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2017

Calorimeter development for the SuperNEMO double beta decay experiment

A.S. Barabash, A. Basharina-Freshville, S. Blot, M. Bongrand, Ch. Bourgeois, D. Breton, V. Brudanin, H. Burešovà, J. Busto, A.J. Caffrey, S. Calvez, M. Cascella, C. Cerna, J.P. Cesar, E. Chauveau, A. Chopra, G. Claverie, S. De Capua, F. Delalee, D. Duchesneau, V. Egorov, G. Eurin, J.J. Evans, L. Fajt, D. Filosofov, R. Flack, X. Garrido, H. Gómez, B. Guillon, P. Guzowski, R. Hodák, K. Holý, A. Huber, C. Hugon, A. Jeremie, S. Jullian, M. Kauer, A. Klimenko, O. Kochetov, S.I. Konovalov, V. Kovalenko, K. Lang, Y. Lemière, T. Le Noblet, Z. Liptak, X.R. Liu, P. Loaiza, G. Lutter, J. Maalmi, M. Macko, F. Mamedov, C. Marquet, F. Mauger, I. Moreau, B. Morgan, J. Mott, I. Nemchenok, M. Nomachi, F. Nova, H. Ohsumi, R.B. Pahlka, J.R. Pater, F. Perrot, F. Piquemal, P. Povinec, P. Přidal, Y.A. Ramachers, A. Rebii, A. Remoto, B. Richards, J.S. Ricol, C.L. Riddle, E. Rukhadze, R. Saakyan, R. Salazar, X. Sarazin, J. Sedgbeer, Yu. Shitov, F. Šimkovic, L. Simard, A. Smetana, K. Smolek, A. Smolnikov, S. Snow, S. Söldner-Rembold, B. Soulé, M. Špavorová, I. Štekl, J. Thomas, V. Timkin, S. Torre, Vl.I. Tretyak, V.I. Tretyak, V.I. Umatov, C. Vilela, V. Vorobel, D. Waters, A. Žukauskas)

Nuclear Inst. and Methods in Physics Research, A (Available online 6 July 2017, In Press, Corrected Proof)

SuperNEMO is a double-β decay experiment, which will employ the successful tracker–calorimeter technique used in the recently completed NEMO-3 experiment. SuperNEMO will implement 100 kg of double-β decay isotope, reaching a sensitivity to the neutrinoless double-β decay (0νββ) half-life of the order of 1026 yr, corresponding to a Majorana neutrino mass of 50-100 meV. One of the main goals and challenges of the SuperNEMO detector development programme has been to reach a calorimeter energy resolution, DE/E, around 3%/sqrt(E(MeV)) times sigma, or 7%/sqrt(E(MeV)) FWHM (full width at half maximum), using a calorimeter composed of large volume plastic scintillator blocks coupled to photomultiplier tubes. We descrive the R&D programme and the final design of the SuperNEMO calorimeter thazt has met this challenge goal.

Measurement of the 2νββ Decay Half-Life and Search for the 0νββ Decay of 116Cd with the NEMO-3 Detector

R. Arnold, C. Augier, J.D. Baker, A.S. Barabash, A. Basharina-Freshville, S. Blondel, S. Blot, M. Bongrand, V. Brudanin, J. Busto, A.J. Caffrey, S. Calvez, C. Cerna, J. P. Cesar, A. Chapon, E. Chauveau, D. Duchesneau, D. Durand, V. Egorov, G. Eurin, J.J. Evans, L. Fajt, D. Filosofov, R. Flack, X. Garrido, H. Gomez, B. Guillon, P. Guzowski, R. Hodak, A. Huber, P. Hubert, C. Hugon, S. Jullian, A. Klimenko, O. Kochetov, S.I. Konovalov, V. Kovalenko, D. Lalanne, K. Lang, Y. Lemiere, T. Le Noblet, Z. Liptak, P. Loaiza, G. Lutter, F. Mamedov, C. Marquet, F. Mauger, B. Morgan, J. Mott, I. Nemchenok, M. Nomachi, F. Nova, F. Nowacki, H. Ohsumi, R.B. Pahlka, F. Perrot, F. Piquemal, P. Povinec, P. Pridal, Y.A. Ramachers, A. Remoto, J.L. Reyss, B. Richards, C.L. Riddle, E. Rukhadze, R. Saakyan, R. Salazar, X. Sarazin, Yu. Shitov, L. Simard, F. Simkovic, A. Smetana, K. Smolek, A. Smolnikov, S. Söldner-Rembold, B. Soulé, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, J. Thomas, V. Timkin, S. Torre, Vl.I. Tretyak, V.I. Tretyak, V.I. Umatov, I. Vanushin, C. Vilela, V. Vorobel, D. Waters, and A. Zukauskas (NEMO-3 Collaboration)

(ref...)

The NEMO-3 experiment measured the half-life of the 2νββ decay and searched for the 0νββ decay of 116Cd. Using 410 g of 116Cd installed in the detector with an exposure of 5.26 y, (4968±74) events corresponding to the 2νββ decay of 116Cd to the ground state of 116Sn have been observed with a signal to background ratio of about 12. The half-life of the 2νββ decay has been measured to be T1/2 = [2.74 ± 0.04(stat.) ± 0.18(syst.)] × 1019 y. No events have been observed above the expected background while searching for 0νββ decay. The corresponding limit on the half-life is determined to be T1/2 ≥ 1.0×1023 y at the 90% C.L. which corresponds to an upper limit on theeffective Majorana neutrino mass of hmνi≤ 1.4−2.5 eV depending on the nuclear matrix elementsconsidered. Limits on other mechanisms generating 0 νββ decay such as the exchange of R-parity violating supersymmetric particles, right-handed currents and majoron emission are also obtained.

Search for neutrinoless quadruple-β decay of 150Nd with the NEMO-3 detector

R. Arnold, C. Augier, A.S. Barabash, A. Basharina-Freshville, S. Blondel, S. Blot, M. Bongrand, D. Boursette, V. Brudanin, J. Busto, A.J. Caffrey, S. Calvez, M. Cascella, C. Cerna, J.P. Cesar, A. Chapon, E. Chauveau, A. Chopra, L. Dawson, D. Duchesneau, D. Durand, V. Egorov, G. Eurin, J.J. Evans, L. Fajt, D. Filosofov, R. Flack, X. Garrido, H. Gomez, B. Guillon, P. Guzowski, R. Hoda´k, A. Huber, P. Hubert, C. Hugon, S. Jullian, A. Klimenko, O. Kochetov, S.I. Konovalov, V. Kovalenko, D. Lalanne, K. Lang,11 Y. Lemière, T. Le Noblet, Z. Liptak, X. R. Liu, P. Loaiza, G. Lutter, M. Macko, C. Macolino, F. Mamedov, C. Marquet, F. Mauger, B. Morgan, J. Mott, I. Nemchenok, M. Nomachi, F. Nova, F. Nowacki, H. Ohsumi, C. Patrick, R.B. Pahlka, F. Perrot, F. Piquemal, P. Povinec, P. Pridal, Y.A. Ramachers, A. Remoto, J.L. Reyss, C.L. Riddle, E. Rukhadze, R. Saakyan, R. Salazar, X. Sarazin, Yu. Shitov, L. Simard, F. Simkovic, A. Smetana, K. Smolek, A. Smolnikov, S. Söldner-Rembold, B. Soulé, D. Stefanik, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, J. Thomas, V. Timkin, S. Torre, Vl.I. Tretyak, V.I. Tretyak, V.I. Umatov, I. Vanushin, C. Vilela, V. Vorobel, D. Waters, F. Xie, and A. Zukauskas (NEMO-3 Collaboration)

We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-β decay of 150Nd using a total exposure of 0.19 kg·y recorded with the NEMO-3 detector at the Modane Underground Laboratory (LSM). We find no evidence of this decay and set lower limits on the half-life in the range T1/2 > (1.1–3.2) × 1021 y at the 90% CL, depending on the model used for the kinematic distributions of the emitted electrons.


