Bibliographical Page Contents

The papers below reflect the activities in which the author was involved while at the Geological Survey of Canada (GSC). Beginning with the development of instrumentation for geochemical applications in the early 70's, before returning to gamma-ray spectrometry in the late 70's. From then on the his focus was on borehole geophysics and he has continued to remain active in this field as an Emeritus Scientist, following retirement from the GSC in 1995.

Evaluation of the Quartz Crystal Microbalance
as a Mercury Vapour Sensor for Soil Gases.

This 1972 paper was published in the first issue of the 'Journal of Geochemical Exploration'. The reason for measuring mercury vapour in soil gases was the fact that its presence was frequently associated with Gold deposits. The traditional technique was to lay out gold leaf absorbers in boxes on the surface in likely areas. These were then heated in a laboratory to release the vapour into suitable measurement instrument. The paper described experiments in the development of a digital techhique based on the change in frequency of a standard radio crystal coated with gold, when it absorbed nanogram amounts of mercury vapour. At one point the author made a field trip to Arizona to try out the instrument, which turned out to be interesting in more ways than one. A personal account is on another section of this website.

Vapour Sensing for Mineral Exploration

This review paper was presented at the 1972 Prospectors and Developers annual meeting in Toronto and was subsequently published in the Canadian Mining Journal. It covered the various techniques, including airborne ones, for the detection and measurement of a wide variety of vapours of interest in the fields of mineral exploration and environmental monitoring

Solid State Interface and update Unit for existing
Perkin Elmer Double Beam Atomic Absorption Spectrophotometers

This paper, published in the International journal "Analytical Chemistry" in 1974, drew 49 expressions of interest World-wide. The unit was able to be connected to the vacuum tube era instrument with a single lead and processed the non-linear absorption analogue signal to produce a linear digital absorbance signal suitble for computer processing. Years later a former Perkin Elmer technician revealed that the paper had caused considerable consternation in the company at the time, because the update unit could have put hundreds of older instruments on a par with their latest offerings. Lack of resources to transfer the technology to a Canadian Company ensured that it never happened.

A Computer Controlled Geochemical Analysis System
for Existing Perkin Elmer Atomic Apsorbtion Spectrophotometers

This 1975 paper, published in the International 'Journal of Geochemical Exploration', describes a full blown automated analysis system incorporating the Update unit described in the previous paper. A major feature was the automatic 'sample dipper', designed by the author, which allowed up to ten calibration samples stored separately to be accessed at any time, rather than having them included as part of the sample population.

The Application of Airborne Gamma-Ray Spectrometry
in the search for Radioactive Debris from the Russian Satellite COSMOS-954

This 1978 paper in the GSC Current Research series, described experiments and the development of a statistical technique to determine the specific probability of being able to detect radioactive debris of a given intensity at a given altitude with an airborne Gamma-Ray system with a specific detector sensitivity.

Gamma-Ray Spectrometric Methods in Uranium Exploration 1979

This conference paper described the airborne spectrometer that was developed by the author and which discovered the first piece of radioactive debris from the Russian nuclear powered satellite on the surface of Great Slave Lake, during "Operation Morning Light" in January 1978. Among other features were a graphic display which showed both spectra and text with which the operator could interact in a Windows-like environment. That was about 15 years before Microsoft Windows made its debut.

Temperature Gradient Measurements in Boreholes using
Low Noise High Resolution Digital Techniques"

This 1984 paper, in The GSC Current Research series,describes a borehole temperature probe and recording system processing software developed by the author. Field data recorded with it, showed that it was possible to connect temperature gradients in boreholes with lithological boundaries. The fact that they are astonishingly repeatable from year to year, prompted the author to suggest that this property might be used in earthquake-prone areas to detect strains due to impending earth quakes, if for example logs were taken on a suitable time schedule in holes drilled in faultline areas.

Field Evaluation of a Magnetic Susceptibility Logging Tool

The Finnish company Geoinstruments produced an excellent borehole probe for the measurement of Magnetic Susceptibility in the early 80's This paper describes a comparison of the result of using it to log a well-documented GSC test borehole, against measurements made on the drill core. It was clear that the logging method, which took less than an hour, was every bit as good as the painstaking and labour intensive measurements made on sections of the drill core, using a hand held device.

Application of Inverse Filtering to Gamma-Ray Logs, a Case Study

This 1984 paper, published in the International journal 'Geophysics', describes how a technique known as deconvolution, was able to strip off the blurring effect of the movement of the gamma sensor toward and away from a thin stratum of radioactive material, which normally 'smears' the spatial response function obtained, from a thin line to a conical-shaped peak. In this case the experimental data obtained from the Uranium spiked calibration 'holes' at the Department of Energy site in Grand Junction Colorado U.S.A., showed that the published data for the artificial 'strata' in one of the holes was incorrect.

A System for the Digital Transmission and Recording of Induced Polarisation Measurments in Borholes

This 1983 Borehole Geophysics Symposium paper described an advanced computer-based digital system for the measurement of induced polarisation in boreholes. Among other features it had provision for real-time auto-ranging of the current suppply for the down-hole current electrode, based on the resistivity being measured as the logging progressed. This enabled it to handle previously impossible dynamic ranges of resistivity. It was used extensively in-house at the GSC for more than twenty years, but as in previous situations, the lack of a serious policy within government at that time to assign the necessary resources for effective technology-transfer to the private sector, meant that it did not happpen.

Multi-Frequency Slim Hole Inductive Conductivity and Magnetic Susceptibility Probe

This 1987 International Borehole Geophysics Symposium paper, described a traditional Conductivity/Magnetic-Susceptibility probe with some new elements. One was the multi-frequency capability, another was the use of a crystal-controlled oscillator from which was derived the different working frequencies, selectable via a computer keyboard with the probe in-situ. Another one was a technique for nulling out the ohmic resistance of the coil that was used. This effectively eliminated the mutual interference between the conductivity and magnetic susceptibility channels, which is almost always present in other probes of similar design to a greater or lesser degree.

A New Method for Post-Acquisition Correction of Spectral Distortion due to Pulse-Pileup

This 1992 paper published in the procedings of the 1992 IEEE Nuclear Science Symposium, describes a statistical technique for removing the distortion in a radiation spectrum, caused by overlapping pulses at high count rates being recorded as single higher energy pulses.

Pulse Pileup can be Hazardous to the Health of your Spectra, but the Distortion can be Corrected

This 1994 paper, published in the journal "Radioactivity & Radiochemistry", is a less academically oriented version of the IEEE paper on this topic. It was aimed at the Neutron Activation community, where the pulse-pileup phenomenon can cause serious analytical errors if the basic causes are not properly understood.