Design and Performance of an Atomic Hydrogen Maser

The design and construction of a relatively compact device for use as a frequency standard is discussed. Hydrogen scavenging is done by titanium sorption pumps having a continuous operating lifetime of one year. The magnetic and thermal shielding of the cavity is described, and frequency errors due to various effects are discussed. Preliminary data of measurements of relative stability between two masers is presented and a means for measuring short- and long-term stability is discussed.