Wavelength Identification of Ultrasoft X Rays by the Critical Angle of Total Reflection

Abstract

If absorption in the reflector is low, ultrasoft x rays exhibit a well-defined critical angle of total reflection. Experiments with simple apparatus verify critical angles calculated for paraffin of θc≈4° for carbon radiation (λ=44.7 Å) and θc≈6° for boron radiation (λ=67.7 Å). Utilization of this concept in a low-resolution (10<λ/Δλ<20) instrument for the chemical analysis of carbon and boron by a paraffin reflector and of nitrogen, oxygen, and fluorine by a lithium fluoride mirror is suggested.