Studies of the Measurement of Temperature in Shock Compressed Crystalline Solids using X-ray Diffraction

Temperature measurement in opaque laser-shocked solids is a long-standing research problem. The diagnosis of temperature using x-ray diffraction, in particular the Debye-Waller effect, has long been proposed as a potential solution, though no experimental measurement has ever been published. This thesis investigates the obstacles present in such a temperature measurement scheme.

A code was developed to efficiently analyse simulated x-ray diffraction patterns from molecular dynamics simulations so as to observe the Debye-Waller effect. This code was used to critically assess previous work performed in this area of research. It was found that material strength has a distinct impact on the behaviour of the Debye-Waller effect, though the impact on temperature measurement is minimal. It was also found that dislocations cause a significant error in temperature measurement, in conflict with the long-standing Wilkens theory of dislocations and x-ray diffraction.

An experiment was performed at the Orion laser facility to assess the experimental limits of Debye-Waller temperature measurement. The diffuse nature of the x-ray diffraction signal from shocked samples inhibited efforts to remove background while leaving signal intact. Brighter x-ray sources with narrower energy spectra are recommended to treat this problem.