https://en.wikipedia.org/wiki/Atomic_spies#Notable_examples

Morris Cohen — an American, "Thanks to Cohen, designers of the Soviet atomic bomb got piles of technical documentation straight from the secret laboratory in Los Alamos," the newspaper Komsomolskaya Pravda said. Morris and his wife, Lona, served eight years in prison, less than half of their sentences before being released in a prisoner swap with the Soviet Union. He died without revealing the name of the American scientist who helped pass vital information about the United States atomic bomb project.[13]

David Greenglass — an American machinist at Los Alamos during the Manhattan Project. Greenglass confessed that he gave crude schematics of lab experiments to the Russians during World War II. Some aspects of his testimony against his sister and brother-in-law (the Rosenbergs, see below) are now thought to have been fabricated in an effort to keep his own wife, Ruth, from prosecution. Greenglass was sentenced to 15 years in prison, served 10 years, and later reunited with his wife.[18]

Harry Gold — an American, confessed to acting as a courier for Greenglass and Fuchs. He was sentenced in 1951 to thirty years imprisonment. He was paroled in May 1966, after serving just over half of his sentence.[17]

Theodore Hall (born Theodore Alvin Holtzberg) — an American, the youngest physicist at Los Alamos who gave a detailed description of the Fat Man plutonium bomb, and of several processes for purifying plutonium, to Soviet intelligence. His identity as a spy was not revealed until very late in the 20th century. He was never tried for his espionage work, though he admitted to it in later years to reporters and to his family.[19]

George Koval — the American-born son of a Belorussian emigrant family that returned to the Soviet Union where he was inducted into the Red Army and recruited into the Main Intelligence Directorate, GRU. He infiltrated the United States Army and became a radiation health officer in the Special Engineer Detachment. Acting under the code name Delmar he obtained information from Oak Ridge National Laboratory and the Dayton Project about the Urchin detonator used on the Fat Man plutonium bomb. His work was not known to the west until he was posthumously recognized as a hero of the Russian Federation by Vladimir Putin in 2007.

Irving Lerner — an American film director, he was caught photographing the cyclotron at the University of California, Berkeley in 1944.[20] After the war he was blacklisted.

Julius and Ethel Rosenberg — Americans who were involved in coordinating and recruiting an espionage network that included Ethel's brother, David Greenglass. Julius and Ethel Rosenberg were tried for conspiracy to commit espionage, since the prosecution seemed to feel that there was not enough evidence to convict on espionage. Treason charges were not applicable, since the United States and the Soviet Union were allies at the time.

Saville Sax — an American, acted as the courier for Klaus Fuchs and Theodore Hall.[19]

Morton Sobell — the American engineer tried and convicted along with the Rosenbergs who was sentenced to 30 years imprisonment, but released in 1969, after serving 17 years and 9 months.[25] After proclaiming his innocence for over half a century, Sobell admitted spying for the Soviets, and implicated Julius Rosenberg, in an interview with The New York Times published on September 11, 2008.[26]

Melita Norwood -- British Communist, an active Russian spy from at least 1938 and never detected. Employed as a secretary in the British Non-Ferrous Metals Research Association since 1932, she was linked to the Woolwich Arsenal spy ring of 1938 and in wartime was seconded to "Tube Alloys", the secret British nuclear research project, thus later considered "the most important female agent ever recruited by the USSR". She was first suspected as a security risk in 1965 but never prosecuted. Her spying career was revealed by Vasili Mitrokhin in 1999 when she was still alive but long retired.

(http://www.autoadmit.com/thread.php?thread_id=3848778&forum_id=2#35075772)

(http://www.autoadmit.com/thread.php?thread_id=3848778&forum_id=2#35087732)