Outline of a slow-positron facility at the Electrotechnical Laboratory

A new facility producing high-intensity low-energy positrons has been constructed at the Electrotechnical Laboratory. Electrons of ∼75MeV hit an assembly of an electron-to-positron converter and a positron moderator to gererate high-intensity low-energy positrons. At present, 107 low-energy positrons/sec are delivered to a sample chamber through a 22m transporting system with ∼4μA incident electrons. By the use of a linear storage section of 4m long, pulse duration of low energy positron beams has successfully been stretched to more than 10 msec. Also described are several experimental devices being constructed and refined. (author)