Thermo-Mechanical Analysis of Single-Disc Edge-Cooled Silicon Nitride Millimeter Wave Window for 200 kW CW Gyrotrons
Source: International Journal of Infrared and Millimeter Waves, Volume 21, Number 4, April 2000 , pp. 485-504(20)
Abstract:This paper investigates the possibility of using Silicon Nitride Composite (Kyocera SN-287) as single-disc, edge-cooled window for gyrotrons operating below 200 kW CW in the frequency range 28-42 GHz. Rotationally symmetric TE_0n, and TEM_00 Gaussian modes of rf transmission through the window have been considered. Analysis performed using a one dimensional (1D) finite difference (FD) code reveals that thermal stresses developed due to non-uniform temperature distribution on the disc surface are well within manageable limits for a 200 kW 42 GHz gyrotron proposed for some ECRH applications. For industrial gyrotrons, for microwave material processing and operating at a maximum power level of 100 kW CW, Si_3N_4 windows may be a cost effective replacement for sapphire windows. It is found that a TE_02 profile results in lower peak temperature at the window disc in comparison to a Gaussian beam profile and allows the use of smaller discs.
Document Type: Regular Paper
Affiliations: 1: Central Electronics Engineering Research Institute (CEERI), Pilani-333 031, India 2: Forschungszcentrum, Karlsruhe (IHM, Association EURATOM-FZK), Postfach 3640, D-76021, Karlsruhe, Germany 3: Electronics Engineering Department, IT, BHU, Varanasi-221 005, India
Publication date: April 1, 2000