Operation Totem Operation Totem Operation Totem was a pair of British atmospheric nuclear tests which took place at Emu Field in South Australia on 15 October 1953. They followed the Operation Hurricane test of the first British atomic bomb, which had taken place at the Montebello Islands a year previously. The main purpose of the trial was to determine the acceptable limit on the amount of plutonium-240 which could be present in a bomb. In addition to the two main tests, there was a series of five subcritical tests. These did not produce nuclear explosions, but used conventional explosives, polonium-210, beryllium and
Atomic clock Atomic clock An atomic clock is a clock device that uses an electron transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element. Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS. The principle of operation of an atomic clock is based on atomic physics; it uses the microwave signal that electrons in atoms emit when they