James Chadwick : Discoverer of Neutron

Chadwick was the son of J. J. Chadwick. who had a laundry business in Manchester, and of Ann Mary Knowles. After attending the Manchester Municipal Secondary School he won a scholarship to Manchester University, where he studied physics under Ernest 0. Rutherford. He was awarded a first-class degree in 1911, then was accepted by Rutherford as a research student for the M.Sc. At this time the department of physics at Manchesterwas at its height, for besides Rutherford its staff included Hans Geiger. Ernest Marsden, Charles Galton Darwin, György Hevesy, and Henry G. J. Moseley. as well as, for a while, Niels Bohr. The Rutherford and Bohr atoms both date from this period. In 1913 Chadwick went to work with Geiger in Berlin and was still there when war broke out the following year. He was interned until the end of the war in 1918.

Quick facts

FULL NAME :  Sir James Chadwick

FAMOUS AS : Discoverer of Neutron

NATIONALITY : British

BORN ON : 20 October 1891

BIRTHDAY : 20th October

DIED AT AGE : 82

SUN SIGN : Libra

PLACE OF BIRTH : Bollington, Cheshire, England

DIED ON : 24 July 1974

PLACE OF DEATH : Cambridge

Major Works

Discovery of neutron is Chadwick’s greatest work. It not only contributed to the better understanding of nucleus, but also paved the way towards the fission of Uranium 235, which ultimately led to the creation of the atomic bomb.
Through his researches Chadwick established that neutron is an elementary particle that does not contain electrical charge and therefore unlike helium, it does not need to overcome any electric barrier. It is therefore capable of penetrating as well as splitting the nuclei of even the heaviest atoms.

Early Life and Education

James Chadwick was born in the small town of Bollington, England, UK on October 20, 1891.

His parents were Joseph, a railway storekeeper, and Anne, a domestic servant. When he was aged 11, James won entry to the prestigious Manchester Grammar School. Unfortunately, his parents were too poor to afford the small amount of money they would need for fees. Instead, James Chadwick was educated at Manchester’s Central Grammar School for Boys; his favorite subjects were mathematics and physics. Aged 16, he won a scholarship which enabled him to enroll at the Victoria University of Manchester.

He had intended studying mathematics, but he was interviewed by a physicist who assumed Chadwick wanted to study physics. Chadwick was too shy to contradict him, so ended up enrolling as a physics major!

Carrier

In 1921, James Chadwick was elected as a Fellow of Gonville and Caius College and served in that capacity until 1935. Two years later in 1923, he was appointed as an Assistant Director of Research at Cavendish Laboratory where Rutherford was the Director. Again in 1927, he was elected a Fellow of the Royal Society.
In 1932, while still working at Cavendish Laboratory at Cambridge, he made an important discovery. He proved the existence of neutron, which could be used as a new tool of atomic disintegration and later paved the way for the creation of atomic bombs.
Chadwick remained at the University of Cambridge until 1935. In the same year in May he received an offer from the University of Liverpool. There he was elected to the Lyon Jones Chair of Physics and assumed the position on October 1, 1935.
He then set out improve the infrastructure at the university. As the total cost of the renovation was more than what was received as grant he paid the rest from his own pocket, using the money he had received as Nobel Prize that very year.
When the Second World War broke out in 1939, he was holidaying with his family in northern Sweden. He promptly came back to England using whatever means he could and promptly joined his duty.
In October 1939, he received a letter from the Secretary of the Department of Scientific and Industrial Research, in which his opinion on the feasibility of creating an atomic bomb was sought. He did not dismiss the idea, but sighted many difficulties that may arise.
In February 1940, Otto Frisch and Rudolf Peierls of University of Birmingham announced the possibility of fast fission in uranium-235. Very soon the Military Application of Uranium Detonation (MAUD) Committee was formed with Chadwick as one of the members.
A team of scientist led by Chadwick was next entrusted with the task of determining the nuclear cross section of uranium-235. The team submitted its reports by April 1941. In July 1941, Chadwick was asked to write the final draft of the Maud Committee report. It was finally presented to President Roosevelt in October 1941.
At the same time, it became clear that it will not be feasible for Britain to manufacture atomic bombs alone. Contrarily, the US government was ready to invest millions of dollar on it. They already had Manhattan Project running.
Although the USA did not need British cooperation they were nonetheless eager to use Chadwick’s talent.
Accordingly, Quebec Agreement was signed and this resulted in cooperation between USA, Great Britain and Canada. James Chadwick became the head of the British Mission. He then moved to USA.
Chadwick remained in USA from 1943 to 1946. He was present at the meeting where it was decided that atomic bomb will be dropped on Japan and when the first atomic bomb was detonated at the Trinity Nuclear Test on July 16, 1945, he was also a witness to it.
He came back to England in 1946, mentally and physically exhausted. In 1948, Chadwick became the Master of Gonville and Caius College and served in that capacity till 1959.
from 1957 to 1962, Chadwick was inducted as a part time member in the United Kingdom Atomic Energy Authority.

