Before getting to specifics about Canberra, let’s deal with the awkwardness long associated with the name. NIM stands for Nuclear Instrumentation Module yet, over the decades, suppliers and users alike have often used the term NIM Module(s). I understand that this is called an “acronym redundancy” and there are many others in common use. PIN number comes to mind. At an IEEE Committee Meeting once, Lou Costrell, who more than anyone was responsible for the NIM Standard, joked that NIM stood for Nuclear Instrument Method. We have misused other names over the years. Take, for example, the PIPS (Passivated Implanted Planar Silicon) Detector, which is a great product with great name. We once heard a Canberra sales engineer refer to a single unit as a PIP.
Emery and Chuck did not know if Henry Webb, the British engineer who came with Sturrup had the necessary skills and knowhow to design new instruments on his own. Henry was not a degreed engineer but he had experience working on radar in WW-II. When Charlie Gingell, who had supplied designs to Sturrup, refused the offer to consult with Canberra, they had little choice but to entrust Henry with the responsibility for new designs.
There were a few hiccups at first, but Henry soon proved his mettle and began cranking out new instruments at a rapid pace. The benchmark product was the Model 1410 Linear Amplifier, a 3 NIM Width module, which mimicked the ORTEC 410 in features and more-or-less matched its performance. Simpler and cheaper amplifiers followed along with preamplifiers and Single Channnel Analyzers (SCAs) both timing and non-timing types, and scalers (counters) with those awful columnar neon light displays. When a competitor (ORTEC?) introduced an amplifier having an exotic-sounding feature called Pole-Zero Cancellation, we were mystified at first until Orren made the connection to Laplace Transforms, a college class that he barely passed. He explained this (the complex plane) to Henry who immediately responded that the 1410 has just such a feature called “overload compensation”, an internal control which soon made its way to the front panel on all our amplifiers as P/Z.
Henry was an extremely energetic and resourceful Chief Engineer, often doing his own PC board layout and packaging drawings. He would work ceaselessly getting new designs ready for the trade shows associated with the IEEE Nuclear Science Symposium, the Scintillation Symposium, and the APS Meeting. If we had new instruments to exhibit, Henry would be asked to attend these meetings, and he pulled many an over-nighter just to qualify.
The lab standard of linear amplifiers during the late 1960s was the Tennelec TC-200, designed by Ed Fairstein. This big expensive bench-top instrument was the acknowledged performance leader for years, despite the popularity of NIM instruments which did not pretend to compete in performance. This all ended with the introduction of the Canberra 1416, a single-wide NIM amplifier which was intended to be a workhorse amplifier to complement the 1410. To our surprise, the 1416 gave much better resolution than we expected when used with Ge(Li) detectors. Chuck Greer took a prototype 1416 on a trip out West and put it up against the TC-200 in every lab that would allow it, and it beat the TC-200 everywhere it was tested. Henry was as surprised anyone at this, not knowing why it should be so good. Chuck immediately put out a memorandum of some sort identifying the test sites and detailing the test results. The only pushback came from Russ Heath at Idaho Falls who was mad as hell that we cited his laboratory without his permission, so we issued a public apology to him. The 1416 and its double-wide brother, the 1417, were great successes in the marketplace, and gave Canberra recognition as a leader in the nuclear instruments field. Even ORTEC began to take notice.
The pace of development in the late 1960s was astounding, especially when compared to that of today. When the 1416 and 1417 came out, baseline restoration, if needed, was provided by a separate Baseline Restorer module. One day Chuck called in from the field reporting that a competitor had introduced an amplifier with built-in baseline restoration. By the time Chuck got back to Middletown we had the 1416B and 1417B, with baseline restorers, ready for release to production.
Les Daniels, who had worked with Orren Tench at Hamilton Standard in Broadbrook, CT, joined Canberra around 1966. Les was a clever designer and he soon began to crank out designs alongside Henry. Les focused on digital products such as scalers, timers, and printout devices. Canberra launched the 800 Series of NIM for the educational market about this time and Les designed many of them. We were still giving more than lip service to the NIM Standard for power consumption at that time. Indeed the current draw for each of the supply lines was etched on the front panel of our instruments. For one set of scalers, Les ran out of 12 volt current, so he cleverly stacked one set of counters (flip-flops) above another on the 24 volt supply, balancing the voltage drop between the chains so that they shared the same current. Eventually of course, decade counter chips in TTL became available and it became much easier and more efficient to make scalers, timers and counters.
