Before revision: While weightless in the toss , the atoms are measured to set the frequency of an atomic URL How the NIST-F1 Caesium Fountain Clock Works The primary motivation behind the development of the atomic fountain derives from the Ramsey method of measuring the frequency of atomic transitions.
After revision: While in free-fall , the atoms are measured to set the frequency of an atomic URL How the NIST-F1 Caesium Fountain Clock Works The primary motivation behind the development of the atomic fountain derives from the Ramsey method of measuring the frequency of atomic transitions.