2016

Measurement of the 2νββ decay half-life of 150Nd and a search for 0νββ decay processes with the full exposure from the NEMO-3 detector

R. Arnold et al (The NEMO–3 Collaboration)

Phys. Rev. D 94, 072003 (2016) – Published 11 October 2016

We present results from a search for neutrinoless double-β (0νββ) decay using 36.6 g of the isotope 150Nd with data corresponding to a live time of 5.25 y recorded with the NEMO-3 detector. We construct a complete background model for this isotope, including a measurement of the two- neutrino double-β decay half-life of T1/2 = [9.34 +- 0.22 (stat.) +0.620.60 (syst.)] x 1018y for the ground state transition, which represents the most precise result to date for this isotope. We perform a multivariate analysis to search for 0νββ decays in order to improve the sensitivity and, in the case of observation, disentangle the possible underlying decay mechanisms. As no evidence for 0νββ decay is observed, we derive lower limits on half-lives for several mechanisms involving physics beyond the Standard Model. The observed lower limit, assuming light Majorana neutrino exchange mediates the decay, is T1/2> 2.0 x 1022 y at the 90% C.L., corresponding to an upper limit on the effective neutrino mass of ν> < 1.6 - 5.3 eV.

Measurement of the double-beta decay half-life and search for the neutrinoless double-beta decay of 48Ca with the NEMO-3 detector

R. Arnold et al (The NEMO–3 Collaboration)

Phys. Rev. D 93, 112008 (2016) DOI : 10.1103/PhysRevD.93.112008

The NEMO-3 experiment at the Modane Underground Laboratory investigates the double-beta decay of 48Ca. Using 5.25 yr of data recorded with a 6:99 g sample of 48Ca, approximately 150 double-beta decay candidate events are selected with a signal-to-background ratio greater than 3. The half-life for the two-neutrino double-beta decay of 48Ca is measured to be T1/2 = [6.4+0.7-0.6(stat.) +1.20.9(syst.)] x 1019 yr. A search for neutrinoless double-beta decay of 48Ca yields a null result and a corresponding lower limit on the half-life is found to be T1/2<0ν> > 2.0 x 1022 yr at 90% confidence level, translating into an upper limit on the effective Majorana neutrino mass of ββ < 6.0 - 26 eV, with the range reflecting diFFerent nuclear matrix element calculations. Limits are also set on models involving Majoron emission and right-handed currents.

Reference material for natural radionuclides in glass designed for underground experiments

P. P. Povinec, M. K. Pham, J. Busto, C. Cerna, D. Degering, Y. Hamajima, K. Holý, M. Hult, M. Ješkovský, M. Köhler, A. Kováčik, M. Laubenstein, P. Loaiza, F. Mamedov, Ch. Marquet, J. Mott, M. Műllerová, F. Perrot, F. Piquemal, J.-L. Reyss, R. Saakyan, H. Simgen, B. Soulé, J. Staníček, I. Sýkora, I. Štekl

J Radioanal Nucl Chem (2016) 307 : 619 DOI:10.1007/s10967-015-4202-6

A reference material designed for the determination of natural radionuclides in solid samples (glass pellets) is described and the results of certification are presented. The material has been certified for 7 natural radionuclides (40K, 226Ra, 228Ra, 228Th, 232Th, 235U and 238U). An information value is given for 210Pb. Radon (222Rn) emanation experiments showed results comparable within participating laboratories, however, the number of data and precision was too low to carry out a certification process. The reference material may be used for quality management of analytical laboratories engaged in the high-sensitive analysis of radionuclides in the construction materials of detectors placed in ultra low background underground laboratories.


2015

Result of the search for neutrinoless double-β decay in 100Mo with the NEMO-3 experiment

R. Arnold, C. Augier, J.D. Bakery, A.S. Barabash, A. Basharina-Freshville, S. Blondel, S. Blot, M. Bongrand, V. Brudanin, J. Busto, A.J. Caffrey, S. Calvez, C. Cerna, A. Chapon, E. Chauveau, D. Duchesneau, D. Durand, V. Egorov, G. Eurin, J.J. Evans, L. Fajt, D. Filosofov, R. Flack, X. Garrido, H. Gomez, B. Guillon, P. Guzowski, R. Hodak, A. Huber, P. Hubert, C. Hugon, S. Jullian, A. Klimenko, O. Kochetov, S.I. Konovalov, V. Kovalenko, D. Lalanne, K. Lang, Y. Lemiere, T. Le Noblet, Z. Liptak, P. Loaiza, G. Lutter, F. Mamedov, C. Marquet, F. Mauger, B. Morgan, J. Mott, I. Nemchenok, M. Nomachi, F. Nova, F. Nowacki, H. Ohsumi, R.B. Pahlka, F. Perrot, F. Piquemal, P. Povinec, P. Pridal, Y.A. Ramachers, A. Remoto, J.L. Reyss, B. Richards, C.L. Riddle, E. Rukhadze, R. Saakyan, X. Sarazin, Yu. Shitov, L. Simard, F. Simkovic, A. Smetana, K. Smolek, A. Smolnikov, S. Soldner-Rembold, B. Soule, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, J. Thomas, V. Timkin, S. Torre, Vl.I. Tretyak, V.I. Tretyak, V.I. Umatov, I. Vanushin, C. Vilela, V. Vorobel, D. Waters, and A. Zukauskas

NEMO-3 Collaboration

Physical Review D 92(2015) 072011

The NEMO-3 detector, which had been operating in the Modane Underground Laboratory from 2003 to 2010, was designed to search for neutrinoless double β (0νββ) decay. We report final results of a search for 0νββ decays with 6:914 kg of 100Mo using the entire NEMO-3 data set with a detector live time of 4.96 yr, which corresponds to an exposure of 34.3 kg.yr. We perform a detailed study of the expected background in the νββ signal region and find no evidence of 0νββ decays in the data. The level of observed background in the 0νββ signal region [2.8 - 3.2] MeV is 0.44 - 0.13 counts/yr/kg, and no events are observed in the interval [3.2 - 10] MeV. We therefore derive a lower limit on the half-life of 0νββ decays in 100Mo of T1/2 (0νββ) > 1.1 x 1024 yr at the 90% Confidence Level, under the hypothesis of decay kinematics similar to that for light Majorana neutrino exchange. Depending on the model used for calculating nuclear matrix elements, the limit for the effective Majorana neutrino mass lies in the range (mν) < 0.33 - 0.62 eV. We also report constraints on other lepton-number violating mechanisms for 0νββ decays.

First results of the search for neutrinoless double beta decay with the NEMO 3 detector

R. Arnold, C. Augier, J. Baker, A. Barabash , G. Broudin, V. Brudanin, A.J. Caffrey, E. Caurier, V. Egorov, K. Errahmane, A.I. Etienvre, J.L. Guyonnet, F. Hubert, Ph. Hubert, C. Jollet, S. Jullian, O. Kochetov, V. Kovalenko, S. Konovalov , D. Lalanne, F. Leccia, C. Longuemare, G. Lutter, Ch. Marquet, F. Mauger, F. Nowacki, H. Ohsumi, F. Piquemal, J.L. Reyss, R. Saakyan, X. Sarazin, L. Simard, F. Simkovic, Yu. Shitov, A. Smolnikov, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, J. Thomas, V. Timkin, V. Tretyak, V. Umatov, L. Vala, I. Vanushin, V. Vasilyev, V. Vorobel and Ts. Vylov

NEMO-3 Collaboration

Phys. Rev. Lett. 95:182302,2005

DOI : 10.1103/PhysRevLett.95.182302

The NEMO 3 detector, which has been operating in the Fréjus underground laboratory since February 2003, is devoted to the search for neutrinoless double beta decay (ββ0ν). The half-lives of the two neutrino double beta decay (ββ2ν) have been measured for 100Mo and 82Se. After 389 effective days of data collection from February 2003 until September 2004 (Phase I), no evidence for neutrinoless double beta decay was found from ∼7 kg of 100Mo and ∼1 kg of 82Se. The corresponding limits are T1/2(ββ0ν) > 4.6×1023 years for 100w/sup>Mo and T1/2(ββ0ν) > 1.0×1023 years for 82Se (90% C.L.). Depending on the nuclear matrix element calculation, the limits for the effective Majorana neutrino mass are < 0.7−2.8 eV for 100Mo and < 1.7−4.9 eV for 82Se.

Journal of Environmental Radioactivity

Possibility of wine dating using the natural Pb-210 radioactive isotope

Ph. Hubert, M. S. Pravikoff and J. Gaye

Journal of Environmental Radioactivity 142 (2015) 132-135

DOI : 10.1016/j.jenvrad.2015.01.017

To control the authenticity of an old wine without opening the bottle, we developed a few years ago a method based on the measurement of the 137Cs activity. However, for recent vintages, the 137Cs activity drops to far too low values for this method to perform correctly. In this paper we examine the possibility to date wines using the natural radio-element 210Pb which has a 22-year period. This new method we propose implies the opening of the bottle and the follow-on destruction of the wine itself, which means that it can only be used for investigating non-expensive bottles.


