Earth sciences - Geochemistry
As was indicated earlier, our small and innovative group at AECL, was in effect competing with the private sector and to the extent that we had become rather good at it, the pressure from other commercial manufacturers of instrumentation was such that the management had to react. They dithered, unsure how to deal with the obvious dichotomy, but loathe to forgo the lucrative business that we were creating for the company. During that time several of us, including Chris Thompson the New Zealander, Dieter Donhoffer the Austrian and I, decided that we better find something else as soon as maybe before the axe actually fell.

I did some preliminary job hunting without much success and was pleasantly surprised one evening to get a call from somebody at the Geological Survey of Canada (henceforth referred to as the GSC). He was with the Geochemistry goup there and had nothing whatever to do with Arthur Darnley's airborne gamma spectrometry project. It seemed that they needed someone with my sort of background to lead a project to develop methods of vapour sensing as an aid to mineral exploration. The currently fashionable one being mercury vapour, because it was known to be associated with gold and silver deposits among other precious metals.

The GSC was a part of the same government department that the Canadian Hydrographic Service had belonged to, so that after thirteen years I had come full circle. I accepted the offer, which was of course dependent on passing a selection board in a formal competition process. I was ambivalent about moving back into the orbit of the Civil Service, or rather the Public Service, which it had become since I had left it five years earlier. On the one hand it would be a welcome relief not to have to justify one's continued existence on the basis of revenue generated from sales, but on the other hand it would mean having to conform to the petty rules and regulations connected with the public policy and social engineering objectives, which goverments always impose on their civil servants "pour encourager les autres" in the private sector, over whom they have no direct control.

The vapour sensing project involved starting from scratch and learning the elements of a whole new aspect of science for the third time in my career. This time it was geoscience, or at least the facets of it that involved geochemistry and geology. I took one of the first-year Bachelors degree courses in geology at Carleton University, attending evening classes from September through to May and somewhat to my surprise passed out with an "A" grade. It was a good course and well worth the effort as a means of getting up to speed on unfamiliar concepts and terminology.

In the course of that first year with the GSC, the axe did finally fall on those who were left in the AECL group. It was done with the ham-handedness and insensitivity which seems to be so typical of so many company managements, both public and private. The people were given minimum notice, despite the long time which had passed since it became apparent that the group would not be tolerated as a competitor by industry.

One day I got a call from somebody over there who wanted to know if I would like to have any of the many prototype instruments that I had been involved with as souvenirs, because they were all going to be tossed into the garbage within a day or so. I went round to the building and upstairs into what had been our development laboratory, a place where I and others had spent too many evenings and weekends, toiling away (with no extra remuneration incidentally) to solve problems and make the breakthroughs necessary to keep us at the leading edge of what we were so good at, the development of compact and advanced radiation measurement instrumentation.

What I found was the place stripped bare of all the laboratory equipment, with a lot of the prototype instruments that we had developed, and some production units, piled up in an untidy heap in the middle of the room. It was one of the more depressing experiences of my career and seemed to be almost a deliberate act of malice with the implied message that this is what happens to people and their work who are too successful in the public sector.

Mercury - Mercurial indeed.
Mercury has long been known to be one of the "Pathfinder" elements associated with the precious metal deposits. Because the vapour emanates continuously from the metal and can diffuse rapidly in dry porous soil, it can sometimes be detected at the surface, thereby giving clues to buried deposits. The technique had been successfully used in the arid desert regions of the South Western USA in states like Arizona and Nevada, where all the right conditions existed.

The detection apparatus consisted of pieces of gold leaf housed inside simple plastic tents, laid out on a grid pattern over the area of interest, where they were left for one or two days before being collected. The method hinged on the fact that gold has a strong affinity for mercury vapour, with which it forms an amalgam, similar to that used in dental fillings.

Gold is basically inert and non-reactive to other vapours, so that it is highly specific absorber of mercury vapour. Just the ticket, except that the simple apparatus described above required that the gold leaves from each sample site be heated to drive off the mercury which was then passed through a laboratory instrument known as an "Atomic Absorption Spectrophotomter", which finally provided a quantitative measurement of the mercury absorbed by the gold leaves.

Not surprisingly, this laborious procedure was not adopted with overwhelming enthusiasm by the exploration community. What was needed was something compact, with an immediate readout. Obviously that was going to be easier said than done. I spent a great deal of time and effort trying to dream up a sensor for mercury that would provide a reliable electrical output of some sort.

