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Accueil du site > ANGLAIS > Research > NEMO - Neutrino & Feeble Radioactivity Measurements > Publications > The 1990’s > The 1990’s


The 1990’s

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1999

Testing the Pauli exclusion principle with the NEMO-2 detector

R. Arnold, C. Augier, J. Baker, A. Barabash, D. Blum, V. Brudanin, A.J. Carey, J.E. Campagne, E. Caurier, D. Dassié, V. Egorov, T. Filipova, R. Gurriaran, J.L. Guyonnet, F. Hubert, Ph. Hubert, S. Jullian, O. Kochetov, I. Kisel, V.N. Kornoukhov, V. Kovalenko, D. Lalanne, F. Laplanche, F. Leccia, I. Linck, C. Longuemare, Ch. Marquet, F. Mauger, H.W. Nicholson, I. Pilugin, F. Piquemal, J-L. Reyss, X. Sarazin, F. Scheibling, J. Suhonen, C.S. Sutton, G. Szklarz, V. Timkin, R. Torres, V.I. Tretyak, V. Umatov, I. Vanyushin, A. Vareille, Yu. Vasilyev, Ts. Vylov

The European Physical Journal A - Hadrons and Nuclei November 1999, Volume 6, Issue 3, pp 361-366

The Pauli Exclusion Principle (PEP) was tested with the NEMO-2 detector. Limits at the 90 % C.L. on the violation of PEP for p-shell nucleons in 12C were obtained. Specifically, transitions to the fully occupied 1s1/2-shell yielded a limit of 4.2x1024 y for the process with emission of a γ-quantum. Similarly limits of 3.1x1024 y for β- and 2.6x1024 y for β+ Pauli-forbidden transitions of 12C -> 12N(12B) are reported here.

Double-β decay of 96Zr

R. Arnold, C. Augier, J. Baker, A. Barabash, D. Blum, V. Brudanin, A.J. Caffrey, J.E. Campagne, E. Caurier, D. Dassié, V. Egorov, T. Filipova, R. Gurriaran, J.L. Guyonnet, F. Hubert, Ph. Hubert, S. Jullian, I. Kisel, O. Kochetov, V.N. Kornoukhov, V. Kovalenko, D. Lalanne, F. Laplanche, F. Leccia, I. Linck, C. Longuemare, Ch. Marquet, F. Mauger, H.W. Nicholson, I. Pilugin, F. Piquemal, J-L. Reyss, X. Sarazin, F. Scheibling, J. Suhonen, C.S. Sutton, G. Szklarz, V. Timkin, R. Torres, V.I. Tretyak, V. Umatov, I. Vanyushin, A. Vareille, Yu. Vasilyev, Ts. Vylov

Nuclear Physics A, Volume 658, Issue 4, 1 November 1999, Pages 299-312

After 10357 h of running the NEMO-2 tracking detector with an isotopically enriched zirconium source (0.084 mol yr of 96Zr), a ββ2ν decay half-life of T1/2=(2.1+0.8(stat)−0.4(stat)±0.2(syst))·1019 y was measured. Limits with a 90% C.L. on the 96Zr half-lives of 1.0·1021 y for ββ0ν decay to the ground state, 3.9·1020 y to the 2+ excited state and 3.5·1020 y for ββ0νχ0 decay with a Majoron (χ0) were obtained. The data also provide direct limits at the 90% C.L. for the 94Zr half-lives. These limits are 1.1·1017 y for ββ2ν decay to the ground state, 1.9·1019 y for ββ0ν decay to the ground state and 2.3·1018 y for ββ0νχ0 decay to ground state.


1998

Double-β decay of 82Se

NEMO Collaboration

R. Arnold, C. Augier, J. Baker, A. Barabash, D. Blum, V. Brudanin, A.J. Caffrey, J.E. Campagne, E. Caurier, D. Dassié, V. Egorov, R. Eschbach, T. Filipova, R. Gurriaran, J.L. Guyonnet, E Hubert, Ph. Hubert, S. Jullian, I. Kisel, O. Kochetov, V.N. Kornoukhov, V. Kovalenko, D. Lalanne, E Laplanche, F Leccia, I. Linck, C. Longuemare, Ch. Marquet, E Mauger, P. Mennrath, H.W. Nicholson, I. Pilugin, E Piquemal, O. Purtov, J-L. Reyss, X. Sarazin, E Scheibling, J. Suhonen, C.S. Sutton, G. Szklarz, V. Timkin, R. Torres, V.I. Tretyak, V. Umatov, I. Vanyushin, A. Vareille, Yu. Vasilyev, Ts. Vylov, V. Zerkin

Nuclear Physics A, Volume 636, Issue 2, 22 June 1998, Pages 209-223

The NEMO-2 tracking detector located in the Fréjus Underground Laboratory was designed as a prototype of the NEMO-3 detector to study neutrinoless (Oν) and two neutrino (2ν) double-beta decay (ββ) physics. After 10357 h of running with an isotopically enriched selenium source (2.17 mol yr of 82Se) a ββ2ν decay half-life of T1/2 = (0.83 ± 0.10(stat)± 0.07 (syst)) × 1020 yr was measured. Limits with a 90% C.L. on the 82Se half-lives of 9.5 × 1021 yr for ββ0ν decay to the ground state, 2.8 × 1021 yr to the (2+) excited state and 2.4 × 1021 yr for ββ0νχ0 decay with a Majoron (χ0) were also obtained.


1995

Performance of a prototype tracking detector for double beta decay measurements

NEMO Collaboration

R. Arnold, A. Barabash, D. Blum, V. Brudanin, J.E. Campagne, F. Danevich, D. Dassié, V. Egorov, R. Eschbach, J.L. Guyonnet, F. Hubert, Ph. Hubert, M.C. Isaac, C. Izac, S. Jullian, 0. Kochetov, V.N. Komoukov, V. Kouts‘, V. Kovalenko, D. Lalanne, T. Lamhamdi, F. Laplanche, F. Leccia, Yu. Lepikhin, I. Linck, C. Longuemare, F. Mauger, P. Mennrath, F. Natchez, H.W. Hicholson, A. Nozdrin, G. Pichenot, F. Piquemal, F. Scheibling, C.S. Sutton, G. Szklarz, V.I. Tretyak, V. Umatov, I. Vanushin, Yu. Vassilyev, A. Vareille, Ts. Vylov, Sh. Zaparov, Yu. Zdesenko

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 354, Issues 2–3, 30 January 1995, Pages 338-351

To investigate double beta decay processes, the NEMO collaboration began a long-range research and development program in 1988. The NEMO 2 detector, which is now running in the Fréjus underground laboratory (L.S.M. Laboratoire Souterrain de Modane), is the second prototype. It consists of a 1 m2 source foil sandwiched between Geiger cell drift chambers for electron tracking and two plastic scintillator walls for energy and time-of-flight measurements. The technical description of the detector is followed by the study of the various sources of background.