2014

Search for neutrinoless double-beta decay of 100Mo with the NEMO-3 detector

R. Arnold, C. Augier, J. D. Baker, A. S. Barabash, A. Basharina-Freshville, S. Blondel, S. Blot, M. Bongrand, V. Brudanin, J. Busto, A. J. Caffrey, C. Cerna, A. Chapon, E. Chauveau, D. Duchesneau, D. Durand, V. Egorov, G. Eurin, J. J. Evans, R. Flack, X. Garrido, H. Gómez, B. Guillon, P. Guzowski, R. Hodák, P. Hubert, C. Hugon, S. Jullian, A. Klimenko, O. Kochetov, S. I. Konovalov, V. Kovalenko, D. Lalanne, K. Lang, Y. Lemière, Z. Liptak, P. Loaiza, G. Lutter, F. Mamedov, C. Marquet, F. Mauger, B. Morgan, J. Mott, I. Nemchenok, M. Nomachi, F. Nova, F. Nowacki, H. Ohsumi, R. B. Pahlka, F. Perrot, F. Piquemal, P. Povinec, Y. A. Ramachers, A. Remoto, J. L. Reyss, B. Richards, C. L. Riddle, E. Rukhadze, R. Saakyan, X. Sarazin, Yu. Shitov, L. Simard, F. Šimkovic, A. Smetana, K. Smolek, A. Smolnikov, S. Söldner-Rembold, B. Soulé, I. Štekl, J. Suhonen, C. S. Sutton, G. Szklarz, J. Thomas, V. Timkin, S. Torre, Vl. I. Tretyak, V. I. Tretyak, V. I. Umatov, I. Vanushin, C. Vilela, V. Vorobel, D. Waters, and A. Žukauskas

(The NEMO–3 Collaboration)

Phys. Rev. D 89, 111101(R) (2014) DOI : http://dx.doi.org/10.1103/PhysRevD....

We report the results of a search for the neutrinoless double-β decay (0νββ) of 100Mo, using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7  kg⋅y, no evidence for the 0νββ signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of T1/2(0νββ)>1.1×1024 years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the nuclear matrix elements this corresponds to an upper limit on the Majorana effective neutrino mass of ⟨mν⟩<0.3–0.9  eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0νββ decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.2–10] MeV is observed for an exposure of 47  kg⋅y.

Investigation of double beta decay of 100Mo to excited states of 100Ru

R. Arnold, C. Augier, A.S. Barabash, A. Basharina-Freshville, S. Blondel, S. Blot, M. Bongrand, V. Brudanin, J. Busto, A.J. Caffrey, P. Čermák, C. Cerna, A. Chapon, E. Chauveau, L. Dragounová, D. Duchesneau, D. Durand, V. Egorov, G. Eurin, J.J. Evans, R. Flack, X. Garrido, H. Gomez, B. Guillon, P. Guzowski, R. Hodák, P. Hubert, C. Hugon, J. Hulka, S. Jullian, A. Klimenko, O. Kochetov, S.I. Konovalov, V. Kovalenko, D. Lalanne, K. Lang, Y. Lemiere, Z. Liptak, P. Loaiza, G. Lutter, F. Mamedov, C. Marquet, F. Mauger, B. Morgan, J. Mott, I. Nemchenok, M. Nomachi, F. Nova, F. Nowacki, H. Ohsumi, R.B. Pahlka, F. Perrot, F. Piquemal, P. Povinec, Y.A. Ramachers, A. Remoto, J.L. Reyss, B. Richards, C.L. Riddle, E. Rukhadze, N. Rukhadze, R. Saakyan, X. Sarazin, Yu. Shitov, L. Simard, F. Simkovic, A. Smetana, K. Smolek, A. Smolnikov, S. Söldner-Rembold, B. Soulé, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, J. Thomas, V. Timkin, S. Torre, V.I. Tretyak, Vl.I. Tretyak, V. Umatov, C. Vilela, V. Vorobel, G. Warot, D. Waters, A. Zukauskas

(The NEMO–3 Collaboration)

Nuclear Physics A925 (2014) 25–36

Double beta decay of 100Mo to the excited states of daughter nuclei has been studied using a 600 cm3 low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic 100Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of 100Mo. The half-life for the two-neutrino double beta decay of 100Mo to the excited 01+ state in 100Ru is measured to be T1/2 = [7.5 ± 0.6(stat) ± 0.6(syst)] · 1020 yr. For other (0ν + 2ν) transitions to the 21+, 22+, 02+, 23+ and 03+ levels in 100Ru, limits are obtained at the level of ∼ (0.25 − 1.1) · 1022 yr.


2013

210Pb as a Marker of Natural Radioactivity : Would it Play a Role in Some Human Diseases ?

V. Beillet-Kovalenko, Ch. Marquet, J. Gaye, M. S. Pravikoff, Ph. Hubert

Nuclear Physics News, Vol. 23, No. 4, 2013, p. 24-28

Lead-210 is unknown to the general public but one of its daughters, polonium-210, made newspaper head-lines several times in 2006 and 2012. In 2006 the whole world learned that a former Russian KGB agent named Alexander Litvinenko had been poisoned by polonium-210, a powerful short-lived alpha emitter. The ingested poisoning activity was estimated to be more than 1–3 GBq, which is 6 μg of pure 210Po. The experts agree that it is an ideal weapon, impossible to detect with the naked eye and that a lethal dose can be held in a volume the size of a homeopathic pill. In 2012 we learned that traces of 210Po were found on the underwear, hat, and toothbrush of Yasser Arafat, the Palestinian leader who died in 2004. Calculation of the activity at the time of his death shows that poisoning with 210Po is not excluded. The different samples collected during the exhumation will probably answer the question. Those two spectacular cases raise the following question : if a huge dose of polonium is lethal and since this radioactive nucleus is very common in nature, what is the impact of a daily low dose on a human body ?

Nuclear Physics News Intl Double Beta Decay Experiments : Beginning of a New Era

Alexander Barabash & Fabrice Piquemal

Nuclear Physics News, Vol. 23, No. 3, 2013, p. 12-18

Interest in neutrinoless double beta decay (0νββ) has seen a significant renewal in the recent 10 years after evidence for neutrino oscillations was obtained from the results of atmospheric, solar, reactor, and accelerator neutrino experiments. These results are impressive proof that neutrinos have a nonzero mass. The detection and study of 0νββ decay may clarify the following problems of neutrino physics : (i) lepton number non-conservation, (ii) neutrino nature : whether the neutrino is a Dirac or a Majorana particle, (iii) absolute neutrino mass scale, (iv) the type of neutrino mass hierarchy (normal, inverted, or quasidegenerate), and (v) CP violation in the lepton sector (measurement of the Majorana CP-violating phases).

Future double beta decay experiments

F. Piquemal

Nuclear Physics B (Proc. Suppl.) 235–236 (2013) 273–280

The search of neutrinoless double beta decay is very challenging because of the expected half-life of the process and the backgrounds from the natural radioactivity. Many projects exist to try to reach a sensitivity of ∼ 50 meV on the effective neutrino mass corresponding to a mass of isotopes of ∼ 100 kg. In this article some of the futur projects are presented.


2012

Journal of Environmental Radioactivity

Evidence of 131I and 134,137Cs activities in Bordeaux, France due to the Fukushima nuclear accident

F. Perrot, P. Hubert, Ch. Marquet, M. S. Pravikoff, P. Bourquin, H. Chiron, Py. Guernion, A. Nachab

Journal of Environmental Radioactivity, Vol. 114, p.61, 2012

Following the Fukushima nuclear accident, low-background gamma spectrometry measurements were performed with HPGe detectors at the PRISNA platform located at the CENBG laboratory in Bordeaux, France. Different kinds of samples were collected and measured between March 26 and May 14, 2011. The first fission product observed was 131I with maximum activity values of 2.4 mBq/m3 in atmospheric dusts in air, 3.5 Bq/L in rain water, 15 Bq/kg in grass and 0.9 Bq/L in cow milk. The 134,137Cs isotopes were also detected in air and in grass at a maximum level of 0.2 mBq/m3 and 0.7 Bq/kg respectively, around one order of magnitude less than 131I activity, but they were below detection limits in the other samples. All these activity values were consistent with others measured in France by IRSN and were well below those reported in May 1986 after the Chernobyl accident.

