DEVELOPMENT OF A VERY-LOW ENERGY MU+ BEAM AT PSI

At PSI we are investigating the technique of decelerating an existing very intense secondary beam of surface mu+ (approximately 4 MeV) to an energy of approximately 10 eV using appropriate moderators. These mu can then be used as a source of a tertiary beam of low energy muons w ith tunable kinetic energy between approximately 10 eV and approximate ly 10 keV. With a 1000 angstrom layer of solid Argon deposited on an A l substrate we obtain a moderation efficiency (with respect to the num ber of incoming surface mu+ ) of the order of 10(-4). Results of our i nvestigations and the present status of the project are presented toge ther with future plans and possibilities.