Design of a Double Focalization in a Hydrogen Maser

An atomic hydrogen maser utilizes the hyperfine transition between states with F=1, mF= O and F= 0, mF= O, respectively. Conventionally, atoms in the F=1, mF=1 state, which do not take part in the clock transition, also are focused by a hexapolar magnet on the aperture of a storage bulb. A selector for eliminating the F = 1, mF= 1 atoms from the atomic beam utilizes a first hexapolar magnet, adiabatic rapid passage transition for converting the mF=1 state to the mF = -1 state, and a second hexapolar magnet; thus, only atoms in the F = 1, mF= 0 state penetrate into the cavity. Calculation by the phase-plane method, applicable to other multiple-focalization systems, is shown to be advantageous in achieving improved focalization efficiency.