Design study for a 500 MeV positron beam at the Mainz Microtron MAMI

A design study has been performed for a positron beam with an energy of 500 MeV to be realized at the applied physics area Mainz Microtron MAMI. Positrons will created after pair conversion bremsstrahlung, produced by 855 electron af MAMI in tungsten converter target. From two conceivable geometries (i) bremsstrahlung target itself, and (ii) separated lead foil, former was considered detail. selected within outside open beam-line bending magnet, bent back additional sector magnet. Magnetic focusing elements between are designed prepare well shielded chamber about 6 m away from horizontal vertical emittances epsilon_v = 0.055 pi mm mrad (1 sigma), epsilon_h 0.12 respectively, 10 micro thick amorphous negligible momentum spread. At accepted band width 1 MeV, spots expected vertically angular spread 0.064 size 5.0 (FWHM), horizontally 0.64 7.7 (FWHM). The yield amounts 13.1 per second, width, nA current.