Authors:	Backe, Hartmut Lauth, Werner Drexler, Peter Heil, Philipp Klag, Pascal Ledroit, Ben Stieler, Frederic
Title:	Design study for a 500 MeV positron beam at the Mainz Microtron MAMI
Online publication date:	19-Dec-2022
Year of first publication:	2022
Language:	english
Abstract:	A design study has been performed for a positron beam with an energy of 500 MeV to be realized at the applied physics area of the Mainz Microtron MAMI. Positrons will be created after pair conversion of bremsstrahlung, produced by the 855 MeV electron beam at MAMI in a tungsten converter target. From the two conceivable geometries (1) pair conversion in the bremsstrahlung converter target itself, and (2) bremsstrahlung pair conversion in a separated lead foil, the former was considered in detail. Positrons will be energy selected within an outside open electron beam-line bending magnet, and bent back by an additional sector magnet. Magnetic focusing elements in between are designed to prepare in a well shielded positron target chamber about 6 m away from the target a beam with horizontal and vertical emittances of ϵv = 0.055 π mm mrad (1 σ), and ϵh=0.12π mm mrad (1 σ), respectively, for a 10 μm thick amorphous tungsten target and negligible momentum spread. At an accepted positron band width of 1 MeV, spots are expected vertically with an angular spread of 0.064 mrad and a size of 5.0 mm (FWHM), and horizontally with an angular spread of 0.64 mrad and a size of 7.7 mm (FWHM). The positron yield amounts to 13.1 per second, 1 MeV positron energy band width, and 1 nA electron beam current.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-8361
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	The European physical journal : D 76
Pages or article number:	150
Publisher:	Springer
Publisher place:	Berlin u.a.
Issue date:	2022
ISSN:	1434-6079
Publisher DOI:	10.1140/epjd/s10053-022-00465-9
Appears in collections:	DFG-491381577-H