A four arm electrical bridge with
two of the platinum arms taped over,
leaving two active arms
The first attempt was to use thin films of platinum (which also has a specific affinity for mercury) in an electrical bridge circuit, the idea being that the electrical conductivity of the films would increase as the mercury was absorbed onto the surfaces. The effect was there alright, but I could never construct bridges that gave consistent and repeatable readings when subjected to known concentrations of mercury vapour.

I was almost at my wits end when I came across an article describing the use of conventional quartz crystals used for radio sets as "micro balances". Normally the crystals (tiny wafers of quartz, cut to precise specifications and mounted in protective cans) are connected into electrical oscillator circuits to hold them to the precise frequencies demanded of transimitter/receivers in the crowded commercial communications bands.

If however the crystal wafers acquired even a few micrograms (millionths of a gram) of additional weight on their surfaces, then the frequencies would shift by a small but easily measureable amount, hence the term "microbalance". This property had been used by various workers to measure the concentrations of all sorts of organic vapours by coating the crystal surfaces with appropriate absorbing chemicals.

This was a revelation to me, because if I could pre-coat crystals with a fresh surface of gold, then these surfaces would absorb mercury from an atmosphere containing mercury vapour and I would have my compact mercury detector in the form of a quartz crystal microbalance, with the readout being the frequency shift.

Small tubes were attached to each face of the cover
to blow the air stream against the gold surfaces
I managed to acquire some un-packaged crystals with gold electrodes rather than the aluminium ones normally supplied, from a firm in Toronto. The electrodes covered about seventy percent of the surface on each side of a crystal wafer, which was about half an inch in diameter. I designed the necessary circuits to have two crystals operating, one was the active one with the gold coating and the other one was a standard crystal packaged in a can and nominally the same frequency as the gold coated one.

This reference crystal would not respond to any mercury vapour present. The nominal frequencies were 15 Mhz (15,000,0000 cycles per second) and by mixing the two, the difference could be extracted, which could be as low as a few cycles per second. This made it very easy to sense very low concentrations of mercury vapour, because the difference frequency would change quite dramatically as soon as the gold coating on the active crystal started to absorb additional mass.

Nobody it seemed had used the quartz crystal microbalance technique in this application before, so I was on my own in wrestling with the surface chemistry effects involved. Eventually I discovered for example that the sample air containing the vapour had to impinge directly against the gold surfaces from small jets to get full efficiency, rather than merely flow past them.

The mercury vapour detector packaged for use
After a lot more experimentation I had a handle on the total mass of mercury that a crystal would absorb before saturating, and had established what the relationship was between mercury vapour concentration and frequency shift per unit time. I also had to devise a method for generating known concentrations of mercury vapour in air, which was not an easy trick to do. I published a lengthy article detailing all of this in a scientific journal in 1972, which has now become something of a classic. As a result of that I was contacted by some one who was also working on the problem at Arizona State University and got an invitation to go there and try my device out over some known gold and silver deposits, which generated detectable mercury vapour at the surface.

An Eventful Field Trip
It was December 1972 that I took up the invitation. One of the many problems associated with the whole technique of making surface measurements of mercury vapour concentration was extracting it from the soil in a consistent and repeatable way. My solution was a metal tube driven down into the soil, with the equivalent of a bicycle pump working backwards to draw the soil gas up the metal tube and through a piece of flexible tubing connected to the instrument. I carried all this pariphenalia in a cheap golf bag bought for the purpose which had the metal tube sticking out of the top.

My itinerary took me via the Chicago O'Hare airport. At that time the mandatory security checks at airports had only been in force for a little while, in response to the rash of international hijacking of aircraft. As I proceeded down a long corridor toward the gate for my connecting flight, carrying the golf bag over my shoulder, I became aware of two security guards shadowing me with semi-automatic weapons at the ready. They were of course intensely interested in the metal tube sticking out of the golf bag. After examining it from every conceivable angle, they were finally convinced that it was indeed nothing more sinister than a metal tube and I was allowed to proceed unmolested.

I met up with the principal researcher John McNerney, who had made the invitation, when I got to Arizona State University and we compared notes on our techniques. He turned out to be an Australian who had taken life pretty much as it came and had emigrated on a whim much as I had done. One of his first comments was that he had guessed that I was probably British from the way the paper was written. Interestingly he was pursuing the thin- film conductivity techniqe which I had abandoned earlier on.

The gold deposit that he used as a reference was about a hundred miles into the Navajo desert and the route took us through one of the large Indian reserves. There was a lot of friction between the Navajo Indians and the administation in Washington at that time and we saw some very sullen (if not hostile) groups as we went through the middle of the reserve in McNerney's car, which made us both a little nervous. There had been heavy rain a day or so before I arrived and the normally barren desert was covered in a light carpet of greenery and small flowers.

