Imperfect boundaries: thermal response of the cathode surface of a potted heater-cathode assembly

Abstract

This paper extends the thermal analysis of the potted heater-cathode assembly described in our earlier paper [1] to show the effect of non-ideal interfaces formed during fabrication of the potted structure. The present analysis also accounts for the variable thermo-physical properties of the various materials used. The results of steady- and transient-state analyses are presented for some typical values of the interface heat transfer coefficient. Our results reaffirm the superiority of the pancake heater performance when considered for thermal response to the cathode surface but in the case where uniformity of surface temperature is desired, a helical heater is still preferred even in the situation of nonideal interfaces. Co-axial heat shield calculation with reference to the Spectra-Mat 600 ion source design has also been modified by taking into account the possible imperfections at the respective interfaces. © 1991.