Childhood in Manchester (1891-1908)
Manchester University (1908-1913)
Berlin and the War (1913-1918)
The Cavendish Laboratory (1919-1935)
Assistant Director (1922-1935)
The Neutron (1932)
Liverpool (1935-1943)
The Second World War (1939-1945)
The Manhattan Project (1943-1945)
Return to Liverpool (1946-1948)
Gonville and Caius (1948-1958)
Retirement (1958-1974)

James Chadwick

Childhood in Manchester

On 20th October 1891 James Chadwick was born in Bollington near Macclesfield, Cheshire. When his father left to open a laundry business in Manchester, Chadwick remained with his grandmother, was educated locally and later entered Manchester Municipal Secondary School. Chadwick specialised in applied mathematics and at the age of 16 succeeded in gaining two scholarships to attend Manchester University.

Chadwick was immature and very shy. He applied to Manchester to read mathematics, but was accidentally interviewed as a potential physics student. He was too shy to mention the mistake, but was so impressed by the interviewer that he decided to do physics.

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Manchester University

Chadwick found the first year classes large and noisy, but in his second year he met the Professor, Ernest Rutherford. When Rutherford set Chadwick his third year research project he left a deliberate mistake in the method to see if Chadwick was alert. Chadwick noticed the mistake but didn't dare correct the Professor, so Rutherford thought he had missed it!

Chadwick got his First Class Honours degree in 1911 and began research for a Masters degree. He stayed in Manchester and was interested in Geiger and Marsden's scattering of alpha particles, research that led to Rutherford's discovery of the nucleus. In 1913 Chadwick received his Masters, and Rutherford recommended him for an 1851 Exhibition scholarship.

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Berlin and the War

The scholarship required that Chadwick move from Manchester. He wanted to speacialise in radioactivity, so went with Geiger to the Reichsanstalt in Berlin where he quickly learnt German. Geiger supervised Chadwick and introduced him to other leading German scientists, including Albert Einstein.

The First World War brought a sudden end to this way of life. Geiger was called away as a reserve officer, but Chadwick stayed in Germany. When war was declared it was too late for Chadwick to leave, and soon afterwards he was imprisoned at a racecourse at Ruhleben. He lived with five others in a stable built to hold two horses, and suffered from inadequate food and bitter cold.

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The Cavendish Laboratory

In 1918 the War ended. After four years of imprisonment, poor and in bad health, Chadwick was free to return to England and Manchester, where Rutherford offered him a job. A year later Rutherford became the Cavendish Professor, and invited Chadwick to join him in Cambridge. From the start Chadwick played a very important part in the running of the Cavendish Laboratory, which Rutherford had decided would concentrate on the experimental study of the atomic nucleus.

Chadwick was offered a Wollaston Studentship of £120 a year by Gonville and Caius College. In 1921 he was elected as a research fellow by the college, increasing his income to £350 a year. The following year Chadwick was funded by the Department of Scientific and Industrial Research to become the Assistant Director of Research in the Cavendish.

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Assistant Director

Chadwick now concentrated solely on research, and no longer had to teach or lecture. He and Rutherford would allocate research problems, and each morning at 11 o'clock Chadwick reported any progress to the Professor. Their close friendship lasted for sixteen years.

Chadwick was married in 1925 and arranged to have a house built by October 1926. The building actually took longer, and the Chadwicks spent some time living in a cold and draughty house. At the time Chadwick was revising Rutherford's book on radioactivity, and is said to have worked each night until midnight, wrapped up in an overcoat and wearing gloves!

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The Neutron

In 1932 Chadwick discovered the neutron. He and Rutherford had discussed the possibility of the particle for more than ten years, and had tried many 'silly' experiments to find it. The successful discovery changed the world, and won Chadwick a Nobel Prize in Physics in 1935. Soon after the discovery Cockcroft and Walton's accelerator split nuclei of lithium and Chadwick was keen to build a more powerful accelerator in the Cavendish.

But Rutherford was reluctant to ask for money and refused Chadwick's request. Chadwick had to look elsewhere for his accelerator, so in 1935 was delighted to accept the Lyon Jones Chair of Physics at Liverpool University.

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Liverpool

When Chadwick moved to Liverpool its physics department was run down and lacking equipment, but by the time he left he had built up a high level of teaching and research. In 1936 he began by starting the construction of a '37-inch cyclotron', a circular particle accelerator nearly a metre across, using £2000 from the Warren Fund of the Royal Society.

Chadwick had asked Cockcroft to design the magnet for his cyclotron. This annoyed Rutherford, who was still opposed to building expensive accelerators. When Chadwick visited Cambridge in June 1936, Rutherford attacked him about the cyclotron and for encouraging his new director of research, Mark Oliphant, to leave for a chair at Birmingham. Chadwick was surprised and shocked, and returned to Liverpool on bad terms with Rutherford.

