Abstract The NEMO-3 results for the double- $$\beta $$ β decay of $$^{150}$$ 150 Nd to the 0 $$^+_1$$ 1 + and 2 $$^+_1$$ 1 + excited states of $$^{150}$$ 150 Sm are reported. The data recorded during ...5.25 year with 36.6 g of the isotope $$^{150}$$ 150 Nd are used in the analysis. The signal of the $$2\nu \beta \beta $$ 2 ν β β transition to the 0 $$^+_1$$ 1 + excited state is detected with a statistical significance exceeding 5 $$\sigma $$ σ . The half-life is measured to be $$T_{1/2}^{2\nu \beta \beta }(0^+_1) = \left 1.11 ^{+0.19}_{-0.14} \,\left( \hbox {stat}\right) ^{+0.17}_{-0.15}\,\left( \hbox {syst}\right) \right \times 10^{20}$$ T 1 / 2 2 ν β β ( 0 1 + ) = 1 . 11 - 0.14 + 0.19 stat - 0.15 + 0.17 syst × 10 20 year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the $$2\nu \beta \beta $$ 2 ν β β decay to the 2 $$^+_1$$ 1 + level the limit is $$T^{2\nu \beta \beta }_{1/2}(2^+_1) > 2.42 \times 10^{20}~\hbox {year}$$ T 1 / 2 2 ν β β ( 2 1 + ) > 2.42 × 10 20 year . The limits on the $$0\nu \beta \beta $$ 0 ν β β decay to the 0 $$^+_1$$ 1 + and 2 $$^+_1$$ 1 + levels of $$^{150}$$ 150 Sm are significantly improved to $$T_{1/2}^{0\nu \beta \beta }(0^+_1) > 1.36 \times 10^{22}~\hbox {year}$$ T 1 / 2 0 ν β β ( 0 1 + ) > 1.36 × 10 22 year and $$T_{1/2}^{0\nu \beta \beta }(2^+_1) > 1.26 \times 10^{22}~\hbox {year}$$ T 1 / 2 0 ν β β ( 2 1 + ) > 1.26 × 10 22 year .
Main goal of the project CZELTA (CZEch Large-area Time coincidence Array) is to study global properties of high-energetic cosmic rays. To present date, project consists of 5 stations covering large ...area in the Czech republic capable of detection of extensive air showers with energy exceeding 10 14 eV. Such a network of distant stations can be an ideal tool for probing global structure of cosmic rays. We present the design of the detection system and obtained results.
Abstract Using data from the NEMO-3 experiment, we have measured the two-neutrino double beta decay ($$2\nu \beta \beta $$ 2νββ ) half-life of $$^{82}$$ 82 Se as $$T_{\smash {1/2}}^{2\nu } \!=\! ...\left 9.39 \pm 0.17\left( \text{ stat }\right) \pm 0.58\left( \text{ syst }\right) \right \times 10^{19}$$ T1/22ν=9.39±0.17stat±0.58syst×1019 y under the single-state dominance hypothesis for this nuclear transition. The corresponding nuclear matrix element is $$\left| M^{2\nu }\right| = 0.0498 \pm 0.0016$$ M2ν=0.0498±0.0016 . In addition, a search for neutrinoless double beta decay ($$0\nu \beta \beta $$ 0νββ ) using 0.93 kg of $$^{82}$$ 82 Se observed for a total of 5.25 y has been conducted and no evidence for a signal has been found. The resulting half-life limit of $$T_{1/2}^{0\nu } > 2.5 \times 10^{23} \,\text{ y } \,(90\%\,\text{ C.L. })$$ T1/20ν>2.5×1023y(90%C.L.) for the light neutrino exchange mechanism leads to a constraint on the effective Majorana neutrino mass of $$\langle m_{\nu } \rangle < \left( 1.2{-}3.0\right) \,\text{ eV }$$ ⟨mν⟩<1.2-3.0eV , where the range reflects $$0\nu \beta \beta $$ 0νββ nuclear matrix element values from different calculations. Furthermore, constraints on lepton number violating parameters for other $$0\nu \beta \beta $$ 0νββ mechanisms, such as right-handed currents, majoron emission and R-parity violating supersymmetry modes have been set.
Abstract The NEMO-3 results for the double- $$\beta $$ β decay of $$^{150}$$ 150 Nd to the 0 $$^+_1$$ 1 + and 2 $$^+_1$$ 1 + excited states of $$^{150}$$ 150 Sm are reported. The data recorded during ...5.25 year with 36.6 g of the isotope $$^{150}$$ 150 Nd are used in the analysis. The signal of the $$2\nu \beta \beta $$ 2 ν β β transition to the 0 $$^+_1$$ 1 + excited state is detected with a statistical significance exceeding 5 $$\sigma $$ σ . The half-life is measured to be $$T_{1/2}^{2\nu \beta \beta }(0^+_1) = \left 1.11 ^{+0.19}_{-0.14} \,\left( \hbox {stat}\right) ^{+0.17}_{-0.15}\,\left( \hbox {syst}\right) \right \times 10^{20}$$ T 1 / 2 2 ν β β ( 0 1 + ) = 1 . 11 - 0.14 + 0.19 stat - 0.15 + 0.17 syst × 10 20 year, which is the most precise value that has been measured to date. 90% confidence-level limits are set for the other decay modes. For the $$2\nu \beta \beta $$ 2 ν β β decay to the 2 $$^+_1$$ 1 + level the limit is $$T^{2\nu \beta \beta }_{1/2}(2^+_1) > 2.42 \times 10^{20}~\hbox {year}$$ T 1 / 2 2 ν β β ( 2 1 + ) > 2.42 × 10 20 year . The limits on the $$0\nu \beta \beta $$ 0 ν β β decay to the 0 $$^+_1$$ 1 + and 2 $$^+_1$$ 1 + levels of $$^{150}$$ 150 Sm are significantly improved to $$T_{1/2}^{0\nu \beta \beta }(0^+_1) > 1.36 \times 10^{22}~\hbox {year}$$ T 1 / 2 0 ν β β ( 0 1 + ) > 1.36 × 10 22 year and $$T_{1/2}^{0\nu \beta \beta }(2^+_1) > 1.26 \times 10^{22}~\hbox {year}$$ T 1 / 2 0 ν β β ( 2 1 + ) > 1.26 × 10 22 year .
