[en] An assessment has been made of the defect structure in the single crystal diacetylene PTS both in the monomer and polymer form, using White Beam Radiation Topography. A one-to-one relationship was found between defects present in the monomer and subsequent polymer crystal. The strain induced during the polymerization process has also been recorded. This strain is seen to relax out when polymerization is complete, to leave a polymer crystal with the defect structure of the original monomer crystal 'frozen in'. It has been shown that the technique of White Beam Synchrotron Radiation Topography is an extremely useful and essential tool for studies of this nature. (author)

[en] Information about texture is traditionally obtained from the two-dimensional distributions of crystallographic directions in the reference frame of the specimen. The distributions can be measured using the angular dispersive diffractometry. In such measurements the rotation of the specimen brings the crystallographic planes of differently oriented crystals into the diffraction position. The distribution (pole figure) can be measured continuously or alternatively the angular space can be scanned in different directions and with required accuracy. The subject is discussed, with examples. (author)

[en] The following are discussed: reasons for using powder method; two main approaches for dealing with overlapping reflections; (1) careful calibration of a diffractometer with known standards whose peak shape functions are then used to strip an unknown pattern producing a set of structure factors which can be used in the usual manner to refine the structure; (2) method developed by Rietveld, which is a least squares procedure whereby the total diffraction pattern is fitted to a model containing parameters which describe the peak positions (cell constants and instrumental aberrations) parameters which describe the diffraction peak shape and its variation with Bragg angle; X-ray sources; techniques for recording diffraction data. Examples are discussed. (U.K.)

[en] The subject is discussed under the headings: introduction (general description of white radiation topography experiments with the Daresbury SRS); experimental; results and discussion (ammonium perchlorate - orthorhombic lattice; sodium nitrate -rhombohedral lattice; sodium chlorate - modified cubic lattice; ammonium dihydrogen phosphate - tetragonal lattice; calcium carbonate - trigonal lattice). Mechanisms for the radiation effects observed are proposed. (U.K.)

[en] The present paper describes how the diffraction approach can be used to determine a grain boundary structure and the advantages of synchrotron radiation for such studies; presents the first determination of a projected boundary structure made using only diffraction information; compares boundary structures in different metals; discusses grain boundary structural width measurements; and then makes generalizations concerning the structure of large angle [001] twist boundaries based on diffraction observations. (author)

[en] It has been demonstrated that a White Beam Synchrotron reflection technique can be used to characterize the fracture surface of Mo and Nb single crystals. This technique when used in conjunction with Berg-Barrett (or in the future monochromatic synchrotron topography) gives detailed information which correlates the internal defect structure to the cleavage surface morphology. In particular, synchrotron fractography has revealed the full extent of the plastic zone associated with a precursor crack, has clearly identified the nature of the initial crack where more than one precursor could have existed, and give detailed information on the extent of twinning and microtwinning. In comparison with other fractography methods for such semi-brittle metals the White Beam Synchrotron method not only achieves rapid data collection, but also provides internal defect structure correlation non-destructively. (author)

[en] A brief introductory survey is presented of the properties and generation of synchrotron radiation and the main techniques developed so far for its application to materials problems. Headings are:synchrotron radiation; X-ray techniques in synchrotron radiation (powder diffraction; X-ray scattering; EXAFS (Extended X-ray Absorption Fine Structure); X-ray fluorescent analysis; microradiography; white radiation topography; double crystal topography); future developments. (U.K.)

[en] This paper reports some preliminary results of X-ray topography investigations of terfernol (Tbsub(0.27)Dysub(0.73)Fe₂) crystals exhibiting high densities of inclusions and precipitates. (author)

[en] Synchrotron Radiation excited X-Ray Fluorescence is a potentially powerful tool for the routine quantitative chemical analysis of materials, with minimum detection limits typically of the order of a tenth of a ppm, and with the added advantages of simultaneous multi-element detection capability, spatial resolution on a micron scale, large signal to noise ratios and short analysis times. This paper presents a brief review of the use of Synchrotron Radiation in Trace Element Analysis and discusses the requirements for a microprobe for chemical analysis utilising SR. Data obtained at the Synchrotron Radiation Source, Daresbury Laboratory include XRF spectra of standard reference materials and an application of the technique to the study of ion implanted layers in semiconductors is outlined. (author)

[en] The subject is discussed under the headings: introduction; basic physics of Bloch wall statics (magnetization (a) parallel (b) perpendicular, to the surface); magnetostrictive strains; detectability of magnetostrictive strains by means of X-ray imaging techniques; interactions of individual lattice defects and moving walls (optical studies; X-ray studies); conclusion. (U.K.)