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An experimental apparatus has been designed and built at the Elliot Lake Laboratory (Mining Research Laboratory, CANMET, Energy, Mines and Resources Canada) to measure the 222 Rn emanation rate from 226 Ra-bearing solid materials by the vacuum emanation method. Several materials that are potential candidates for use in the Sudbury Neutrino Observatory (SNO) project were tested. The emanation characteristics of the different materials tested varied significantly from one another. A variety of other materials is presently being tested. The vacuum emanation method represents a “worst-case scenario” in that it provides (at constant temperature) an upper value for the emanation rate, which is useful for design purposes and other engineering and scientific purposes. The same apparatus, with some operational procedure modifications and different α-particle detection system, has been used successfully to measure the 220 Rn emanation rate for the same and other samples.

As photodisintegration of deuterons mimics the disintegration of deuterons by neutrinos, the accurate measurement of the radioactivity from thorium and uranium decay chains in the heavy water in the Sudbury Neutrino Observatory (SNO) is essential for the determination of the total solar neutrino flux. A radium assay technique of the required sensitivity is described that uses hydrous titanium oxide adsorbent on a filtration membrane together with a beta-alpha delayed coincidence counting system. For a 200 tonne assay the detection limit for 232Th is a concentration of 3 x 10^(-16) g Th/g water and for 238U of 3 x 10^(-16) g U/g water. Results of assays of both the heavy and light water carried out during the first two years of data collection of SNO are presented., Comment: 12 pages, 4 figures

The adsorption of gold sols on the surface of amosite and chrysotile asbestos has been investigated under a series of different conditions. The gold sols had diameters near 300 A and their negative charge was measured by an electrophoresis technique. Asbestos fibres were added to sol solutions with pH from 5.0 to 6.8 and the location and density of the deposited sols were determined by electron microscopy. Per cent surface area coverage by sols ranged from 11 to 4% for amosite and 27 to 3% for chrysotile. The surface coverages were interpreted to give the amount and location of the surface charges for the asbestos fibres as a function of solution pH. The results were also correlated with the surface ion impurities as measured for the asbestos samples (reported here) and the zeta potentials for similar asbestos (as reported elsewhere). In general, it is concluded that for chrysotile, which has a positive zeta potential, the negative sols are attracted to Mg2+ or impurity cation sites on the brucite surface layer. On the other hand, since amosite and the sols both have negative zeta potentials, a specific adsorption mechanism possibly involving Fe3+ ions on the amosite surface is required. These results were compared with predictions of a current calculation of charged surface interactions in an electrolytic solution [1].

The frequency-wave vector dispersion relations of the lattice vibrations in the symmetry directions of body centred cubic iron at room temperature have been measured by means of neutron inelastic scattering. Most of the measurements were made with the Chalk River triple axis crystal spectrometer in the constant Q mode of operation. Results for 40 modes, well spaced along the symmetry directions [ς00], [ςς0], [ςςς], [ςς1], and [ 1 2 1 2 ς], are reported here, together with an analysis in terms of Born-von Karman general forces. Forces to third neighbours are required to obtained a fit at all; forces probably exist beyond fifth neighbours. The force system could be axially symmetric. The forces between first neighbours are found to be attractive if considered as arising from a potential, a fact which suggests that bonding occurs. It is noted that this is true also for all the body centred cubic transition metals yet studied (W, Ta, Mo, Nb), but not for any of the non-transition B.C.C. metals nor for any transition and non-transition F.C.C. metals.

Using inelastic scattering of slow neutrons, the frequency-wavevector dispersion relations for the lattice vibrations in the face-centered cubic alloys Ni3Fe, Ni0.5Fe0.5, Ni0.3Fe0.7, and Cu3Zn have been measured at 296 °K. Measurements were also made at 573 °K for the Ni0.3Fe0.7 alloy. The results for the nickel–iron alloys are very similar to those for nickel, with mean frequency ratios (alloy/nickel) of 0.990, 0.950, 0.953 for the Ni3Fe, Ni0.5Fe0.5, and Ni0.3Fe0.7 alloys respectively. Significant deviations of the limiting slopes of the dispersion curves for Ni0.3Fe0.7 from velocities reported by Alers et al. from ultrasonic measurements are thought to be caused by magnetic contributions which are small at the frequencies measured here. The temperature dependence of the frequencies for Ni0.3Fe0.7 is consistent with that observed for nickel. For Cu3Zn, the results are similar to those for copper; except that the mean frequency ratio (alloy/copper) is 0.932. A neutron diffraction method was used to characterize the homogeneity and composition of the alloys. Born – von Kármán fits to the data, the frequency distributions, and Debye temperature vs. temperature relations are also given.

The lattice constants of a number of large (5–30 cc) single crystals of alloys have been determined by neutron diffraction to an accuracy of about 2 parts in 10 4 . (The precision can readily be improved.) Because the large neutron beam takes in and penetrates almost the whole ingot, the lattice constants obtained characterize the mean composition of the ingot and the spreads in lattice constant characterize its homogeneity. The method has been applied to alloys of PbTl, BiTl, CuAu, CuZn, CuNi and NiFe.