The SHI slow positron beam facility with a compact cyclotron

Abstract

The SHI slow positron beam facility has been constructed. A compact cyclotron based slow positron beam production system was developed for the first time by Sumitomo Heavy Industries (SHI) in 1993. However, in the primary slow positron beam facility, the length of the slow positron beam line is very long (about 25 m) and the efficiency of the slow positron beam transportation is not so high. In order to solve the problem, we have constructed a new compact cyclotron and a new slow positron beam facility next to the primary ones. We have named it `The SHI Slow Positron Beam Facility.' The new facility is the first accelerator based `compact' slow positron beam facility realized by using a compact cyclotron. And the new facility is the first accelerator based slow positron beam facility that was planned to be constructed `before' the accelerator construction. On the other hand, a general accelerator based slow positron beam facility is very `large' and was planned to be constructed `after' the accelerator construction. The new slow positron beam facility has some improvements in annealing the moderator, cooling the target, transporting the beam, monitoring the beam and so on, compared with the primary facility. An intense slow positron beam has already been produced by making use of the 27 Al (p,n) 27 Si reaction in the new facility. Variable-energy positron lifetime spectroscopy with a new positron pulsing system has also been arranged in the new facility.