[en] ⁴⁰Ti β decay was studied at GANIL using the LISE3 spectrometer. A decay scheme was deduced from twenty-one observed β-delayed proton transitions feeding the ground and first excited states of ³⁹Ca. ⁴⁰Ti half-life was found to be 51.7(6) ms. These results imply that the ICARUS ⁴⁰Ar detector has an effective absorption cross section for ⁸B solar neutrinos 73% of the total cross section arises from Gamow-Teller transitions. (author)

[en] The measurement of half-life of the ground state ²¹³Po was performed by the three dimensional single crystal scintillation time spectrometer. A more precise value of this nuclear constant - T₁/2=3.70(3) μm has been received. (author)

[en] In the particle standard model the electron neutrino has a vanishing mass and exists only in two states, right and left (parity violation) and under two particle forms, particles and anti-particles, which superimpose to the chirality states; although there is no obstacle to the existence of the massive neutrinos in the theories more extended and than the standard model. The current upper limit for the neutrino mass obtained from the study of the tritium beta decay is 7.2 eV. The double β decay is a process which by means of a nuclear decay allows probing the neutrino properties and the high energy processes; if, for instance, the neutrino is a Majorana slightly massive particle then the ββ is possible and manifests itself by a violation of the leptonic number conservation in the WW interaction. Among the possible natural double β emitters ⁷⁶Ge was studied and the calorimetric experiments have given the best limit for neutrino mass, (ee)> < 1.3 eV. Other nuclei as for instance ¹⁰⁰Mo must allow new measurements in better condition since the transferred energy is larger. The paper enumerates the stages of the collaboration aiming at a grand ββ experiment to be installed as NEMO at LSM (Modane). The best data for ¹⁰⁰Mo are T_1/2 (2ν) = 0.95 ± 0.10 · 10¹⁹ y and T_1/2 (0ν) > 6.40 ± 0.10 · 10²¹ y. Measurements with an improved version of NEMO on ¹¹⁶Cd resulted in the value T_1/2 (2ν) = 3.6 ± 0.6 · 10¹⁹ y. The LPC contribution between 1992-1994 is summarized. The prospective concerning the measurements on ⁹⁶Zr and ⁸²Se are also sketched

[en] The requirements to uniformity of the guide magnetic field in the T-violation of the free neutron decay experiment which are necessary to exclude false effects are analyzed

[en] TGV and NEMO, two international collaboration projects are described. The TGV project deals with the double beta decay of ⁴⁸Ca. In 1998, this project was augmented with the examination of the double beta decay of ¹⁰⁶Cd - the β⁺β⁺, β⁺/EC, and EC/EC modes. The main objective of this experiment consists in recording the 2νEC/EC mode (0⁺ → 0⁺, ground state), giving rise to the emission of 2 gamma quanta of roughly 21 keV. The NEMO project deals with ¹⁰⁰Mo. The main objective of the NEMO-3 experiment consists in the measurement of the half-life of the neutrinoless double decay of this nuclide (about 10²⁵ years)

[en] ⁴⁰Ti β decay was studied at GANIL using the LISE3 spectrometer. A decay scheme was deduced from twenty-one observed β-delayed proton transitions feeding the ground and first excited state ³⁹Ca. The ⁴⁰Ti half-life was found to be 51.7(6) ms. These results imply that the ICARUS ⁴⁰Ar detector has an effective absorption cross section for ⁸B solar neutrinos of 14.5(4) x 10^-43 cm²; 73% of the total cross section arises from Gamow-Teller transitions that were neglected in earlier estimates of the ICARUS efficiency. (authors)

[en] Radioactive decay study gives an access to the interaction which rules the β decay process as well as the structure of the nuclear states involved. This work describes the observation of the decay of N = Z nuclei with mass A > 70. For the odd-odd N = Z nuclei ⁷⁸Y, ⁸²Nb and ⁸⁶Tc, the decay has been established as superallowed Fermi type transitions. The results pave the way for more precise measurements and extend the mass range nowadays used to understand the behaviour of the weak interaction in the nuclear matter. The observation of the decay of the even-even N = Z ⁷²Kr leads us to build the Gamow-Teller strength distribution from which some clues about the ground state deformation of this isotope can be obtained. More complete experimental observation and some developments of the calculations used to interpret the distribution of the Gamow-Teller strength are needed. Finally, this work describes the developments and tests of a prototype detector the aim of which to determine the contribution of β particles to energy distribution observed in germanium detector. The tests we have performed show that this prototype can identify and reject 80% of the β particles emitted by a source with a 2,3 MeV end-point. The very satisfactory performances of this prototype need now to be confirmed under experimental conditions. (author)

[en] The decay function from radioisotope ¹³N formed in the reaction ¹⁴N(γ,n)¹³N was registered by high resolution gamma spectrometer in multiscanning mode with gamma energy 511 keV. The experimental data was processed by common and kinetic function method. The continuous comparison of the decay function on time permits to determinate possible deviation from purely exponential decay curve. The results were described by several decay theories. The degrees of corresponding between theories and experiment were evaluated by goodness factor. A complex type of decay was considered. (author). 9 refs, 2 tabs, 6 figs

[en] Investigations ino alpha-decay properties of isotopes with Z=89-93 are carried out

No abstract available