Positron Beam Characteristics at NEPOMUC Upgrade

13th International Workshop on Slow Positron Beam Techniques and Applications

Hugenschmidt, C.^1,2 ; Ceeh, H.^2 ; Gigl, T.^2 ; Lippert, F.^2 ; Piochacz, C.^1,2 ; Reiner, M.^2 ; Schreckenbach, K.^1,2 ; Vohburger, S.^1 ; Weber, J.^2 ; Zimnik, S.^1,2

Technische Universität München, Forschungs-Neutronenquelle Heinz Maier-Leibnitz, Lichtenbergstraße 1, D-85748 Garching, Germany^1

Technische Universität München, Physik Department, Lehrstuhl E21, James-Franck-Straße, D-85748 Garching, Germany^2

关键词: Beam profiles;    Electron positron pair production;    High intensity;    NEPOMUC;    Positron beams;    Positron sources;    Primary beams;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/505/1/012029/pdf
DOI  :  10.1088/1742-6596/505/1/012029

来源: IOP

【 摘 要 】

In 2012, the new neutron induced positron source NEPOMUC upgrade was put into operation at FRMII. Major changes have been made to the source which consists of a neutron-γ-converter out of Cd and a Pt foil structure for electron positron pair production and positron moderation. The new design leads to an improvement of both intensity and brightness of the mono-energetic positron beam. In addition, the application of highly enriched113Cd as neutron-γ-converter extends the lifetime of the positron source to 25 years. A new switching and remoderation device has been installed in order to allow toggling from the high-intensity primary beam to a brightness enhanced remoderated positron beam. At present, an intensity of more than 109moderated positrons per second is achieved at NEPOMUC upgrade. The main characteristics are presented which comprise positron yield and beam profile of both the primary and the remoderated positron beam.