Editing Theodore Hall (section)

==Career after Los Alamos==
In June 1946, Hall's security clearance was revoked by the US Army, not over suspicions of being a Soviet asset but because of discovery of a letter he had received from his British sister-in-law, his brother Edward's wife Edith, who inquired jokingly of him: "I hear you're working on something that goes up with a big bang! Can you send us one of them for Guy Fawkes Day?" as well as left-wing publications he had been receiving at Los Alamos over the prior year that overworked censors had apparently overlooked at the time. Furloughed out of the military with an honorable discharge and a citation from President Truman for the achievements of the Army's Special Engineering Detachment at Los Alamos, Hall headed that fall for the [[University of Chicago]], where he finished out his master's and doctoral degrees in physics, met his wife, and started a family.<ref name=Albright /><ref name=Goodrow /> After graduating he became a [[biophysics|biophysicist]].<ref>{{Cite news |last=Cowell |first=Alan |date=1999-11-10 |title=Theodore Hall, Prodigy and Atomic Spy, Dies at 74 |language=en-US |work=The New York Times |url=https://www.nytimes.com/1999/11/10/world/theodore-hall-prodigy-and-atomic-spy-dies-at-74.html |access-date=2023-09-29 |issn=0362-4331}}</ref>

In Chicago, as a graduate student research assistant he pioneered important techniques in X-ray microanalysis. In 1952, he left the University of Chicago's Institute for Radiobiology and Biophysics to take a research position in biophysics at Memorial Sloan-Kettering in New York City.<ref name=AlbrightKunstel/> In 1962, he became unsatisfied with his equipment and the techniques available to him. He then moved to [[Vernon Ellis Cosslett]]'s electron microscopy research laboratory at [[University of Cambridge|Cambridge University]] in England.<ref name=Hastedt>{{cite book|last=Hastedt|first=Glenn|title=Spies, Wiretaps, and Secret Operations: An Encyclopedia of American Espionage|url=https://archive.org/details/spieswiretapssec00hast|url-access=limited|year=2010|publisher=ABC-CLIO|location=Santa Barbara, CA|isbn=978-1851098071|page=[https://archive.org/details/spieswiretapssec00hast/page/n372 352]}}</ref> At Cambridge he created the Hall Method of continuum normalization, developed for the specific purpose of analyzing thin sections of biological tissue.<ref name=Goodrow /> He remained working at Cambridge until he retired at the age of 59 in 1984.<ref>{{Cite news |last=Jackson |first=Harold |date=1999-11-16 |title=Theodore Hall |language=en-GB |work=The Guardian |url=https://www.theguardian.com/news/1999/nov/16/guardianobituaries.haroldjackson |access-date=2023-09-29 |issn=0261-3077}}</ref>

Hall later became active in obtaining signatures for the [[Stockholm Appeal|Stockholm Peace Pledge]].<ref name=Hastedt />