Unfortunately the rain had also put paid to any chance of detecting mercury vapour. It is not particularly soluble in water, but enough that the tiny amounts that normally make their way up to the surface were for all practical purposes wiped out. I was not able to get any sort of anomalous readings over the deposit which meant that I did not know whether it was because my instrument was not sensitive enough, or because the rain had washed away the signal.

On the return journey McNerney spotted a tarantula (the large furry legged spider) wandering around apparently dazed by the sun. They do not normally show themselves in the daytime and McNerney was determined to bag the outsized insect and take it home with him to add to his collection of wildlife. It looked every bit as menacing in the flesh as all the various TV nature series make it look and I was all for leaving it to live a nice quiet life in the Navajo desert. We had a small canvas sample bag, about a foot long by nine inches wide with a draw string, and after a lot of coaxing, the tarantula and all of its furry legs was persuaded or tricked into going into it. McNerney was triumphant and handed the bag to me with the entirely unnecessary admonishment "for God's sake - don't let him get out".

I sat in the back seat clutching the damn bag tight shut with a vice-like grip for the couple of hours it took to re-cross the Indian reserve and get back to civilisation as I knew it. McNerney cheerfully assured me that a tarantula bite is not much worse than a mosquito bite, but in view of its size I was (a) utterly unconvinced and (b) not about to put the theory to the test. I remember at one point wondering how on earth an expedition to test out a scientific phenomenon had led me into a situation whereby I was travelling across a fairly remote stretch of desert full of hostile Indians, while holding in one hand (by now practically numb with muscular cramp) a rather small canvas bag, containing one of the world's largest and (as far as I was concerned) most unpleasant spiders, which was probably seething with animosity and struggling to get out and finish me off.

The plumbing to take in the water samples was strapped
on to the back of the seats.
Another minor project was the development of a 'geochemonitor' to introduce some hi-tech to the business of measuring the pH, and conductivity of lake water samples. These are paramaters which indicate the acidity and dissolved mineral content, which can have a bearing on the likelihood of ore deposits being in the vicinity. They also have considerable relevance to enviromental studies. Traditionally the method used was to collect water samples and bring them back to a laboratory for analysis. A helicopter was the fastest way to collect them, because it could hop from lake to lake, landing on each one to draw off a sample.

The blue box measured pH, conductivity
and temperature of the lake water samples
It occurred to me that if a portable instrument could be devised together with a small pump and some plumbing, then samples could be taken in and the meausurements made while en route to the next location. Thereby removing the necessity for physical transport of the samples back to the laboratory for analysis. I got into the theory of physical chemistry enough to see what the problems involved in pH and conductivity measurements were, and what sort of sensors were available. The pH sensors were essentially soft glass membranes which required incredibly high input impedance sensing circuits to make valid measurements. At that time no manufacturer of analytical instrumentation seemed to have used the latest high impedance 'Field Effect' transistors. So I set to work to come up with a design using these devices. It wasn't too difficult to do and soon we had a suitable instrument packaged up with a digital readout. A helicopter was fitted out with the necessary plumbing to draw up the samples and we did a field test. It worked pretty well and the helicopter company put out a brochure advertising the scheme as a service.

The Nixon Presidency self-destructs.
Richard Milhaus Nixon, the man whom I have mentioned twice before in this saga in uncomplimentary terms, succeeded Lyndon Johnson as President of the United States in 1968 and was re- elected in 1972. In the Watergate affair he was his own worst enemy with his decision to have a voice-actuated tape system installed in the White House Oval Office, which would store every pearl of wisdom that he let fall and every memorable and inspirational phrase that he uttered.

This was surely the action of a man so beset by self-doubt that he needed to create the evidence that would in time justify a place for himself among the premier statesmen of the twentieth century. He must have felt somehow that a living record of his Presidency would secure that place and thereby eradicate all the failures in his political career; the years of unsuccessful attempts to win high elected office, and the character flaws which saddled him with epithets like "Tricky Dick", that had dogged him ever since he had lost his first presidential election to the unstoppable Kennedy in 1960.

