James Chadwick
James Chadwick was born on the 20th of October 1891 in Cheshire, England. His father John Joseph Chadwick worked as a cotton spinner while his mother Anne Mary Knowles served as a domestic servant. The family moved to Manchester in 1895 and left young James with his maternal grandparents for three years. He attended Bollington Cross Primary School before receiving a scholarship offer from Manchester Grammar School that his parents could not afford due to small fees. Instead he enrolled at the Central Grammar School for Boys where he reconnected with his parents and two younger brothers Harry and Hubert. A sister had died in infancy during those early years.
At age sixteen Chadwick passed two university scholarship examinations simultaneously. He entered Victoria University of Manchester in 1908 intending to study mathematics but accidentally enrolled in physics instead. Most students lived away from home but Chadwick walked the distance daily between his parents' house and the university campus. During his first year he received the Heginbottom Scholarship to continue studying physics under Ernest Rutherford who headed the department. Rutherford assigned final-year students research projects including one asking Chadwick to compare radioactive energy amounts from different sources using radium activity measurements known as curies.
Rutherford's suggested approach proved unworkable yet Chadwick knew this without voicing his concerns. He pressed forward anyway and eventually devised the required method himself. This work became his first paper co-authored with Rutherford and published in 1912. He graduated with First Class Honours in 1911 after measuring gamma radiation absorption by various gases and liquids. The resulting paper appeared under his name alone earning him an M.Sc. degree in 1912 and appointment as a Beyer Fellow.
In January 1932 Hugh Webster duplicated results obtained by Walther Bothe and Herbert Becker in Germany. They had used polonium to bombard beryllium with alpha particles producing unusual radiation that Chadwick recognized as evidence of something hypothesized for years: the neutron. A theoretical nuclear particle with no electric charge remained elusive until Frédéric and Irène Joliot-Curie succeeded in knocking protons from paraffin wax using polonium and beryllium as sources. They believed they observed gamma radiation but Chadwick disagreed since protons were too heavy for such effects.
Chadwick dropped all other responsibilities to prove the neutron's existence while assisted by Norman Feather working late into nights. He designed simple apparatus containing a cylinder with polonium source and beryllium target directing resulting radiation at materials like paraffin wax. Displaced protons entered small ionization chambers detectable via oscilloscope. After only about two weeks of experimentation he sent a letter titled Possible Existence of a Neutron to Nature magazine in February 1932. Detailed findings followed in May within Proceedings of the Royal Society A under The Existence of a Neutron title.
Robert Bacher and Edward Condon reading Chadwick's paper realized anomalies in current theory regarding nitrogen spin would resolve if neutrons possessed half-unit spin alongside seven protons forming nitrogen nuclei. Niels Bohr and Werner Heisenberg debated whether neutrons represented fundamental particles or proton-electron pairs. Heisenberg concluded neutrons best described new nuclear particles though exact nature stayed unclear. In his 1933 Bakerian Lecture Chadwick estimated neutron mass around one atomic unit implying binding energy calculations sounded reasonable despite stability questions.
The Great Depression struck the United Kingdom making government funding increasingly scarce for scientific endeavors. Lawrence's recent invention promised revolutionizing experimental nuclear physics yet Chadwick felt Cavendish Laboratory would fall behind without acquiring similar equipment himself. Rutherford clung believing good nuclear physics could still occur without large expensive equipment turning down requests repeatedly. Chadwick chafed under this constraint while considering Lawrence's approach careless focusing technology over science.
In March 1935 Chadwick accepted Lyon Jones Chair of Physics at University of Liverpool succeeding Lionel Wilberforce assuming office on the 1st of October 1935. The laboratory ran direct current electricity proving antiquated but Chadwick seized opportunity immediately. His Nobel Prize announced November 1935 bolstered university prestige significantly. Starting refurbishment costs £700 allowed some components made in-house persuading university providing £2,000 plus Royal Society grant another £2,000 total reaching £5,184 exceeding initial funds so Chadwick paid remainder from his £8,243 prize money.
Two young experts Bernard Kinsey and Harold Walke previously worked with Lawrence bringing cyclotron construction expertise locally. A cable manufacturer donated copper conductor coils while Metropolitan-Vickers manufactured 50-ton magnet producing vacuum chamber in Trafford Park. Cyclotron completely installed running July 1939 enabling Medicine Science faculties collaboration closely together appointed commission headed Lord Derby investigating cancer treatment arrangements Liverpool anticipated neutrons radioactive isotopes produced studying biochemical processes becoming weapon fight against cancer.
During Second World War Chadwick conducted research part Tube Alloys project building atom bomb while Manchester lab environs harassed Luftwaffe bombing. He did not believe likelihood another war Germany existing 1939 taking family holiday remote lake northern Sweden news outbreak therefore came shock determined avoid spending another war internment camp making way Stockholm fastest possible arriving finding air traffic suspended between cities returning England tramp steamer instead. Upon reaching Liverpool found Joseph Rotblat Polish postdoctoral fellow destitute cut off funds Poland promptly hired Rotblat lecturer despite poor grasp English language skills.
October 1939 Edward Appleton Secretary Department Scientific Industrial Research asked opinion feasibility atomic bomb responding cautiously dismissing possibility carefully going over theoretical practical difficulties involved deciding investigate properties uranium oxide further Rotblat. March 1940 Otto Frisch Rudolf Peierls University Birmingham reexamined theoretical issues paper known Frisch-Peierls memorandum considering sphere pure uranium-235 finding chain reaction occur requiring as little 10 kilograms uranium-235 unleashing energy tons dynamite.