Journal of Environmental Radioactivity

Air radioactivity levels following the Fukushima reactor accident measured at the Laboratoire Souterrain de Modane, France

P. Loaiza, V. Brudanin, F. Piquemal, J.-L. Reyss, I. Stekl, G. Warot, M. Zampaolo

Journal of Environmental Radioactivity 114 (2012) 66-70

The radioactivity levels in the air of the radionuclides released by the Fukushima accident were measured at the Laboratoire Souterrain de Modane, in the South-East of France, during the period 25 March -18 April 2011. Air-filters from the ventilation system exposed for one or two days were measured using low-background gamma-ray spectrometry. In this paper we present the activity concentrations obtained for the radionuclides 131I, 132Te, 134Cs, 137Cs, 95Nb, 95Zr, 106Ru, 140Ba/La and 103Ru. The activity concentration of 131I was of the order of 100 mBq/m3, more than 100 times higher than the activities of other fission products. The highest activities of 131I were measured as a first peak on 30 March and a second peak on 3e4 April. The activity concentrations of 134Cs and 137Cs varied from 5 to 30 mBq/m3. The highest activity concentration recorded for Cs corresponded to the same period as for 131I, with a peak on 2-3 April. The results of the radioactivity concentration levels in grass and mushrooms exposed to the air in the Modane region were also measured. Activity concentrations of 131I of about 100 mBq/m2 were found in grass.

The NEMO-3 results after completion of data taking

L Simard (On behalf ofthe Nemo-3 collaboration)

12th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2011)

IOP Publishing

Journal of Physics : Conference Series 375 (2012) 042011 DOI:10.1088/1742-6596/375/4/042011

The double beta decay experiment NEMO-3 has compleated data taking in January 2011. The aim of the experiment is to search for the neutrinoless double beta decay and investigate the two-neutrino double beta decay in seven different isotopes (100Mo, 82Se, 116Cd, 150Nd, 96Zr, 48Ca and 130Te). After analysis of the most part of available data corresponding to 4.5 yr no evidence for 0νββ decay in 100Mo and 82Se is found. The half-life limits at 90% C.L. are 1.0x1024 yr and 3.2x1023 yr respectively. The two-neutrino decay half live values were precisely measured for all investigated isotopes.

The NEMO-3 Experiment

R. B. Pahlka on behalf of the NEMO-3 Collaboration

Nuclear Physics B (Proc. Suppl.) 229–232 (2012) 491

The NEMO-3 (Neutrino Ettore Majorana Observatory) experiment, located in the Modane Underground Laboratory, is currently searching for neutrinoless double beta decay (0νββ). The experiment has been taking data since 2003 with seven double beta isotopes and is scheduled to complete data acquisition in late 2010. Two neutrino double beta decay (2νββ) results for the main isotopes (7 kg of 100Mo and 1 kg of 82Se), new results for 150Nd, as well as results for 96Zr, 48Ca, 130Te and 116Cd are presented. NEMO-3 uses a unique technique that allows for the in situ measurement of background contamination. No evidence for neutrinoless double beta decay has been found to date. The data are also interpreted in terms of alternative models such as weak right-handed currents and Majoron emission.


2011

Improved limits on β+EC and ECEC processes in Sn112

A.S. Barabash, Ph. Hubert, C. Marquet, A. Nachab, S. I. Konovalov, F. Perrot, F. Piquemal, V. Umatov

Physical Review C 83 (2011) 045503

Limits on β+EC and ECEC processes in Sn112 have been obtained using a 380 cm3 HPGe detector and an external source consisting of 100 g enriched tin (94.32% of Sn112). A limit with 90% C.L. on the Sn112 half-life of 1.3×1021 yr for the ECEC(0ν) transition to the 03+ excited state in Cd112 (1871 keV) has been established. This transition has been discussed in the context of a possible enhancement of the decay rate. The limits on other β+EC and ECEC processes in Sn112 have also been obtained on the level of (0.1-1.6)×1021 yr at the 90% C.L.

Measurement of the Double Beta Decay Half-life of 130Te with the NEMO-3 Detector

R. Arnold, C. Augier, J. Baker, A. S. Barabash, A. Basharina-Freshville, S. Blondel, M. Bongrand, G. Broudin-Bay, V. Brudanin, A. J. Caffrey, A. Chapon, E. Chauveau, D. Durand, V. A. Egorov, R. Flack, X. Garrido, J. Grozier, B. Guillon, Ph. Hubert, C. M. Jackson, S. Jullian, M. Kauer, A. Klimenko, O. Kochetov, S. I. Konovalov, V. V. Kovalenko, D. Lalanne, T. Lamhamdi, K. Lang, Z. Liptak, G. Lutter, F. Mamedov, Ch. Marquet, J. Martin-Albo, F. Mauger, J. Mott, A. Nachab4, I. Nemchenok, C. H. Nguyen, F. Nova, P. Novella, H. Ohsumi, R. B. Pahlka, F. Perrot, F. Piquemal, J. L. Reyss, B. Richards, J. S. Ricol, R. Saakyan, X. Sarazin, Yu. Shitov, L. Simard, F. Šimkovic, A. Smolnikov, S. Söldner-Rembold, I. Štekl, J. Suhonen, C. S. Sutton, G. Szklarz, J. Thomas, V. Timkin, S. Torre, V. I. Tretyak, V. Umatov, L. Vála, I. Vanyushin, V. Vasiliev, V. Vorobel, T. Vylov, A. Zukauskas

NEMO Collaboration(s)

Physical Review Letters 107 (2011) 062504

This Letter reports results from the NEMO-3 experiment based on an exposure of 1275 days with 661g of 130Te in the form of enriched and natural tellurium foils. With this data set the double beta decay rate of 130Te is found to be non-zero with a significance of 7.7 standard deviations and the half-life is measured to be T1/2 = (7.0 +/- 0.9(stat) +/- 1.1(syst)) x 10^20 yr. This represents the most precise measurement of this half-life yet published and the first real-time observation of this decay.

Spectral modeling of scintillator for the NEMO-3 and SuperNEMO detectors

J. Argyriades, R. Arnold, C. Augier, J. Baker, A.S. Barabash, M. Bongrand, G. Broudin-Bay, V.B. Brudanin, A.J. Caffrey, S. Cebrián, A. Chapon, E. Chauveau, Th. Dafni, Z. Daraktchieva, J. Díaz, D. Durand, V.G. Egorov, J.J. Evans, N. Fatemi-Ghomi, R. Flack, A. Basharina-Freshville, K.-I. Fushimi, X. Garrido, H. Gómez, B. Guillon4, A. Holin, K. Holy, J.J. Horkley, Ph. Hubert, C. Hugon, F.J. Iguaz, I.G. Irastorza, N. Ishihara, C.M. Jackson, S. Jullian, S. Kanamaru, M. Kauer, O. I. Kochetov, S.I. Konovalov, V.E. Kovalenko, D. Lalanne, K. Lang, Y. Lemière, G. Lutter, G. Luzón, F. Mamedov, Ch. Marquet, J. Martin-Albo, F. Mauger, F. Monrabal, A. Nachab, I. Nasteva, I.B. Nemchenok, Chi-Hung Nguyen, F. Nova, P. Novella, H. Ohsumi, R.B. Pahlka, F. Perrot, F. Piquemal5, P.P. Povinec, B. Richards, J.S. Ricol, C.L. Riddle, A. Rodriguez, R. Saakyan, X. Sarazin, J.K. Sedgbeer, L. Serra, L. Simard, F. Simkovic, Yu.A. Shitov, A.A. Smolnikov, S. Söldner-Rembold, I. Stekl, Y. Sugaya, C.S. Sutton, G. Szklarz1, Y. Tamagawa, J. Thomas, R. Thompson, V.V. Timkin, V.I. Tretyak, Vl.I. Tretyak, V.I. Umatov, L. Vála, I.A. Vanyushin, R. Vasiliev, V. Vorobel, Ts. Vylov, D. Waters, N. Yahlali, A. Zukauskas

Nuclear Instruments and Methods in Physics Research Research : Accelerators, Spectrometers, Detectors and Associated Equipment 625 (2011) 20-28

Proceedings of the First International Workshop on Multiple Partonic Interactions at the LHC (MPI08)

We have constructed a GEANT4-based detailed software model of photon transport in plastic scintillator blocks and have used it to study the NEMO-3 and SuperNEMO calorimeters employed in experiments designed to search for neutrinoless double beta decay. We compare our simulations to measurements using conversion electrons from a calibration source of ^207Bi and show that the agreement is improved if wavelength-dependent properties of the calorimeter are taken into account. In this article, we briefly describe our modeling approach and results of our studies.

