The Australian physics community has suffered another great loss with the recent passing of Emeritus Professor Anthony (Tony) Klein AM FAA.

He served as AIP President from 1989 to 1991, was joint recipient of the 1990 AIP Walter Boas Medal for excellence in physics research in Australia, and an AIP Honorary Fellow.

Prof Klein was an internationally recognised physicist in the field of neutron optics.

Having completed a Bachelor of Electrical Engineering and his PhD degrees at the University of Melbourne, he returned in 1965 as a senior lecturer in the School of Physics. He eventually became the Head of the School of Physics (1987-1996) and held a Personal Chair in Physics until his retirement in 1998.

Prof Klein’s research legacy includes significant fundamental experimental studies in quantum physics using beams of slow neutrons. Together with the late Professor Geoffrey Opat, he developed the technique of neutron interferometry and used it to demonstrate that the wave function of a spin-1/2 particle changes sign when the particle is rotated by 360 degrees. His work earned him a shared ‘R&D 100’ Award for “developing one of the 100 most technologically significant products of the year 1995”.  

He was not only a talented teacher, but a great science communicator. He wrote reports for the ABC and provided commentary on the first moon landing during the live broadcast of the event on Australian TV, as well as for the following Apollo 12 and 13 missions.

He also generously gave his time to serve as President of the Australian Optical Society in 1985-86 (now Australian & New Zealand Optical Society or ANZOS) and was Chair of several committees, including the Standards Advisory Committee of the CSIRO National Measurement Laboratories (1985-1995), Research Committee of the Royal Victorian Eye and Ear Hospital (1991-2010), and Beam Instrument Advisory Committee for OPAL (1997-2007). A Life Member of ANZOS, he won its Beattie Steele Medal in 2016.

For his significant contributions to Australian Physics, Prof Klein was named a Fellow of the Australian Academy of Science in 1994 and was appointed as a Member of the Order of Australia in 1999.

On a personal front, Prof Klein was known to be a memorable character with a “great sense of humour and a seemingly infinite supply of jokes”, according to the Australian Academy of Science’s tribute to him on social media.

Many other personal tributes have been posted, including ones from science communicator Dr Shane Huntington OAM: “Many memories of Tony. Nobody taught me optics as well as he did.” and from Prof Deb Kane (Macquarie University): “Profs Klein and Opat were a great duo at AIP congresses. Big and positive personalities.”

Vale Tony.

Image credit: Australian Academy of Science.