Special subcommittee Committee Scientific Survey Air Warfare CSSAW created investigating matter further chaired George Paget Thomson original membership included Chadwick Mark Oliphant John Cockcroft Philip Moon. While other teams investigated uranium enrichment techniques Chadwick's team Liverpool concentrated determining nuclear cross section uranium-235. By April 1941 experimentally confirmed critical mass uranium-235 might be 16 kilograms less complicated all-but-incessant Luftwaffe bombings environs Liverpool lab windows blown out replaced cardboard repeatedly.
In July 1941 Chadwick chosen write final draft MAUD Report presented Vannevar Bush President Franklin D. Roosevelt October 1941 inspiring U.S government pour millions dollars pursuit atom bomb. When George B. Pegram Harold Urey visited Britain see project now known Tube Alloys going Chadwick able tell them wish could tell bomb not going work 90 percent sure will succeed. Graham Farmelo wrote recent book Bomb project Chadwick did more any scientist give Churchill Bomb tested almost breaking point so worried sleep resorted sleeping pills continued taking most remaining years.
Chadwick later realized nuclear bomb inevitable sooner ideas peculiar country would put action. Sir Hermann Bondi suggested fortunate Chadwick Rutherford doyen UK physics latter prestige otherwise overpowering Chadwick interest looking forward prospects. Owing danger aerial bombardment Chadwicks sent twins Canada part government evacuation scheme reluctant move Tube Alloys believing United Kingdom better location isotope separation plant enormous scope effort became apparent 1942 pilot separation plant cost over £1 million strain Britain resources full-scale plant estimated vicinity £25 million built America necessary.
September 1943 Prime Minister Winston Churchill President Roosevelt negotiated Quebec Agreement reinstating cooperation Britain United States Canada. Chadwick Oliphant Peierls Simon summoned United States director Tube Alloys Sir Wallace Akers work Manhattan Project. Quebec Agreement established new Combined Policy Committee directing joint project Americans disliked Akers Chadwick appointed technical advisor Combined Policy Committee head British Mission leaving Rotblat charge Liverpool beginning tour Manhattan Project facilities November 1943 except Hanford Site plutonium produced allowed see.
Shortly after war ended Chadwick appointed Advisory Committee Atomic Energy ACAE also appointed British scientific advisor United Nations Atomic Energy Commission clashed fellow member Patrick Blackett disagreeing conviction Britain needed acquire own nuclear weapons position ultimately adopted returning Britain 1946 find country still beset wartime rationing shortages. Sir James Mountford Vice Chancellor University Liverpool wrote diary never seen man physically mentally spiritually tired Chadwick plumbed depths moral decision more fortunate men called upon even peer into almost insupportable agonies responsibility arising scientific work.
In September 1949 Edward Teller England discuss nuclear power safety dining Sir James Chadwick wife home Cambridge charming conversationalist typically taciturn making unflattering comment Groves became very talkative saying project never succeeded without Groves acknowledging dislike British. By 1970s Chadwick became frail seldom left flat traveled Liverpool celebrations eightieth birthday lifelong atheist saw reason adopt religious faith later life died sleep the 24th of July 1974 Cambridge age 82.
In 1948 Chadwick accepted offer become Master Gonville Caius College Cambridge job prestigious ill-defined titular head college authority actually resided council thirteen fellows one Master. As Master strove improve academic reputation college increased number research fellowships 31 to 49 seeking bring talent college involved controversial decisions hiring 1951 Chinese biochemist Tien-chin Tsao Hungarian-born economist Peter Bauer known Peasants Revolt fellows led Patrick Hadley voted old friend Chadwick off council replaced Bauer friends removed following years retired November 1958.
During mastership Francis Crick Ph.D student Gonville Caius College Rosalind Franklin James Watson discovered structure DNA. Chadwick described United Kingdom Atomic Energy Authority official historian Lorna Arnold physicist scientist-diplomat good wise humane man papers held Churchill Archives Centre Cambridge accessible public Chadwick Laboratory University Liverpool Sir James Chadwick Chair Experimental Physics named 1991 part celebrations centenary birth James Chadwick Building houses School Chemical Engineering Analytical Sciences Industrial Hub Sustainable Engineering.
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Common questions
When and where was James Chadwick born?
James Chadwick was born on the 20th of October 1891 in Cheshire, England. His father John Joseph Chadwick worked as a cotton spinner while his mother Anne Mary Knowles served as a domestic servant.
What discovery did James Chadwick make in February 1932?
James Chadwick discovered the neutron in February 1932 after sending a letter titled Possible Existence of a Neutron to Nature magazine. He proved the existence of this theoretical nuclear particle with no electric charge by designing apparatus containing a cylinder with polonium source and beryllium target.
How much money did James Chadwick spend from his Nobel Prize to refurbish the University of Liverpool laboratory?
James Chadwick spent £5,184 total to refurbish the laboratory which exceeded initial funds so he paid the remainder from his £8,243 prize money. The university provided £2,000 plus Royal Society grant another £2,000 starting costs at £700 allowed some components made in-house.
Why did James Chadwick travel to Sweden during World War II?
James Chadwick traveled to Sweden in 1939 because he feared being interned in an enemy camp if war broke out between Germany and Britain. He took a family holiday to a remote lake in northern Sweden when news of the outbreak came as a shock.
What role did James Chadwick play in the Manhattan Project?
James Chadwick served as technical advisor for the Combined Policy Committee head British Mission after the Quebec Agreement established new cooperation in September 1943. He toured Manhattan Project facilities except Hanford Site plutonium produced while leaving Joseph Rotblat charge Liverpool beginning tour November 1943.