Low background germanium planar detector for gamma-ray spectrometry

P. Loaiza-, C. Chassaing, Ph. Hubert, A. Nachab, F. Perrot, J.-L. Reyss, G.Warot

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment

Volume 634, Issue 1, 1 April 2011, Pages 64–70

A new ultra-low background planar germanium spectrometer has been developed. The planar geometry improves the sensitivity and energy resolution below 600 keV. The integral background counting rate in the Laboratoire Souterrain de Modane (4800 m water equivalent) in the energy range from 20 to 1500 keV for the planar Ge (mass around 800 g) is 140 counts/day. After 40 days of statistics, the background counting rates for all expected single lines are below 0.5count/day with the exception of 210Pb (46 keV line) which was measured to be (1.76+-0.25) counts /day. Monte-Carlo simulations have been performed to explain the origin of the remaining background and to calculate the detection efficiencies. Sensitivities around 1 mBq/kg are obtained within a fewdays of statistics for 226Ra and 228Th. The main achievement is the high sensitivities for 210Pb (46 keV line) and 238U (234Th : 63 and 93 keV lines). For an aluminum sample (mass 1 kg) the limits obtained in 15 days are 210P < 9 mBq/kg and 238U < 3mBq/kg.


2010

Probing New Physics Models of Neutrinoless Double Beta Decay with SuperNEMO

R. Arnold, C. Augier, J. Baker, A. S. Barabash, A. Basharina-Freshville, M. Bongrand, V. Brudanin, A. J. Caffrey, S. Cebrián, A. Chapon, E. Chauveau, Th. Dafni, F. F. Deppisch, J. Diaz, D. Durand, V. A. Egorov, J. J. Evans, R. Flack, K-I. Fushima, I. García Irastorza, X. Garrido, H. Gómez, B. Guillon, A. Holin, K. Holy, J. J. Horkley, Ph. Hubert, C. Hugon, F. J. Iguaz, N. Ishihara, C. M. Jackson, S. Jullian, M. Kauer, O. Kochetov, S. I. Konovalov, V. V. Kovalenko1, T. Lamhamdi, K. Lang, G. Lutter, G. Luzón, F. Mamedov, Ch. Marquet, F. Mauger, F. Monrabal, A. Nachab, I. Nasteva, I. Nemchenok, C. H. Nguyen6, M. Nomachi, F. Nova, H. Ohsumi6, R. B. Pahlka, F. Perrot, F. Piquemal, P. P. Povinec, B. Richards, J. S. Ricol, C. L. Riddle, A. Rodríguez, R. Saakyan, X. Sarazin, J. K. Sedgbeer, L. Serra, Yu. Shitov, L. Simard, F. Šimkovic, S. Söldner-Rembold, I. Štekl, C. S. Sutton, Y. Tamagawa, J. Thomas, V. Timkin, V. Tretyak, Vl. I. Tretyak, V. I. Umatov, I. A. Vanyushin, R. Vasiliev, V. Vasiliev, V. Vorobel, D. Waters, N. Yahlali, A. Žukauskas

SuperNEMO Collaboration(s)

European Physical Journal C 70 (2010) 927-943

The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double beta decay experiment SuperNEMO is discussed. Its ability to study different isotopes and track the outgoing electrons provides the means to discriminate different underlying mechanisms for the neutrinoless double beta decay by measuring the decay half-life and the electron angular and energy distributions.

Measurement of the two neutrino double beta decay half-life of Zr-96 with the NEMO-3 detector

J. Argyriades, R. Arnold, C. Augier, J. Baker, A.S. Barabash, A. Basharina-Freshville, M. Bongrand, G. Broudin-Bay, V. Brudanin, A.J. Caffrey, A. Chapon, E. Chauveau, Z. Daraktchieva, D. Durand, V. A. Egorov, N. Fatemi-Ghomi, R. Flack, B. Guillon4, Ph. Hubert, S. Jullian, M. Kauer, S. King, A. Klimenko, O. Kochetov, S.I. Konovalov, V. V. Kovalenko, D. Lalanne, T. Lamhamdi, K. Lang, Y. Lemière, C. Longuemare, G. Lutter, F. Mamedov, Ch. Marquet, J. Martin-albo, F. Mauger, A. Nachab, I. Nasteva, I. Nemchenok, Chi-Hung Nguyen, F. Nova, P. Novella, H. Ohsumi, R.B. Pahlka, F. Perrot, F. Piquemal, J.L. Reyss, J.S. Ricol, R. Saakyan, X. Sarazin1, Yu. Shitov, L. Simard1, F. Šimkovic, A. Smolnikov, S. Snow, S. Söldner-Rembold, I. Štekl, J. Suhonen, C.S. Sutton, G. Szklarz1, J. Thomas, V. Timkin, V.I. Tretyak, V. Umatov, L. Vála, I. Vanyushin, V. Vasiliev, V. Vorobel, Ts. Vylov

NEMO Collaboration(s)

Nuclear Physics A 847 (2010) 168-179

Using 9.4 g of 96Zr isotope and 1221 days of data from the NEMO-3 detector corresponding to 0.031 kg y, the obtained 2νββ decay half-life measurement is View the MathML source. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2ν nuclear matrix element is extracted using the measured 2νββ half-life and is M2ν=0.049±0.002. Constraints on 0νββ decay have also been set.

Results of the BiPo-1 prototype for radiopurity measurements for the SuperNEMO double beta decay source foils

J. Argyriades, R. Arnold, C. Augier, J. Baker, A. S. Barabash, A. Basharina-Freshville, M. Bongrand, C. Bourgeois, D. Breton, M. Briére, G. Broudin-Bay, V. B. Brudanin, A. J. Caffrey, S. Cebrián, A. Chapon, E. Chauveau, Th. Dafni, J. Díaz, D. Durand, V. G. Egorov, J. J. Evans, R. Flack, K-I. Fushima, I. G. Irastorza, X. Garrido, H. Gómez, B. Guillon, A. Holin, K Holy, J. J. Horkey, P. Hubert, C. Hugon, F. J. Iguaz, N. Ishihara, C. M. Jackson, S. Jenzer, S. Jullian, M. Kauer, O. I. Kochetov, S. I. Konovalov, V. V. Kovalenko, T. Lamhamdi, K. Lang, Y. Lemière, G. Lutter, G. Luzón, F. Mamedov, Ch. Marquet, F. Mauger, F. Monrabal, A. Nachab, I. B. Nemchenok, C. H. Nguyen, M. Nomachi, F. Nova, H. Ohsumi, R. B. Pahlka, F. Perrot, F. Piquemal, P. P. Povinec, B. Richards, J. S. Ricol, C. L. Riddle, A. Rodríguez, R. Saakyan, X. Sarazin1, J. K. Sedgbeer, L. Serra, Yu. A. Shitov, L. Simard1, F. Šimkovic, S. Söldner-Rembold, I. Štekl, C. S. Sutton, Y. Tamagawa, G. Szklarz1, J. Thomas, V. Timkin, V. Tretyak, Vl. I. Tretyak, V. I. Umatov, L. Vála, I. A. Vanyushin, R. Vasiliev, V. A. Vasiliev, V. Vorobel, D. Waters, N. Yahali6, A. Žukauskas, J. Hommet

SuperNEMO Collaboration(s)

Nuclear Instruments and Methods in Physics Research Research : Accelerators, Spectrometers, Detectors and Associated Equipment 622 (2010) 120-128

The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in 208Tl and 214Bi for the SuperNEMO double beta decay source foils. A modular prototype, called BiPo-1, with 0.8 $m2 of sensitive surface area, has been running in the Modane Underground Laboratory since February, 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in 208Tl. After more than one year of background measurement, a surface activity of the scintillators of A208Tl) $ 1.5 µBq/m2 is reported here. Given this level of background, a larger BiPo detector having 12 m2 of active surface area, is able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A208Tl < 2 µBq/kg (90% C.L.) with a six month measurement.

Search for neutrinoless double beta decay - NEMO3 and SuperNEMO

Marquet C.

