The spectrometric properties of some crystals in the soft X-ray region.
thesisposted on 19.11.2015, 09:17 by Bryan. Leigh
Following a brief introduction, including a background of X-ray Astronomical studies, basic crystal structure concepts, and X-ray reflection theory, practical methods of measuring the three principal spectrometric parameters are discussed. Of the three parameters, the diffraction profile F.W.H.M. (WC), the peak reflection coefficient (P), and the integrated reflection coefficient (RC) the latter is considered the most important in practice. Several methods (both single crystal and two crystal) by which unambiguous measurements of R can be obtained are developed and described. Particular attention is paid to the form of the correction factor relating the two crystal integrated coefficient (RCC) to the single crystal parameter. Measurements of the three principal spectrometric parameters as functions of wavelength for three of the acid phthalates are described and the results compared with values computed from the Perfect Crystal and Ideal Mosaic models. Observations of a previously reported enhancement in RC at the OK absorption edge wavelength in K.A.P. are confirmed, and new observations of a similar phenomenon in R.A.P. and A. A.P. are described. In addition, an anomalous reflection at the wavelength of the CK edge by the 001 planes of A.A.P. is reported. An explanation in terms of anomalous dispersion theory is given which explains the observations at least semi-quantitatively. The problem of adequately testing thetheory quantitatively is discussed. A catalogue of the three principal parameters as functions of wavelength for Gypsum (020), S.H.A. (110), A.D.P. (101), E.D.d.T. (020), and P.E.T. (002), is given and both experimental and theoretical considerations are discussed. Computed values for Pyrolytic Graphite (002), LiF (200), and LiH (200), are also included. The shortcomings of the work are discussed and the author's recommendations for possible continuations of the studies are noted.