William Penney, Baron Penney
William George Penney, Baron Penney, was an English mathematician and professor of mathematical physics at the Imperial College London and later the rector of Imperial College London. He had a leading role in the development of High Explosive Research, Britain's clandestine nuclear programme that started in 1942 during the Second World War which produced the first British atomic bomb in 1952.
As the head of the British delegation working on the Manhattan Project at Los Alamos Laboratory, Penney initially carried out calculations to predict the damage effects generated by the blast wave of an atomic bomb. Upon returning home, Penney directed the British nuclear weapons directorate, codenamed Tube Alloys and directed scientific research at the Atomic Weapons Research Establishment which resulted in the first detonation of a British nuclear bomb in Operation Hurricane in 1952. After the test, Penney became chief advisor to the new United Kingdom Atomic Energy Authority. He was later chairman of the authority, which he used in international negotiations to control nuclear testing with the Partial Nuclear Test Ban Treaty.
Penney's notable scientific contributions included the mathematics for complex wave dynamics, both in shock and gravity waves, proposing optimisation problems and solutions in hydrodynamics During his later years, Penney lectured in mathematics and physics; he was the Rector of Imperial College London 1967–1973.
Early life and education
William George Penney was born in Gibraltar on 24 June 1909, the oldest child and only son of William Alfred Penney, a sergeant-major in the British Army's Ordnance Corps who was then serving overseas, and Blanche Evelyn Johnson, who had worked as a cashier before her marriage. His parents moved about frequently, but Penney did not always accompany them. After the outbreak of the First World War, Penney, his mother and his sisters moved to Sheerness, Kent, where he went to primary school. He then attended a school near Colchester, and finally, was at Sheerness Technical School for Boys from 1924 to 1926, where he displayed a talent for science. He participated in boxing and athletics, winning the school's dash. He also played cricket, and he was centre-forward on the school football team.In 1927, Penney's passion for science landed him in a local science laboratory where he worked for 10 shillings a week as a laboratory assistant. This helped him to gain a Kent county scholarship and a royal scholarship to the Royal College of Science, a constituent college of Imperial College London. He played centre-forward on the RCS soccer team. He was permitted to skip the first year of the course, and graduated in 1929, obtaining his Bachelor of Science degree in mathematics with First Class Honours at age 20. His talent was recognised by the Governor's Prize for Mathematics from the faculty of science.
Penney was offered a research position at the London University, where he studied for a doctorate. He spent a term at the University of Groningen in the Netherlands, where he worked with Ralph Kronig. Together, they developed the Kronig–Penney model, which described the motions of electrons in periodic fields. Penney was awarded his Doctor of Philosophy in Mathematics in 1931. He accepted a Commonwealth Fund Fellowship and travelled to the United States, where he became foreign research associate at the University of Wisconsin–Madison, studying under John H. Van Vleck, and was awarded a Master of Arts degree. While in the United States he visited Carl Anderson's laboratory at the California Institute of Technology and Ernest Lawrence's Radiation Laboratory at the University of California. He was a guest at Robert Oppenheimer's ranch in New Mexico, saw Babe Ruth play baseball, and was a spectator at the 1932 Los Angeles Olympics.
On returning to England in 1933, Penney was granted the 1851 Exhibition Scholarship to attend Trinity College, Cambridge. He changed his mathematical career to physics, and conducted a thorough research and theoretical investigation into the structure of metals and the magnetic properties of crystals with John Lennard-Jones. In 1935, Penney submitted his final thesis, which contained the fundamental work in the applications of quantum mechanics to the physics of crystals. The University of Cambridge awarded him a PhD in 1935 and a Doctor of Science in Mathematical Physics in 1936. In 1936, he was elected to the Stokes studentship at Pembroke College, Cambridge, but in the same year he returned to London and was appointed Reader in Mathematics at Imperial College London, a post he held from 1936 to 1945. On 27 July 1935, Penney married Adele Minnie Elms, a university student from Kent he had known since his days in Sheerness. They had two sons, Martin, who was born in 1938, and Christopher, who was born in 1941.
