Millman S, Kusch P (September 1940) On the radiofrequency spectra of sodium, rubidium, and caesium. Physical Review 58:438-445.
 Essen L, Parry J (August 1955) An atomic standard of frequency and time interval: A caesium resonator.
The current primary clock at the National Physical Laboratory, the caesium
fountain NPL-CsF2, contributes to the international timescale UTC (coordinated universal time) and is the reference for the national timescale UTC.
 Micrometer-level naked-eye detection of caesium
particulates in the solid state
Comparison of the trends in WEF and CEF with the trend in CS is limited because only two caesium samples were taken in the upper half of each transect (Fig.
This may indicate an inadequate number of caesium samples, that erosion due to causes other than overland flow and cultivation can be significant, that the start-up dilution effect is significant, or that the theory given for these processes is inadequate.
For instance, processing milk to make cheese or butter decreases the Caesium
137 and Strontium 90 content by 10 times or more.
The clock is one of an elite group of caesium fountain clocks that have been built by the timing labs in Europe, the United States, and Japan as their national "primary frequency standard" for the measurement of time.
clock also can be used to evaluate the caesium fountain clocks of other countries, substantially improving the world's most accurate methods of keeping time.
Until they reach this accuracy, caesium
fountain clocks, however, need a certain measurement time.
Vast areas were contaminated with caesium
134 and caesium
137 following the accident at the Chernobyl nuclear power station on April 26, 1986 (1).