Using a Low Phase Noise H-Maser as a Local Oscillator for an Rb Fountain Discriminator

One of the main problem of achieving a quantum noise limited frequency stability in atomic clocks operating in cycle mode, e.g. fountain or pulsed optically pumped (POP) atomic clock, is a phase noise of interrogation signal probing the atom transition. In the present work a solution of the problem via application of a special hydrogen maser with increased power radiated by atomic beam or a low phase noise H-maser as a reference in synthesis scheme of the interrogation signal is described. This solution caused by simplicity because it requires neither cryogenic microwave oscillators nor complicated optical systems techniques.