The Neutrino Ettore Majorana Observatory (NEMO experiment) is an international collaboration of scientists searching for neutrinoless double beta decay (0νββ). The collaboration has been active since 1989. Observation of 0νββ would indicate neutrinos are Majorana particles and could be used to measure the neutrino mass. It is located in the Modane Underground Laboratory (LSM) in the Fréjus Road Tunnel. The experiment has (as of 2018) had 3 detectors, NEMO-1, NEMO-2, NEMO-3 (and a demonstrator module of SuperNEMO-detector) and is planning (as of 2018) to construct a new detector SuperNEMO.[1] The NEMO-1 and NEMO-2 prototype detectors were used until 1997. Latest experiment NEMO-3 was under design and construction from 1994 onwards, took data from January 2003 to January 2011 and the final data analysis was published in 2018.[2] The NEMO-2 and NEMO-3 detectors produced measurements for double neutrino decays and limits for neutrinoless double-beta decay for a number of elements, such as molybdenum-100 and selenium-82. These double beta decay times are important contributions to understanding the nucleus and are needed inputs for neutrinoless decay studies, which constrain neutrino mass.
The NEMO collaboration remains active[3] and is constructing an improved SuperNEMO detector. Planning of SuperNEMO and commissioning of SuperNEMO demonstrator module is on-going as of 2019.[2]
Other 0νββ experiments use the same material for the source of double beta decays and the detector. This allows a large mass of source material to be used and thereby maximizes the sensitivity of the experiment, but limits its flexibility. NEMO takes a different approach, using thin foils of source material surrounded by a separate tracking calorimeter.
This allows the use of any source material which can be formed into a thin foil. Also, because its tracking is more accurate, it can reliably detect if two electrons come from the same place, thereby reducing false detections of double beta decays.
The experiment has a cylindrical shape with 20 sectors that contain different isotopes in the form of thin foils with a total surface of about 20 m2. The main isotopes used for the neutrinoless double beta decay search are about 7 kg of enrichedmolybdenum-100 and about 1 kg of selenium-82. The experiment also contains smaller amounts of cadmium-116, neodymium-150, zirconium-96 and calcium-48 foils. Tellurium and copper foils are used for background measurements.
A tracking detector on each side of the foil detects electrons and positrons from the double beta decay. They are identified by their curvature in a magnetic field and particle energy is measured in a calorimeter. In 0νββ, the sum of the electron and positron energies will be the(Q value) released in double beta decay. For standard double beta decay the neutrinos, which cannot be observed directly, reduce the detected energy.
Results
Neutrinoless double beta decay (0νββ) has not been observed in 5 years of data taking and limits have been set for several isotopes.
NEMO-2 reported 0νββ limits for Majoron models of 100Mo, 116Cd, 82Se and 96Zr.[4]
NEMO-3 reported precision 2νββ half-lives for its 7 isotopes and 0νββ limits for 96Zr, 48Ca, 150Nd at Neutrino08.[5]
NEMO-3 reported 2νββ and more 0νββ limits at SUSY08.[6]
In 2014, NEMO-3 reported a 47 kg⋅y search for 0νββ of molybdenum-100 yielded T1/2 > 1.1×1024 years. This can be translated into an upper limit on the effective neutrino mass: mv < 0.3–0.9 eV, depending on the nuclear model.[7]
The 96Zr decay is particularly relevant because of its high Q and use in searches for time-dependence of the physical constants. Geochemical measurements of ZrSiO4 allow comparison of its historic and present rates,[9] by extracting the resultant 96Mo.
The final results of NEMO-3 were published in 2018.[2]
SuperNEMO
A next generation experiment, SuperNEMO, is under construction. It is based on technology used by the NEMO-3 experiment, but will be more than a factor of ten bigger.[10] The SuperNEMO detector will consist of 20 modules each containing approximately 5 kg of enriched double beta decay emitting isotope in the form of a thin foil. The installation of a first module (using selenium-82) in the LSM is under way, with data taking expected in the second half of 2015.[11] As of 2019, the commissioning of the SuperNEMO demonstration module (basically one of the 20 modulus of the whole SuperNEMO) is underway, and the collaboration continues to plan to construct the whole 20-module SuperNEMO detector.[2]
^"NEMO3 / SuperNEMO International Collaboration Meeting". Caen. 13–16 October 2014. Retrieved 2015-04-23.
^NEMO collaboration (9 October 2000). "Limits on different Majoron decay modes of 100Mo, 116Cd, 82Se and 96Zr for neutrinoless double beta decays in the NEMO-2 experiment". Nuclear Physics A. 678 (3): 341–352. Bibcode:2000NuPhA.678..341A. doi:10.1016/S0375-9474(00)00326-2.
