Editing Joseph Rotblat (section)

== Nuclear fallout ==
Rotblat returned to Britain to become senior lecturer and acting director of research in nuclear physics at the [[University of Liverpool]].<ref name="Curriculum Vitae">{{cite web  |url=https://www.nobelprize.org/nobel_prizes/peace/laureates/1995/rotblat-bio.html  |title=Joseph Rotblat – Biographical – Curriculum Vitae  |access-date=24 November 2016 |archive-date=11 October 2016 |archive-url=https://web.archive.org/web/20161011164907/http://www.nobelprize.org/nobel_prizes/peace/laureates/1995/rotblat-bio.html  |url-status=live  }}</ref> He was naturalised as a British subject on 8 January 1946.<ref>{{London Gazette|issue=37461|date=8 February 1946 |page=865}}</ref> Most of his family had survived the war. With the help of a Polish man, his brother-in-law Mieczysław (Mietek) Pokorny had created false Polish Catholic identities for Rotblat's sister Ewa and niece Halina. Ewa, taking advantage of the fact that she was an ash blonde who, like Rotblat, spoke fluent Polish as well as [[Yiddish]], smuggled the rest of the family out of the [[Warsaw Ghetto]]. Mietek, Rotblat's brother Mordecai (Michael) and Michael's wife Manya, Rotblat's mother Scheindel, and two Russian soldiers lived in a concealed bunker underneath a house near [[Otwock]], in which Ewa and Halina lived with a Polish family. Displays of Polish anti-Semitism that she witnessed during the [[Warsaw Ghetto uprising]] embittered Ewa towards Poland, and she petitioned Rotblat to help the family emigrate to England. He therefore now accepted Chadwick's offer of British citizenship so he could help them escape from Poland.{{sfn|Brown|2012|pp=65–69}} They lived with him in London for some time before becoming established.{{sfn|Brown|2012|p=97}} Halina would go on to graduate from [[Somerville College, Oxford]], and [[University College London]], and become an editor of the ''[[Dictionary of National Biography]]''.<ref>{{cite news |url=https://www.theguardian.com/theguardian/2009/aug/12/obituary-halina-sand |title=Obituary – Halina Sand |newspaper=[[The Guardian]] |last=Sand |first=Katherine |date=13 August 2009 |access-date=24 November 2016 |archive-date=24 November 2016 |archive-url=https://web.archive.org/web/20161124095902/https://www.theguardian.com/theguardian/2009/aug/12/obituary-halina-sand |url-status=live }}</ref>

Rotblat felt betrayed by the use of atomic weapons against Japan, and gave a series of public lectures in which he called for a three-year moratorium on all atomic research.<ref name=Abe /> Rotblat was determined that his research should have only peaceful ends, and so became interested in the medical and biological uses of radiation. In 1949, he became Professor of Physics at [[St Bartholomew's Hospital]] ("Barts"), London,<ref>{{Cite journal | last1 = Burrows | first1 = H. | last2 = Gibson | first2 = W. | last3 = Rotblat | first3 = J. | doi = 10.1103/PhysRev.80.1095 | title = Angular Distributions of Protons from the Reaction O16(d,p)O17 | journal = Physical Review | volume = 80 | issue = 6 | pages = 1095 | year = 1950  | bibcode = 1950PhRv...80Q1095B }}</ref><ref>{{cite web |url=http://www.qmul.ac.uk/alumni/alumninetwork/notablealumni/index.html |archive-url=https://web.archive.org/web/20081222045836/http://www.qmul.ac.uk/alumni/alumninetwork/notablealumni/index.html |archive-date=22 December 2008 |title=Queen Mary, University of London Notable Alumni and Staff |access-date=23 September 2007}}</ref> a teaching hospital associated with the University of London. He remained there for the rest of his career, becoming a [[professor emeritus]] in 1976.<ref name="The Guardian">{{cite news |url=https://www.theguardian.com/science/2005/sep/02/obituaries.obituaries |title=Obituary – Sir Joseph Rotblat |newspaper=[[The Guardian]] |date=2 September 2005 |access-date=24 November 2016 |archive-date=13 May 2019 |archive-url=https://web.archive.org/web/20190513123323/https://www.theguardian.com/science/2005/sep/02/obituaries.obituaries |url-status=live }}</ref> He received his PhD from Liverpool in 1950, having written his thesis on the "Determination of a number of neutrons emitted from a source".<ref name="rotblatphd">{{cite thesis |degree=PhD |first=Joseph|last=Rotblat |title=Determination of a number of neutrons emitted from a source |publisher=University of Liverpool |year=1950 |id={{ProQuest|301122892}}}}</ref> He also worked on several official bodies connected with nuclear physics, and arranged the ''Atom Train'', a major travelling exhibition for schools on civil nuclear energy.<ref name="Leaving the Bomb Project" />

At St Bartholomew's, Rotblat worked on the effects of radiation on living organisms, especially on ageing and fertility. This led him to an interest in [[nuclear fallout]], especially [[strontium]]-90 and the safe limits of ionising radiation. In 1955, he demonstrated that the contamination caused by the [[Nuclear fallout|fallout]] after the [[Castle Bravo]] [[Nuclear testing|nuclear test]] at [[Bikini Atoll]] by the United States had been far greater than that stated officially.  Until then the official line had been that the growth in the strength of atomic bombs was not accompanied by an equivalent growth in radioactivity released.  Japanese scientists who had collected data from a fishing vessel, the ''[[Daigo Fukuryū Maru|Lucky Dragon]]'', which had inadvertently been exposed to fallout, disagreed with this. Rotblat was able to deduce that the bomb had three stages and showed that the fission phase at the end of the explosion increased the amount of radioactivity by forty times. His paper was taken up by the media and contributed to the public debate that resulted in the ending of atmospheric tests by the [[Partial Nuclear Test Ban Treaty]].{{sfn|Brown|2012|pp=107–118}}