Laser Plasma X-Ray Source Using Cryogenic Target of Inert Atomic Element

Abstract

X-ray spectra from 0.53 μm wavelength laser-produced plasmas are investigated for the photon energy range of 0.1-3Ke V as a function of the atomic number Z. Several spectral humps are found to move towards higher energy side as Z increases. These series of the humps are interpreted as the transitions in K, L, M, N, O shells of ions. The square root of the photon energy at the spectral hump is found to be approximately linearly dependent on Z, suggesting that a semi-Moseley's law holds in the plasma x-rays. From this result liquid or solid cryogenic targets using Xenon or Krypton are found to be very useful as a practical x-ray source. A preliminary experimental result of the cryogenic target is presented and a practical system is proposed.