Meet a Metrologist: Dr Murray Early
Dr Murray Early is a Principal Research Scientist at the Measurement Standards Laboratory (MSL). For over 30 years, he has played a leading role in MSL’s Electrical metrology team, with his areas of expertise including AC voltage and current, DC voltage and resistance, the quantum Hall effect, and cryogenic current comparators (CCCs).
Dr Early is also the Co-Chair for CPEM 2022; the premier conference for all scientists working on precision electromagnetic measurements. This year, for the first time in its long history, CPEM is coming to Aotearoa, New Zealand. The event is being held in Wellington, on 12-16 December. We caught up with Dr Early to talk about his background, his career, and his hopes for the conference.
How did you become interested in electrical metrology?
I did a PhD in physics at Victoria University with the late Professor David Beaglehole. Our work was around phase transitions of liquid mixtures, which might sound ‘chemical’ but is actually relevant to a whole range of disparate phenomena, like superconductivity and magnetism. I was studying the electric properties of the phase transition, which involved looking at small changes and trying to measure them accurately. I kind of fell into precision measurement that way.
But I think I’ve always been interested in unravelling what's really going on – seeing past the various factors that might incorrectly influence your interpretation, to get to the underlying, fundamental phenomenon. I had a bit of an instinct for that type of work, and the importance of accurate measurement. Back then, I was probably the only person in the university physics department who got their instruments calibrated – I used to come out here to MSL before it was MSL to do that! I even included calibration certificates in my thesis.
Calibration is vitally important because it allows you to trust what an instrument is telling you. Many people unjustifiably trust their instruments without fully knowing what's happening inside them. One of the things I enjoy most about metrology is that you just strip all that away and push hard to get the fundamental behaviour correct.
Has electrical metrology changed since you first started working in the sector?
In some ways my job hasn’t changed in 32 years! I’m partly joking, but honestly, science really is like that – you grow the job as you work; as you delve deeper and more broadly into an increasingly wide range of things. It’s about continuously pushing the boundary. So I started off doing AC-DC measurements in digital instruments, and I'm still doing that today. What’s changed are the instruments and our knowledge of the fundamentals. We understand things at a much deeper level than we used to, and as we’ve pushed harder, we’ve found all sorts of interesting phenomena.
Of course, we also have our ultimate goal, which is to deliver measurement standards for New Zealand; ensuring that we have demonstrable proof that people are doing accurate measurements around the country. One of the ways that we interface with industry is offering calibration services. And in the electrical space, that involves a very large number of parameters, which makes it challenging to cover! But today’s society is heavily dependent on that kind of work – if we didn’t have that assurance, it would be absolute chaos. Fortunately, all this happens at quite a high level, and we can operate at much greater accuracy than the public needs for day-to-day work. But high-tech work – you know, flying planes, building engines, maintaining the electricity grid – all requires metrology. A lot of the high-quality products we see today are reflections of the continuous pursuit of better metrology, because once you can measure something, and detect any peculiarities, you can fix it and make it better.
In general though, we are constantly improving. Brian Petley from NPL (National Physical Laboratory) once wrote that in metrology, things get better by a factor of 10 every 15 years. It’s a rule of thumb, something comparable to Moore’s Law, but it has held up surprisingly well. Improvements haven’t happened uniformly – there have been jumps, gaps, and incremental change – but when you plot it out for, say, DC voltage, and look across the accuracy claims for all the NMIs (national measurement institutes), it matches that trend very well!
How involved are you in international metrology organisations and efforts?
I spent three years as Chair of the TCEM (Technical Committee for Electricity and Magnetism), which is part of the Asia-Pacific Metrology Programme (APMP). That work was challenging, but it was wonderful to collaborate with people from across the region. I also attend the Consultative Committee for Electricity and Magnetism (CCEM), which is the world’s preeminent technical committee for electrical metrology, facilitated by the BIPM (the International Bureau of Weights and Measures). That led me to being invited to become Chair of a CCEM working group – one focused on low frequency (< 1 MHz) electrical metrology – and I’ve been involved with that for about four years now. It seems that every day I open my inbox, there are emails from people all over the world; most recently, Ukraine, South Africa, and Argentina. A lot of goodwill and mutually-beneficial relationships come from those efforts – building and maintaining those are central to the way metrology works in our connected world.
I’ve also been a regular contributor to CPEM (the Conference on Precision Electromagnetic Measurements) since I first attended in 1994, and was elected to their Executive Committee in 2014. I led the successful bid to host the conference here in 2022 – the first time it’s ever been held on New Zealand soil.
How are you feeling about hosting CPEM in December?
To give you a completely honest answer, I’m most looking forward to the end of the conference! Those of us organising it are having to navigate a lot of uncertainty. It’s been incredibly challenging to put together an in-person conference at this time. People are hesitant to travel for various reasons: e.g., instability in Europe, COVID, environmental concerns, and business pressures. So we’re being quite realistic and modest in terms of our expectations. The experience has made me wonder about the future of science meetings. I used to say that the benefit of conference attendance was 50% personal interactions and 50% content. But the shift to online-only conferences that was necessary for the past few years has made me revise that proportion – I now think it’s 90% about personal interactions. Actually being in the room with people, knowing that you’ll have lots of time to chat in detail with them over morning tea, etc. – none of that can happen online.
For me, the true significance of CPEM 2022 is that it's the first in-person conference since the landmark SI redefinition. So it's a good platform for us to think about where we’re going and what the future of metrology looks like. The redefinition brought those working in the mass field closer to those of us working in electrical measurements – that will likely lead to new areas of research opening up. So I look forward to those sorts of discussions.
The programme itself is coming together, too. I’ve no doubt that the event will be interesting and successful. It will be a wonderful opportunity to showcase New Zealand’s metrology expertise on a global stage, and for our young scientists to establish important connections with overseas experts. We’re particularly excited to welcome our collaborators and colleagues who have generously helped us over the years.
Conference website: https://www.cpem2022.nz/