What are atomic clocks used for ?
Atomic clock working and applications :
Thewere developed in the mid-1950s They are based on the laws of applied to among transitions of levels of chosen properly.
Applications of atomic clocks:
Their precision and stability are such that they now constitute time (or) standards and that is why they are used to define the second since 1967.
It was indeed during the 13 th General Conference of the weights and measures that it was decided that the second was theof 9,192,631,770 periods of radiation corresponding to the transition between the two hyperfine levels of the of the 133 atom .
3.International atomic time(TAI):
Atomic clocks are also used to establish a world time scale, “international atomic time” (TAI).
We are also seeking to develop increasingly precise newto make finer measurements of phenomena , for example to test the laws of relativity as we propose to do with the project (Clock project atomic by cooling atoms in ).
Atomic clocks were born in the early 1950s. They promise time measurement with extraordinary precision.A drift of less than 1 second every 30 million years.
What synchronize the billions of exchanges that take place almost simultaneously on the Web or satellites at the heart of the GPS system.
International Bureau of weights and measures :
In 1956, the International Bureau of Weights and Measures chose to define the second as “theof 9,192,631,770 periods of radiation corresponding to the transition between the hyperfine levels F = 3 and F = 4 of the 6S½ ground state of the cesium 133 “. A sentence which may seem complicated but which can be explained very simply.
Indeed, when a cesium 133 atom receives anat a certain , it passes from a state of low to a state of higher energy, from state F = 3 to state F = 4 .
Then, it re-emits the absorbed energy in precisely 1 / 9,192,631,770. Much like a Comtoise clock counts the oscillations of its pendulum, the is there to count the number of these transitions.
How an atomic clock works?
An atomic clock consists of afurnace which generates a very directive jet of cesium atoms. On the path of these atoms, a device – magnetic deflection ( ) or optical pumping – makes it possible to select those which are in the level of energy sought, the state F = 3.
Then there is a resonant cavity, called, in which the atoms interact with a microwave generated by a – electric signal with frequency 9,192,631,770 .
Finally, a detection device (magnet, ionizer andmultiplier or and photo detector) provides information on the atoms that have actually undergone the expected transition. The system then modifies the frequency of the to arrive at a maximum number of atoms in the state F = 4.
Finally, the operation of a cesium jet atomic clock:
Finally, the operation of a cesium jet atomic clock is based on a quartz oscillator. Cesium atoms play the simple role of controllers and adjusters of the frequency of the signal generated by quartz (there are also, for example,clocks , less efficient or clocks , extremely effective on the short term).