An Optically Excited Metastable Krypton Atomic Beam Source

We report the construction of an optically excited metastable krypton atomic beam source. Ground-state Kr atoms are excited to the $5s[3/2]_1$ state by a 123 nm photon from a krypton resonance line lamp, then to the $5p[5/2]_2$ state by an 819 nm photon from a diode laser. From the $5p[3/2]_2$ state, they spontaneously decay into the $5s[3/2]_2$ ($^3P_2$) metastable state with $77\% $ probability. We characterize the source using both resonant fluorescence at 811 nm and a surface ionization detector. The source will be used to load a Kr* magneto-optical trap for Kr background evaluation by Atom Trap Trace Analysis.