allbatros
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Cs and atomic clock
Do you know that the isotope Cs-137 used for atomick clock (the freuqency of Cs-137)?
What u think about Cs or other elements which used for atomic clock 
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12AX7
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137 is rather radioactive.
Cs (and to a lesser extent, Rb) are capable of making very accurate clocks yes.
Tim
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Jdurg
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| Quote: | Originally posted by allbatros
Do you know that the isotope Cs-137 used for atomick clock (the freuqency of Cs-137)?
What u think about Cs or other elements which used for atomic clock
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Just so you know, your statement there is well..... wrong.  The isotope of
cesium used in atomic clocks is Cs-133 which is quite stable and not radioactive. The definition of the second is based upon a certain number of
cycles of light absorbed by a Cs-133 atom and not Cs-137.
\"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists of the unmistakable scent of broccoli, and usually
requires wiping afterwards.\"
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Twospoons
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Typical accuracy is in the region of 1 part in 10^14 for Cs clocks.
Best quartz oscillator I could produce while working at Rakon was accurate to 2 in 10^11 (over -30C to +70C). Rubidium clocks are around 1 in 10^13
IIRC.
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allbatros
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In first half of this year, I think it was in Physical Review, scientist built the more precise atomic clock of the only one atom Hg. His accuaracy is
1 s delay in 400 * 10<sup>6</sub>.
And yes u right, Cs-133
My mistake  
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_1v4_
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Ofc I knew Cs-133 is used because of his frequency (9,192,631,770Hz).
The time unit, second, is defined as "the duration of 9,192,631,770 cycles of microwave light absorbed or emitted by the hyperfine transition of
cesium-133 atoms in their ground state undisturbed by external fields".
It is used 'cause its verry accurate (one second in 1,400,000 years, if I recall it correctly?).
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