In late 1973, Dave Hall, the first of several engineers to come from Norden, joined Canberra. An analog engineer, he worked alongside Henry Webb for about six months and when Henry left the company, Dave more-or-less became the analog design expert for the instruments business, a position he has held for decades. Among Dave’s early contributions were the 1413 Amplifier, the 1412 Amplifier (replacement for the 1410), and the1468 PUR-LTC (Pile-up Rejector-Live Time Corrector).
The latter product involved a very interesting development. Although Live-Time Correction was in use on MCAs to correct for the rather long pulse processing times, it was not very significant in amplifiers with short shaping time constants and had been virtually ignored. With the advent of Ge(Li) and Si(Li) detectors, particularly the latter, much longer shaping times were in use and pulse pile-up and associated dead time became more important. Henry Webb had been thinking about this and he devised an up-down counter of just a few bits which used the unfiltered (fast) preamp output to trigger an up count and the filtered amplifier output pulse to trigger a down count. If the up counts exceeded the down counts, he would stop the live-time clock until balance was achieved. This method worked and something like it was probably headed toward production.
This is when Orren got a phone call from Bob Lowes, an Englishman who had sold for Canberra in the UK and in northern California before taking a job with KEVEX. Bob told Orren that he had had an eureka moment in the shower that morning and went on to describe the revelation which was exactly what Henry had devised except Bob’s counter was a simple flip-flop. Somehow we had failed to realize that Henry’s counter could be reduced to one bit. KEVEX went on to patent this invention and it became known as the Lowes Live-Time Corrector. We paid a small royalty ($4000/year) to KEVEX for a few years until our newer amplifiers were introduced. Then we told Dick Frankel, the KEVEX President, that we no longer infringed his patent and quit paying the royalty. Our next patent infringement case would cost a bit more.
By 1976 Canberra offered some 120 different products including about 100 NIMs. Dick McKernan, getting a jump on the new millennium, introduced the Century 2000 Series of NIMs which eventually replaced the 1400 Series. By 1978 most of the 800 Series Educational NIM had been phased out. A few were simply re-badged. The 840 Coincidence Analyzer, for example, became the 2040 which is still in production but probably with new guts.
Dave Hall continued in his role as our analog design specialist for decades. He was joined by Mat Kastner and by George Woodard later. All of these engineers made a great contribution to our NIM product line over the years and they contributed their expertise to analog circuit design in many MCA and application-specific products such as alpha-beta counters, alpha spectometers, and radiation monitoring instruments.
Les Daniels had a hand in designing the early digital NIMs, including scalers, timers, and print-out devices. The early instruments had those awful “columnar neon” displays which required the aging of these neon lamps in the false hope that they would become stable. Chuck Greer, who would accommodate any customer in a pinch, thought it was quite acceptable to offer a single customer a Nixie tube version of these scalers for a particle sizing instrument that the customer had in development. We sold one set of these. Larry East from Los Alamos, who later worked for Canberra, wanted scalers with a single input that would accept and discriminate either the slow (positive) or fast (negative) NIM signals. Les tried to design something but was having little success so Chuck sent him to see Walter LeCroy (LeCroy Electronics) who was genius in fast electronics. Les returned a day later with a circuit that worked even if none of us could figure out how. Chuck also sold a completely custom PC Board based counting system to MIT? for a balloon experiment, which required a half-dozen or so new PC Board designs which we cobbled together with little confidence in their integrity. Fortunately we never found out how good or bad they were because the retrieval truck ran over and crushed the rack when it landed after its first flight. It was all a lot of fun however.
By the mid-1970s the old scalers were replaced by instruments having 7-Segment LED numerals which were infinitely more reliable than the neons.
Later Walt Kremser, reporting to Harvey Roberts, designed new digital NIMs with early liquid crystal displays. These displays were compact so we could use single-wide NIMs instead of the double wide units required for the earlier models. Even with backlighting these were difficult to read but this series lasted until no one cared about scalers and counters anymore.
Although I would rather not remember the experience, it is a matter of record that we were accused of infringing the ORTEC patent on their Automatic Pole-Zero circuit, and after a long and expensive defense, we capitulated and paid Perkin-Elmer (ORTEC) a huge amount in compensation. It was either this or go to court in Tennessee.