[en] Measurements have been made of the small angle scattering of x-rays by a range of materials. A 60-kV x-ray source and a position-sensitive detector were used to investigate the scattering angle range of 2-20⁰ for several plastics and for 20 samples of normal or diseased breast tissue. The scatter shows a peak away from the forward direction and its distribution can be used as a signature of the sample. Absolute differential scattering cross sections for water in the range of 2-10⁰ were measured at 60 keV using an isotope source. The results agree to within 5% of theoretical calculations

[en] In the oil and gas industry management of alpha-active sludge is made more complex by the presence of hydrocarbons and heavy metals. This presentation discusses the origin of radioactivity in sludge, management of risk in terms of safe working procedures, storage and possible disposal options. The several options will generally involve aspects of dilution or of concentration; issues to be discussed will include sludge farming, bioremediation and incineration. (author)

[en] Physical methods, which include x-ray fluorescence (XRF) and fast neutron activation, are rapidly becoming established as powerful tools in the study of body composition. Particular foci of attention are the monitoring of heavy metal exposure, either in the living environment or occupationally, biological processes, organ dysfunction and the efficacy of therapeutic regimes including chelation. The relative simplicity of the facilities which are required have allowed increasing interest to be shown in the development of portable in-vivo systems. This talk will attempt to review some of the important developments which have occurred. Efforts to enhance the ratio of measurement sensitivity to radiation dose will be highlighted. Examples will include monitoring of occupational Pb exposure and possibilities for the monitoring of iron overload which sometimes occurs in association with the treatment of thalassemia. (author)

[en] In the process of nuclear excitation in positron-electron annihilation (NEPEA) experimental results for the cross-section have been found to be greater than theoretical predictions. In our previous work we applied an analysis based on our model of indistinguishable quantum oscillators to the case of NEPEA for 1078 keV in ¹¹⁵In and obtained very good agreement between experiment and theory. In the present work we extend this approach to the case of 1330 keV in ¹¹¹Cd and again obtain excellent agreement between experiment and a recent theoretical prediction

[en] A xenon-filled, X-ray imaging, multi-wire proportional-counter (MWPC) has been utilised to examine small-angle (1.5 upto 16 deg) total differential-scattering of hard X-rays (60 KVp) by H₂O and a number of other low-Z media including several bio-materials. Corroborative evidence for the validity of experimentally-based molecular form-factors has also been sought using a relatively low photon-energy, low-activity point-source, gamma-ray diffractometer in an annular-target, point-detector arrangement. Advances in measurement techniques, developments in radiation source and detector technology and current lines of interest in application-based research are surveyed within the area of the medical sciences. (author). 32 refs., 7 figs

[en] The use of plastic track detectors in teaching institutions is discussed. The fundamentals of track detection are described and studies that may be performed within the confines of a modestly equipped laboratory are discussed and illustrated. (author)

[en] Discrepancies between theory and experiment have been reported in the small-momentum-transfer region x < 10 A^-1 for the coherent scattering of moderate-energy photons. In the present experiment an investigation has been made of the performance of each of the primary components of an annular target setup, arranged for 662 keV photon scattering at angles in the range 5⁰-15⁰. The conventional double-cone primary-beam stop is found to significantly degrade the full-energy peak-to-valley ratio compared to that obtained with a parallel-sided arrangement. Asymmetry has been found in the response of the detector to an auxiliary point source radially distributed over the scattering plane. Appropriate experimental procedures and corrections have been adopted in obtaining differential cross sections of reduced uncertainty. Results obtained on the basis of present measurements are found to be in accordance with theory. A reanalysis of an earlier set of experimentally determined differential cross sections has been produced. (author)

[en] A radiation dosimeter based on Ge-doped silica fibre is described. Parameters concerning thermoluminescence (TL) induced by ⁶⁰Co irradiation are investigated, including activation energies, frequency factors, and reproducibility with dose and fading. It is concluded that Ge-doped silica fibres provide a good basis for medical radiation dosimetry at therapy levels. In particular, doses are reproducible to within 3%, the fibres are reusable and show linearity of dose versus TL output over the approximate range of dose 1 Gy to in excess of 100 Gy. At room temperatures, fading within the first 30 d following irradiation has been found to be of the order of 7%. (author)

[en] Short communication

[en] For broad-beam soft X-ray sources, assessment of the quality of image produced by such units is made complex by the low penetration capabilities of the radiation. In the present study we have tested the utility of several types of test tool, some of which have been fabricated by us, as part of an effort to evaluate several key image defining parameters. These include the film characteristic, focal-spot size, image resolution and detail detectability. The two sources of X-rays used in present studies were the University of Malaya flash X-ray device (UMFX1) and a more conventional soft X-ray tube (Softex, Tokyo), the latter operating at peak accelerating potentials of 20 kV_p. We have established, for thin objects, that both systems produce images of comparable quality and, in particular, objects can be resolved down to better than 45 μm