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 NEMO-3 results for the double-
β
decay of
150
Nd to the 0
1
+
and 2
1
+
excited states of
150
Sm are reported. The data recorded during 5.25 year with 36.6 g of the isotope
150
Nd are used in the ...analysis. The signal of the
2
ν
β
β
transition to the 0
1
+
excited state is detected with a statistical significance exceeding 5
σ
. The half-life is measured to be
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
ν
β
β
decay to the 2
1
+
level the limit is
T
1
/
2
2
ν
β
β
(
2
1
+
)
>
2.42
×
10
20
year
. The limits on the
0
ν
β
β
decay to the 0
1
+
and 2
1
+
levels of
150
Sm are significantly improved to
T
1
/
2
0
ν
β
β
(
0
1
+
)
>
1.36
×
10
22
year
and
T
1
/
2
0
ν
β
β
(
2
1
+
)
>
1.26
×
10
22
year
.
ACTIVIA: Calculation of isotope production cross-sections and yields Back, J.J.; Ramachers, Y.A.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2008, Letnik:
586, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present a
C
++
computer package, ACTIVIA, that can calculate target–product cross-sections and the production and decay yields of isotopes from cosmic ray activation using data tables and ...semi-empirical formulae. We describe the structure and user interface of the computer code as well as provide comparisons between the calculations and experimental results. We also outline suggestions on how the code can be improved and extended for other applications.
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 Formula omittedMo to the ground state of Formula omittedRu, Formula omitted ...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 Formula omitted events and a signal-to-background ratio of Formula omitted 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 Formula omitted, as well as constraints on Lorentz invariance violation and on the bosonic neutrino contribution to the two-neutrino double beta decay mode are obtained.
A local principal curve algorithm has been implemented in three dimensions for automated track and shower reconstruction of neutrino interactions in a liquid argon time projection chamber. We present ...details of the algorithm and characterise its performance on simulated data sets.
Liquid scintillator time projection chamber concept McConkey, N.; Ramachers, Y.A.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Letnik:
718
Journal Article
Recenzirano
Odprti dostop
Results are presented from a small-scale experiment to investigate the use of room temperature organic liquid scintillators as the active medium for a time projection chamber (TPC). The optical ...properties of liquid scintillators have long been known, but their ability to transport charge has remained, until now, largely untested. The idea of using room temperature liquids as an active medium for an ionisation chamber was first presented in 1. Since then the range of liquid scintillators available has been greatly developed. We present successful transport of ionization charges in a selection of both, pure organic liquid solvents and liquid scintillator cocktails over 20mm using a variety of electric drift field strengths. The target of this research is to offer a cost effective alternative to liquid noble gas detectors in neutrino physics.
By exploiting structural differences between electromagnetic and hadronic showers in a multivariate analysis we present an efficient Electron-Hadron discrimination algorithm for liquid argon time ...projection chambers, validated using Geant4 simulated data.
A Cellular Automaton algorithm has been implemented in three dimensions for automated track reconstruction of neutrino interactions in a Liquid Argon Time Projection Chamber. We present details of ...the algorithm and characterise its performance on simulated data sets.
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