[en] Members of our Physics of Solids and Macromolecules Group have developed a new method for producing self-supporting transmission gratings for the soft x-ray region. The method employs holographic techniques and permits, for the first time, gratings to be fabricated with characteristics optimized to the soft x-ray region from approx. 10 to approx. 1000 A. Members of the group, in collaboration with members of the Photophysics Group of the Chemical Physics Section, have also developed a resonance ionization source for a mass spectrometer. This process enables the detection of very low levels of atoms of a given species on the surface of a solid. One application is the measurement of isotope ratios. The program in High Voltage Research dealing with the development of superior gaseous and liquid dielectrics for energy conservation during electrical energy distribution has continued to increase. Members of our Atomic, Molecular, and High Voltage Physics Group have been asked by the Department of Energy to host the Second International Symposium on Gaseous Dielectrics. Members of the group have developed fast gas mixtures for use in gas-filled particle detectors that are far superior to conventional gases. Use of these fast gases is anticipated in many areas

[en] A report of the IAEA Seminar on Safety in Nuclear Power Plant Operation held in Vienna in November 1983 is given. The seminar was largely devoted to management with emphasis on motivation and creation of a good working climate, quality assurance and performance. (U.K.)

[en] It is a fundamental precept that all prudent precautions should be taken. The secondary contribution to public safety derived by a proper choice of site must therefore be utilised. A siting policy should limit the choice of site but give the Utility sufficient freedom of choice to enable the more remote sites to be available for the adoption of new reactor types. For a significant release few people should be affected sufficiently to require evacuation, and account must also be taken of population centres possibly up to 20 miles from the site. (orig.)

[en] The main emphasis is placed on the legal responsibility of the utility in UK to build and operate its plant to avoid any nuclear hazard. The regulatory practices have endeavoured to inculcate a proper emphasis towards safety by the people who comprise the management of the utility, and to avoid any erosion of their legal responsibility as the best and possibly only practical means to achieve adequate safety standards. (orig./HP)

[en] Effects of the presence of inhomogeneities in tissue irradiated by negative pion beams are investigated. Soft-tissue targets are considered with embedded regions of bone and cavities of air. The absorbed dose is calculated as a function of position in the targets for parallel and converging beams and for two parallel beams that enter the target from opposite sides. Isodose contours are calculated and displayed in each case. While these studies show expected trends, they indicate that specific calculations are needed for other beam parameters and target geometries. The contributions of neutrons to the dose contours can be seen from several calculations made both with and without neutrons

[en] We present the results of the following Monte Carlo track-segment calculations for protons with energies of 1, 2, 5, and 10 MeV in liquid water: (1) radial dose around a long segment of a proton track; (2) energy-loss straggling distributions for protons of different energies in 1 μm of water; (3) the distribution in the average absorbed dose around track segments of various lengths; (4) the relative standard deviations in these distributions as functions of the length of the track segments. Calculations such as those presented here are useful for studying track phenomena on a microdosimetric scale, where statistical fluctuations are substantial

[en] It has long been recognized that nonuniformities in dose distributions may occur in the immediate vicinity of a boundary between two different media. Considerable work has been done to determine interface effects in media irradiated by photons or in media containing β- or α-particle emitters. More recently interface effects have become of interest in additional problems, including pion radiotherapy and radiation effects in electronic microcircuits in space vehicles. These problems arise when pion capture stars or proton-nucleus interactions produce a spectrum of charged nuclear fragments near an interface. The purpose of this paper is to examine interface effects in detail as to their specific origin. We have made Monte Carlo calculations of dose distributions near an interface in a systematic way for a number of idealized cases in order to indicate the separate influences of several factors including different stopping powers of the two media, nonconstancy (e.g., Bragg peak) in the energy loss curve for the particles, different particle spectra in the two media, and curvature of the boundary between the two media

No abstract available

[en] This lecture describes briefly the chronological order of events which may arise for a very serious emergency situation in a nuclear power plant for which preparations should be made even though the situation has an extremely low probability of happening. The planning and preparedness required are expected to cope with a whole spectrum of emergency situations, from minor accidents to serious plant failures which also lead to releases of significant quantities of radioactive material beyond the site boundary. Fire protection aspects will be briefly covered, and some guidance will be provided on exercises to ensure the plans are feasible and the appropriate personnel and facilities are in a satisfactory state of preparedness. (orig./RW)

[en] Histories from a Monte Carlo electron transport calculation in liquid water are analyzed to obtain the distance distribution functions, t(x) and T(x), of energy transfer events. These functions, which give the average energy transferred within a distance x from an arbitrary transfer event, are presented for irradiation by monoenergetic electrons of several energies between 500 eV and 1 MeV, for monoenergetic photons of 10, 50, and 200 keV energy and for 65 kVp and 200 kVp x rays and ⁶⁰Coγ rays. The dose average lineal energy in spherical sites as a function of site radius is also presented for these same photon spectra