Browsing by Author "Gibson, DK"
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- ItemAn analysis of the preliminary water management proposal for the Ranger Uranium Mine(Australian Atomic Energy Commission, 1980-07) Gibson, DKSome of the problems expected to arise as a result of contamination of rainfall run-off by the ore and waste rock heaps of the Ranger Uranium Mine, at Jabiru in the Northern Territory of Australia, have been re-examined. A computer program has been written to estimate the quantity of run-off water resulting from any given rainfall pattern. The program was calibrated against measured stream flows in Galungul Creek; it was then applied to the two major catchment areas surrounding the mine site, and estimates of the quantity and quality of discharge water were made. The effects of the discharge are discussed in relation to the levels tolerable to fish and, in the case of radium, permitted as uptake by humans. A possible modification to the water management plan, which would increase the time for sedimentation before discharge, is suggested.
- ItemAn apparatus for measuring the energy and angular distribution of electrons ejected in ion-atom collisions(Australian Atomic Energy Commission, 1978-07) Gibson, DK; Petersen, MCEThere is a need for further data on the energy and angular distribution of electrons ejected from atoms and molecules by ion impact. An apparatus in which simultaneous measurements can be made of the energy and angular distributions of such electrons is described. The advantages of the apparatus are the possibility of fast data collection and the ability to make measurements over the whole range of scattering angle. Preliminary tests and a trial measurement with the apparatus are described.
- ItemDouble differential cross sections for electron ejection from helium by fast protons.(Australian Atomic Energy Commission, 1985-12) Gibson, DK; Reid, IDMeasurements of the angular and energy distributions of electrons ejected from helium atoms by protons with energies between 20 and 100 keV are presented in tabular and graphical form. The electron energy range is between 5 and 100 eV and the angular range is between 0 and 100 degrees. The distributions have been converted to double differential cross sections by normalisation against other published data. An analysis of the accuracy of the results is presented.
- ItemDouble differential cross sections for electrons ejected from H2, O2, N2, CO2, CH4, H2O and Ar by 50 KeV protons.(Australian Atomic Energy Commission, 1987-04) Gibson, DK; Reid, IDTabulated values of double differential cross section measurements are presented for electrons ejected from H2, O2, N2, CO2, CH4, H2O and Ar by 50 keV protons. The angular range extends from 0 to 100 deg and the electron energy from 5 to 150 eV.
- ItemMathematical study of a lysimeter.(Australian Nuclear Science and Technology Organisation, 1987-11) Gibson, DKIn studies of the rehabilitation of mine overburden heaps at Rum Jungle in the Northern Territory of Australia simple buried water collectors have been used as lysimeters to measure the infiltration into the heaps. This report describes the development and results of a study state finite difference computer code which calculates the movement of water in such systems. It is shown that the water collection efficiency of this type of lysimeter depends strongly on the hydraulic properties of the soil in which it is buried as does the rate of capillary loss during periods of zero infiltration.
- ItemMeasurement of the energy and angular distribution of electrons(The Australian Insitute of Nuclear Science and Engineering, 1979-02-05) Gibson, DK; Petersen, MCEKnowledge of the energy and angular distributions of electrons ejected in collisions between fast particles (10-100 keV), particularly protons, is of great importance in understanding of the damaging effects of neutrons in biological matters. For this reason the AAEC has a program to extend the knowledge of these electron distributions to the atoms and molecules which constitute living cells. Clearly there are a large number of measurements involved in such a project, the ejection, angle, ejection energy, incident ion species and energy and the target atom all being variables. For this reason our aim was to design an apparatus which would permit rapid accumulation of data. Our design is based on the 30° electrostatic analyser, in which the charged particles originating from an object point travel in a filed free region from some distance before entering a plane electrostatic field at 30° to the field boundary. The particles are focused, to second order, along a line situated outside the field region, symmetrically placed with respect to the object point. The principle if the "fountain" spectrometer has been applied to this analyser, resulting in a device which accepts particles from a point source through a small annular gap into an electrostatic field region. In applying this analyser to measurements of ejected electrons, a proton beam is fired through one point of the input annular slit. The protons, with, with energies mostly are least 100 times that of the electrons they produce, are deflected only to a negligible extent and pass out of the analyser through a small hole in the back electrostatic plate. Electrons originating from collisions at the object point enter the analyser at all points around the annual input slit, each point corresponding to a different eject angle, varying between 0 and 120°. Cannelton detectors placed around the output focal circle simultaneously measure electrons at one energy and variety of angles. Varying the electrostatic field permits the energy to be scanned. A number of measurements have been made with this apparatus.