. The power dissipated into the liquid coolant by the superconducting coil was negligible and therefore its output frequency is determined by the electrical response of the circuit. However, the second design incorporates low-power signals to control an SCR circuit so that the coil´s current is allowed to peak at a value which corresponds to a given magnetic field intensity. PSpice simulation showed that this current peak could be attained in 4 msec