The reality, as he knew all too well, was that in 1968 he would almost certainlly have lost his second bid for the Presidency to yet another charismatic and apparently unstoppable Kennedy clan member, Robert Kennedy, the younger brother of his former Nemesis. The younger Kennedy might have been politically unstoppable, but when in the second tragedy to befall the Kennedy family in five years, he was struck down by the bullet from the gun of a deranged simpleton during the election campaign, he was no more immortal than his brother had been in 1963. Nixon was nothing if not fiercely competitive, and it must have been galling for him to know that because of that tragedy, the world regarded him essentially as having been elected President by default. Nixon the realist had probably also come to terms with the the unpleasant political truth that the mantle of statesman was a natural inheritance for a Kennedy, but would never fit easily on the man who had too often revealed his ruthless expediency and shameless opportunism in a long and controversial career in public life.

It was an ironic twist therefore that it was ultimately the tape system (his monument to his own ego) and the historical record it was creating for posterity, that struck him down. The incredible aspect of the whole business was that he did not do the obvious and destroy the incriminating tapes as soon as it became apparent that word of the Watergate break in had leaked out. He surely had every opportunity to do so and limitless resources to create convincing and plausible reasons for their disappearence for weeks (if not months) before it became known that they contained the evidence that could be his dowfall. Once that had been established, the incriminating tapes immediately became the subject of legal proceedings.

Nixon knew the jig was up when the no-nonsence special prosecutor Archibald Cox, who had been appointed to investigate the whole matter, won a crucial battle in court to force him to yield up the tapes. Nixon insisted that as President, he was in effect above the law and agreed only to provide an edited transcript. There then followed the unedifying spectacle of a President of the United States dismissing the Attorney General, for refusing to fire a special prosecutor who was getting too close to Presidential wrong-doing, and then within hours, dismissing his sucessor when he too refused.

The ultimate confrontation between the executive and legislative branches of the United States government, which that provoked as the momentum for impeachment started to grow, was as far as I was concerned almost an exact replica of the one that had been played out in England more than three hundred years earlier. That confrontation had boiled over into civil war, before the question had been settled as to whether or not an arrogant ruler (in that case King Charles the second) ultimately had to submit to the will of the legislative body (Parliament), irrespective of the credentials of the ruler.

At that time the credentials of the ruler in question were impeccable, he ruled by the divine right of Kings. His sin was to assert that he was therefore above the law of the land that applied to everyone else. So it was in the Watergate affair. Nixon's credentials as a ruler were equally impeccable, he was the victor in a presidential election. His sin was the same one, his assertion that he was therefore above the law that applied to everyone else.

In the end of course King Charles (Stuart) the second finally lost his battle in 1649 and paid the price with his head. When King Richard (Nixon) the first (and hopefully last) finally lost his battle with the Congress in 1974, he not only kept his head, but he was granted a pardon which allowed him to keep his freedom and all his worldy goods as well, while some of his most loyal lieutenants languished in jail for their devotion to his cause.

The failure to exact an appropriate price from Nixon for his crimes there and then, generated a political and emotional schism which divided and demoralised the American nation for years afterwards. I always maintain rightly or wrongly, that that aftermath was a classic and avoidable example of the well known axiom that those who do not learn from history are condemned to repeat it.

The new airborne gamma-ray spectrometer had
new detectors shown here installed in the
twin turpo prop 'Skyvan' aircraft
A change in responsibilities.
As a result of various reorganisations within the GSC, I eventually found myself leading a small group of people with a mandate to develop all sorts of instrumentation for geochemical and geophysical applications, including airborne ones. This led to the development of a second-generation airborne gamma-ray spectrometer in 1977, to replace the original one which by that time was becoming obsolescent. The original scintillation detectors (twelve cylindrical sodium Iodide crystals, each nine inches in diameter by four inches thick), were replaced by twelve 'bar' configuration crystals, sixteen inches long with a square cross-section, four inches on a side. They were packed in sheet metal boxes, six to a box, with layers of insulation around them, in the same way the previous ones had been. They presented a bigger area to the incoming radiation flux than the old ones, making them more efficient. The major advantage was that they each had only one photomultiplier tube instead of four, which greatly simplified the electronics and the routine calibration, which had to be done to ensure that each detector gave the same pulse amplitudes for a given radioisotope energy.

The new version used a "NOVA" minicomputer, made by the Data General Corporation. This company was a spin-off from the Digital Equipment Corporation, formed by the process which was the nightmare scenario of Hi-tech companies of the sixties and seventies - the splinter group syndrome.

In the world of finance and commerce the key people are not the young ones toiling away at the bottom of the "miserarchy", they are the seasoned executives with all the contacts and the case histories of all the deals going on in the financial community. They are unlikely to defect in droves (although obviously it does happen) because it has always been a sine-qua-non that senior managers have the biggest pay-cheques and the most perks (stock options and so on), in other words they are paid according to their worth.

