Open AccessCalculations on Cylindrical Metal Vacuum Chambers in Pulsed Magnetic Fields
Author(s) -
R. Helm
Publication year - 1964
Language(s) - English
Resource type - Reports
DOI - 10.2172/763863
Subject(s) - gasket , materials science , leak , glass wool , helium , composite material , pressure measurement , seal (emblem) , mashing , indium , analytical chemistry (journal) , metallurgy , chemistry , physics , thermodynamics , atomic physics , art , visual arts , layer (electronics) , biochemistry , chromatography
It has been suggested that metallic vacuum chambers might be suitable for pulsed magnets operating at audio frequencies, with pulse widths nominally 1/360 sec. In the present note calculations are given for a simple model of such a system, in order to estimate the effects of field attenuation and eddy current losses. The results of the calculation may be summarized briefly as follows, where the results apply to a cylindrical chamber of non-maeyletic stainless steel, 3.0 cm in inside diameter and 0.15 an wall thickness: (1) With steady-state harmonic excitation, the field in the interior Is reduced by a factor of {approximately} 1.03 at 2,000 cps compared to dc; (2) With transient operation, the exponential decay time is about 0.021 millisecond; (3) With square-wave excitation, at 200 gauss and 180 pps, the power dissipation in the stainless steel is about 24 watts/foot, or about a factor of 20 less if half-sine-wave pulses are used instead of square pulses. These results seem encouraging enough to warrant experimental investigation of this type of vacuum chamber for pulsed steering