The project aims at the measurement of very rare processes of double-beta decay of Cd-106 and Ca-48. The experimental facility TGVII (Telescope Germanium Vertical) makes use of 32 HPGe planar detectors mounted in one common cryostat. The detectors axe interleaved with. thin foils containing beta beta sources. Besides passive shielding against background radiation made of pure copper, lead and boron dopped polyethylene additional techniques for background suppression based on digital pulse shape analysis are used. The experimental setup is located in Modane underground laboratory (France). A review of the TGVII facility, its performance parameters and capabilities are presented.

The positrons and coincident gamma-rays following the pure Fermi 0+ → 0+ branch of β+-decay in 14O were measured. The Doppler shift of the γ-quantum observed is sensitive to the beta-neutrino correlation coefficient, which is unity (α = 1) in the absence of scalar coupling. The interatomic interaction of recoiling daughters was noticed, which has prevented to obtain an improved result for scalar coupling despite of the excellent statistical accuracy of the measurement. At the same time, it was shown that the method described can be used as a very sensitive and flexible tool to probe the interatomic interactions in matter at the hundred eV energy level. Perspectives in this direction as well as the future angular-correlation experiments aimed to search for scalar coupling in beta-decay are discussed.

The IC(4) software developed to compare calculated internal conversion coefficients (ICC) has been enhanced by adding new features through the use of Borland Delphi and TeeChart. Particularly, the 3D-graph option enhances the possibilities of analyzing calculated ICC values. For example, the comparison between the results given by three sets of theoretical ICC tables for any arbitrary pair of calculated ICC can be presented in a much clearer manner. Their differences can be displayed as energy vs. atomic number surfaces. Results from the analyses of K-shell and total ICCs for E2, E3, M2, M3, and M4 multipolarity are discussed.

A precision measurement of the 277 keV gamma ray produced by capturing muons in gaseous oxygen was performed using high-resolution HPGe detectors. The Doppler-broadened shape of this line is sensitive to the possible admixture into muon capture of genuine scalar interaction. This experiment complements, in the muon sector, in principle, similar ones undertaken recently in nuclear beta decay.Using a procedure discussed in earlier papers, a fit to the experimental line-shape allowed us to obtain for the recoil-gamma correlation coefficient the value of a(2)(1) = 0.096 +/- 0.041 (95% CL). The available evaluations of the contributing nuclear matrix elements, performed in the impulse approximation in the absence of scalar interaction, produce correlation coefficients in disagreement with our result. These evaluations are independent of the induced pseudoscalar coupling and so of the validity of the PCAC hypothesis, but their reliability and model dependence remain to be investigated. (C) 2002 Elsevier Science B.V. All fights reserved.

A (CaCO3)-Ca-48 powder sample containing 20.18 g of Ca-48 was measured for 797 h with a 400 cm(3) low-background HPGe detector. New limits on decays of 48Ca were obtained. For single beta transitions to (SC)-S-48 the limits are equal to 0.71 x 10(20) y, 1.1 (X) 10(20) y, and 0.82 x 10(20) y for transitions to the ground state, excited 5(+) and 4(+) states, respectively. The new limits on double beta decay to excited states of Ti-48 are equal to 0.47 x 10(20) y, 1.1 x 10(20) y, and 0.90 x 10(20) y for transitions to the first 2(+), second 2(+) and first 0(+) excited states, respectively. All limits are given at the 90% CL. (C) 2002 Elsevier Science B.V. All rights reserved.

An extensive database has been assembled that contains the three most widely used sets of calculated internal conversion coefficients (ICC): [Hager R.S., Seltzer E.C., 1968. Internal conversion tables. K-, L-, M-shell Conversion coefficients for Z = 30 to Z = 103, Nucl. Data Tables A4, 1-237; Band I.M., Trzhaskovskaya M.B., 1978. Tables of gamma-ray internal conversion coefficients for the K-, L- and M-shells, 10 < or = Z < or = 104, Special Report of Leningrad Nuclear Physics Institute; Rosel F., Fries H.M., Alder K., Pauli H.C., 1978. Internal conversion coefficients for all atomic shells, At. Data Nucl. Data Tables 21, 91-289] and also includes new Dirac Fock calculations [Band I.M. and Trzhaskovskaya M.B., 1993. Internal conversion coefficients for low-energy nuclear transitions, At. Data Nucl. Data Tables 55, 43-61]. This database is linked to a computer program to plot ICCs and their combinations (sums and ratios) as a function of Z and energy, as well as relative deviations of ICC or their combinations for any pair of tabulated data. Examples of these analyses are presented for the K-shell and total ICCs of the gamma-ray standards [Hansen H.H., 1985. Evaluation of K-shell and total internal conversion coefficients for some selected nuclear transitions, Eur. Appl. Res. Rept. Nucl. Sci. Tech. 11.6 (4) 777-816] and for the K-shell and total ICCs of high multipolarity transitions (total, K-, L-, M-shells of E3 and M3 and K-shell of M4). Experimental data sets are also compared with the theoretical values of these specific calculations.

