Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1684683 | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | 2009 | 6 Pages |
Abstract
X-ray and ion emission from gold plasma produced by a sub-nanosecond Nd:glass laser has been studies as a function of distance of the target from the best focus position. Thermal ion (kinetic energy <19Â keV) signals and soft X-ray flux (photon energy >0.7Â keV) measurements decrease as the target is moved closer to the best focus position in spite of an increase in laser intensity. We observe simultaneously a strong correlation between the onset of this drop in the flux of soft X-ray and the growth of harder X-ray (photon energy 3-5Â keV), alongside a growth in fast ion (energy >67Â keV) numbers. This is indicative of the onset of non-linear processes at the higher irradiances (â¼1014Â W/cm2) associated with the best focus position. Our results show that when using laser plasmas as X-ray or ion sources, X-ray and ion emission in a desired spectral range can be optimized by adjusting the focusing on the target.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Surfaces, Coatings and Films
Authors
S. Chaurasia, D.S. Munda, S. Tripathi, N.K. Gupta, L.J. Dhareshwar, G.J. Tallents,