[en] Mechanism of the self-quenching streamer (SQS) mode in a gas counter and its application to nuclear radiation detection are reviewed briefly. New data of SQS transitions in Kr-based mixture gases are shown. (author) 74 refs

[en] Self-quenching streamers (SQSs) induced by charged particles in gas counters are classified into two types on the basis of their formation mechanisms: Photo-mediated SQS and ionization-track induced SQS. The transition condition of α-ray induced SQS has been investigated as a typical example of the ionization-track induced SQS by heavy charged particles. For this purpose, obtainable experimental data are totally compiled and reanalyzed. Effective electric field, E_eff, and average electron density of an α-ray ionization track, ρ_av, are newly introduced and examined with those data. A result of the analysis indicates that the SQS transitions may occur when E_eff·ρ_av reaches a certain value. Following this, the transition characteristics to the SQS mode for protons around 10 MeV are investigated through an experiment

[en] The simulation results of nonlinear propagation properties in the CO² laser system using a simulation model of the SF⁶ saturable absorbers and the CO² laser amplifiers agree well with the experimental results. The technical problems of the simultaneous irradiation of the multi-beams to a target are also discussed. (author)

[en] It is necessary to understand physical processes for ionization in an ion source-plasma to design better multiply-charged heavy ion sources. Equations for ionization, which are applicable the ECR-type ion source and the ECR-EB hybrid-type ion source, are developed and discussed. Charge distributions could be obtained by solving simultaneous equations for various palameters. We could obtain from the analysis a guiding principle for multiply-charged heavy ion sources, that is, the study of the charge distributions makes it clear that the production of multiply-heavy ions depends strongly upon ion confinement time than electron temperature and an ECR-EB hybrid-type ion source shows an effect for enhancement of multiply-charged heavy ions. The ion charge distribution are compared with experimental data from an ECR-type ion source. (author)

[en] Volume integrals of central optical potentials for scatterings of deuterons, ³He and α-particles from nuclei are discussed. The corrections factors of volume integrals of ³He real central optical potentials to those estimated from nucleon-nucleus folded potentials are about 30 % at the incident energy of 10 -- 30 MeV/nucleon and approach to negligibly small values at 70 -- 100 MeV/nucleon region. Volume integrals of imaginary central potentials are also discussed. (author)

No abstract available

[en] Differences of the deformation parameters for the 2⁺₁ states of even-even spherical nuclei extracted from electromagnetic excitation βsup(em)₂ and from proton scattering βsup(pp')₂ are discussed. It is found that the ratio βsup(pp')₂/βsup(em)₂ is equal to about unity and that there is a small isotope dependence for several incomplete shell nuclei. (orig.)

[en] An introductory review is described on nuclear reaction models for particle emission with continuum spectra, before 1980's. Firstly, the evaporation models are derived from the Fermi particle and the compound nucleus models. Secondly, the pre-equilibrium model is described. And, attempts of Kyushu University and Heidelberg groups to interpret the forward-peaked angular distribution, which the pre-equilibrium model can not predict, are described. Finally, the early studies on quantum-statistical theories of the multi-step nuclear reaction models are described briefly. (author)

No abstract available

[en] The symposium 'Research and Development of Accelerators in Atomic Energy Science' was held in August 2001 and the 2nd symposium is planned in this August 2004. This activity is based on emerging development of the field on accelerators and their applications. The problem on changing of national universities from governmental to independent agency in this year is also a background of this activity. Here, the basic motivation of the author for these symposia will be discussed. (author)