The low-energy electron spectrum (0-15 keV) from the Co-57 decay has been examined at high resolution (2-15 eV) by two electrostatic spectrometers and radioactive sources prepared by vacuum evaporation. The relative intensities of the main components in the spectrum are obtained. Absolute and relative energies of KLL, KLM and KMM Anger transitions in iron and their relative intensities are also determined. Precise values for the transition energy and E2 admixture are derived from the measured conversion electron (CE) lines of the 14.4 keV transition in Fe-57. Natural widths of the atomic levels in Fe-57 and those of KLL and KLM Auger lines have been evaluated. Pronounced effects of chemical environement of the decaying Co-57 atoms are observed as broadening of some narrow lines and abnormal relative intensities.

Experiments devoted to the search for scalar interaction in nuclear beta decay and ordinary muon capture and based on the measurement of (beta-nu) and (gamma-nu) angular correlations are described. The idea of the measurement is to detect the Doppler shift of photons due to the recoil of the daughter nuclei by means of high-precision semiconductor gamma spectroscopy.

The low-energy electron spectrum from the 57Co decay has been examined in the region from 0 up to 15 keV at instrumental resolution ranging from 2 to 15 eV. Two electrostatic spectrometers and radioactive sources prepared by vacuum evaporation of 57Co onto Al foils were utilized. Relative intensities of the main spectrum components have been obtained as follows: (TSE+LLX+Shake-off)/LMM/KLL/KLM/KMM/K−14.4/L−14.4/MN−14.4=116±12/51±4/59.7±1.8/15.2±0.4/1.15±0.07/49.6±1.5/5.05±0.15/0.79±0.02 where TSE means “true secondary electrons”. Absolute and relative energies of the LMM, KLL, KLM, and KMM Auger transitions in Fe have also been determined, as well as their relative intensities with the exception of the LMM lines, the shapes of which were strongly distorted due to the inelastic electron scattering and probably also chemical effects. From the measured conversion electron lines of the 14.4 keV M1 transition in 57Fe, a transition energy of 14412.8±0.8 eV and the E2 admixture less than 8×10−6 were derived. Relative intensities of both the KL2,3(M4,5N1) Auger line group and the M4,5N1−14.4 conversion line were found to be lower by about 30% for the “oxide” state of decaying 57Co atoms than for the “metallic” state. Pronounced broadenings of narrow spectrum lines have been observed as a consequence of the oxidation of the 57Co sources in the laboratory atmosphere. Natural widths for most of the KLL, KLM, and KMM Auger lines and those of the K, L1, L2, L3, M1, M2, M3 and N1 atomic levels in 57Fe were also determined.

The KLL Auger spectrum of 131Xe from the 131Cs decay has been measured at an instrumental resolution of 13eV. Energies and relative intensities of the individual KLL lines here been determined and compared with the theoretical results. Our KL1L2(3P0)/(1P1) intensity ratio of 0.33(2) agrees remarkably well with that of 0.34 from the relativistic calculations in intermediate coupling with configuration interaction. This agreement clearly proves the predicted strong influence of the effects of relativity on the KL1L2(3P0) rate even at Z=54, since the relative intensity KL1L2(1P0)/(1P1) has been found to be exceedingly sensitive to these effects.

Secondary ion mass spectrometry (SIMS) is one of the few microscopical methods that potentially can detect and in situ localize the various isotopes of virtually all elements. Recent work with SIMS has demonstrated the possibility of imaging the distribution of various elements in plant cell and tissues. However, in these studies, the elements were incorporated in cell macromolecules or associated with structural polymers, precipitated or immobilized in dry seeds. The localization of mineral ions is of particular significance for the physiology of higher plants owing to their quantitative importance and the impact of their cellular distribution on metabolic regulation. Here we analyse the possibility of mapping different elements (K, Ca, Mg, P, S, 15N and 14N) present as soluble and/or bound forms in highly vacuolated leaf cells. Cryoprocedures to prepare samples for SIMS detection are described and discussed. The quality of the results is assessed at each step of the sample preparation and analysis. Various methodologies are used, including photonic and electronic microscopies, and the agreement of the observed ion distribution with current knowledge of ion compartmentalization in plant cells. The K/Ca emission ratio is proposed as an index of the degree of preservation of the natural ion distribution to critically evaluate the results and identify where artefacts are likely to occur.

