No substitute for experience

John Murphy profiles Bill Trowbridge, for whom entrepreneurial success has come relatively late in his career.

Most people’s idea of a high-technology company is that it was founded by some young maverick working out of a garage. Bill Trowbridge decided to found his company, Vector Fields, when he was 54 – and, 22 years later, still yearns to continue his work developing tools for the design of magnetic systems, despite his retirement. His eagerness to keep working may be because he feels he wasted the first 10 years of his professional life in the merchant navy, before discovering his true vocation in physics.

When he started the company he already had a career behind him as one of the founders of the whole field of computational magnetics. He was in at the very beginning of ‘Big Physics’, working on the pioneering accelerators. He founded a conference and society in the field of computational magnetics, and is probably the best known name in the field today. His company has gone on to become one of the most successful in its field, starting from basic programmes for magnet design to the modern fields of superconductivity and even mobile phone antenna design.

His dynamic personality has enabled him to bring people with him and inspire them to work on the most complex mathematical problems. But at the same time he has run his company, using the business lessons taught to him by his father when he ran a dairy business in the south of England between the two world wars.

Professor Jan Sykulski, head of the Electrical Power Engineering Research Group at the University of Southampton, has known Trowbridge since the early 1980s. He says: ‘He is one of the most fascinating people I have ever met. He is a very modest person and whatever he says about his contribution over the years, it is likely to be understated. He has been a driving force in the area of computational electro-magnetics. His most notable feats are the creation of his company, showing that his work is not just theoretical development of interest to obscure academics, but is actually something that has resulted in a successful commercial venture. He also created the most important conference in this area, which has brought together a community of about 500 people and has resulted in the creation of the Compumag Society.

‘He has great vision. A lot of people are good at what they do, but he has always pursued a vision and was able to get people behind him and motivate people so that they stay with him all these years. The other thing is that despite his prominence in the community, he is always able to establish good relationships with people at any level. He always speaks to you at your level. He always makes a point of speaking to young people at conferences and he speaks to them so that they feel important – he always listens. It’s an explosive combination in a person.

‘Everyone who works in this field will know his name, if not know him personally after meeting him at a conference.

‘He has published about 130 scientific papers and he was the driving force behind the integral equations and finite element methods. He will dominate any social gathering, but in a nice way. He is interested in what people have to say, but he will be controlling the conversations by asking you lots of questions. He is amazingly sociable. He is a great opera fan, which is why the names of his products are from operas. He likes to talk about technical things, but he has a very wide range of interests, so he likes to talk about those as well.’

Trowbridge was born in 1930 in Totton, Hampshire. His father ran a small dairy business and was an amateur scientist. He had been a radio operator during WW1 and liked fiddling with radios, and Trowbridge used to wind coils for him. His favourite subject at school was chemistry. It was extremely difficult to get into university in his young days and, with WW2 ending, he had to decide what to do. He ended up joining the merchant navy, which saw him travelling the world over the next 10 years.

‘It was only later that I regretted it,’ he says. ‘I had a very short-term view and I hadn’t thought about what would happen when I married. I was always interested in mathematics and I trained as a navigator. This experience taught me to be careful about numbers.

‘I decided that I wanted to be a physicist and the Seafarers Education helped me to get A-levels. I had to stay for eight years, because National Service was still around then. If I had come ashore, I would have been called up.’

He had been based ashore for some time in Bristol and started looking for other jobs. He saw a vacancy for technicians advertised at the UK Government’s Atomic Energy Research Establishment in Harwell, near Oxford.

He says: ‘I got on well with Doug Allen, the leading scientist at Harwell, who was building a team to create an electrostatic generator. Something must have stuck, because he invited me back and offered me a job with time off to read for a degree, which I did one day a week at the Regent Street Polytechnic.’

This was the early days of Big Physics and, after building the electrostatic generator, he started working on Van de Graaff generator accelerators. He ended up working on the electron optics. In the early days, magnetic field calculations were done using conductive paper. He was transferred to the Rutherford Appleton Laboratory, which was less burdened by security and started working on a bubble chamber that was due to be installed at CERN. That was stopped by then UK education minister, Margaret Thatcher, and was never built.

Computers were starting to become important in engineering and Trowbridge started working on applications to help with the design of experimental machines, including magnetic lenses for accelerator projects. He had very little access to code libraries and usually had to write his programmes from scratch in Fortran. In 1976 Trowbridge decided to organise a conference on computational magnetics and Compumag was born. This event now attracts about 500 people working in the field, and the Compumag Society that was eventually formed has published about 5,000 papers on the subject.

Trowbridge says: ‘The large societies don’t really cater for these specialities. We are not against them and we collaborate with them. It does have a role and I’m very proud of that.’

The software that his group was developing attracted interest from large research groups in the US such as Los Alamos. Trowbridge says: ‘They needed support, but we could not justify a commercial operation from within the Rutherford Appleton Laboratory. But then funding for our work started to dry up and I had people wanting to use the software. There had been an entrepreneurial streak within me from my father, I think. So, I thought: “Let’s have a look at see what we can do.” I drew up a business plan and got approval from the Science Research Council, provided we paid them a royalty.’