^Flack, R. L.; for the NEMO 3 collaboration (2008). "Results from NEMO 3". Journal of Physics: Conference Series. 136 (2): 022032. arXiv:0810.5497. Bibcode:2008JPhCS.136b2032F. doi:10.1088/1742-6596/136/2/022032. S2CID 17244542.
^NEMO 3 Collaboration (2009). "Neutrinoless double beta decay search with the NEMO 3 experiment". AIP Conf. Proc. 1078 (1078): 332–334. arXiv:0810.0637. Bibcode:2008AIPC.1078..332N. doi:10.1063/1.3051951. S2CID 118398249.
^NEMO-3 Collaboration (2014). "Search for Neutrinoless Double-Beta Decay of 100Mo with the NEMO-3 Detector". Phys. Rev. D. 89 (11): 111101. arXiv:1311.5695. Bibcode:2014PhRvD..89k1101A. doi:10.1103/PhysRevD.89.111101. S2CID 9380926.
^Arnold, R.; Augier, C.; Baker, J.; Barabash, A. S.; Basharina-Freshville, A.; Blondel, S.; Bongrand, M.; Broudin-Bay, G.; Brudanin, V.; Caffrey, A. J.; Chapon, A.; Chauveau, E.; Durand, D.; Egorov, V.; Flack, R.; Garrido, X.; Grozier, J.; Guillon, B.; Hubert, Ph.; Hugon, C.; Jackson, C. M.; Jullian, S.; Kauer, M.; Klimenko, A.; Kochetov, O.; Konovalov, S. I.; Kovalenko, V.; Lalanne, D.; Lamhamdi, T.; Lang, K.; Liptak, Z.; Lutter, G.; Mamedov, F.; Marquet, Ch.; Martin-Albo, J.; Mauger, F.; Mott, J.; Nachab, A.; Nemchenok, I.; Nguyen, C. H.; Nova, F.; Novella, P.; Ohsumi, H.; Pahlka, R. B.; Perrot, F.; Piquemal, F.; Reyss, J. L.; Richards, B.; Ricol, J. S.; Saakyan, R.; Sarazin, X.; Simard, L.; Šimkovic, F.; Shitov, Yu.; Smolnikov, A.; Söldner-Rembold, S.; Štekl, I.; Suhonen, J.; Sutton, C. S.; Szklarz, G.; Thomas, J.; Timkin, V.; Torre, S.; Tretyak, V. I.; Umatov, V.; Vála, L.; Vanyushin, I.; Vasiliev, V.; Vorobel, V.; Vylov, Ts.; Zukauskas, A.; et al. (NEMO-3 Collaboration) (4 August 2011). "Measurement of the ββ Decay Half-Life of 130Te with the NEMO-3 Detector". Physical Review Letters. 107 (6): 062504. arXiv:1104.3716. Bibcode:2011PhRvL.107f2504A. doi:10.1103/PhysRevLett.107.062504. PMID 21902318. S2CID 12707641.
^Wieser, Michael; De Laeter, John (2001). "Evidence of the double β decay of zirconium-96 measured in 1.8×109 year-old zircons". Physical Review C. 64 (2): 024308. Bibcode:2001PhRvC..64b4308W. doi:10.1103/PhysRevC.64.024308.
^ R. Arnold; et al. (2010). "Probing new physics models of neutrinoless double beta decay with SuperNEMO" (PDF). European Physical Journal C. 70 (4): 927–943. arXiv:1005.1241. Bibcode:2010EPJC...70..927A. doi:10.1140/epjc/s10052-010-1481-5. S2CID 51838828.
^Gómez Maluenda, Héctor (3 Jul 2014). Latest results of NEMO-3 experiment and present status of SuperNEMO. ICHEP2014: The 37th International Conference on High Energy Physics. Valencia. Retrieved 2015-04-23. SuperNEMO is at present under construction after a R&D phase (started in 2007) which concluded that all the requirements are achievable. First phase is the construction of a first module that has been started in 2012 and will finish during 2015, when the data taking is expected to start.
