National Bureau of Standards (January 1949) The Atomic Clock: An Atomic Standard of Frequency and Time.
 Essen L, Parry J (August 1955) An atomic standard of frequency and time interval: A caesium resonator.
The atomic standard
of [[blank].sup.15]N ([N.sub.2]; 0.3663 atom%) was used as reference for calculations of excess [[blank].sup.15]N.
These improved mass measurements may also contribute to an ongoing effort to produce an atomic standard
for mass, replacing the platinum-iridium cylinder currently representing a kilogram (SN: 4/24/93, p.264).
"It would be nice to have some atomic standard
of mass" that would be independent of any particular object, Taylor says.
Mancini, "Precision Frequency Generation Utilizing OCXO and Rubidium Atomic Standards
with Applications for Commercial, Space, Military, and Challenging Environments," IEEE Long Island Chapter, 2004
The thing about light is that by atomic standards
it's really very large.
Parker, head of NIST's atomic standards
group, which includes Jefferts' team.
At the beginning of this early period of development of atomic frequency standards, both quartz and atomic standards were achieving frequency uncertainties of about 2 X [10.sup.-8].
While a variety of methods have been used to servo-control a local oscillator to the atomic resonance, most modern atomic standards now use square-wave modulation and digital processing to achieve the lock.