In PoS - Proceedings of Science - 35th International Conference On High Energy Physics (ICHEP2010), France (2010), 307

.

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Reactor neutrinos, double beta and beta decays experimental review

Piquemal F.

In PoS - Proceedings of Science - 35th International Conference On High Energy Physics (ICHEP2010), France (2010), 553

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2009

Radioactivity measurements applied to the dating and authentication of old wines

Ph. Hubert, F. Perrot, J. Gaye, B. Médina, M.S. Pravikoff

Comptes Rendus Physique, Volume 10, Issue 7, Pages 622-629 (2009)

For many years the neutrino group in the CENBG has been involved in the development of low background γ-ray spectrometers, based on the use of HPGe crystals. When applied to radioactivity measurements of wine in bottles, it has been shown that besides the well-known isotope 40K, the wine contains also trace amounts of 137Cs (less than 1 Bq/l) with an activity depending on the vintage. This technique has thus led to the possibility to date the wine bottles of vintages between 1952 and ∼1980 and to verify the year written on the label or on the cork. Since the measurements do not require opening the bottle, the technique has also proved to be very useful for detecting counterfeit wines of the XIXth century and first half of the XXth century.

Measurement of the double-β decay half-life of 150Nd and search for neutrinoless decay modes with the NEMO-3 detector

J. Argyriades, R. Arnold, C. Augier, J. Baker, A.S. Barabash, A. Basharina-Freshville, M. Bongrand, G. Broudin, V. Brudanin, A.J. Caffrey, E. Chauveau, Z. Daraktchieva, D. Durand, V. A. Egorov, N. Fatemi-Ghomi, R. Flack, Ph. Hubert, J. Jerie, S. Jullian1, M. Kauer, S. King, A. Klimenko, O. Kochetov, S.I. Konovalov, V. V. Kovalenko, D. Lalanne, T. Lamhamdi, K. Lang, Y. Lemière, C. Longuemare, G. Lutter, Ch. Marquet, J. Martin-albo, F. Mauger, A. Nachab, I. Nasteva, I. Nemchenok, F. Nova, P. Novella, H. Ohsumi, R.B. Pahlka, F. Perrot, F. Piquemal, J.L. Reyss, J.S. Ricol, R. Saakyan, X. Sarazin, L. Simard1, F. Simkovic, Yu. Shitov, A. Smolnikov, S. Snow, S. Soldner-Rembold, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, J. Thomas, V. Timkin, V. Tretyak, V. Umatov, L. Vala, I. Vanyushin, V. Vasiliev, V. Vorobel, Ts. Vylov

NEMO Collaboration(s)

Physical Review C 80 (2009) 032501

The half-life for double-β decay of 150Nd has been measured by the NEMO-3 experiment at the Modane Underground Laboratory. Using 924.7 days of data recorded with 36.55 g of 150Nd, we measured the half-life for 2νββ decay to be T 2ν 1/2 = (9.11+0.25 −0.22(stat.) ± 0.63(syst.)) × 1018 yr. The observed limit on the half-life for neutrinoless double-β decay is found to be T 0ν 1/2 > 1.8 × 1022 yr at 90% confidence level. This translates into a limit on the effective Majorana neutrino mass of (mν ) < 4.0-6.3 eV if the nuclear deformation is taken into account. We also set limits on models involving Majoron emission, right-handed currents, and transitions to excited states.

Measurement of the background in the NEMO 3 double beta decay experiment

J. Argyriades, R. Arnold, C. Augier, J. Baker, A. S. Barabash, M. Bongrand, G. Broudin-Bay, V. B. Brudanin, A. J. Caffrey, A. Chapon, E. Chauveau, Z. Daraktchieva, D. Durand, V. G. Egorov, N. Fatemi-Ghomi, R. Flack, A. Freshville, B. Guillon, Ph. Hubert, S. Jullian, M. Kauer, S. King, O. I. Kochetov, S. I. Konovalov, V. E. Kovalenko, D. Lalanne, K. Lang, Y. Lemière, G. Lutter, F. Mamedov, Ch. Marquet, J. Martin-Albo, F. Mauger, A. Nachab, I. Nasteva, I. B. Nemchenok, C. H. Nguyen, F. Novam, P. Novella, H. Ohsumi, R. B. Pahlka, F. Perrot, F. Piquemal, J. L. Reyss, J. S. Ricol, R. Saakyan, X. Sarazin, L. Simard, Yu. A. Shitov, A. A. Smolnikov, S. Snow, S. Söldner-Rembold, I. Setekl, C. S. Sutton, G. Szklarz, J. Thomas, V. V. Timkin, V. I. Tretyak-, Vl. I. Tretyak, V. I. Umatov, L. Vala, I. A. Vanyushin, V. A. Vasiliev, V. Vorobel, Ts. Vylov

NEMO Collaboration(s)

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment

Volume 606, Issue 3, 21 July 2009, Pages 449–465

In the double beta decay experiment NEMO3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO3 to evaluate the backgrounds resulting from most if not all possible origins. It also illustrates the power of the combined tracking-calorimetry technique used in the experiment.

Investigation of beta beta decay in 150Nd and 148Nd to the excited states of daughter nuclei

A. S. Barabash, Ph. Hubert, A. Nachab, V. I. Umatov

Physical Review C 79 (2009) 045501

Double beta decay of 150Nd and 148Nd to the excited states of daughter nuclei have been studied using a 400 cm3 low-background HPGe detector and an external source consisting of 3046 g of natural Nd_2O3 powder. The half-life for the two-neutrino double beta decay of 150Nd to the excited 0+1 state in 150Sm is measured to be T1/2=1.33+0.36-0.23(stat)+0.27_-0.13(syst)] 10.20 y. For other (0v + 2v) transitions to the 2^+_1, ^+_2, 2^+_3, and 0^+_2 levels in 150Sm, limits are obtained at the level of $\sim (2-8)\cdot 1020 y. In the case of 148Nd only limits for the (0\nu + 2\nu) transitions to the 2^+_1, 0^+_1, and 2^+2 excited states in 148Sm were obtained and are at the level of \sim (4-8)\cdot 1020 y.

Modeling of 137Cs migration in soils using an 80-year soil archive : role of fertilizers and agricultural amendment

F. Monna, F. van Oort, Ph. Hubert, J. Dominik, J. Bolte, J.-L. Loizeau, J. Labanowski, J. Lamri, C. Petit, G. Le Roux, C. Chateau

Journal of Environmental Radioactivity

Volume 100, Issue 1, January 2009, Pages 9–16

An 80-year soil archive, the 42-plot experimental design at the INRA in Versailles (France), is used here to study long-term contamination by 137Cs atmospheric deposition and the fate of this radioisotope when associated with various agricultural practices : fallow land, KCl, NH4(NO3), superphosphate fertilizers, horse manure and lime amendments. The pertinence of a simple box model, where radiocaesium is supposed to move downward by convectional mechanisms, is checked using samples from control plots which had been neither amended, nor cultivated since 1928. This simple model presents the advantage of depending on only two parameters : a, a proportional factor allowing the historical atmospheric 137Cs fluxes to be reconstructed locally, and k, an annual loss coefficient from the plow horizon. Another pseudo-unknown is however necessary to run the model : the shape of historical 137Cs deposition, but this function can be easily computed by merging several curves previously established by other surveys. A loss of 1.5% per year from the plow horizon, combined with appropriate fluxes, provides good concordance between simulated and measured values. In the 0–25 cm horizon, the residence half time is found to be 18 yr (including both migration and radioactive decay). Migration rate constants are also calculated for some plots receiving continuous long-term agricultural treatments. Comparison with the control plots reveals significant influence of amendments on 137Cs mobility in these soils developed from a unique genoform.


