Showing papers by "Chalk River Laboratories published in 1980"
TL;DR: In this paper, the 16O(d, p1)17O reaction was used to calibrate the Ta2O5 film of known thickness as the primary standard for analyzing the adsorption behavior of various gases on monocrystalline platinum surfaces.
103 citations
TL;DR: Backscattering of MeV 4He+ ions has been used to show that the interplanar spacing between the topmost and second layers of a clean Pt(111) crystal is identical to that in the bulk (to ± 0.4%); the surface is unrelaxed.
60 citations
TL;DR: In this article, the authors used correlated thermal displacements of the lattice atoms to simulate the channeling properties of a trajectory aligned with the rows and of decreasing importance as the direction of the trajectory approaches a random direction.
30 citations
TL;DR: In this article, the half-life of francium isotopes was investigated by alpha spectroscopy following on-line mass separation and the derivation of the mass excess of 202Fr and the systematics of alpha energies and reduced widths were discussed.
Abstract: Neutron-deficient francium isotopes were produced by proton-induced spallation reactions and investigated by alpha spectroscopy following on-line mass separation. The new isotopes201, 202Fr were identified and their half-lives measured. An improved value for the half-life of203Fr was obtained. Alpha branching ratios were determined for198m, g, 199At. The derivation of the mass excess of202Fr and the systematics of alpha energies and reduced widths are discussed.
24 citations
01 Jan 1980
TL;DR: In this article, the release and migration of 90Sr and 137Cs from nepheline syenite-based glass buried since 1960 below the water table in sandy soil at Chalk River have been predicted by models using laboratory glass leaching data.
Abstract: Release and migration of 90Sr and 137Cs from nepheline syenitebased glass buried since 1960 below the water table in sandy soil at Chalk River have been predicted by models using laboratory glass leaching data. Model predications of 90Sr release and migration show good agreement with field measurements. 137Cs concentration profiles in the soil suggest that a simple equilibrium ion exchange model is inadequate to predict 137Cs migration under present test conditions. Soil matrix support of a friable, corrosion-product layer is believed to be largely responsible for observed glass leach rates of the order of 8 x 10−14kg/m2.s after exposure to groundwater for 17 years.
16 citations
TL;DR: In this article, the Gamow-Teller matrix elements were deduced from shell model calculations that employ a modified Kuo-Brown interaction, and a superallowed branch to its mirror, the 49 Cr ground state and a (6.4 ± 2.6)% allowed branch to the 7 2 − state at 272 keV.
15 citations
10 citations
TL;DR: In this article, the excitation function for the deformed nucleus was measured for incident proton energies between 6 and 24 MeV and the results indicated that the giant dipole resonance (GDR) is strongly excited as predicted by the direct-semidirect (DSD) model.
10 citations
TL;DR: During imbibition and germination of jack pine seeds, the composition of the total extractable chromatin varied and the histone levels decreased as the nonhistone chromosomal proteins (NHCP) increased and changed more with time, while the percentage amino acid composition of most histone fractions remained stable.
Abstract: During imbibition and germination of jack pine seeds, the composition of the total extractable chromatin varied. Relative to DNA, the histone levels decreased as the nonhistone chromosomal proteins (NHCP) increased. New chromosomal proteins were synthesized after 2 days of imbibition as judged by recovery of 14C-amino acids from the major protein fractions. Phosphorylation of histones from 32P-phosphoric acid was detected before the incorporation of 14C-amino acids. In the seed the synthesis and relative changes of chromatin coincided with a fall in total soluble protein and free arginine N. By contrast, adenylate energy charge, free glutamine N and in vitro template activity of chromatin increased during chromatin protein synthesis.
When seeds had germinated for 4 days after the start of imbibition more radioactivity, derived from free 14C-amino acids, was recovered from the NHCP than from the histones. The percentage amino acid composition of most histone fractions remained stable, whereas the composition of NHCP changed more with time. The phosphorylation of NHCP was 8- to 41-fold greater than that of the histones. Phosphorylation of histone H4 was not detected at any stage of germination. Correlations between recovery of radioactivity (32P and 14C) from chromosomal proteins and higher adenylate energy charge were positive.
6 citations
TL;DR: The principal mechanism of the 6Li(6Li, 2α)α reaction for E0 = 36 to 46 MeV is the formation and sequential decay of 8Be levels near Ex = 11, 17, and 20 MeV as discussed by the authors.
4 citations
TL;DR: In this paper, the development of models to predict fuel behavior under transient conditions is influenced by the design features of the CANDU-PHW reactor system, which are essentially different from other reactor systems.
TL;DR: In this paper, the authors extended the analysis of power-law damage and ionization distributions for equal projectile and target-atom masses to the unequal-mass case, in which the integral equations are inhomogeneous.
Abstract: Analytical calculations of power-law damage and ionization distributions, done earlier for equal projectile and target-atom masses, are extended to the unequal-mass case, in which the integral equations are inhomogeneous. (The unequal-mass range distribution is given by a homogeneous equation, and so was treated in the earlier work.) More terms are necessary in the asymptotic expansion of the Mellin transform of the distribution than for the homogeneous case; these expansions are given explicitly. The large-depth asymptotic behaviour of the distributions is determined by the projectile range or by the range of the highest-energy recoils, whichever is the greater. Some calculated distributions are shown.
TL;DR: In this paper, a sheath strain rate equation that reflects the physical processes that are involved in strain has been developed, and the average error of predictions by this model is indeed small, but the standard deviation is very large.