Double Beta Decay Of 150Nd Research Articles

Double beta decay of 150Nd to the first 0+ excited level of 150Sm

An experiment to measure the 2β – decay of 150Nd to excited levels of 150Sm using a highly purified 2.381 kg sample of Nd2O3 is in progress in the low-background set-up with 4 HPGe detectors (∼225 cm3 volume each). The detector is located deep underground (3600 m w.e.) at the STELLA facility of the Gran Sasso National Laboratory (LNGS) of the INFN (Italy). Two γ quanta with energies 334.0 keV and 406.5 keV emitted after deexcitation of the 01 + excited level of 150Sm have been observed in the experimental data accumulated over 39898 h. The preliminary half-life value for 2β – decay of 150Nd to the first 0+ excited level in 150Sm (after the exposure of 10.8 kg × yr) was estimated as yr. The experiment is under data taking with the aim to improve the statistical uncertainties.

Double beta decay of 150Nd to the first excited 0+ level of Sm: Preliminary results

The double beta decay of $^{150}$Nd to the first excited 0$^+$ level of $^{150}$Sm ($E_{exc}$ = 740.5 keV) has been investigated with the help of the ultra-low-background setup consisting of four HP Ge (high-purity germanium) detectors (${\approx}$ 225 cm$^3$ volume each one) at the Gran Sasso underground laboratory of INFN (Italy). A highly purified 2.381-kg sample of neodymium oxide (Nd$_2$O$_3$) was used as a source of ${\gamma}$ quanta expected in the decays. Gamma quanta with energies 334.0 keV and 406.5 keV emitted after deexcitation of the $0_1^+$ 740.5 keV level of $^{150}$Sm are observed in the coincidence spectra accumulated over 16375 h. The half-life relatively to the two neutrino double beta decay $^{150}$Nd $\rightarrow$ $^{150}$Sm(0$_1^+$) is measured as $T_{1/2} = [4.7_{-1.9}^{+4.1}\text{(stat)} {\pm} 0.5\text{(syst)}] {\times} 10^{19} y$, in agreement with results of previous experiments.

Investigation of ββ decay in 150Nd and 148Nd to the excited states of 150Sm and 148Sm

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 Nd2O3 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)] · 1020 y. For other (0ν + 2ν) transitions to the 2+1, 2+2, 2+3, and 0+2 levels in 150Sm, limits are obtained at the level of ~ (2 − 8) · 1020 y. In the case of 148Nd only limits for the (0ν + 2ν) transitions to the 2+1, 0+1, and 2+2 excited states in 148Sm were obtained and are at the level of ~ (4 − 8) · 1020 y.

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

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

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

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.

Double beta decay of 150Nd to the First 0+ excited state of 150Sm

Two-neutrino-double-beta decay of 150Nd to the first 0+ excited state in 150Sm is investigated with a 400-cm3 low-background HPGe detector. Data analysis for 11320.5 h shows an excess of events at 333.9 and 406.5 keV. This allows us to estimate the half-life of the investigated process as [1.4−0.2+0.4±0.3(syst.)]×1020 yr.

Double-Beta Decay of 150Nd and 76Ge to Excited States

New results of experimental search for double beta decay of 76Ge (2νββ) and 150Nd (0ν + 2ν) to excited states of the daughter nuclei are presented. Data from 228 days of measurements performed with four HPGe detectors in the low background laboratory of Baksan neutrino observatory yield new limits on life-times T1/2(0+→ 0+1)≥6.2×1021} yr at 90% C.L. for transition of 76Ge to 0+1 level of 76Se and T1/2(0+→ 0+1)≥1.5×1020 yr at 90% C.L. for transition of 150Nd to 0+1 level of 150Sm.

Looking for double beta decay of 150Nd to excited states of 150Sm by gamma ray spectroscopy

We have measured the gamma ray activity of a sample of 6189 grams of metallic Neodimium with a germanium detector. From the gamma energy spectrum recorded during almost 6500 hours we extract lower limits for the halflife of the inclusive (0ν + 2ν) ββ decay of 150 Nd to the first excited states of 150 Sm : t 1 2 (0 + → 0 1 + > 1.0·10 20 , t 1 2 (O + → 0 2 +) > 2.0 · 10 2), t 1 2 (0 + → 2 1 +) > 9.1 · 10 19 .

Search for inclusive double beta decay of 150Nd to excited states of 150Sm at Laboratori Nazionali del Gran Sasso

Double beta decay to excited states of daughter nuclei is poorely studied (even if evidence for the decay has been recently reported). Measurements were performed at Laboratori Nazionali del Gran Sasso with a germanium detector, by searching for the de-excitation gamma rays of the daughter nuclides. New lower limits on the half-lives for double beta decay of 150 Nd to excited states of 150 Sm have been obtained. They range between 6×10 19 and 10×10 19 years (90% C.L.). A further measurement on 6 kg of natural Nd is in progress, preliminary results and a detailed study of intrinsic radioactivity of the sample are presented.

Preliminary results from a study of the double beta decay of 150Nd

We report the preliminary results from a study of the double beta decay of 150 Nd to the first 0 + excited state of 150 Sm. Our data consists of 50 days of counting 5 kg of natural Nd 2 O 3 at the LBNL-Oroville low background facility. The deduced lower limit for the half life of this decay mode is 4.9 × 10 19 years.

Low background scintillation installation for double beta decay experiments

The experimental setup and methods to search for double beta decay of 150Nd and other isotopes are described. The applied method of multidimensional analysis allows the two-neutrino mode of ββ-decay, neutrinoless mode (neutrino mass and right-handed mechanisms separately) and the mode with Majoron emission to be observed directly. The results of measurements of 50.5 g of 150Nd for 2000 h are discussed. Multidimensional spectra calculated for the proposed experiment to search for double positron decay and a crossing process are given.