Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-26T22:17:06.662Z Has data issue: false hasContentIssue false
  • English
  • Français

Transient effects in laser-plasma X-ray spectrometers

Published online by Cambridge University Press:  09 March 2009

J. S. Wark
J. S. Wark
Affiliation:
Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
Get access Rights & Permissions [Opens in a new window]

Abstract

X-ray spectroscopy is a widely used means of diagnosing densities and temperature within laser-produced plasmas. At X-ray energies above approximately 1 keV, Bragg crystal spectrometers are routinely used to record X-ray spectra. Quantitative measurements of plasma conditions can be obtained with a knowledge of crystal reflectivity and film or detector response. In such data analysis it is always assumed that the crystal response is constant in time. However, we show that under certain adverse experimental conditions the X-ray fluxes incident on the crystal are so high as to significantly transiently modify the reflection characteristics of the crystal. Such degradation need not necessarily be accompanied by a loss of observed spectral solution. The transient (nanosecond-time-scale) change in crystal reflectivity is due to a change from dynamical to more kinematic diffraction caused by an X-ray-induced thermal strain gradient in the surface layer of the crystal. The decay time of this strain is typically several nanoseconds. Calculations of some specific crystal reflectivities and rocking curves under such conditions are presented, and methods of minimizing the effect by appropriate filtering are discussed.

Type
Research Article
Information
Laser and Particle Beams , Volume 9 , Issue 2 , June 1991 , pp. 569 - 577
Copyright
Copyright © Cambridge University Press 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Burgeat, J. & Taupin, D. 1968 Acta Crystallogr. A 24, 99.CrossRefGoogle Scholar
Henke, B. L. et al. 1982 At. Data Nucl. Data Tables 27, 1.CrossRefGoogle Scholar
Kilkenny, J. D. et al. 1980 Phys. Rev. A 22, 2746.CrossRefGoogle Scholar
Kilkenny, J. D., Kauffman, R. L. & Lee, R. W. 1990 Private communication.Google Scholar
Klar, B. & Rusticelli, F. 1973 Nuovo Cimento B 13, 249.CrossRefGoogle Scholar
Larson, B. C., White, C. W. & Noggle, T. S. 1982 Phys. Rev. Lett. 48, 337.CrossRefGoogle Scholar
Larson, B. C., Tischler, J. Z. & Mills, D. M. 1986 J. Mater. Res. 1, 144.CrossRefGoogle Scholar
Takagi, S. 1962 Acta Crystallogr. 15, 1311.CrossRefGoogle Scholar
Wark, J. S. et al. 1989 Phys. Rev. B 40, 5705.CrossRefGoogle Scholar
Wie, C. R., Tombrello, T. A. & Vreeland, T. Jr., 1986 J. Appl. Phys. 59, 3743.CrossRefGoogle Scholar
Zachariasen, W. H. 1945 Theory of X-Ray Diffraction in Crystals (Wiley, New York).Google Scholar