▎ 摘　　要

We have successfully fabricated a filament-less X-ray tube using a graphene flower cloth (GFC) field emission cathode. The GFC has numerous nanoprotrusions formed by self-standing graphene structures. The field emission current and the field enhancement factor beta were 500 mu A and 5600, respectively. The stability of voltage defined as a variance coefficient (sigma/mean) of voltage was calculated to be 0.04% while maintaining the X-ray tube current of 300 mu A. We applied our X-ray tube with the GFC field emitter to the X-ray fluorescence (XRF) analysis of stainless steel. (C) 2013 The Japan Society of Applied Physics