A 300 kA Pulsed Power Supply for LBNF

The Long Baseline Neutrino Facility (LBNF) will produce the world's most intense neutrino beam. Three series connected magnetic horns will require 5kV, 300kA, $800\mu \mathrm{s}$ pulses at a rate of 1.4 pps to focus the beam. Fermilab has designed and built pulsed high current supplies for horns in the past. Pulsed currents of 205 kA for Neutrinos at Main Injector (NuMI / NOvA), focusing a 120 GeV beam, and 170 kA for Booster Neutrino Beam (BNB / MiniBooNE) for focusing an 8 GeV beam have been operational for about 18 years. While the magnetic horns are expected to be replaced, the LBNF horn power supply is expected to last the lifetime of the project, 30 years. A resonant, half sine wave pulser was used for NuMI and BNB and has many practical advantages. The system has impedance limited fault currents by design, albeit large ones. Many fault modes of the system have been calculated. Several circuit changes were incorporated so that a single fault can be tolerated. The supply must also be reversible to enable both neutrinos and anti-neutrinos to be produced.