Development of slow, polarized positron beam

In Tokyo Metropolitan University, the precision verification of quantum electrodynamics has been carried out, paying attention to the experimental result of Michigan University. Based on the experience of a series of these positron experiments, the development of slow, polarized positron beam was begun in fiscal year 1994. It was found that the experiment on the formation of polarized positrons has been rarely performed, therefore, it was considered to advance the basic examination on the polarization of positrons and to construct the equipment that can measure accurately the degree of polarization. The polarized positron formation system which is being constructed at present is explained. The multiple scattering when positrons pass through an Al target and the change of spin direction by it were calculated, assuming no decrease of polarization in Al. The general simulation program POEM was made for treating spin motion. Zeeman effect and the instrument for measuring the degree of polarization 'POPAI' are described. The verification of the conservation law in lepton sector, the verification of biomolecule chirality and the elucidation of spin state at artificial multi-layer film interface are planned to be studied. (K.I.)