2006

Limits on different majoron decay modes of 100Mo and 82Se for neutrinoless double beta decays in the NEMO-3 experiment

R. Arnold, C. Augier, J. Baker, A.S. Barabash, V. Brudanin, A.J. Caffrey, E. Caurier, V. Egorov, K. Errahmane, A.I. Etienvre, J.L. Guyonnet, F. Hubert, Ph. Hubert, C. Jollet, S. Jullian, S. King, O. Kochetov, S. Konovalov, V. Kovalenko, D. Lalanne, F. Leccia, C. Longuemare, G. Lutter, Ch. Marquet, F. Mauger, F. Nowacki, H. Ohsumi, F. Piquemal, J.-L. Reyss, R. Saakyan, X. Sarazin, Yu. Shitov, L. Simard, F. Simkovic, A. Smolnikov, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, V. Timkin, J. Thomas, V. Tretyak, V. Umatov, L. Vala, I. Vanyushin, V. Vasilyev, V. Vorobel, Ts. Vylov

NEMO Collaboration

Nucl. Phys. A 765 (2006) 483-494

The NEMO-3 tracking detector is located in the Fréjus Underground Laboratory. It was designed to study double beta decay in a number of different isotopes. Presented here are the experimental half-life limits on the double beta decay process for the isotopes 100Mo and 82Se for different majoron emission modes and limits on the effective neutrino–majoron coupling constants. In particular, new limits on “ordinary” majoron (spectral index 1) decay of 100Mo (T1/2 > 2.7 × 1022 yr) and 82Se (T1/2 > 1.5 × 1022 yr) have been obtained. Corresponding bounds on the majoron–neutrino coupling constant are -gee- < (0.4–1.8) ×10−4 and < (0.66–1.9)×10−4.


2005

Measurement of Neutrino Oscillation with KamLAND : Evidence of Spectral Distortion

The KamLAND Collaboration

T. Araki, K. Eguchi, S. Enomoto, K. Furuno, K. Ichimura, H. Ikeda, K. Inoue, K. Ishihara,- T. Iwamoto, T. Kawashima, Y. Kishimoto, M. Koga, Y. Koseki, T. Maeda, T. Mitsui, M. Motoki, K. Nakajima, H. Ogawa, K. Owada, J.-S. Ricol, I. Shimizu, J. Shirai, F. Suekane, A. Suzuki, K. Tada, O. Tajima, K. Tamae, Y. Tsuda, H. Watanabe, J. Busenitz, T. Classen, Z. Djurcic, G. Keefer, K. McKinny, D.-M. Mei, A. Piepke, E. Yakushev, B.E. Berger, Y.D. Chan, M.P. Decowski, D.A. Dwyer, S.J. Freedman, Y. Fu, B.K. Fujikawa, J. Goldman, F. Gray, K.M. Heeger, K.T. Lesko, K.-B. Luk, H. Murayama, A.W.P. Poon, H.M. Steiner, L.A. Winslow, G.A. Horton-Smith, C. Mauger, R.D. McKeown, P. Vogel, C.E. Lane, T. Miletic,5 .W. Gorham, G. Guillian, J.G. Learned, J. Maricic, S. Matsuno, S. Pakvasa, S. Dazeley, S. Hatakeyama, A. Rojas, R. Svoboda, B.D. Dieterle, J. Detwiler, G. Gratta, K. Ishii, N. Tolich, Y. Uchida, — M. Batygov, W. Bugg, Y. Efremenko, Y. Kamyshkov, A. Kozlov, Y. Nakamura, C.R. Gould, H.J. Karwowski, D.M. Markoff, J.A. Messimore, K. Nakamura, R.M. Rohm, W. Tornow, R. Wendell, A.R. Young, M.-J. Chen, Y.-F. Wang, and F. Piquemal

Phys. Rev. Lett. 94 (2005) 081801

We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 ν¯e candidate events with energies above 3.4 MeV compared to 365.2±23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8±7.3 expected background events, the statistical significance for reactor ν¯e disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from ν¯e oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Δm2=7.9+0.6−0.5×10−5  eV2. A global analysis of data from KamLAND and solar-neutrino experiments yields Δm2=7.9+0.6−0.5×10−5  eV2 and tan2θ=0.40+0.10−0.07, the most precise determination to date.

First results of the search for neutrinoless double beta decay with the NEMO 3 detector

R. Arnold, C. Augier, J. Baker, A. Barabasf , G. Broudin, V. Brudanin, A.J. Caffrey, E. Caurier, V. Egorov, K. Errahmane, A.I. Etienvre, J.L. Guyonnet, F. Hubert, Ph. Hubert, C. Jollet, S. Jullian, O. Kochetov, V. Kovalenko, S. Konovalov , D. Lalanne, F. Leccia, C. Longuemare, G. Lutter, Ch. Marquet, F. Mauger, F. Nowacki, H. Ohsumi, F. Piquemal, J.L. Reyss, R. Saakyan, X. Sarazin, L. Simard, F. Simkovic, Yu. Shitov, A. Smolnikov, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, J. Thomas, V. Timkin, V. Tretyak, V. Umatov , L. Vala, I. Vanushin , V. Vasilyev, V. Vorobel and Ts. Vylov

Phys. Rev. Lett. 95 (2005) 182302

The NEMO 3 detector, which has been operating in the Frejus underground laboratory since February 2003, is devoted to the search for neutrinoless double beta decay (ββ0ν). Half-lives of the two neutrino double beta decays (ββ2ν) have been measured for 100Mo and 82Se. After 389 effective days of data collection from February 2003 until September 2004 (Phase I), no evidence for neutrinoless double beta decay was found from 7 kg of 100Mo and 1 kg of 82Se. The corresponding lower limits for the half-lives are 4.6 x 1023 years for 100Mo and 1.0 x1023 years for 82Se (90 % C.L.). Depending on the nuclear matrix elements calculation, limits for the effective Majorana neutrino mass are mν < 0.7-2.8 eV for 100Mo and mν < 1.7-4.9 eV for 82Se

Technical design and performance of the NEMO 3 detector

R. Arnold, C. Augier-, A.M. Bakalyarov, J. Baker, A. Barabash, Ph. Bernaudin, M. Bouchel, V. Brudanin, A.J. Caffrey, J. Cailleret, J.E. Campagne, D. Dassé, V. Egorov, K. Errahmane, A.I. Etienvre, T. Filipova, J. Forget, A. Guiral, P. Guiral, J.L. Guyonnet, F. Hubert, Ph. Hubert, B. Humbert, R. Igersheim, P. Imbert, C. Jollet, S. Jullian, I. Kisel, A. Klimenko, O. Kochetov, V. Kovalenko, D. Lalanne, F. Laplanche, B. Lavigne, V.I. Lebedev, J. Lebris, F. Leccia, A. Leconte, I. Linck, C. Longuemare, Ch. Marquet, G. Martin-Chassard, F. Mauger, I. Nemchenok, I. Nikolic-Audit, H. Ohsumi, S. Pécourt, F. Piquemal, J.L. Reyss, A. Richard, C.L. Riddle, J. Rypko, X. Sarazin, L. Simard, F. Scheibling, Yu. Shitov, A. Smolnikov, I. Sötekl, C.S. Sutton, G. Szklarz, V. Timkin, V. Tretyak, V. Umatov, L. Valab, I. Vanushin, S. Vasiliev, V. Vasilyev, V. Vorobel, Ts. Vylov, J. Wurtz, S.V. Zhukov

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 536, Issues 1–2, 1 January 2005, Pages 79-122

The development of the Neutrino Ettore Majorana Observatory (NEMO 3) detector, which is now running in the Fréjus Underground Laboratory (L.S.M. Laboratoire Souterrain de Modane), was begun more than ten years ago. The NEMO 3 detector uses a tracking-calorimeter technique in order to investigate double beta decay processes for several isotopes. The technical description of the detector is followed by the presentation of its performance.

Experimental investigation of geologically produced antineutrinos with KamLAND

T. Araki, S. Enomoto, K. Furuno, Y. Gando, K. Ichimura, H. Ikeda, K. Inoue, Y. Kishimoto, M. Koga, Y. Koseki, T. Maeda, T. Mitsui, M. Motoki, K. Nakajima, H. Ogawa, M. Ogawa, K. Owada, J.-S. Ricol, I. Shimizu, J. Shirai, F. Suekane, A. Suzuki, K. Tada, S. Takeuchi, K. Tamae, Y. Tsuda, H. Watanabe, J. Busenitz, T. Classen, Z. Djurcic, G. Keefer, D. Leonard, A. Piepke, E. Yakushev, B.E. Berger, Y.D. Chan, M.P. Decowski, D.A. Dwyer, S.J. Freedman, B.K. Fujikawa, J. Goldman, F. Gray, K.M. Heeger, L. Hsu, K.T. Lesko, K.-B. Luk, H. Murayama, T. O’Donnell, A.W.P. Poon, H.M. Steiner, L.A. Winslow, C. Mauger, R.D. McKeown, P. Vogel, C.E. Lane, T. Miletic, G. Guillian, J.G. Learned, J. Maricic, S. Matsuno, S. Pakvasa, G.A. Horton-Smith, S. Dazeley, S. Hatakeyama, A. Rojas, R. Svoboda, B.D. Dieterle, J. Detwiler, G. Gratta, K. Ishii, N. Tolich, Y. Uchida, M. Batygov, W. Bugg, Y. Efremenko, Y. Kamyshkov, A. Kozlov, Y. Nakamura, H.J. Karwowski, D.M. Markoff, K. Nakamura, R.M. Rohm, W. Tornow, R. Wendell, M.-J. Chen, Y.F. Wang, F. Piquemal

