Advances in simulation and calculation of physical system of hydrogen atomic clock

Hydrogen maser and laser have commons in principle and can achieve stimulated radiation amplification of electromagnetic fields, which is an important part of quantum electronics. The hydrogen atomic clock based on the hydrogen atom maser uses the electromagnetic wave radiated from the hydrogen atom level transition to control and calibrate quartz crystal oscillator, which has excellent short-term and medium-term frequency stability. Hydrogen atom preparation systems, atomic beam optical systems and microwave cavity are key technologies for hydrogen atomic clocks. The simulation and calculation of the hydrogen atomic clock physical system is of great help to the design and optimization of the hydrogen clock system. The hydrogen atomic clock physical system mainly includes three parts: atomic preparation system, atomic beam optical system and microwave cavity with an atomic storage. The lifetime of dissociator bulb is the main focus of atomic preparation system calculation and simulation; atomic incident angle and state-selected magnet structure are the key points of atomic beam optical system simulation and calculation; microwave cavity simulation and design concern the calculation of resonance frequency and quality factor Q value of magnetron microwave cavity and sapphire microwave cavity as well as the relationship between the resonant frequency and the Q value as a function of the cavity size and the thickness of the filling medium (sapphire). At present, most of the hydrogen atomic clock physics system simulations and calculations are based on a single physics field. The simulation of multiphysics based on COMSOL Multiphysics has guiding significance for the future design of the hydrogen clock physics system.