Development of the Ceramic Chamber Integrated Pulsed Magnet Fitting for a Narrow Gap

Abstract

We are pushing forward the development of a pulsed magnet that has a combined structure of magnet coils with a ceramic vacuum chamber, aiming to realize a small gap. The structure we are developing is that single turn air-coils are implanted along the longitudinal axis in the cylindrical ceramic chamber wall with thickness of 5mm. The ceramic wall works for separating the vacuum from the atmosphere, as well as holding the coil structures mechanically and the electrical insulation of coils. By this structure, magnet pole edges can be set close to the inside diameter of the chamber. The small gap increases magnetic field strength, which is for shorter length, and, as a result, the small magnet size reduces the inductance, which is for shorter pulse. We achieved the continuous operation over 200 days, without any failure, of current-excitation with 20 kV, 7.7 kA pulse with 4-μsec width and repetition of 1 Hz, using the dipole type prototype with a bore radius of 30 mm and magnetic length of 0.3m in 2013, while maintaining the vacuum pressure less than 10⁻⁶ Pa. In this conference, we will discuss about the availability and practical utility with the magnetic field output performance.