Nature 436, 499-503 (28 July 2005)

The detection of electron antineutrinos produced by natural radioactivity in the Earth could yield important geophysical information. The Kamioka liquid scintillator antineutrino detector (KamLAND) has the sensitivity to detect electron antineutrinos produced by the decay of 238U and 232Th within the Earth. Earth composition models suggest that the radiogenic power from these isotope decays is 16 TW, approximately half of the total measured heat dissipation rate from the Earth. Here we present results from a search for geoneutrinos with KamLAND. Assuming a Th/U mass concentration ratio of 3.9, the 90 per cent confidence interval for the total number of geoneutrinos detected is 4.5 to 54.2. This result is consistent with the central value of 19 predicted by geophysical models. Although our present data have limited statistical power, they nevertheless provide by direct means an upper limit (60 TW) for the radiogenic power of U and Th in the Earth, a quantity that is currently poorly constrained.


2004

Double-beta decay of 150Nd to the first 0+ excited state of 150 Sm : Current state

A. S. Barabash, F. Hubert, Ph. Hubert, V. I. Umatov

Physics of Atomic Nuclei, March 2004, Volume 67, Issue 3, pp 453-456

Two-neutrino double-beta decay of 150Nd to the first 0+ excited state in 150Sm is investigated with the 400 cm3 low-background HPGe detector. Preliminary data analysis for 6843 h shows an excess of events at 333.9 and 406.5 keV. If this excess is assigned to the investigated transition, then its half-life can be estimated at [1.2−0.3+0.5 ±0.4(syst.)]×1020 yr.


2003

Possible background reductions in double beta decay experiments

R. Arnold, C. Augier, J. Baker, A.S. Barabash, O. Bing, V. Brudanin, A.J. Caffrey, E. Caurier, K. Errahmane, A.-I. Etienvre, J.L. Guyonnet, F. Hubert, Ph. Hubert, C. Jollet, S. Jullian, O. Kochetov, V. Kovalenko, D. Lalanne, F. Leccia, C. Longuemare, Ch. Marquet, F. Mauger, H.W. Nicholson, H. Ohsumi, F. Piquemal, J.-L. Reyss, X. Sarazin, Yu. Shitov, L. Simard, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, V. Timkin, V. Tretyak, V. Umatov, L. V !ala, I. Vanyushi

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 503, Issue 3, 11 May 2003, Pages 649-657

The background induced by radioactive impurities of 208Tl and 214Bi in the source of the double beta experiment NEMO-3 has been investigated. New methods of data analysis which decrease the background from the above mentioned contamination are identified. The techniques can also be applied to other double beta decay experiments capable of measuring independently the energies of the two electrons.


2002

Gamma-ray flux in the Fréjus underground laboratory measured with NaI detector

NEMO Collaboration

H. Ohsumi, R. Gurriaran, Ph. Hubert, R. Arnold, C. Augier, J. Baker, A. Barabash, O. Bing, V. Brudanin, A.J. Caffrey, J.E. Campagne, E. Caurier, D. Dassié, V. Egorov, K. Errahmane, R. Eschbach, T. Filipova, J.L. Guyonnet, F. Hubert, C. Jollet, S. Jullian, I. Kisel, A. Klimenko, O. Kochetov, V.N. Kornoukhov, V. Kovalenko, V. Kuzichev, D. Lalanne, F. Laplanche, F. Leccia, I. Linck, C. Longuemare, Ch. Marquet, F. Mauger, H.W. Nicholson, I. Nikolic-Audit, F. Piquemal, J.L. Reyss, X. Sarazin, A. Smolnikov, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, V. Timkin, V. Tretyak, V. Umatov, L. Vala, I. Vanyushin, A. Vareille, V. Vasiliev, S. Vasiliev, V. Vorobel, Ts. Vylof

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 482, Issue 3, 21 April 2002, Pages 832-839

The γ-ray flux in the Fréjus underground laboratory has been studied using an NaI detector surrounded by different diagonostic shields. Below 4 MeV, the spectrum is dominated by radioactivities in the surrounding materials and rocks. Between 4 and 6 MeV, the shape of the spectrum is well explained by U, Th and daughters, which are internal contaminations in the NaI crystal. Between 6 and 10 MeV, the γ-ray flux is strongly correlated with neutron captures in the surrounding materials. Finally, the γ-ray flux above 10 MeV falls off and is related to the very weak cosmic muon flux via muon Bremsstrahlung.


2001

Chemical purification of molybdenum samples for the NEMO 3 experiment

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

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 474, Issue 1, 21 November 2001, Pages 93-100

Most currently, viable double beta decay experiments require highly enriched isotopic sources. These sources must be extraordinarily free of radioactive contamination. The double beta decay experiment NEMO 3 will study 100Mo, for which physical and chemical purification techniques have been investigated. The success of the chemical purification process is discussed in the context of ultra-low background, high-purity germanium spectrometer measurements.

Influence of neutrons and gamma-rays in the Fréjus underground laboratory on the NEMO experiment

NEMO collaboration

Ch. Marquet, F. Piquemal, R. Arnold, C. Augier, J. Baker, A. Barabash, O. Bing, D. Blum, V. Brudanin, J. Ca !rey, J.E. Campagne, E. Caurier, D. Dassié, V. Egorov, K. Errahmane, R. Eschbach, T. Filipova, J.L. Guyonnet, C. Jollet, S. Jullian, F. Hubert, Ph. Hubert, I. Kisel, O. Kochetov, V.N. Kornoukhov, V. Kovalenko, D. Lalanne, F. Laplanche, F. Leccia, I. Linck, C. Longuemare, F. Mauger, H.W. Nicholson, I. Nikolic-Audit, H. Ohsumi, I. Pilugin, J.L. Reyss, X. Sarazin, F. Scheibling, I. Stekl, J. Suhonen, C.S. Sutton, G. Szklarz, V. Timkin, V. Tretyak, V. Umatov, L. Vala, I. Vanyushin, A. Vareille, V. Vorobel, Ts. Vylov

Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment

Volume 457, Issue 3, 21 January 2001, Pages 487–498

To be sensitive to an effective Majorana neutrino mass, 〈mν〉, on the order of 0.1 eV, the NEMO 3 double beta (ββ(0ν)) decay experiment requires precise knowledge and control of the backgrounds. The effect of neutrons and γ-rays from the Fréjus underground laboratory (LSM, Laboratoire Souterrain de Modane) has been studied during 10 700 h of data collection. The data were taken with a NEMO 2 prototype detector using different shield configurations. Monte Carlo calculations with GEANT/MICAP code and a new library of γ-rays from neutron captures are presented. The implied consequences for the NEMO 3 detector which is under construction are discussed. The neutrinoless double beta decay background induced by neutrons and γ-rays within the LSM will be suppressed to the very suitable level of 0.1 event in a live time of five years given the appropriate shield and magnetic field.


2000

Testing the Pauli exclusion principle with the NEMO-2 detector

NEMO Collaboration

presented by Barabash A.S.

Nuclear Physics B - Proceedings Supplements

Volume 87, Issues 1–3, June 2000, Pages 510–511

Proceedings of the Sixth International Workshop on Topics in Astroparticle and Underground Physics

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Limits on different Majoron decay modes of 100Mo, 116Cd, 82Se and 96Zr for neutrinoless double beta decays in the NEMO-2 experiment

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, 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. Umatov, I. Vanyushin, A. Vareille, V. Vasilyev, Ts. Vylov

Nuclear Physics A

Volume 678, Issue 3, 9 October 2000, Pages 341–352

The NEMO-2 tracking detector located in the Fréjus Underground Laboratory was designed as a prototype for the NEMO-3 detector and to study different modes of double beta decay. Measurements with 100Mo, 116Cd, 82Se and 96Zr were carried out. Presented here are the experimental half-life limits on double beta decays for new Majoron emission modes and limits on effective neutrino–Majoron coupling constants.


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.