So, at the tender age of just 54, Trowbridge decided to found a company with his long-term collaborator John Simkin. They were given some office space at Oxford Instruments in return for some consultancy, and Vector Fields began. Trowbridge remained at Rutherford Appleton, while the software was turned into a commercial package called Tosca. They started to sell a few packages and eventually were making enough money for him to leave and join Vector Fields full time in 1987.

‘My philosophy was never to borrow money. I don’t know whether that was right or wrong. Maybe we could have built a bigger business if we had. I am an opera nut and the programme we developed used two scalar potentials, so I immediately thought of the name To-Sca. Having named the code at Rutherford, we decided to continue the operatic theme.’

Within two years sales of Tosca reached $1m. Trowbridge was able to join the company full time and a sales office was opened in Chicago, where Trowbridge and his colleagues had already made many contacts due to the presence of Argonne. The product line was expanded from static fields to 2D and then 3D versions known as Opera.

Vector Fields was being recognised as a great UK national champion of the technological age and in 1992 the company received the Queen’s Award for Technology. Later Trowbridge himself was honoured with an OBE. Of this, he says: ‘I always felt a bit of a fraud, because really it was a team effort.’

Trowbridge continued to work on new packages as well as bringing out versions of the software for PC platforms and eventually windows, but stuck to the core competence in magnetic field engineering.

He says: ‘Our codes initially were for magnet design and static fields, but real engineering devices have motion, which means time dependence, and the release of the Carmen and Elektra covered that.

‘Another important milestone was securing worldwide deals with companies like Phillips, and some Japanese giants like Toshiba. I made 10 or 15 trips to Japan. Phillips started off collaborating with us at Rutherford because, like most big companies, they did not want to do their own algorithm development – they prefer to buy it in.

‘We were late into the mobile phone market unfortunately; that’s something I’m not too proud of. The whole business of calculating high frequency fields was something we neglected initially, because we didn’t have the expertise in-house. In the end we dealt with that by buying in code from a Polish research group, who had a code called Concerto. It works very well, but it was late onto the market when it came in 2000. It is a much bigger market than our traditional markets.

‘My expertise is in the area of finite element analysis. The other method that people use is finite difference. We tended to look down on finite difference, because you were restricted to orthogonal grids. But in high frequency, finite difference has shown itself to be somewhat superior, and that’s very interesting.’

In recent years Trowbridge’s research effort has been about what he calls ‘multi-physics’. When someone designs a magnet there are other things that they need to consider, like the structural stresses and thermal issues, such as fluid mechanics in superconducting magnets. These products are starting to be released, but they are strictly targeted at the engineering issues around magnetic design problems, rather than trying to move into more general engineering fields.

He says: ‘One of the things we have always emphasised is our relationship with the customers. We have user conferences and meetings, which can be quite critical. My father, who ran a country milk company, always used to say that “the customer is always right, you know”. However irritating they get, you must never show it.’

Trowbridge has been slowly retiring for many years, but he has found it very difficult to stay away from the company. The crunch came not when he wanted to retire, but when his much younger fellow shareholders started talking about retirement and pulling their capital out of the company. In 2005 Vectors Fields was bought by Chelton, the avionics division of the Cobham Group. Trowbridge still visits the company and gives them the benefit of his advice, but he no longer has any formal position with the company. He says that retirement from the company will give him a chance to concentrate on doing science again.

He says: ‘At my age all you can really do is look back on what you have done and see if you could do it any better. I was lucky in that I bumped into a colleague from 35 years ago when we worked on the Van de Graaff generator. He came to me and talked about the problems we tried to solve all those years ago, but couldn’t quite do it. Can we revisit those problems? We have published three papers in recent years, using the tools developed at Vector Fields, to try and get better answers. It’s not science, in a way – it’s just tidying up. But I think we are making a contribution, even though we are not inventing anything.’

He is a firm believer that there is nothing new under the sun and believes that the recent developments in superconducting magnets could lead to a lot of his research on nuclear fusion being revisited. He believes that eventually it will be made to work and is a much more attractive than forests of windmills in the countryside.

He is also spending some of his forced retirement on writing his biography and travelling. He is not short of stories and anecdotes to keep his biography interesting, even to those who know nothing about physics. He says that the worse thing about retirement is that his health is not as good as it was and this prevents him doing quite as much as he would like to do. At the tender age of 76 he is not yet ready to start taking it easy and just listen to some opera.

Bill Trowbridge CV


1958 – 61 The Polytechnic, London, (now Westminster University) B.Sc. honours in physics (2A), external degree of London University


1948 to 1956 Merchant Navy. Navigating officer, Cadet to Chief Officer

1957 to 1961 Atomic Energy Research Establishment, Harwell, UK. Scientific assistant to experimental officer, Ion source development and Van der Graaff generator accelerator design

1961 – 1987 Rutherford Appleton Laboratory, UK. Experimental officer to principal scientific officer then head of computing applications group.

1984 – 2005 Founder and chairman of Vector Fields

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