Obituaries Australia

Ray Spear, n.d.

ANU Archives, ANUA 225-1167

ANU is mourning the death of distinguished nuclear physicist Professor Ray Spear. Ray graduated from University of Melbourne in physics in 1953 and was awarded a PhD in 1959. His supervisor was Noel Dunbar, who was a Fulbright postdoctoral fellow at the California Institute of Technology, Kellogg Radiation Laboratories from 1952 to 1953. Dunbar was appointed as Professor of Physics at Canberra University College in 1959 and subsequently served as ANU Deputy Vice-Chancellor (1968–77). Nobel winner Willy Fowler of Caltech had formed a very favourable impression of Australian researchers from Dunbar and Dale Hebbard (later of ANU), which led to Ray being appointed as a Fulbright Research Fellow at Caltech (1960–61), followed by a sabbatical during 1976–77. At the time (1976), Ziggy Switkowski (past Telstra CEO) was a postdoctoral fellow at Caltech working on reactions of astrophysical significance in supernova explosions and about to return back to Australia. Ray, together with his ex-student Tezer Esat, Caltech graduate students and Graham Sargood, of University of Melbourne, successfully took over and extended these studies.

On his return to Australia (1962), Ray was headhunted from University of Melbourne by Professor Ernest Titterton, who was the head of the ANU Nuclear Physics Department, and Ray arrived in Canberra during the winter of 1964 with wife Valery and nine-month-old daughter Jenny. While at Caltech (1960), Ray was involved in the design and construction of a unique magnetic spectrograph simply labelled by its radius as the 24‑inch spectrometer. In Canberra, Ray supervised the contract for building a version for ANU. A fan of the football club Collingwood, he got into the habit of painting parts of the magnet in black and white, and at one point the whole toilet in his house.

During the early 1970s, together with his ex-student and now postdoctoral fellow Doug Kean and newly arrived prospective PhD student Tezer Esat, Ray embarked on a new experimental program to measure the shapes of nuclei. This was a difficult and risky field, in particular, for a three-year PhD. However, following initial difficulties, the program was highly successful and resulted in numerous publications and PhD theses. The editor of Physics Letters B, Pieter Maarten Endt of Utrecht, would review the submitted papers himself and as a rule accept them without sending out to external reviewers. His expressed opinion in one case, the measurement of the ‘Quadrupole Moment’ of carbon-12, was ‘this is a tour de force’.

In a field littered with irreproducible results, one of the successes was deemed worthy of a news item in New Scientist: ‘The quadrupole moment of 3- state of 208Pb, reported in Physical Review Letters of February 1977: A definitive study that resolved a perplexing discrepancy between experiment and theory while establishing the reliability of the technique’.8 This body of work is still cited and has an average citation rate of ≈30 per paper, which is a very respectable number in the field.

The 24-inch spectrometer was later converted to a ‘thermal-ion mass spectrometer’ for measuring isotope ratios of astrophysical interest in meteorites and is still in use for dating corals with the U-Th clock to investigate past climates and sea levels. Ray was a strong supporter of these projects and took an active interest in their progress.

Following the winding-down of the ‘nuclear shapes’ experimental program, Ray got interested in graduate student issues; in particular, in the quality of supervision provided in different areas of the University. In nuclear physics, contact hours with graduate students was essentially daily and intensive. In other areas, the student might interact with their supervisor on occasion, over months. While, this might be normal in some fields, in others it was inadequate. In May 1990, Ray was appointed the founding Dean of the ANU Graduate School, which he held until his retirement in July 1998. Along the way he did make significant efforts to resolve issues of supervision and thesis writing, often favouring the students versus some recalcitrant supervisors.

After his retirement, Ray collaborated with Tibor Kibèdi of nuclear physics to publish a compilation of ‘electric-octupole’ transition rates in atomic nuclei. It involved extensive reviews of existing data and preparation of diagrams. Ray examined every single piece of information in the literature, working tirelessly and consistently—no details were left out. This work is well recognised internationally, attracting over 250 citations. It was followed by a compilation of ‘electric-monopole’ transitions.

At Caltech, Dunbar was involved in the discovery of the existence of a particular energy state in the carbon nucleus—perhaps the most important finding ever by an Australian nuclear physicist. Yorkshireman and theoretical physicist Fred Hoyle, a frequent visitor at Caltech, had predicted the existence of this state without which the nuclear cycle in stars could not produce the heavier elements starting from hydrogen and helium—a step-by-step process, that relied on specific resonances to enable heavy element formation. Ray was familiar with this work and the subsequent efforts to reconcile discrepant results in the so-called ‘triple-alpha’ reaction rate to form 12-carbon. Ray insisted that Tibor use his specialist equipment built at ANU to tackle the problem. This has led to many successful experiments in Canberra and abroad searching for the correct answer.

During his retirement, Ray kept up his interest in ongoing research projects, discussing details and suggesting improvements. Discussions extended to families, his farm at Burra where he kept bees and Clydesdale horses, and the world. A host of cherished memories, for a life in science well lived.

He is survived by wife, Valerie, and daughters, Jenny, Hillary and Lyndall.