KATRIN background due to surface radioimpurities
- Karlsruhe Institute of Technology (KIT) (Germany)
- Technical University of Munich (Germany); Max–Planck-Institut für Physik, Munich (Germany)
- Max–Planck-Institut für Kernphysik, Heidelberg (Germany)
- Westfälische Wilhelms-Universität Münster (Germany)
- European Organization for Nuclear Research (CERN), Meyrin (Switzerland)
- Max–Planck-Institut für Kernphysik, Heidelberg (Germany); European Organization for Nuclear Research (CERN), Meyrin (Switzerland)
- Institute Laue-Langevin,, Grenoble (France)
- Westfälische Wilhelms-Universität Münster (Germany); Russian Academy of Sciences (RAS), Moscow (Russian Federation)
- University of Applied Sciences (HFD) Fulda (Germany)
The goal of the KArlsruhe TRItrium Neutrino (KATRIN) experiment is the determination of the effective electron antineutrino mass with a sensitivity of 0.2 eV/c2 at 90 % C.L.1. This goal can only be achieved with a very low background level in the order of 10 mcps2 in the detector region of interest. A possible background source are α-decays on the inner surface of the KATRIN Main Spectrometer. Rydberg atoms, produced in sputtering processes accompanying the α-decays, are not influenced by electric or magnetic fields and freely propagate inside the vacuum of the Main Spectrometer. Here, they can be ionized by thermal radiation and the released electrons directly contribute to the KATRIN background. Two α-sources, 223Ra and 228Th, were installed at the Main Spectrometer with the purpose of temporarily increasing the background in order to study α-decay induced background processes. In this paper, we present a possible background generation mechanism and measurements performed with these two radioactive sources. Our results show a clear correlation between α-activity on the inner spectrometer surface and background from the volume of the spectrometer. Two key characteristics of the Main Spectrometer background – the dependency on the inner electrode offset potential, and the radial distribution – could be reproduced with this artificially induced background. These findings indicate a high contribution of α-decay induced events to the residual KATRIN background.
- Research Organization:
- Massachusetts Insitute of Technology (MIT), Cambridge, MA (United States); Univ. of Washington, Seattle, WA (United States); Duke Univ., Durham, NC (United States); University of North Carolina, Chapel Hill, NC (United States); Univ. of California, Santa Barbara, CA (United States); Univ. of California, Oakland, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Helmholtz Association (HGF); Ministry for Education and Research (BMBF); German Ministry of Education, Youth and Sport; Joint Institute for Nuclear Research
- Grant/Contract Number:
- FG02-94ER40818; FG02-97ER41020; FG02-97ER41033; FG02-97ER41041; SC0004036; SC0011091; AC02-05CH11231; 05A17PM3; 05A17PX3; 05A17VK2; 05A17WO3; VH-NG-1055; CANAM-LM2011019
- OSTI ID:
- 1976880
- Journal Information:
- Astroparticle Physics, Vol. 138, Issue C; ISSN 0927-6505
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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