The Billotron is a device designed and built by the LPC Caen to illustrate the methods with which physicists are able to study the basic structure of matter, in particular the nucleus of the atom.
We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-β decay of ^{150}Nd using a total exposure of 0.19 kg yr recorded with the ...NEMO-3 detector at the Modane Underground Laboratory. We find no evidence of this decay and set lower limits on the half-life in the range T_{1/2}>(1.1-3.2)×10^{21} yr at the 90% C.L., depending on the model used for the kinematic distributions of the emitted electrons.
Abstract The full data set of the NEMO-3 experiment has been used to measure the half-life of the two-neutrino double beta decay of $$^{100}$$ 100 Mo to the ground state of $$^{100}$$ 100 Ru, ...$$T_{1/2} = \left 6.81 \pm 0.01\,\left( \text{ stat }\right) ^{+0.38}_{-0.40}\,\left( \text{ syst }\right) \right \times 10^{18}$$ T1/2=6.81±0.01stat-0.40+0.38syst×1018 year. The two-electron energy sum, single electron energy spectra and distribution of the angle between the electrons are presented with an unprecedented statistics of $$5\times 10^5$$ 5×105 events and a signal-to-background ratio of $$\sim $$ ∼ 80. Clear evidence for the Single State Dominance model is found for this nuclear transition. Limits on Majoron emitting neutrinoless double beta decay modes with spectral indices of $$\mathrm{n}=2,3,7$$ n=2,3,7 , as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained.
The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double
β
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
β
decay by measuring the decay half-life and the electron angular and energy distributions.
We describe how the Euclid detectors in the Near Infrared Spectrometer and Photometer (NISP) channel will be read out on board and present an analytic expression for the estimated fluence in each ...pixel with the associated quality factor of the fit per pixel. The method accounts for the Poisson like distribution of the data and includes the effects of noise correlations that arise after the coadding procedure of frames read non-destructively up the ramp during one exposure. The bias of the flux estimator presented in this paper is kept lower than 0.3% over a wide rang of scientifically interesting fluxes of Euclid. The associated error is by 6% lower than the commonly used formula derived in Rauscher et al. in the context of an equally weighted least squares fit. Moreover, the quality factor follows the very well known χ th 2 ( x ; n ) distribution and thus provides a well behaved statistical tool to check the goodness of the ramp fit. The method is proposed in the context of a large amount of data per exposure, produced by the NISP detectors, that cannot be transferred to the ground for the subsequent processing. The method, which is validated using real and simulated test data, can be safely used by most near-infrared instruments which require very accurate measurements to be performed on board.
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
2
ν
β
β
decay half-life measurement is
T
1
/
2
2
ν
=
2.35
±
0.14
(
stat
)
±
0.16
...(
syst
)
×
10
19
yr
. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2
ν nuclear matrix element is extracted using the measured
2
ν
β
β
half-life and is
M
2
ν
=
0.049
±
0.002
. Constraints on
0
ν
β
β
decay have also been set.
Search for low-energy β contaminations in industrial environments requires using Liquid Scintillation Counting. This indirect measurement method supposes a fine control from sampling to measurement ...itself. Thus, in this paper, we focus on the definition of a measurement method, as generic as possible, for both smears and aqueous samples’ characterization. That includes choice of consumables, sampling methods, optimization of counting parameters and definition of energy windows, using the maximization of a Figure of Merit. Detection limits are then calculated considering these optimized parameters. For this purpose, we used PerkinElmer Tri-Carb counters. Nevertheless, except those relative to some parameters specific to PerkinElmer, most of the results presented here can be extended to other counters.
The double-beta decay of 82Se to the 01+ excited state of 82Kr has been studied with the NEMO-3 detector using 0.93 kg of enriched 82Se measured for 4.75 y, corresponding to an exposure of 4.42 kg⋅y. ...A dedicated analysis to reconstruct the γ-rays has been performed to search for events in the 2e2γ channel. No evidence of a 2νββ decay to the 01+ state has been observed and a limit of T1/22ν(Se82,0gs+→01+)>1.3×1021y at 90% CL has been set. Concerning the 0νββ decay to the 01+ state, a limit for this decay has been obtained with T1/20ν(Se82,0gs+→01+)>2.3×1022y at 90% CL, independently from the 2νββ decay process. These results are obtained for the first time with a tracko-calo detector, reconstructing every particle in the final state.
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