An overview of the design of ELIPS-A new slow positron beam line

Abstract

Abstract In this work, the progress made by the positron group from ELI-NP in the design of a new slow positron beam line is summarized. The rays of a brilliant gamma beam will be used to produce a slow positron beam of high intensity. The main results of the simulations, done for the geometry optimization of the Converter/Moderator Assembly (CMA) for γ -to-slow e + conversion, are reported. By using the γ -beam with energy of up to 3.5 MeV and intensity of 2 . 4 × 1 0 10 γ s − 1 , the slow e + beam can be obtained with a maximum intensity of ∼ 2 × 1 0 6 s−1 with tungsten or platinum CMA. Solid neon moderation is applicable, and a successful implementation will result in a slow e + beam of intensity > 1 0 7 s − 1 . The CMA can be operated with a central hole ( ⌀ = 2 . 5 mm) in the foils in parasitic mode, i . e . , simultaneously with other γ -beam experiments, at the cost of reduced intensity by 18%. Furthermore, details on the slow positron transport and the spectroscopic systems, which are under construction, are provided.