Elemental analysis of stainless steel using hard X-ray emission arising from a high-density plasma produced by an intense femtosecond KrF laser pulse

Characteristic hard X-rays emitted from a laser-produced plasma induced by focusing a femtosecond KrF laser pulse are employed for elemental analysis. The emission spectrum of the hard X-ray arising from a stainless steel sample is measured by means of a single-photon-counting X-ray detector equipped with a multichannel analyzer. The elemental analysis is carried out from the photon energy of the Kα line observed in the X-ray emission spectrum, and a calibration curve is constructed for Fe using stainless steel samples prepared at different concentrations (SUS-301, 310, and 316). A continuum band was overlapped on the sharp Kα lines in the X-ray spectrum, which made the assignment of the weak characteristic Kα lines arising from minor elements difficult. In order to suppress this undesirable emission, a prepulse technique was employed. The continuum emission was shifted toward lower energies, and, as a result, the characteristic Kα lines were more clearly observable. The potential advantages of the present approach are also discussed in this study.