The SEM turns 50
2015 marks the 50th anniversary of the commercialisation of the SEM by the Cambridge Instrument Company (CIC). Chris Parmenter attended the meeting to celebrate this landmark in electron microscopy.
As an electron microscopist, I’m always fascinated to learn about both the most recent advances in our field, but also the origins and steps that were required to get us to the modern instruments. You can imagine how I was captivated by the story of the early pioneers who set out to develop a new kind of instrument with the firm belief that it could be used for scientific gain. I don’t suppose any of them could have imagined how revolutionary the SEM would be and how widely adopted it would one day become. The day was organised by Zeiss who now manufactures SEMs in Cambridge (on the site where the Stereoscan and its descendants were made,) and CEO, Bob Taylor and Director of Product Management, Allister McBride were there to say a few words before handing over to Bernie Breton, Dick Paden, and Garry Stewart (all of whom contributed to the story of the SEM) as they guided us through the various developments that lead to the first commercial SEM in 1965.
It was Prof Charles Oatley who in 1945 using surplus army components from his former position at RSRE Malvern returned to Cambridge with the aim of assembling a scanning electron microscope. Prior to this, some work had been done in the US by Zworkin and by von Ardenne in Germany, but it was Oatley and the team that he assembled in Cambridge over the following years that would make the SEM a reality. Over the next few years Dennis McMullan worked alongside Oatley and the workshop to make the first prototype (SEM 1) in 1948. Ken Smith (1952-1956) noted that secondary electron images were an improvement over backscattered ones and built SEM 3 (1957-58). It was Tom Everhart (1956-58) and Richard Thornley (1957-59) who worked on detectors, signal contrast and instrumentation, who developed the now ubiquitous Everhart-Thornley detector (ETD) during their time in the department. Over the following years more breakthroughs were made as new brainpower joined the team in the form of Bill Nixon, Garry Stewart and Fabian Pease, as others left. Alongside this, in a nearby lab, the electron microanalyser (EPMA) was being developed in the lab of Prof Cosslett and the labs at Tube Investments who were involved in the design of the EPMA and EMMA Analytical TEM. Discussions concerning the commercialisation by CIC were mooted in 1960/61, as they had already begun production of a version of the EPMA (1959) under the name of the Microscan.
An image of a Mk1 Stereoscan (Courtesy of Zeiss)
Funding from the UK government was non-existent and predictions of potential sales of the SEM were unsure, despite the resolution now standing at 10 nm in the form of SEM 5. Despite this, the work continued and CIC took the instrument on the SEM idea along with Garry Stewart to manage the transition of expertise and knowledge and then developed the Stereoscan Mk 1 within CIC. A cautious 15 units were initially forecast for the first year. By 1968 sales were 100 per year and by 1971 there were 520 Stereoscans compared to 150 Microscans.
A picture of the Duke of Edinburgh inspecting the Stereoscan at Micro 66, operated by Celia Moss and overseen by Gary Stewart (front) (courtesy Zeiss)
Dr Dick Padden joined the company in 1967 after completing his studies in Cambridge and over the next 30 years was involved in the development of the SEM in its many incarnations. Bernie Breton who is semi-retired, was a former installation engineer and the service manager for CIC in the USA. He subsequently moved to Cambridge and worked with Bill Nixon and KCA Smith on SEM related projects. He also maintained the now knighted Prof Sir Charles Oatley’s SEM! The story of the SEM is fascinating and it was so amazing to hear it from those who had worked on the development of the early and later instruments and were responsible for having a hand in the birth of this revolutionary instrument.
The final talk of the day came from Dr Alex Ball, Head of Imaging at the Natural History Museum. He charted the museum’s history of SEM, which began in 1964 with the building of the EM lab. Their first recorded student to use SEM was in 1965 and in 1966 there is record of a Stereoscan purchased for £18,500. The museum obviously liked what it saw because it placed another order for a Stereoscan (Mk2a) in 1967 and then a variable pressure SEM (ISA-60A) in 1981 to allow the imaging of non-conductive samples. The latest incarnation of the facilities includes multiple SEMs, X-ray CT and light microscopes.
Bernie Breton and Dick Paden recounting the good old days. (Zeiss)
Alongside the talks, there were displays of components, brochures, and images from the early days of the Stereoscan. The chance to talk to former Cambridge Instruments employees and hear them reminisce was a privilege as I took in the sense of the occasion. The talks and drinks were followed by a tour of the Whipple Museum, which is dedicated to the history of science. In honour of the occasion we were shown around and there was an opportunity to see an early Microscan instrument, which prompted many on the tour (many of whom were former CIC employees) to share stories of their time in the company and working on the Stereoscan in its various stages of evolution.
All in all, this was a unique opportunity to peek back in time and it should help us all realise how much we owe to those who have gone before us, regardless of which type of microscopy we’re involved in. What’s more, it can help to inspire us to be trailblazers in our respective fields and remind us that people are doing this even now (remember 2014’s Nobels?) I, for one, am hoping that I’ll be around to cover future events such as the 100th Anniversary of the birth of the TEM and perhaps even the 100th anniversary of the SEM.