It was a joint award to Freeman and Professor Roger Blin-Stoyle, for their work on beta-radioactivity of complex nuclei. She was the leader of the Harwell Tandem Accelerator Group carrying out the experimental work, while he and his students at Sussex University pursued the theoretical studies.
Their collaboration on the basic weak interaction theory began in the 1960s. Beta- radioactivity, the spontaneous emission of negative or positive electrons from unstable nuclei, is a manifestation of the four recognised interactions in nature. These are the weak interaction, the gravitational, the electromagnetic, and the strong or nuclear. The weak interaction plays a secondary but vital role in a nuclear reactor.
On meeting Joan Freeman, people were surprised to find she was a somewhat timid person. She herself wrote, in her book A Passion for Physics (1991), of her shyness and her gratitude to colleagues who bolstered her self- confidence. She also wrote that to succeed in science a woman needed determination, enthusiasm and independence of mind. She showed all of these.
Her early life was difficult. She was born in 1918 in Perth, Western Australia, the only child of a musically talented mother, frustrated by unexpected poverty resulting from collapse in the 1900s of the great gold boom: and a father who was an accountant and given to flares of rage. They moved to Sydney in 1922. Family problems were exacerbated by the 1929 crash, when her father lost his bank job and her mother desperately struggled to earn money by running a kindergarten. She was anxious to maintain Joan's fees at Sydney Church of England Girls' School, recognised to be the best available and where Joan was an extremely hard-working pupil, regularly winning prizes for being the top of her class. Maths and science fascinated her. The school recognised her ability and commitment, and remitted her fees.
Even Sceggs - as it was locally known - could not meet Joan Freeman's avid interest in chemistry and physics. For two years she managed to join evening classes at the Sydney Technical College - a lone, tiny schoolgirl among classes of engineering apprentices in a rather rough part of this city. The Principal insisted she be accompanied by an adult on the journey. Her mother came, dragging her students' exercise books for marking during the two-hour sessions.
Joan repaid Sceggs' faith in her by passing her Intermediate Certificate Examination (the equivalent of O Level) with 7 As and 1 B: surprisingly the B was in chemistry. In the Leaving Certificate Examination she secured a scholarship, a medal, and a prize. This assured her a place at the University of Sydney in 1936. She also faced a difficult time, for the strains of marriage proved too much for her father, who left the family. Joan and her mother struggled on together.
If her experience at the Sydney Technical College had not proved the point, she was in no doubt at university that physics was not an easy road for a woman. One of her lecturers was Phyllis Nichol - only the second woman to graduate in physics at Sydney University. She strongly advised her pupil to take chemistry, where prospects for employment were slightly brighter. Joan Freeman showed the required independence of mind: she stuck with physics.
She was the only woman in the second year - a point emphasised by the space officially designated between her and the next man. One unfortunate who sat next to her was informed by the lecturer, "Officially, you are not here."
She worked with her habitual concentration, achieved a BSc with a double first in 1940, was awarded a Commonwealth Research Scholarship and started on her MSc. A few months later, in June 1941, she was accepted as a Research Officer at the Radiophysics Laboratory of the Council for Scientific and Industrial Research. Accepting that she would have to complete her MSc in her spare time, Freeman plunged into the somewhat frenzied activity of radar research, whose results were so urgently needed by the Allied armed forces in the Second World War. She was one of only two women so employed: and was grateful for the practical training she had undergone in her Honours year - in glass blowing, metalwork, soldering, mechanical design and drawing.
The war ended unexpectedly in August 1945; and Freeman undertook, with some misgivings, her first peacetime research project, concerning the behaviour of low-pressure gas discharges at microwave frequencies. In 1946, soon after achieving satisfactory results for this project and, to her complete surprise, she was awarded a Senior Studentship by the Council for Scientific and Industrial Research enabling her to go to Cambridge University in England and read for her PhD.
The experience filled her now with euphoria, now with despair. Newnham College, chosen because it was near into town, was welcoming, but defensively formal in the masculine culture of Cambridge. The general ambience contrasted sharply with more casual Australian ways and the bitterly cold wet weather was equally shocking. The Cavendish Laboratory was in turmoil with an overwhelming number of research students for the teaching staff available. She was advised to join the Nuclear Physics Department, and spent six frustrating months trying to find a project. None had been assigned to her, and her named supervisor never arrived.
At one stage she nearly broke down; but then showed a remarkable ability to find a niche for herself. With the use of considerable tact and diplomacy she succeeded in teaming up with Alex Baxter in work on the HT1 accelerator to study short-range alpha particles.
This proved the turning point in her life and career. In 1951 she moved to Harwell as a Senior Scientific Officer and decided, after some worries of conscience, not to return to Australia - a decision which the Australian authorites met with generosity and understanding. Her mother joined her in Abingdon soon after that.
She met John Jelley at Harwell in 1948, and married him in 1958. She retired in 1978 - somewhat unwillingly, as 60 was the retirement age for women and 65 for men. Still she had the consolation of the Rutherford Medal, a Fellowship of the Institute of Physics, a Fellowship of the American Physical Society and an Honorary Doctorate from Sydney University. And she continued as a consultant for some time. Meanwhile, Jelley took early retirement. Together they embarked on a happy period of travel and sailing, until he was smitten by illness in 1995, and died in 1997. Freeman, who had nursed him devotedly, was much saddened by his death.
Joan Maie Freeman, physicist: born Perth, Western Australia 7 January 1918; married 1958 John Jelley (died 1997); died Oxford 18 March 1998.