Using data from the NEMO-3 experiment, we have measured the two-neutrino double beta decay (
2
ν
β
β
) half-life of
82
Se as
T
1
/
2
2
ν
=
9.39
±
0.17
stat
±
0.58
syst
×
10
19
y under the ...single-state dominance hypothesis for this nuclear transition. The corresponding nuclear matrix element is
M
2
ν
=
0.0498
±
0.0016
. In addition, a search for neutrinoless double beta decay (
0
ν
β
β
) using 0.93 kg of
82
Se observed for a total of 5.25 y has been conducted and no evidence for a signal has been found. The resulting half-life limit of
T
1
/
2
0
ν
>
2.5
×
10
23
y
(
90
%
C.L.
)
for the light neutrino exchange mechanism leads to a constraint on the effective Majorana neutrino mass of
⟨
m
ν
⟩
<
1.2
-
3.0
eV
, where the range reflects
0
ν
β
β
nuclear matrix element values from different calculations. Furthermore, constraints on lepton number violating parameters for other
0
ν
β
β
mechanisms, such as right-handed currents, majoron emission and R-parity violating supersymmetry modes have been set.
The new pocket size read-out interface device dedicated for silicon photomultipliers (SiPM) has been designed and developed. While it was designed as a miniaturized and low power device it still ...provides a wide spectrum of functionality necessary for measurements and testing of SiPMs and SiPM based detectors. Full signal processing has been integrated within the device involving variable gain amplification, filtration and digitization. Signal acquisition can be performed with sampling frequency 400 MSa/s at 12 bit resolution or 600 MSa/s at 8 bit resolution while achieving full waveform capture & download rate about 20 000 events per second. The read-out interface is fully powered from the USB bus allowing operation without need of additional power line connection. An integrated bias source can be set in range from 0V to +200V with 12 bit precision. The read-out interface is primarily dedicated for spectroscopy purposes. There are two input signal channels with different optimization regarding the signal gain to cover a low energy range corresponding to single photo-electron detector response as well as to cover a high energy range corresponding to a detector response operated with scintillator registering gamma radiation in order of MeVs. Both input channels are equipped with fine gain adjustment in range from -9 dB to 26 dB with 1 dB step in addition to the fixed gain of each signal channel. The FPGA based design of the read-out interface allowed implementation of advanced triggering functionality like a data driven trigger, external trigger, gating of trigger to extend read-out interface capability even further in a way of complex experiments. A set of functional tests and experiments with SiPM called micropixel avalanche photodiode (MAPD) and MAPD based detectors have been performed to characterize real properties of the read-out interface.
The NEMO-3 results for the double-$\beta$ decay of $^{150}$Nd to the 0$^+_1$
and 2$^+_1$ excited states of $^{150}$Sm are reported. The data recorded during
5.25 yr with 36.6 g of the isotope ...$^{150}$Nd are used in the analysis. For the
first time, the signal of the $2\nu\beta\beta$ transition to the 0$^+_1$
excited state is detected with a statistical significance exceeding 5$\sigma$.
The half-life is measured to be $T_{1/2}^{2\nu\beta\beta}(0^+_1) = \left 1.11
^{+0.19}_{-0.14} \,\left(\mbox{stat}\right) ^{+0.17}_{-0.15}\,
\left(\mbox{syst}\right) \right \times10^{20}\,\mbox{yr}$. The limits are set
on the $2\nu\beta\beta$ decay to the 2$^+_1$ level and on the $0\nu\beta\beta$
decay to the 0$^+_1$ and 2$^+_1$ levels of $^{150}$Sm.
Double-beta decays of \(^{100}\)Mo from the 6.0195-year exposure of a 6.914 kg high-purity sample were recorded by the NEMO-3 experiment that searched for neutrinoless double-beta decays. These ...ultra-rare transitions to \(^{100}\)Ru have a half-life of approximately \(7\times10^{18}\) years, and have been used to conduct the first ever search for periodic variations of this decay mode. The Lomb-Scargle periodogram technique, and its error-weighted extension, were employed to look for periodic modulations of the half-life. Monte Carlo modeling was used to study the modulation sensitivity of the data over a broad range of amplitudes and frequencies. Data show no evidence of modulations with amplitude greater than 2.5% in the frequency range of \(0.33225\,{\rm y^{-1}}\) to \(365.25\,{\rm y^{-1}}\).
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