Eur. Phys. J. C (2018) 78: 778
https://doi.org/10.1140/epjc/s10052-018-6244-8

Regular Article - Experimental Physics

Reduction of stored-particle background by a magnetic pulse method at the KATRIN experiment

¹ Helmholtz-Institut für Strahlen- und Kernphysik, Rheinische Friedrich-Wilhelms Universität Bonn, Nussallee 14-16, 53115, Bonn, Germany
² Institute of Experimental Particle Physics (ETP), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Str. 1, 76131, Karlsruhe, Germany
³ Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 9, 48149, Münster, Germany
⁴ Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099, Mainz, Germany
⁵ Institute for Data Processing and Electronics (IPE), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
⁶ Institute for Nuclear Physics (IKP), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
⁷ Institute for Nuclear Research of Russian Academy of Sciences, 60th October Anniversary Prospect 7a, 117312, Moscow, Russia
⁸ Institute for Technical Physics (ITeP), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
⁹ Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
¹⁰ Max-Planck-Institut für Physik, Föhringer Ring 6, 80805, Munich, Germany
¹¹ Technische Universität München, James-Franck-Str. 1, 85748, Garching, Germany
¹² Laboratory for Nuclear Science, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02139, USA
¹³ Department of Physics, Center for Experimental Nuclear Physics and Astrophysics, University of Washington, Seattle, WA, 98195, USA
¹⁴ Nuclear Physics Institute of the CAS, v. v. i., 250 68, Řež, Czech Republic
¹⁵ Department of Physics, Faculty of Mathematics und Natural Sciences, University of Wuppertal, Gauss-Str. 20, 42119, Wuppertal, Germany
¹⁶ Department of Physics, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
¹⁷ Universidad Complutense de Madrid, Instituto Pluridisciplinar, Paseo Juan XXIII, no 1, 28040, Madrid, Spain
¹⁸ Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC, 27599, USA
¹⁹ Triangle Universities Nuclear Laboratory, Durham, NC, 27708, USA
²⁰ Commissariat à l’Energie Atomique et aux Energies Alternatives, Centre de Saclay, DRF/IRFU, 91191, Gif-sur-Yvette, France
²¹ University of Applied Sciences (HFD) Fulda, Leipziger Str. 123, 36037, Fulda, Germany
²² Department of Physics, Case Western Reserve University, Cleveland, OH, 44106, USA
²³ Institute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
²⁴ Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489, Berlin, Germany
²⁵ Project, Process, and Quality Management (PPQ), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
²⁶ Present address: Wisconsin IceCube Particle Astrophysics Center (WIPAC), 222 West Washington Ave., Madison, WI, 53703, USA
²⁷ Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA

^* e-mail: jan.behrens@kit.edu

Received: 4 May 2018
Accepted: 13 September 2018
Published online: 26 September 2018

Abstract

The KATRIN experiment aims to determine the effective electron neutrino mass with a sensitivity of (%90 CL) by precision measurement of the shape of the tritium -spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. A common background source in this setup is the decay of short-lived isotopes, such as and , in the spectrometer volume. Active and passive countermeasures have been implemented and tested at the KATRIN main spectrometer. One of these is the magnetic pulse method, which employs the existing air coil system to reduce the magnetic guiding field in the spectrometer on a short timescale in order to remove low- and high-energy stored electrons. Here we describe the working principle of this method and present results from commissioning measurements at the main spectrometer. Simulations with the particle-tracking software Kassiopeia were carried out to gain a detailed understanding of the electron storage conditions and removal processes.