The possibility of using superconducting pulsed magnet for high energy physics has been studied in many laboratories around the world. Problems and requirements of the pulsed magnets tested in those laboratories are reviewed in conjunction with conductors developed for them. Most serious problems involved in the pulsed magnets are degradation and training effects. Brief reviews on AC losses and stability are also given. Design requirements of the conductors for the pulsed magnets are considered in terms of several parameters, such as number of filaments, diameter, Cu/SC ratio, alloy compositions and twist pitch. Since requirements of the conductors for high stability and low AC losses are conflicting, some of the parameters are optimized.
The dynamic behavior of liquid helium in a glass dewar (7cm i.d. and 74cm length) rigidly set on the vertically vibrating shake table was observed. The shake table was excited at amplitudes of 4, 10, and 20mm, and at frequencies up to 500cpm. The increased loss rate due to the vibration, which depended on the amplitude and frequency of the excitation and the depth of liquid in the dewar, was about 0.1W at most in this experiment. The amplitude of the liquid motion was increased at the resonant frequency, but had no corrlation with the magnitude of the loss rate. The vibration losses were considered to be caused by the enhancement of convective heat transfer in a vapour column above the liquid.
A simple NMR marginal oscillator with a single MOSFET has been improved by incorporating an amplifier with additional MOSFET; the main part (cryogenic box) is immersed in liquid N2 or He and is put between the pole pieces of an electromagnet. The influence of static magnetic field upon the characteristics of the commercial MOSFET element was studied and the element was found to work well at low temperatures under magnetic fields up to 20.1kG. The stationary NMR measurements of Al27 nucleus in ruby crystal were carried out over the temperature range 1.5-300K by using the built-in NMR apparatus; in particular, the temperature dependence of the NMR linewidth was measured in this work.