Measurement of double beta decay of ¹⁰⁰Mo to excited states in the NEMO 3 experiment

The double beta decay of ¹⁰⁰Mo to the 0_{1}^{+} and 2_{1}^{+} excited states of ¹⁰⁰Ru is studied using the NEMO 3 data. After the analysis of 8024 h of data the half-life for the two-neutrino double beta decay of ¹⁰⁰Mo to the excited 0_{1}^{+} state is measured to be T_{1/2}^{2v} = [5.7_{-0.9}^{+1.3} (stat.) ± 0.8 (syst.)] x 10²⁰ y. The signal-to-background ratio is equal to 3. Information about energy and angular distributions of emitted electrons is also obtained. No evidence for neutrinoless double beta decay to the excited 0_{1}^{+} state has been found. The corresponding half-life limit is T_{1/2}^{0v} (0⁺→0_{1}^{+}) > 8.9 x 10²² y (at 90% C.L.). The search for the double beta decay to the 2_{1}^{+} excited state has allowed the determination of limits on the half-life for the two neutrino mode T_{1/2}^{0v} (0⁺→2_{1}^{+}) > 1.1 x 10²¹ y (at 90% C.L.) and for the neutrinoless mode T_{1/2}^{0v} (0⁺→2_{1}^{+}) > 1.6 x 10²³ y (at 90% C.L.)

Measurement of double beta decay of 100Mo to excited states in the NEMO 3 experiment

The double beta decay of 100Mo to the 0^+_1 and 2^+_1 excited states of 100Ru is studied using the NEMO 3 data. After the analysis of 8024 h of data the half-life for the two-neutrino double beta decay of 100Mo to the excited 0^+_1 state is measured to be T^(2nu)_1/2 = [5.7^{+1.3}_{-0.9}(stat)+/-0.8(syst)]x 10^20 y. The signal-to-background ratio is equal to 3. Information about energy and angular distributions of emitted electrons is also obtained. No evidence for neutrinoless double beta decay to the excited 0^+_1 state has been found. The corresponding half-life limit is T^(0nu)_1/2(0^+ --> 0^+_1) > 8.9 x 10^22 y (at 90% C.L.). The search for the double beta decay to the 2^+_1 excited state has allowed the determination of limits on the half-life for the two neutrino mode T^(2nu)_1/2(0^+ --> 2^+_1) > 1.1 x 10^21 y (at 90% C.L.) and for the neutrinoless mode T^(0nu)_1/2(0^+ --> 2^+_1) > 1.6 x 10^23 y (at 90% C.L.).Comment: 23 pages, 7 figures, 4 tables, submitted to Nucl. Phy

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

The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in $^{208}$Tl and $^{214}$Bi for the SuperNEMO double beta decay source foils. A modular prototype, called BiPo-1, with 0.8 $m^2$ 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 $^{208}$Tl. After more than one year of background measurement, a surface activity of the scintillators of $\mathcal{A}$($^{208}$Tl) $=$ 1.5 $\mu$Bq/m$^2$ is reported here. Given this level of background, a larger BiPo detector having 12 m$^2$ of active surface area, is able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of $\mathcal{A}$($^{208}$Tl) $<$ 2 $\mu$Bq/kg (90% C.L.) with a six month measurement.Comment: 24 pages, submitted to N.I.M.

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

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 $\rm ^{207}Bi$ 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.Comment: 16 pages, 10 figure

A large‑scale comparison of reproduction and recruitment of the stalked barnacle Pollicipes pollicipes across Europe

