Temperature and density dependence of μ-catalysis cycling rate in dense D/T and H/D/T gas mixtures

Muon catalyzed dt fusion in dense D/T and H/D/T gas mixtures of hydrogen isotopes is studied by the MCF collaboration at JINR. The measurements were carried out with a high pressure target at the JINR phasotron in the temperature range 300-800 K at mixture densities . Tentative experimental results obtained by several analysis methods are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Status of an experiment aimed at laboratory searches for the electron-antineutrino magnetic moment at a level of μ ν ≤3±10− μ B

An experiment aimed at directly detecting antineutrino-electron scattering by using a 40-MCi tritium β-active source will make it possible to lower the present-day laboratory limit on the neutrino magnetic moment by two orders of magnitude. The experiment brings together novel unique technologies in studying rare processes of neutrino-electron scattering: (i) an artificial source of antineutrinos from tritium decay of 40-MCi activity with the antineutrino flux density of about 6×10¹⁴ cm^?2 s^?1 and (ii) new types of detectors capable of detecting electrons of energy down to about 10 eV, namely, a silicon cryogenic detector based on the ionization-into-heat conversion effect and a high-pure germanium detector with an internal signal amplification in the electric field. A compact installation located at a specially equipped underground laboratory (≤100 mwe) will provide favorable background conditions for running the experiment. With a background level of about 0.1 event/(kg keV d) and detector assembly masses of 3 and 5 kg for the silicon and germanium ones, respectively, a limit of μ _ν ≤3±10^? μ _B on the electron-antineutrino magnetic moment will be obtained within 1 to 2 years of data acquisition. The status of the experiment and the state of the art are presented.     

Soft dipole mode in 8He

The low-lying spectrum of ⁸He was studied in the ³H(⁶He, p)⁸He transfer reaction for small center of mass angles. The 0⁺ ground state (g.s.) of ⁸He and excited states, 2⁺ at 3.6–3.9 MeV and (1⁺) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μb/sr. Some evidence for the excited state at about 7.5 MeV can be found in the data. The possible nature of the near-threshold anomaly above 2.14 MeV in ⁸He is related to the population of a 1⁻ continuum (soft dipole excitation) with a peak energy value at about 3 MeV. This assumption can probably resolve the problem of a large uncertainty existing in the experimental data on the ⁸He 2⁺ state energy. The article is published in the original.     

Experimental measurements of the compressibility, temperature, and light absorption in dense shock-compressed gaseous deuterium

Experimental data on the shock compression, temperature, and absorptivity of gaseous deuterium with an initial density close to its value in the liquid state were obtained on a spherical explosion shock-wave generator in a pressure range of 80–90 GPa. The obtained results are compared with the existing experimental and theoretical data.     

Accumulation and transport of hydrogen in RUSFER-EK-181 ferritic-martensitic steel

The influence of heat treatment on interaction between hydrogen and RUSFER-EK-181 Russian ferritic-martensitic steel is studied by the method of thermodesorption mass spectrometry. Based on our experimental data combined with published data for the structure of ferritic-martensitic steels, it can be supposed that the precipitation of fine carbides considerably facilitates the hydrogen sorption. Numerical simulation of hydrogen transport in the steel is conducted.     

First measurements of dtμ cycle characteristics in liquid H/D/T mixture

Muon catalyzed fusion in a dense triple mixture of hydrogen isotopes was investigated for the first time. The experimental method is based on the registration of neutrons from dtμ fusion by a full absorption detector in 4π geometry. The measurements were performed in H/D/T mixture at T=21 K and φ≃ 1.1 LHD using four sets of isotope concentrations. The basic parameters of the dtμ cycle (neutron yield, cycling rate and total sticking) in H/D/T mixtures obtained from neutron time distributions are presented and discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Experimental Results on Muon Catalyzed dt Fusion in H/D/T Mixture

Experimental study on muon catalyzed dt fusion in a triple mixture of hydrogen isotopes (H/D/T) was carried out at the JINR phasotron. The measurements have been performed at various temperatures and densities with liquid and gaseous H/D/T mixtures. Results are presented for the main characteristics of the dtμ cycle. A reduction of the number of dt fusions is observed when hydrogen is added to the D/T mixture, This is mainly due to muon loss to the pt and pd cycles, which have a high sticking probability. We also observe an increase of the cycle rate when the temperature of the H/D/T mixture rises. This confirms the theoretical prediction. This revised version was published online in August 2006 with corrections to the Cover Date.     

Influence of hydrogen on the strength and ductility of 30KhGSA and EI659 steels in quasi-static and shock-loading tests

The influence of hydrogen on the strength and ductility of 30KhGSA and EI659 steels in quasi-static and shock-loading tests was studied experimentally. The sensitivity of the steels to hydrogenation in air under normal pressure or in hydrogen at a pressure of 25 MPa was determined from the results of tests of as-received and pre-hydrogenated samples at a temperature of 773 K and a hydrogen pressure of 50 MPa for 24 h. It is found that EI659 steel doped with tungsten and vanadium is less sensitive to hydrogenation than 30KhGSA steel doped with manganese and chromium.