Detection of accelerated particles from pulsed plasma discharge using solid state nuclear track detector

The ion beam of a Mather-type 23.25 J plasma focus device operated with air filling at 10 Torr was registered using CR-39 nuclear track detector. The irradiated samples were etched in NaOH solution at 70°C for 1 h. It is found here that plasm a beam contains multi-components of microbeams. The individual track density of microbeams is estimated and the total current density of the plasma stream is measured to be 1.2 mA/cm². A model for counting the track density of individual microbeams is proposed here. Faraday cup measurements showed the ion pulse with energy ranging from 5.8 keV to 3.3 keV.      

VH-nuclei cosmic ray tracks in silicate minerals of howardites: A regolith stage of parent body formation

Natural tracks in pyroxene and plagioclase crystals from Erevan and Kapoeta howardites are due to irradiation by both galactic and solar cosmic rays.     

MeV-ion-induced defects in organic crystals

We present scanning force microscope images of crater-like defects induced by MeV atomic ions incident on single-crystal L-valine surfaces. For grazing incidence ions, the craters are elongated alongthe ion azimuth of incidence and are followed by raised tails in the surface above the ion track. Craters formed by off-normal ions are wider than craters formed by nrmally incident ions. The crater volume is highly nonlinear in (dE/dx)_e. We discuss our observations qualitatively in terms of thermal-spike and pressure-pulse/shock-wave models for the sputtering of organic solids.     

Observation of diffusion through ion irradiated Makrofol KG

The features of the latent track in polycarbonate can be analysed by measuring the diffusion constant under ultra high vacuum conditions. Stacks of 30 μm Makrofol KG foils were irradiated with uranium ions of 11.4 MeV/u at the GSI Darmstadt, Germany. We used different fluences from 3·10¹⁰ to 5·10¹¹ ions/cm². The diffusion constant was determined by the time-lag-method [1]. A quadrupole mass filter was used to observe the diffusion of the gas. We measured the diffusion of argon through different foils of each stack at room temperature. In all cases also unirradiated foils were measured. The dependence of the permeability and the diffusion constant on the ion fluence and the energy loss of the ions will be given and indications on the size of latent ion tracks concerning gas diffusion will be discussed.     

Nuclear tracks created by 90 MeV carbon ions in ZnO crystal

The distribution of the lengths of the tracks, created by 90 Mev Carbon ions in Zno crystal consists of three groups with an average value about 52, 67 and 102 micrometers. The first group of the tracks may be treated as unchannelling particles. The second group corresponds to channeling particles and the third one represents superchannelling particles.     

Track structure in dielectric and semiconductor single crystals irradiated by heavy ions with high level of inelastic energy losses

The phenomenological model of the track formation processes during a heavy ion passing through materials is discussed. This model is based on the scanning tunneling and electronic microscopy investigations of diamond single crystals and stainless steel subjected to ⁴⁰Ar, ⁸⁴Kr and ¹²⁹Xe ion irradiation with energies in the MeV region. The energy and temperature criteria when crater formation on the surface during the heavy ion irradiation takes place are introduced.     

两体衰变径迹

在19MeV/u ⁴⁰Ar+²⁰⁹Bi反应中,云母片固体径迹探测器记录了几例连续两次衰变径迹.分析表明,这些事件两次衰变的时间间隔约为10^－13s.根据位垒穿透的WKB理论,这样的裂变是可能的.     

A hybrid multi-objective imperialist competitive algorithm and Monte Carlo method for robust safety design of a rail vehicle

This paper deals with the robust safety design optimization of a rail vehicle system moving in short radius curved tracks. A combined multi-objective imperialist competitive algorithm and Monte Carlo method is developed and used for the robust multi-objective optimization of the rail vehicle system. This robust optimization of rail vehicle safety considers simultaneously the derailment angle and its standard deviation where the design parameters uncertainties are considered. The obtained results showed that the robust design reduces significantly the sensitivity of the rail vehicle safety to the design parameters uncertainties compared to the determinist one and to the literature results.     

Observation of nuclear track in organic material by Atomic Force microscopy in real time during etching

The developments of Atomic Force Microscopy (AFM) allow to investigated solid surfaces with a nanometer scale. These techniques are useful methods allowing direct observation of surface morphologies. Particularly in the nuclear track fields, they offer a new tool to give many new informations on track formation. In this paper we present the preliminary results of a new use of this technique to characterize continuously the formation of the revealed track in a cellulose nitrate detector (LR115) after an alpha particle irradiation. For that, a specific cell has been used to observe, by nano-observations, the evolution of track shapes simultaneously with chemical treatment. Thus, the track shape evolution has been studied; visualizing the evolution of the tracks in real time, in situ during the chemical etching process.     

A disjunctive graph model and framework for constructing new train schedules

Train scheduling is a complex and time consuming task of vital importance in many countries. To create completely new train schedules that are more accurate and efficient than permitted by current techniques, a novel “hybrid” job shop approach is proposed and implemented in this paper. Unique characteristics of train scheduling are firstly incorporated into a disjunctive graph representation of the solution. Dedicated “stand-alone” constructive algorithms that utilise this representation are then developed. The modelling approach and the constructive algorithms are essential as they provide the basis for which meta-heuristics and other iterative refinement algorithms can be applied. A numerical investigation and case study is provided and demonstrates the viability of the modelling approach. Furthermore it is demonstrated that good quality solutions are provided with reasonable computational effort.