The KLL Auger spectrum of thulium from 169Yb decay has been analysed at an instrumental resolution of 13eV using a combined electrostatic spectrometer. Energies and relative intensities of the individual KLL transitions have been determined and compared with calculations. A reliable value of 0.67(5) for the KL1L2(3P0)/(1P1) transition intensity ratio obtained from our partly resolved KL1L2 doublet proved, for the first time, a sharp increase of the KL1L2(3P0) intensity in the high Z region due to the relativistic effects predicted by relativistic calculations in intermediate coupling with configuration interaction. For the first time, a broadening of the KLL Auger lines, probably due to the two different excitation ways of the 169Tm atoms in 169Yb decay (K-internal conversion and K-electron capture), has been observed. A value of 19.5(8)eV was obtained for the energy separation of the two thulium KLL Auger spectra shifted to each other, arising from the individual excitation modes, and that of 0.81(9) for their intensity ratio (`K-conversion' to `K-capture'). © 1997 Elsevier Science B.V.

Two laser spectroscopy methods to extract nuclear ground state properties are presented. The first one, collinear laser spectroscopy, has been used to measure the nuclear moments and the isomeric shift of the isomer Hf-178m2 produced in microweight quantities at the Dubna cyclotron. The second one, using multi-step photoionization (COMPLIS), is well suited to measure the same quantities for elements not directly produced by isotope separators.

The formalism developed elsewhere for the theoretical description of the dynamics involved in the heavy nuclei fusion is applied in this paper to study the “history” of the fusion of two identical heavy nuclei experiencing central collision. The evolution of the shape and of the temperature of symmetrical fusing systems is studied. The role of the elastoplasticity of nuclear matter in the nonmonotonical changes of the shape is elucidated in this way. A tentative explanation of the “extra push” phenomenon is given in terms of the competition between elastic properties of fusing systems driving to the re-separation of colliding nuclei and the dissipative (plastic) properties of nuclear matter transforming the energy of collective motion into the energy of statistical excitation and thus leading to the fusion. The fingerprints of the heavy-nuclei fusion history as it is depicted by the model are traced in the anisotropy of the dipole and quadrupole γ-radiation emitted during the fusion. The parallels in the description of the fusion dynamics given by the simple model used in this paper and by the more fundamental approaches based on the kinetic equation are emphasised.

A heavy-ion multiple Coulomb excitation experiment on a very exotic target containing microweight quantities of $^{178}$Hf in the K$^\pi = 16^+$ isomeric state has been performed at 4.77 MeV/u $^{208}$Pb beam energy. The first excited I$^\pi = 17^+$ state has been observed at an excitation energy of $357.4\pm0.3$ keV with respect to the isomeric state. The intrinsic electric quadrupole moment of $Q_0=8.2\pm1.1$ b has been derived from the experimental data within the rigid rotor model.

The mechanical behaviour of three polymeric resins (two thermosets and one thermoplastic) was studied. Mechanical rests were performed on the unreinforced resins and on the same resins as matrices in transversely loaded unidirectional composites. In the latter case the plastic strain was revealed from the distorsions of microgrids settled on the specimen surface. Despite differences between the plain resins, their behaviour inside composites is similar, the deformation being heterogeneously confined between the fibres near the rips of microcracks. The strain level and the interfacial strength nevertheless allow a distinction between the three systems. In all cases, strain extension is limited by the nearest fibres. The overall mechanical response under transverse loading is, therefore, macroscopically brittle. (C) 1996 Elsevier Science Limited

A high sensitivity double beta spectrometer TGV (Telescope Germanium Vertical) has been developed. It is based on 16 HPGe detectors of volume 1200 × 6 mm3 each in the same cryostat. The TGV spectrometer was proposed for the study of ultrarare nuclear processes (e.g. 2νββ, 0νββ, 2νEC/EC). Details of the TGV spectrometer construction are described, the principles of background suppression, the results of Monte Carlo simulations and the results of test background measurements (in Dubna and Modane underground laboratory) are provided.

A phenomenological model that takes into consideration the Coriolis coupling of octupole bands is proposed for studying the properties of negative-parity states in deformed nuclei. The nonadiabatic behavior of electric dipole transitions is investigated by introducing a parametrization of the intrinsic matrix element of the operator that generates dipole gamma transitions and which involves both electric dipole and toroidal dipole moments. Calculations are performed for Ra-220,Ra-226. The energy spectra and E1-, E2-, and E3-transition probabilities are calculated. The matrix element of the toroidal moment is determined. The energy-weighted sum rule for El transitions is calculated, and the contribution of the toroidal moment to the sum rule is estimated.