Francis Alwyn Rushworth, physicist: born Cleckheaton, West Yorkshire 2 July 1920; Assistant Lecturer in Physics, St Andrews University 1947- 49, Lecturer 1949-61, Senior Lecturer 1961-71, Reader 1971-82; FRSE 1961; married 1947 Gwen Johnson (three sons, one daughter); died near St Andrews, Fife 19 August 1997.

Alwyn Rushworth was an early pioneer of nuclear magnetic resonance (nmr) research in Britain. Just after he first came to St Andrews University in 1947, as an Assistant Lecturer in Physics, to work for a PhD, nmr became, on the initiation of the newly arrived Professor of Natural Philosophy, Jack Allen, the focus of Rushworth's attention. It remained so for the rest of his career.

Nuclear magnetic resonance was initially developed as an analytical technique for physics and chemistry, by which the atomic structure of solids could be measured using a magnetic field and radio waves, and the technique has more recently been developed into one of the standard scanning techniques in hospitals world-wide, used in place of X-rays.

The first nmr signals were observed in mid-1948; with apparatus culled from ex-War Department communications equipment, little blips on an oscilloscope screen signalled the arrival of nmr in Scotland, and St Andrews became one of the principal centres for nmr research in the UK. For a while, Raymond Andrew, another pioneer in the field, who in 1956 published the first textbook on nmr, joined Rushworth at St Andrews before going on to a chair in Bangor. A succession of research students were piloted through to their PhDs. Other nmr specialists joined the physics staff and nmr remains a thriving activity in both the chemistry and physics departments; it will be a prominent feature of research in the new Biomolecular Science Building now rising on the science campus. All this is due in no small part to Rushworth's influence.

His research interest at St Andrews was into the properties of the solid state, typically organic solids, where he exploited the power of the nmr method to characterise quantitatively the internal dynamics of the solid. The measurements obtained were combined with theoretical calculations to define these motional effects. Materials such as cyclobutane, cyclopentene, ethylene at low temperature, and pentane and anthacene were subjected to detailed analysis. During all this, permanent magnet design became a problem, since nmr requires large homogenous magnetic fields, and significant contributions, particularly on the use of shims to improve homogeneity, were published by Rushworth on this topic.

In the 1960s, the crisis over the siting of a new physics building in St Andrews soon swept Rushworth into a vital role in planning the detail of the first university development on the science campus at the North Haugh. Government controls on building were not quite so rigorously parsimonious in those early days and Rushworth and Allen together were able to create a fine legacy for succeeding generations of, initially, physics students, now shared amicably with the computational science department.

Rushworth was born in Cleckheaton, West Yorkshire, the son of a primary school headmaster, in 1920. He became an undergraduate at Imperial College, London, took a BSc degree in Physics, and an ARCS in 1941 and was awarded the Tyndall Prize by Imperial. For six years thereafter war work in the Admiralty as an Experimental Officer, mainly concerned with sonar detection of enemy boats, took him to Fairlie, Ayrshire, and to Portland, Dorset.

Before he joined the staff in 1947, the teaching complement at the St Andrews physics department had been three. Rushworth was promoted to Lecturer in 1949, Senior Lecturer in 1961 and Reader in 1971. With staff thin on the ground and with the traditional Scottish four-year undergraduate programme, teaching loads were heavy right up to the Robbins expansion in the 1960s. Perhaps because of this background, teaching for Rushworth remained always a prime consideration, and his lectures were models of organisation and clarity. He co-authored (with me) a successful introductory textbook on nmr, Nuclear Magnetic Resonance (1973).

In later years administration became important and the Universities Central Council for Admissions (better known as Ucca) in Cheltenham occupied much of his time; Rushworth was the Scottish representative on the executive committee. He earned much respect and gratitude from students, and derived much personal satisfaction in his faculty roles as Adviser of Studies and Admissions Officer.