H A H ('Harry') Boot was born on 27 July 1917 in Birmingham. Educated at King Edward's School, Boot went to Birmingham University to study physics and was awarded a BSc in 1938 and a PhD in 1941.
Centrimetric radar
After the outbreak of war, Boot worked in the physics department under M L E Oliphaunt on the development of centimetric radar. Radar at that time was based on long wavelengths and required bulky equipment. This meant that the search area had to be 'flooded' in order to detect any moving objects. Boot and his colleague, J A Randall, were trying to produce wavelengths of 10cm or less for use in a radar 'beam' which would be more accurate.
Boot and Randall's pioneering work
Initially, Boot and Randall were using the klystron, an American invention, but were not able to produce short enough waves. In 1940 they turned instead to the magnetron and after a few months were able to produce wavelengths of 9.8 cm using a decidedly ramshackle magnetron. This was quickly developed into usable equipment, and the first magnetron radar system was built at TRE Swanage in May of that year. In September it was first used by Bomber Command to detect submarines.
The invention of the magnetron had a profound impact on the outcome of the Second World War. In the Battle of the Atlantic centimetric radar provided the Allies with a means of locating surfaced U-boats in any weather, day or night. It was also decisive in the defeat of the German night bombers in 1943-1944 and in the improvement in the accuracy of the Allies' own night bombing.
Boot and Randall were honoured for their invention with the award in 1943 of the RSA Thomas Gray Memorial Prize for 'improving the safety of life at sea'. In 1946 they were awarded a Royal Commission Inventors Award; in 1958 the Franklin Institute John Price Wetherill Medal; and in 1959 the City of Pennsylvania John Scott award.
After a brief time at BTH, Rugby, in the latter years of the war, Boot returned to Birmingham as the Nuffield Research Fellow. In 1948, he was appointed Principal Scientific Officer (PSO) at Services Electronic Research Laboratories, Baldock, where he undertook research on microwaves, magnetrons, plasma physics and lasers. He retired in 1977 and died in Cambridge on 8 February 1983.