Optically pumped small cesium beam standards; A status report

The authors report on a project to study and to demonstrate the potential performance achievable in cesium beam frequency standards in which laser driven optical pumping is used for the atomic state selection and state detection in place of the conventional magnetic state selection. The beam tubes used have been derived from commercial devices. In the first unit the only functional change was a simple replacement of state selection magnets with optics. In a second unit, the magnetic shields and c-field have been extended to include the regions of optical pumping