Leslie Hodson

WHILE working 11,000ft up Mount Evans at Echo Lake in Colorado, Dr Leslie Hodson, who has died aged 84, took the photograph that proved the existence of a highly-elusive sub-atomic particle.

He was, at the time, hunting for the most basic elements of the universe.

Leslie Hodson went to Thorne Grammar School, near Doncaster, and in 1943 took up a place to read physics at Manchester University.

Hide Ad
Hide Ad

Thanks to the war, his course was compressed into two years and one term, but nevertheless. this exceptional scholar obtained an excellent First.

He remained at Manchester to undertake research into cosmic rays – the high-energy particles that originate in outer space.

He was an outstanding member of the very influential research group directed by the eminent physicist, Professor (later Lord) P M S Blackett, FRS, and his work, which led to several significant papers, won praise for its originality. He was awarded his MSc in 1947 and his PhD, for a thesis on cosmic ray showers, in 1951.

Throughout his long academic career, cosmic ray physics continued to be his area of research interest.

Hide Ad
Hide Ad

Having been an assistant lecturer at Manchester from 1947 to 1951, Dr Hodson moved to the USA to become a research associate at Princeton University.

His research work there contributed further to his reputation, and he assumed the main responsibility for a major cloud chamber experiment in Colorado.

Originally developed at the turn of the century by the Scottish physicist C T R Wilson, the cloud chamber is a device to detect and photograph elementary particles, the most basic physical constituents of the universe, and other ionizing radiation.

The experiment involved Dr Hodson spending much of his time 11,000ft up Mt Evans at Echo Lake in Colorado, since this location enabled cosmic ray research to be conducted with reduced effects from atmospheric interaction.

Hide Ad
Hide Ad

If the price of making a useful contribution to particle physics was isolation near the top of the highest paved road in North America, the young scientist was content to pay it.

His work produced a number of important breakthroughs, but the one he would be most famously associated with was the cloud chamber photograph he captured that proved the existence of a sub-atomic particle which he announced to the world at the May 1954 meeting of the American Physical Society in Washington.

The "K+ meson" was identified by its decay products which had never before been observed.

Dr Hodson was appointed to a lectureship in the Department of Physics at Leeds in 1954 and was promoted to senior lecturer in 1964.

Hide Ad
Hide Ad

One of his first tasks at Leeds was to design and construct what was then the largest cloud chamber ever made, weighing more than 10 tons, with the aim of making measurements of interactions at energies well beyond the reach of man-made accelerators.

Consolidating his reputation as a superlative experimentalist, he made extensive use of the new cloud chamber and associated detector arrays to continue his studies of high energy cosmic rays.

He also played a prominent part designing and monitoring the construction of a new building for physics during the 1960s, and could justifiably boast that he had insisted it must not contain asbestos which was then fashionable – his stubbornness making him unpopular is some quarters.

Lessons he learnt during that project were put to good use when he designed his own home on the outskirts of Leeds.Leslie HodsonDr Hodson retired in 1990, and is survived by his wife Joyce, their three sons, David, Brian and John – all of them science or engineering graduates – and a granddaughter.