Status of the project for a positron laboratory at ELI-NP

14th International Workshop on Slow Positron Beam Techniques & Applications

Djourelov, N.^1 ; Oprisa, A.^1 ; Dinescu, D.^1 ; Leca, V.^1

Extreme Light Infrastructure - Nuclear Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, 30 Reactorului Street, P.O. Box MG-6, Magurele, Ilfov county

077125, Romania^1

关键词: Compton backscattering;    Gamma ray interactions;    Longitudinal polarization;    Pair production;    Polarization degree;    Tungsten foils;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/791/1/012011/pdf
DOI  :  10.1088/1742-6596/791/1/012011

来源: IOP

【 摘 要 】

We report on the plans of a positron laboratory to be built at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility. The slow e+source is based on e--e+pair production in a converter made of tungsten foils by a brilliant gamma beam (Eγγ= 2.4×1010γ s-1) which will be generated by Compton back-scattering of photons from a high power laser on electrons from a LINAC. Numerical simulations of γ-ray interactions with the designed converter showed that, if the tungsten foils are used for moderation of the created fast e+, a slow e+beam of an intensity of ∼1×106s-1can be obtained. Circular polarization of the γ-beam is proposed to be one of the ELI-NP's upgrades. The slow e+will be extracted perpendicularly to the γ-beam and will have ∼ 30% transversal polarization degree. By using a transmission re-moderation stage and electrostatically turning the re-moderated beam by 90°, the transversal polarization will be changed to longitudinal. Longitudinal polarization can then be preserved in the longitudinal magnetic guiding field. The heat load to the converter was estimated at +moderation by frozen neon is applicable.