1. Precision measurement of the electron energy-loss function in tritium and deuterium gas for the KATRIN experiment
- Author
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Aker, M, Beglarian, A, Behrens, J, Berlev, A, Besserer, U, Bieringer, B, Block, F, Bornschein, B, Bornschein, L, Böttcher, M, Brunst, T, Caldwell, TS, Carney, RMD, Chilingaryan, S, Choi, W, Debowski, K, Deffert, M, Descher, M, Barrero, D Díaz, Doe, PJ, Dragoun, O, Drexlin, G, Edzards, F, Eitel, K, Ellinger, E, Miniawy, A El, Engel, R, Enomoto, S, Felden, A, Formaggio, JA, Fränkle, FM, Franklin, GB, Friedel, F, Fulst, A, Gauda, K, Gil, W, Glück, F, Groh, S, Grössle, R, Gumbsheimer, R, Hannen, V, Haußmann, N, Heizmann, F, Helbing, K, Hickford, S, Hiller, R, Hillesheimer, D, Hinz, D, Höhn, T, Houdy, T, Huber, A, Jansen, A, Karl, C, Kellerer, J, Kleesiek, M, Klein, M, Köhler, C, Köllenberger, L, Kopmann, A, Korzeczek, M, Kovalík, A, Krasch, B, Krause, H, Kunka, N, Lasserre, T, La Cascio, L, Lebeda, O, Lehnert, B, Le, TL, Lokhov, A, Machatschek, M, Malcherek, E, Mark, M, Marsteller, A, Martin, EL, Meier, M, Melzer, C, Menshikov, A, Mertens, S, Mostafa, J, Müller, K, Niemes, S, Oelpmann, P, Parno, DS, Poon, AWP, Poyato, JML, Priester, F, Ranitzsch, PC-O, Robertson, RGH, Rodejohann, W, Rodenbeck, C, Röllig, M, Röttele, C, Ryšavý, M, Sack, R, Saenz, A, Schäfer, P, Schaller, A, Schimpf, L, and Schlösser, K
- Subjects
Nuclear & Particles Physics ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Quantum Physics - Abstract
AbstractThe KATRIN experiment is designed for a direct and model-independent determination of the effective electron anti-neutrino mass via a high-precision measurement of the tritium $$\upbeta $$ β -decay endpoint region with a sensitivity on $$m_\nu $$ m ν of 0.2 $$\hbox {eV}/\hbox {c}^2$$ eV / c 2 (90% CL). For this purpose, the $$\upbeta $$ β -electrons from a high-luminosity windowless gaseous tritium source traversing an electrostatic retarding spectrometer are counted to obtain an integral spectrum around the endpoint energy of 18.6 keV. A dominant systematic effect of the response of the experimental setup is the energy loss of $$\upbeta $$ β -electrons from elastic and inelastic scattering off tritium molecules within the source. We determined the energy-loss function in-situ with a pulsed angular-selective and monoenergetic photoelectron source at various tritium-source densities. The data was recorded in integral and differential modes; the latter was achieved by using a novel time-of-flight technique. We developed a semi-empirical parametrization for the energy-loss function for the scattering of 18.6-keV electrons from hydrogen isotopologs. This model was fit to measurement data with a 95% $$\hbox {T}_2$$ T 2 gas mixture at 30 K, as used in the first KATRIN neutrino-mass analyses, as well as a $$\hbox {D}_2$$ D 2 gas mixture of 96% purity used in KATRIN commissioning runs. The achieved precision on the energy-loss function has abated the corresponding uncertainty of $$\sigma (m_\nu ^2)< {{10}^{-2}}{\hbox {eV}^{2}}$$ σ ( m ν 2 ) < 10 - 2 eV 2 [1] in the KATRIN neutrino-mass measurement to a subdominant level.
- Published
- 2021