Understanding large-scale spatial and temporal patterns of marine populations is a central goal in ecology, which has received renewed attention under climate change. However, few studies explore the large-scale dynamics of populations using standardized protocols and during the same time frames. We studied the phenology and intensity of reproduction and recruitment for the intertidal stalked barnacle Pollicipes pollicipes over an European scale and described their potential linkages with environmental variables. This species supports profitable fisheries in the Iberian Peninsula (Spain and Portugal). In Brittany (France), we had observed a significant lower reproductive effort (long non-breeding season, short breeding period in summer) and low values of recruitment intensity. This pattern may be related to the fact that Brittany corresponds to the northern limit of the distribution of this species in continental Europe. On the Iberian Peninsula, the most different region was Galicia (Spain), with Asturias (Spain) and SW Portugal being more similar. In Galicia, we have observed a contradictory pattern characterized by the absence of a non-breeding period and by a shorter recruitment season than observed in other Iberian regions. Our results suggest that air temperature, SST and chlorophyll-a might be related to the variability in reproduction and recruitment patterns of P. pollicipes. Moreover, spring and early summer upwelling in SW Portugal and Galicia might be inhibiting recruitment in this period. At the northern limit, the expected increase in performance under climate change might facilitate the recovery of populations after exploitation, increasing the resilience of the resource to fishing pressure

Measurement of the beta beta Decay Half-Life of Te-130 with the NEMO-3 Detector

We report results from the NEMO-3 experiment based on an exposure of 1275 days with 661 g of Te-130 in the form of enriched and natural tellurium foils. The beta beta decay rate of Te-130 is found to be greater than zero with a significance of 7.7 standard deviations and the half-life is measured to be T-1/2(2v)=[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

Displacement fields evolution in plain strain grooved tensile (PSGT) specimens during traction and creep loading

International audienceHigh Density PolyEthylene (HDPE) is a material widely used for the distribution of drinking water and gas. ISO/TC 138 provides test methods for determining the resistance to internal pressure, due to water flow, which are essential for assessing the properties and durability of thermoplastics piping system parts [1]. These test methods constitute a basis for the determination of short-term and long-term strength characteristics. However, with regard to moulding materials for pipes and fittings, until the publication of the ISO 23228:2011 [2], no satisfactory test method has existed in which the material can be exposed to stress conditions that mimic internally pressurized pipes.The method specified has been shown to replicate the stress conditions of internally pressurized end-capped pipes by the use of plaque specimen. Plain strain grooved tensile (PSGT) specimens produces a biaxial state of stress on uni-axial loading, which is taken to be indicative of the stress conditions found in pressurized solid-wall plastics pipes. This method is useful for evaluating the stress-rupture resistance of moulding materials and experimental resins being developed for pipes and fittings as well as for those pipes that are difficult to test, such as larger diameter pipes.In this study, PSGT specimens were cut-out from HDPE pipes. Both the thickness axial and transverse displacements fields were followed with a Digital Image Correlation (DIC) camera during monotonic traction and creep loading. The experimental data observations, under the light of the ISO standard [2], will be discussed.[1] ISO/TC 138, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids – Determination of the resistance to internal pressure, 1167-1:2006(E), 2006.[2] ISO/TC 138, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids – Determination of the stress-rupture resistance of moulding materials using plain strain grooved tensile (PSGT) specimens, 23228:2011(E), 2011

IMPECAPE « Étude des pressions et impacts des activités humaines sur les habitats benthiques côtiers pour la mise au point d’indicateurs et de protocoles de surveillance de l’état écologique de ces habitats »

Ce rapport présente les travaux réalisés dans le cadre du projet IMPECAPE sur l’étude des pressions et impacts des activités humaines sur les habitats benthiques côtiers pour la mise au point d’indicateurs et de protocoles de surveillance de l’état écologique dans le cas spécifique de l’extraction minière sur les sables fins à moyens du site Natura 2000 « Baie de Morlaix » (FR5300015 et FR5310073). Après un rappel des objectifs du projet, il présente la stratégie d’échantillonnage mise en oeuvre, et les résultats obtenus sur les caractéristiques biocénotiques de la communauté étudiée. Le volet ‘Développement et test d’indicateurs’ sera traité à l’échelle de l’ensemble des acteurs du projet IMPECAPE et non pas sur l’exemple particulier de la baie de Morlaix

Current events in immunotherapy for upper aerodigestive tract cancer

International audienc