Clock Produces Microwaves Direct.
Chemical & Engineering News · 1955
Atomic clock, developed at Columbia University, measures time with an accuracy that exceeds by a considerable margin, the currently-accepted standard of the earth's rotation rate. The clock is said to vary no more than one second in 300 years. Called the Maser (short for Microwave Amplification by Stimulated Emission of Radiation), the unit can also be operated as an amplifier of radio signals in the microwave frequency range. It uses a new principle which for the first time permits amplification of high-frequency radio waves without vacuum tubes. In operation, a stream of ammonia gas is forced under slight pressure into one end of a sealed chamber. As the ammonia molecules enter, they come under the influence of an electrostatic field, which focuses the beam of molecules into two parts. One part consists of molecules in low-energy states, the other in high-energy. The low-energy molecules are diverted from the beam ...