Operation Grapple with the American Manhattan Project in August 1943. Many of Britain's top scientists participated in the British contribution to the Manhattan Project. After the war, fearing that Britain would lose its great power status, the British government resumed the atomic bomb development effort, now codenamed High Explosive Research. The successful test of an atomic bomb in Operation Hurricane in October 1952 represented an extraordinary scientific and technological achievement, but Britain was still several years behind the United States in nuclear weapons technology. In July 1954, the Cabinet decided to develop the hydrogen bomb. The United Kingdom Atomic Energy Authority Atomic
Agathe (atomic test) "Vive La Bombe!". The French Defence Minister Pierre Messmer and other officials and civilians were present in the command post and were contaminated too (around >200 mSv). The millisievert (mSv) is commonly used to measure the effective dose in diagnostic medical procedures. See radiation poisoning for a more complete analysis of effects of various dosage levels. Data provided by the French Defense Ministry on January 2007. Agathe (atomic test) Agathe (aka Agate) was the name of the first French nuclear underground test. It was an atomic bomb detonated in the Hoggar mount (near In Ekker) of the then French Sahara