The new Hi-Tech Companies did not fit the standard private sector hierarchical profile. Their fortunes depended not on the financial acumen of their executives and the contacts which they had with people in high places, but on the continuing evolution of ideas dreamt up by bright young engineers who toiled away on the lower rungs of company ladders. The brightest and the best frequentlly realised that although their talents and drive were what kept such companies in business, their compensation was a pittance compared with that of the senior executives, most of whom were (and still are) technically illiterate. They would then walk away with their valuable but intangible expertise and form companies of their own and compete vigorously and often very successfully with their former employers.

It was not always a success story by any means, but it very often was because the people concerned invariably either had formulated, or were in the process of formulating, new ideas which they were not able to implement (because of pressure of current projects or whatever) when they were with their previous companies. Starting with a clean slate however and being their own masters, they then had the opportunity to push the state of the art one stage further. Meanwhile the luckless former employers not only did not have the benefit of the new ideas, but had to mark time while other engineers with the necessary adaptability were found who could just hold the line and plug the dykes left by the defectors.

The NOVA machine was very similar to many other "minicomputers" of the 60's and 70's that proliferated from many manufacturers. Each one had its own assembly language which had to be learnt if one was ever to do anything useful with it. I spent the time to master this one (the third one that I had learnt; like people-languages, each one gets a little bit easier) and after much blood, sweat, toil and tears, produced a really sophisticated system. At that time the standard method of communicating with minicomputers was via a data terminal, a device similar to an electric typewriter, with the keyboard and printer sections in a single console.

The graphics/text display capability was unusual
for a data acquistion instrument in the 1970's
I decided that this was not adequate for an instrument where it was crucial to be able to see the different peaks in the gamma ray spectra as they were being acquired and recorded on magnetic tape at one second intervals. I ended up designing an interactive graphics display which was quite unique for any sort of airborne scientific instrument at that time. It was one of the most daunting tasks that I and my team had ever undertaken, involving as it did some incredibly complicated "real-time" software to make the minicomputer keep track of servicing all the gadgets connected to it without tripping over itself. These included: acquiring navigational, airspeed and altitude data, magnetometer data, keeping track of keyboard inputs and executing them in between the higher priority tasks, updating the display, doing the calculations necessary to process the gamma-ray data, and finally recording all the data once per second on magnetic tape. It is worth noting that the operating system that I put together to do all that, fitted into 32 kilobytes of memory. A far cry from the megabytes that modern PCs need to accommodate even a basic word processing program.

The new instrument had lots of bells and whistles
Because the business of airborne gamma ray spectrometry was still evolving, I had included all sorts of options that would probably never be needed for routine use, but just might be useful in experimental work where the exception is always the norm. One of these enabled the operator to program a variety of moderately complicated functions which could be plotted on the six-channel strip chart recorder in real time. The standard ones were simply the intensities of the Potassium, Uranium and Thorium signals as they varied along a flight line. The additional functions which I included allowed the sums, products or ratios of any of these signals, or indeed of the signals from any other regions in the spectra (recorded at one second intervals) to be plotted on the chart recorder.

The system being loaded into the 'Skyvan aircraft'
It was late in the autumn of 1977 before it was ready for a test flight. The first concern was that it would stand up to the vibration and electrically noisy environment of an aircraft. Everything looked good. I was particularly pleased with the interactive graphics display and felt that it had indeed been worth all the extra effort, (there were times when I thought I had been side-tracked into putting a lot of development time into something that was of marginal value in the overall project). That first test was more of a shakedown flight than any thing else. Some more rigorous tests would certainly be needed before it could be declared operational. In the event the weather closed in and there were no further flights. That was of no particular concern because there would be plenty of time in the spring for some more methodical and exhaustive testing.

Meanwhile I turned my attention to a different project. This involved the design of another system to measure all sorts of parameters in boreholes. These are holes two or three inches in diameter, drilled down to depths of thousands of feet by mineral exploration companies to test for the presence of ore-bearing rock. Normally the drills used are hollow tubes which allow "drill cores", rod-like samples of the rock, to be brought to the surface for examination by geologists. The drilling is a very expensive operation in the hard crystalline rocks where ore deposits are most likely to be found, and much additional information can be found by lowering instrumented probes down the holes to measure all sorts of parameters, including gamma radiation from Potassium, Uranium and Thorium among others. I decided to design this system also around the Data General NOVA minicomputer, with the idea that the two systems would have as much hardware and software in common as possible.