Bryan Kibble's pioneering work on the Kibble balance has enabled accurate measurements of numerous physical constants and will aid in redefining the SI kilogram
Known for his work on the eponymous Kibble balance, Dr Kibble was a world-leader in the field of metrology. After reading Physics at Jesus College, University of Oxford, he was awarded a DPhil in atomic spectroscopy and continued his research at the University of Windsor, Ontario, as a Postdoctoral Fellow.
In 1967, Dr Kibble began work as a senior postdoctoral fellow at NPL, where he became interested in measurements of the high-field gyromagnetic ratio of the proton. His work helped to outline a problem with the SI unit for current, the ampere. He realised a limitation of the current balance, the instrument used to define the ampere, in the early 1970s and began work on a method for improving it.
Kibble's new measuring device, the moving-coil watt balance, was first made in 1978 and it dramatically improved the accuracy with which the ampere could be measured. Its invention played an important part in defining the values of the Josephson and von Klitzing constants, which are widely used in the field of quantum physics today.
Working with Dr Ian Robinson and Janet Belliss at NPL, he developed a further version of his balance which operated in a vacuum chamber. This design allowed for measurements accurate enough for use in the redefinition of the SI unit of mass: the kilogram.
Dr Kibble became a leader in the field of measurement. He remained active even after his retirement in 1998, winning numerous prizes, offering guest lectures and talks all over the world and continuing to work tirelessly on his research.
After his death in 2016, the international metrology community made the decision to rename the moving-coil watt balance the Kibble balance, in remembrance of Dr Kibble's commitment to his field. In 2018, results from Kibble balances will be used to support the redefinition of the kilogram.