[en] The work contains tables of dose and energy gamma ray build-up factors for 29 elements, prepared on the basic data of H.Goldstein and J.E.Wilkins. (author)

No abstract available

[en] A reassessment of the possible systematic errors in the low-energy positron scattering experiments of Canter et al (J. Phys. B.; 5:L167 (1972) and 6:L201 (1973)) suggests that the total cross section deduced from the measurements are more reliable than had hitherto been supposed. The recent assertion of Humberson (J. Phys. B.; 11:L343 (1978)) that the cross sections are quite accurate is now supported by experimental considerations. (author)

[en] Theoretical estimates of the classical part of the stopping power of an Ohmic medium for a fast charged particle are obtained for the two limiting cases of a strongly and a weakly conducting medium. Conforming to the fact that any Cherenkov radiation that is emitted is rapidly absorbed and converted into heat in a strongly conducting medium, there is a single expression for the energy loss, which is Ohmic in nature. On the other hand, in a weakly conducting medium the total energy loss splits up into a Cherenkov loss given by the Frank and Tamm expression and an additional Ohmic loss, whose power spectrum exhibits a marked contrast with it

[en] The theory of electron pickup by fast protons in solids is reviewed. The important physics involved has not been well discussed in the literature. It is shown here that the charge states for high energy protons may be simply understood in terms of capture into and subsequent loss from bound states on the proton within the solid. Collective screening and the short lifetime of the bound state are not important. The surface does not play an important role. For high enough proton velocities, capture and loss cross sections for single atoms may be directly transferred to the solid. The solid behaves as a gas scaled to higher densities. A comparison with other theories is given, and the intermediate energy range is briefly discussed

[en] The results of recent neutron scattering measurements of the energies and linewidths of long-wavelength acoustic-phonon modes in PbF₂ at temperatures between 10 and 898 K are described, and then interpreted in terms of theoretical expressions for the effects of anharmonicity, the hopping motion of the anions, and the time-averaged defect structure. The dynamical properties of PbF₂ are of particular interest, since this compound exhibits a diffuse specific heat anomaly and a rapid increase in ionic conductivity due to a dynamic disorder of the anion sublattice at a temperature Tsub(c) approximately 700 K, which is well below its melting point Tsub(m) = 1100 K. The neutron data show that the elastic constants decrease linearly with temperature as Tsub(c) is approached from below, but decrease more rapidly in the vicinity of Tsub(c). This is particularly marked for C₁₁ which halves in value between 600 K and 800 K. At 570 K and above, the linewidths of transverse acoustic phonons increase as the square of the phonon wavevector, approximately independently of direction, implying that the measurements are in the hydrodynamic regime. The widths vary linearly with temperature below Tsub(c) but increase rapidly in the region of Tsub(c). Theoretical considerations show that the low-temperature behaviour is consistent with the effects of anharmonicity and that the rapid change in linewidth near Tsub(c) is attributable to the effects of defects in the lattice. Anion hopping contributes only slightly to the linewidth. (author)

No abstract available

[en] Double differential flux spectra are presented for 6 MeV gamma photons penetrating aluminium steel, lead and lead-aluminium shielding slabs. A large diameter disc radiator filled with activated primary cooling water from the Universities Research Reactor provides the source of high energy photons. Experimental pulse height distributions from a NaI spectrometer have been unfolded with the code RADAK. Comparisons are made with theoretical values using the code PIPE. Good agreement is established for most of the energy range, but experimental results show the need for the inclusion of secondary sources of photons in theoretical calculations. (author)

[en] Influence of possible chemical effects on the stopping power of BeO, Al₂O₃, TiO₂, ZnO, Nb₂O₅ and Ta₂O₅ was studied between 0.5 and 0.7 MeV amu^-1 for BeO and at approx. equal to 2,5 MeV amu^-1 for the other oxides. The method of study was the 'average stopping power method'. No chemical effect is detected at 2.5 MeV amu^-1. For BeO, energy dependant deviations from Bragg-Kleeman's rule are observed. (orig.)

[en] The structure of excited d-states of some odd Zr and Mo isotopes is studied by measuring the angular correlation (p,p'γ) between inelastic protons and subsequent 2⁺ → 0⁺ γ-rays, at the analogue resonances corresponding to these states. The analysis includes the compound-nucleus enhancement, using the method of Hofmann, Richert, Tepel and Weidenmuller (Ann. Phys.; NY 90: 403 and 391 (1975)). Spectroscopic decay amplitudes are deduced and compared with shell-model calculations. (author)