External links
NEMO Experiment's official Site
January 24, 2023
neutrino, ettore, majorana, observatory, confused, with, neutrino, mediterranean, observatory, which, also, abbreviated, nemo, other, uses, nemo, disambiguation, coordinates, 1785471, 6890208, 1785471, 6890208the, nemo, experiment, international, collaboration. Not to be confused with the Neutrino Mediterranean Observatory which is also abbreviated NEMO For other uses see Nemo disambiguation Coordinates 45 10 43 N 6 41 20 E 45 1785471 N 6 6890208 E 45 1785471 6 6890208The Neutrino Ettore Majorana Observatory NEMO experiment is an international collaboration of scientists searching for neutrinoless double beta decay 0nbb The collaboration has been active since 1989 Observation of 0nbb would indicate neutrinos are Majorana particles and could be used to measure the neutrino mass It is located in the Modane Underground Laboratory LSM in the Frejus Road Tunnel The experiment has as of 2018 had 3 detectors NEMO 1 NEMO 2 NEMO 3 and a demonstrator module of SuperNEMO detector and is planning as of 2018 to construct a new detector SuperNEMO 1 The NEMO 1 and NEMO 2 prototype detectors were used until 1997 Latest experiment NEMO 3 was under design and construction from 1994 onwards took data from January 2003 to January 2011 and the final data analysis was published in 2018 2 The NEMO 2 and NEMO 3 detectors produced measurements for double neutrino decays and limits for neutrinoless double beta decay for a number of elements such as molybdenum 100 and selenium 82 These double beta decay times are important contributions to understanding the nucleus and are needed inputs for neutrinoless decay studies which constrain neutrino mass The NEMO collaboration remains active 3 and is constructing an improved SuperNEMO detector Planning of SuperNEMO and commissioning of SuperNEMO demonstrator module is on going as of 2019 2 Contents 1 Experiment 2 Results 3 SuperNEMO 4 References 5 External linksExperiment EditOther 0nbb experiments use the same material for the source of double beta decays and the detector This allows a large mass of source material to be used and thereby maximizes the sensitivity of the experiment but limits its flexibility NEMO takes a different approach using thin foils of source material surrounded by a separate tracking calorimeter This allows the use of any source material which can be formed into a thin foil Also because its tracking is more accurate it can reliably detect if two electrons come from the same place thereby reducing false detections of double beta decays The experiment has a cylindrical shape with 20 sectors that contain different isotopes in the form of thin foils with a total surface of about 20 m2 The main isotopes used for the neutrinoless double beta decay search are about 7 kg of enriched molybdenum 100 and about 1 kg of selenium 82 The experiment also contains smaller amounts of cadmium 116 neodymium 150 zirconium 96 and calcium 48 foils Tellurium and copper foils are used for background measurements A tracking detector on each side of the foil detects electrons and positrons from the double beta decay They are identified by their curvature in a magnetic field and particle energy is measured in a calorimeter In 0nbb the sum of the electron and positron energies will be the Q value released in double beta decay For standard double beta decay the neutrinos which cannot be observed directly reduce the detected energy Results EditNeutrinoless double beta decay 0nbb has not been observed in 5 years of data taking and limits have been set for several isotopes NEMO 2 reported 0nbb limits for Majoron models of 100Mo 116Cd 82Se and 96Zr 4 NEMO 3 reported precision 2nbb half lives for its 7 isotopes and 0nbb limits for 96Zr 48Ca 150Nd at Neutrino08 5 NEMO 3 reported 2nbb and more 0nbb limits at SUSY08 6 In 2014 NEMO 3 reported a 47 kg y search for 0nbb of molybdenum 100 yielded T1 2 gt 1 1 1024 years This can be translated into an upper limit on the effective neutrino mass mv lt 0 3 0 9 eV depending on the nuclear model 7 NEMO 2nbb Half life Measurements Nuclide Half life years48Ca 4 4 0 5 0 4 0 4 101982Se 9 6 0 3 1 0 101996Zr 2 35 0 14 0 16 1019116Cd 2 8 0 1 0 3 1019130Te 7 0 0 9 stat 1 1 syst 1020 8 150Nd 9 11 0 25 0 22 0 63 1018100Mo 7 11 0 02 stat 0 54 syst 1018NEMO Highest 0nbb Decay Lower