The 10 Millisecond 150 Kiloampere Pulsed Power Supply for the Fermilab Neutrino Focussing Horn

During this past run for neutrinos to the 15´ Bubble Chamber, approximately 750,000 pulses have been obtained from the power supply wihtout incident or failure of any tupe. To enhance reliability, the primary voltage was limited to 5.5 kv with an 80 kA secondary current. Initial problems during the test period were largely related to damage to the high current connections, i.e., pitting of the contact surfaces. This problem was resolved by copper plating the aluminum surfaces, followed by silver plating. Bolted connections with lock nuts were required in all cases to insure long term intimate contact. It is planned to raise the current to 120 kA for a substantial test period at the end of the present run to test the system under more stringent conditions. It is clear that for applications similar to this, a transformer is an excellent choice. The low primary current simplifies the ignitron circuit and the low voltage on the secondary simplifies the insulation requirements on the load circuit. These two factors substantially improve the total operational reliability and ease installation.