Personal Life & Legacy

• In August 1925, James Chadwick married Aileen Stewart-Brown, the daughter of a Liverpool stockbroker. The couple had twin daughters Joanna and Judith, born in 1927. Gardening and fishing were two of his favorite hobbies.
• Chadwick passed away in sleep on 24 July 1974, at the age of 82, in Cambridge, England.
• The Chadwick Laboratory at the University of Liverpool has been named after him. In 1991, Sir James Chadwick Chair of Experimental Physics was established as part of centenary celebration of his birth. He also has a crater on the moon in his name.

 Death

James Chadwick died peacefully, at the age of 82, on July 24, 1974.

Awards & Achievements

• In 1932, he was awarded the Hughes Medal by the Royal society for his discovery of neutron.
• In 1935, James Chadwick was awarded the Nobel Prize in Physics for his discovery of neutron. He used part of his prize money to build a cyclotron at the University of Liverpool.
• In 1945, Chadwick was awarded knighthood by King George VI of Great Britain for his war time efforts.
• In 1950, he received Copley Medal and in 1951, the Franklin Medal of the Franklin Institute, Philadelphia.
• In 1970, he was made a Member of Order of the Companions of Honour by Queen Elizabeth II of Great Britain.
• In addition, Chadwick received honorary doctorate degrees from a number of universities such Reading, Dublin, Leeds, Oxford, Birmingham, Montreal (McGill), Liverpool, and Edinburgh.
• He was an Honorary Fellow of the Institute of Physics and Honorary Member of the American Philosophical Society, the American Physical Society and many other internationally distinguished institutes.

Some Unknown Facts About Chadwick

• Chadwick was born in Bollington, England and was the eldest son of laborers.
  Because his parents were poor he could not afford private grammar school but passed the exams for two university scholarships.
• In 1908 he entered the Victoria University of Manchester and lived at home.
• In 1909 he received a Heginbottom Scholarship to study physics.
• The head of the physics department was Ernest Rutherford and he assigned Chadwick to devise a means of comparing the amount of radioactive energy in two different sources.
• Chadwick graduated with honors in 1911 and in 1912 wrote his first paper on the successful results of his energy experiments.
• In 1912 he received his M.S. in Science and wrote a paper on the absorption of gamma rays by various gases and liquids.
• In 1913 he was awarded a scholarship to the Physikalisch-Technische Reichsanstalt in Berlin where he studied under Hans Geiger.
• When World War I started he was a prisoner at the Ruhleben Internment camp near Berlin.
• In November 1918 he returned to England and secured a teaching position at the University of Manchester.
• In April 1919 Ernest Rutherford became director of Cavendish Laboratory at the University of Cambridge and he brought Chadwick to Cambridge.
• Chadwick was awarded a Clerk-Maxwell studentship in 1920 and in 1921 he received his PhD.
• His research with radioactivity had for years pointed to the presence of a light particle with no electrical charge in the nucleus of atoms and in February 1932 Chadwick sent his paper “Possible Existence of a Neutron” to Nature magazine.
• In May he sent a detailed account of his results entitled “the Existence of a Neutron” to the Royal Society.
• This discovery made it possible to artificially create elements heavier than uranium.
• For his discovery of the neutron Chadwick received the Hughes Medal of the Royal Society in 1932, the Nobel Prize in Physics in 1935, the Copley Medal in 1950 and the Franklin Medal in 1951.
• He was knighted in England in 1945 for his achievements in physics.

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