Quench protection heater design for superconducting solenoids

Abstract

The National High Magnetic Field Laboratory is responsible for the design and construction of a large bore 900 MHz NMR magnet. The magnet's protection system consists of an active quench detector circuit controlling a persistent switch electrically in series with the magnet. The quench heater network is electrically in parallel with this persistent switch and powered when the switch is resistive. Heater network design entails a definition of the design constraints required to operate the 900 MHz magnet, a review of the material properties, and the developmental data to validate the design. Quench heater development will entail power testing and quench initiation studies. Heater power testing will establish the reliability of the epoxy heater interface. Quench initiation studies will measure the characteristic times required to induce quench in coils at design fields. This paper presents developmental progress on the power testing results, and a discussion of the power testing results on the heater network design for 900 MHz.