Rutherford didn't bear any lasting grudge, and even allowed Cockcroft to build his accelerator, but in October 1937 Rutherford died of a strangulated hernia. Although he had resumed writing to Chadwick on good terms the two men had not met since their argument. Chadwick always regretted this sad ending to their long friendship. Chadwick was not elected as a successor to the Cavendish Chair.

While the cyclotron was being built, Chadwick took a keen interest in teaching and medical physics. During the first few months of 1939 he spent half his time organising classes and reorganising cancer therapy. He was an able Department Head and brilliant researcher.

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The Second World War

History came close to repeating itself as Chadwick almost found himself behind enemy lines at the start of the Second World War. In September 1939 he was on a fishing holiday in Sweden, and when he got back to Stockholm found no immediate way home. Fortunately he obtained a flight to Amsterdam, and after a few days was able to return to England.

The Liverpool cyclotron became operational at the start of the Second World War. Uranium fission had been discovered by Hahn and Strassmann at the start of 1939, and a few months later the possibility of a nuclear chain reaction had been demonstrated.

E.V. Appleton, the Secretary of the Department of Scientific and Industrial Research, asked Chadwick if a nuclear bomb was a possibility. It appeared that such a bomb would need more than a ton of uranium to explode, but Chadwick wasn't sure, and decided to use the Liverpool cyclotron for a feasibility study.

By the end of 1940 Chadwick and others found that the first American experiments had underestimated the sizes needed to maintain a chain reaction, and found that only a few kilograms of uranium would be needed to create a nuclear weapon. Chadwick and many of Britain's other leading physicists joined to form 'the Maud Committee', and produced a report saying that a nuclear bomb could be ready by 1943. Only P.M.S. Blackett doubted this timescale. The power plant needed to produce the nuclear material was built in Canada.

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The Manhattan Project

America entered the war after the Japanese attack on Pearl Harbour in December 1941. It became clear that the Amercian nuclear weapons project could quickly overshadow the British efforts, and Chadwick expressed that every effort should be made to allow complete cooperation between the two allied nations. On 19 August 1943 the Quebec Agreement on Anglo-American collaboration was signed by Prime Minister Churchill and President Roosevelt, and British scientists were transferred to the United States.

Chadwick quickly established a friendly relationship with Major General Groves, the executive officer in charge of America's nuclear bomb projects, collectively called the Manhattan Project. Groves and Chadwick respected each other, were wholly straightforward and honest. Chadwick was determined to keep Anglo-American relations as strong as possible. He helped draft agreements to provide uranium for the Project, maintained the morale of British scientists during their time in America, and was responsible for British observers being present at the bombing of Nagasaki.

After the War Chadwick encouraged cooperation with the United States on nuclear energy matters, and considered the construction of reactors capable of producing plutonium to be the first priority. This cooperation weakened, and by 1955 was extremely limited.

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Return to Liverpool

In 1946 Chadwick returned to Britain and Liverpool, physically, mentally and spiritually tired. He became involved with Britain's nuclear energy programme, continued his work on fundamental research in universities, and advised the British delegation to the United Nations in 1947. At Liverpool he made plans to produce a new synchrocyclotron, so that by the time he left in 1948 Liverpool had the most powerful accelerator outside America.

When a European research centre into nuclear physics was proposed, Chadwick was keen that Britain should be involved, seeing it as the only way British scientists could stay competitive with the large accelerators in the United States. He recommended that European scientists be allowed to gain experience on the Liverpool accelerator, and in 1952 recommended that Britain join the Council of Representatives for the European project. Meeting at Cambridge with eleven other physicists, it was decided that Britain should contribute £250,000 a year for eight years. At the end of 1952 Britain agreed to set up C.E.R.N., contributing nearly a quarter of the required resources.

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Gonville and Caius

In 1948 Chadwick returned to Cambridge to become the Master of Gonville and Caius College, a move which surprised many of his friends in Liverpool. He missed his laboratory, but was pleased to have more contact with undergraduates. The College Bursar was absent through illness on Chadwick's arrival, so he handled the finances, managing to make a good return by investing in equities rather than securities. Chadwick was also responsible for building a new court, and relaxing the rules about arriving back late at night!

Chadwick accepted the post of Vice-Chancellor at Cambridge, but was overcome with exhaustion before he could take up the role.

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Retirement

In 1958 Chadwick became unhappy with the emotional and personal criticism levelled at him as Master, so he resigned from Gonville and Caius and retired to a cottage in North Wales.

Chadwick was happy to be back near Liverpool again, and stayed in Liverpool for eleven years. The Chadwicks returned to Cambridge in 1969 to be near their two daughters, and James Chadwick died on 24th July, 1974. More than four hundred attended his funeral at Great Saint Mary's on the 26th October.

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