Second World War
Physex
Penney registered himself as available for scientific war work, but heard nothing for several months after the outbreak of the Second World War in September 1939. He was then approached by Geoffrey Taylor. Taylor was an expert on fluid dynamics, and was dealing with more questions from government departments regarding the effects of explosions than he had time to answer. He asked Penney if he could investigate the behaviour of an underwater explosion. Penney became a member of the Physics of Explosives Committee, and reported his results to another committee, Undex, which was run by the Admiralty and was interested in underwater explosions such as those created by mines, torpedoes and depth charges, and their effects on the hulls of ships and submarines. Most of the data on underwater explosions was from the First World War.With Royal Navy engineer officers Penney designed and supervised development of Bombardon breakwaters, steel structures that formed part of the Mulberry harbours that were placed off the Normandy beaches after the D-Day invasion. These mobile breakwaters protected landing craft and troops from the Atlantic rollers. Penney's job was to calculate the effects of waves on the Bombardons and devise the most efficient arrangement of them.
Manhattan Project
The August 1943 Quebec Agreement provided for British support of the American Manhattan Project, which aimed to develop atomic bombs. Over the objections of the Admiralty and Imperial College, Penney was sent to join the team of British scientists at the Manhattan Project's Los Alamos Laboratory in New Mexico, where expertise on explosions and their effects was in demand. At Los Alamos Penney gained recognition for his scientific talents, and also for his leadership qualities and ability to work in harmony with others. Within a few weeks of his arrival he was added to the core group of scientists making key decisions in the direction of the programme. Major General Leslie Groves, the director of the Manhattan Project, later wrote:One of Penney's assignments at Los Alamos was to predict the damage effects from the blast wave of an atomic bomb. Soon after he arrived at Los Alamos, he gave a talk on the subject. Fellow Manhattan Project scientist Rudolf Peierls recalled that:
Penney's wife never recovered from post-natal depression after Christopher's birth, and died on 18 April 1945. He arranged for Joan Quennell, a nurse, to look after the boys. He wanted to return home, but Groves told James Chadwick, the British liaison to Manhattan Project in Washington, D.C., that Penney was too important to the project to be released. On 27 April 1945 Penney went to Washington for a target selection meeting. He gave advice regarding the height of the detonation which would ensure optimum destructive effects, whilst ensuring the fireball did not touch the earth, thereby avoiding permanent radiation contamination on the ground. The committee selected four cities from a list of seventeen. Penney attempted to forecast casualties and damage effects, but this was difficult because the exact energy of the bombs was not known. This was answered by the Trinity test detonation on 16 July 1945. Penney was assigned as an observer on an aircraft, but the flight was cancelled due to bad weather, and he did not witness the test. Five days later, Penney gave a presentation on the results of the test, during which he predicted that the bomb would level a city of three or four hundred thousand people.
The following month Penney went to Tinian Island as part of Project Alberta, the group of scientists and military personnel that assembled the atomic bombs. Along with Royal Air Force Group Captain Leonard Cheshire from the British Joint Staff Mission in Washington, he represented the United Kingdom. The American authorities stopped them observing the bombing of Hiroshima but, after an appeal to Chadwick, they were permitted to accompany the second mission. On 9 August 1945 Penney witnessed the bombing of Nagasaki, flying with Cheshire in the B-29 observation plane Big Stink. Big Stink missed its rendezvous with the bomber Bockscar, so they witnessed the flash of the Nagasaki detonation from the air at too great a distance to photograph the fireball and the target was obscured by clouds. As the leading expert on the effects of explosions, Penney was a member of the team of scientists and military analysts who entered Hiroshima and Nagasaki following the Japanese surrender on 15 August 1945 to assess the effects of nuclear weapons.
Penney returned to the United Kingdom on a civilian flight from the United States in September 1945. He brought artefacts from Hiroshima and Nagasaki with him, and was charged for excess baggage. He married Joan Quennell on 3 November 1945. Penney returned to Imperial College, where he wrote a report on Hiroshima and Nagasaki. He estimated that the bomb dropped on the former had a yield of and that of the Nagasaki bomb of about. He wanted to return to academic life, and he was offered a chair of mathematics at the University of Oxford.