Miniature X-ray Sources and the Effects of Spot Size on System Performance

Miniature x-ray sources present unique challenges due to the cost, power and space constraints placed upon them. One of the key functional differences from larger traditional x-ray tubes is that the x-ray spot is comprised of the entirety of the electrons produced by the filament without the benefit of active focusing elements in most cases. The result is an x-ray spot that is not well described by a traditional Full Width Half Maximum (FWHM) type of measurement due to the irregular nature of the spots. This paper presents an alternate method called an intensity integral curve that can be used in conjunction with a Gaussian FWHM measurement. The intensity integral curve gives important additional spatial information about the x-ray spot and more predictive power in how the x-ray spot on the tube may perform in a given application. The experimental setup, curve generation and curve interpretation are discussed for a number of currently available and prototype miniature x-ray sources.