Limits Isotope T1 2 yr Neutrino mass limit eV 82Se 2 1 1023100Mo 1 1 1024 0 9116Cd 1 6 102296Zr 8 6 1021 20 1150Nd 1 8 1022 6 348Ca 1 3 1022 29 7The 96Zr decay is particularly relevant because of its high Q and use in searches for time dependence of the physical constants Geochemical measurements of ZrSiO4 allow comparison of its historic and present rates 9 by extracting the resultant 96Mo The final results of NEMO 3 were published in 2018 2 SuperNEMO EditA next generation experiment SuperNEMO is under construction It is based on technology used by the NEMO 3 experiment but will be more than a factor of ten bigger 10 The SuperNEMO detector will consist of 20 modules each containing approximately 5 kg of enriched double beta decay emitting isotope in the form of a thin foil The installation of a first module using selenium 82 in the LSM is under way with data taking expected in the second half of 2015 11 As of 2019 the commissioning of the SuperNEMO demonstration module basically one of the 20 modulus of the whole SuperNEMO is underway and the collaboration continues to plan to construct the whole 20 module SuperNEMO detector 2 References Edit SuperNEMO a b c d http www rcnp osaka u ac jp dbd18 Data Prog S0303 Patrick pdf bare URL PDF NEMO3 SuperNEMO International Collaboration Meeting Caen 13 16 October 2014 Retrieved 2015 04 23 NEMO collaboration 9 October 2000 Limits on different Majoron decay modes of 100Mo 116Cd 82Se and 96Zr for neutrinoless double beta decays in the NEMO 2 experiment Nuclear Physics A 678 3 341 352 Bibcode 2000NuPhA 678 341A doi 10 1016 S0375 9474 00 00326 2 Flack R L for the NEMO 3 collaboration 2008 Results from NEMO 3 Journal of Physics Conference Series 136 2 022032 arXiv 0810 5497 Bibcode 2008JPhCS 136b2032F doi 10 1088 1742 6596 136 2 022032 S2CID 17244542 NEMO 3 Collaboration 2009 Neutrinoless double beta decay search with the NEMO 3 experiment AIP Conf Proc 1078 1078 332 334 arXiv 0810 0637 Bibcode 2008AIPC 1078 332N doi 10 1063 1 3051951 S2CID 118398249 NEMO 3 Collaboration 2014 Search for Neutrinoless Double Beta Decay of 100Mo with the NEMO 3 Detector Phys Rev D 89 11 111101 arXiv 1311 5695 Bibcode 2014PhRvD 89k1101A doi 10 1103 PhysRevD 89 111101 S2CID 9380926 Arnold R Augier C Baker J Barabash A S Basharina Freshville A Blondel S Bongrand M Broudin Bay G Brudanin V Caffrey A J Chapon A Chauveau E Durand D Egorov V Flack R Garrido X Grozier J Guillon B Hubert Ph Hugon C Jackson C M Jullian S Kauer M Klimenko A Kochetov O Konovalov S I Kovalenko V Lalanne D Lamhamdi T Lang K Liptak Z Lutter G Mamedov F Marquet Ch Martin Albo J Mauger F Mott J Nachab A Nemchenok I Nguyen C H Nova F Novella P Ohsumi H Pahlka R B Perrot F Piquemal F Reyss J L Richards B Ricol J S Saakyan R Sarazin X Simard L Simkovic F Shitov Yu Smolnikov A Soldner Rembold S Stekl I Suhonen J Sutton C S Szklarz G Thomas J Timkin V Torre S Tretyak V I Umatov V Vala L Vanyushin I Vasiliev V Vorobel V Vylov Ts Zukauskas A et al NEMO 3 Collaboration 4 August 2011 Measurement of the bb Decay Half Life of 130Te with the NEMO 3 Detector Physical Review Letters 107 6 062504 arXiv 1104 3716 Bibcode 2011PhRvL 107f2504A doi 10 1103 PhysRevLett 107 062504 PMID 21902318 S2CID 12707641 Wieser Michael De Laeter John 2001 Evidence of the double b decay of zirconium 96 measured in 1 8 109 year old zircons Physical Review C 64 2 024308 Bibcode 2001PhRvC 64b4308W doi 10 1103 PhysRevC 64 024308 R Arnold et al 2010 Probing new physics models of neutrinoless double beta decay with SuperNEMO PDF European Physical Journal C 70 4 927 943 arXiv 1005 1241 Bibcode 2010EPJC 70 927A doi 10 1140 epjc s10052 010 1481 5 S2CID 51838828 Gomez Maluenda Hector 3 Jul 2014 Latest results of NEMO 3 experiment and present status of SuperNEMO ICHEP2014 The 37th International Conference on High Energy Physics Valencia Retrieved 2015 04 23 SuperNEMO is at present under construction after a R amp D phase started in 2007 which concluded that all the requirements are achievable First phase is the construction of a first module that has been started in 2012 and will finish during 2015 when the data taking is expected to start External links EditNEMO Experiment s official Site Retrieved from https en wikipedia org w index php title Neutrino Ettore Majorana Observatory amp oldid 1131436342, wikipedia, wiki, book, books, library,
