Positron beam brightness enhancement: Low energy positron diffraction and other applications.

The implementation and application of the first brightness enhanced slow positron beam is described. The general concept of brightness enhancement by positron remoderation and the importance of such a technique for improving the phase space parameters (beam diameter D and angular divergence 0) of positron beams is reviewed. A theoretical brightness gain per remoderation stage of 180 is derived, corresponding to a reduction in D by a factor of 26.