National Physical Laboratory

2017 NPL Rayleigh Award recognises landmark publication

Robin Underwood, Michael de Podesta, Gavin Sutton, Leigh Stanger, Richard Rusby, Peter Harris, Paul Morantz and Graham Machin's paper, Estimates of the difference between thermodynamic temperature and the ITS-90 in the range 118 K to 303 K, published in Phil. Trans. Roy. Soc. 374: 201550048 (2016) 205–229, has won this year's NPL Rayleigh Award.

John William Strutt, Lord Rayleigh
John William Strutt, Lord Rayleigh

Using measurements of the speed of sound in Argon, the authors have made estimates of the difference between thermodynamic temperature, T, and the temperature estimated using the International Temperature Scale of 1990, T90, over a temperature range spanning 118 K to 303 K, around the triple point of water. Thermodynamic temperature was estimated using the technique of relative primary acoustic thermometry employing the NPL-Cranfield quasi-spherical acoustic resonator.

The Rayleigh judges were greatly impressed by the quality of writing, the level of detail and analysis contained in this publication, and the significance of the development described, which reports the most accurate measurements of thermodynamic temperature ever made. In particular, the uncertainties realised by the acoustic thermometry are lower than the uncertainties of the ITS-90, the first time that this has been achieved. Through automating the measurement process, the authors were able to explore the quantity T-T90 with unprecedented resolution and so reveal hitherto unknown features, which were previously obscured due to all the historical data being sparse in nature and having significantly higher uncertainties. This landmark publication will make an enduring contribution to the 'mise en pratique' for the definition of the kelvin and contribute to any future temperature scale.

Choosing a winner

The Rayleigh Award is NPL's most prestigious internal award, given yearly to the author(s) of the most outstanding published paper. The award is highly-competitive, and papers are judged on their creativity and novelty, the extent and quality of the scientific investigation, potential impact, and clarity and accessibility.

Special recognition

Two other papers scored highly, and equally, and were awarded as joint runners-up:

N A Martin, V Ferracci, N Cassidy and J A Hoffnagle, The application of a cavity ringdown spectrometer to measurements of ambient ammonia using traceable primary standard gas mixtures, Appl. Phys. B. (2016) 255–265.

E R Woolliams et al, Thermodynamic temperature assignment to the point of inflection of the melting curve of high-temperature fixed points, Phil. Trans. R. Soc. 374: 20150044 (2016) 99–120.

Finally, the panel were impressed with a number of publications from 'early career scientists', those submitting authors who were within the first 10 years of their professional career and conferred the 'Early Career Award' on:

A Lourenço, R Thomas, H Bouchard, A Kacperek, V Vondracek, G Royle and H Palmans, Experimental and Monte Carlo studies of fluence corrections for graphite calorimetry in low- and high-energy clinical proton beams, Med. Phys. (2016) 4122–4132.

Honouring a distinguished legacy

The Rayleigh Award is granted each year in memory of the scientific distinction and influence of John William Strutt, the 3rd Baron Rayleigh.

Lord Rayleigh was a distinguished scientist and was instrumental in the establishment and early running of NPL. Recognising the need for a national laboratory to further British physical research, he used his considerable influence with royalty and senior government ministers to gain support for the creation and funding of NPL. Rayleigh Chaired NPL's first Executive Committee; appointed NPL's first, and eminent, director, Sir Richard Tetley Glazebrook; and was influential in the decision to site NPL at Bushy Park.

In addition to his bureaucratic acumen, Lord Rayleigh was a scientific polymath. He published research on a broad range of topics, from wave theory, to light-scattering, to photography, even on the dynamic soaring of seabirds. Rayleigh was the second Cavendish Professor of Physics at the University of Cambridge (after James Clerk Maxwell), a Fellow of Trinity College, President of the Royal Society, and was awarded the Nobel Prize for Physics in 1904 for his discovery of argon with William Ramsay.

Learn more about Lord Rayleigh's life and work

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Last Updated: 8 May 2017
Created: 8 May 2017


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