학술논문
Precision measurement of the electron energy-loss function in tritium and deuterium gas for the KATRIN experiment
Document Type
article
Author
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; Schlösser, K
Source
The European Physical Journal C. 81(7)
Subject
Language
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.