Theoretical aspects of direct conversion of radio-chemical energy in electric by radiation-stimulated SiC*/Si heterostructure

The authors consider their own CVD technology for the SiC growing on a Si substrate in order to create a beta converter. Since the beta converter contains a heavy C-14 atom, the finished beta converter works as an ”inner sun”, and the structure has specific mark * in the name: SiC*/Si. Authors focus on the problems of the theoretical description of: 1) the growth of the SiC*/Si film (with C-14 atoms inside) and the position of the p-n junction in the doping process; 2) method of a placement radioisotopes into a semiconductor material; 3) physical properties of radioisotopes; 4) defects formation; 5) generation of secondary electrons in the region of the p-n junction.

PRODUCT YIELDS FOR THE PHOTOFISSION OF 239Pu WITH BREMSTRAHLUNG AT 17.5 MeV BOUNDARY ENERGY

The values of relative cumulative yields of 12 products (85mKr, 91mY, 92Sr, 97Zr, 99Mo, 105Ru, 133I, 134I, 135I, 138Cs, 139Ba, 142La, 143Ce) of the 239Pu photofission was measured at a maximum bremsstrahlung energy of 17.5 MeV (av-erage excitation energy ~ 12.03 MeV). 239Pu photofission reaction was stimulated on the electron accelerator of the Institute of Electron Physics NAS of Ukraine – M-30 microtron to simulate the spectra of bremsstrahlung’s photons, secondary electrons, and photoneutrons that hit the 239Pu target, the GEANT4 code was used. The input of accom-panying nuclear reactions to the yield of 239Pu photofission products for the given experimental parameters was also evaluating. The obtained experimental data of the yields of products 239Pu photofission were compared with the program codes GEF and Talys1.9.5 simulations.

Fitting electron spectrum from AMS-02 by pulsar electrons

In this work, we aim to explain the latest data of cosmic-ray electrons from AMS-02 by an electron background model and pulsar electrons. We consider an electron background model which includes primary and secondary electrons. We assume that pulsars are major sources of the electron excess. Since electrons easily lose their energy through the interstellar radiation field and the magnetic field via inverse Compton scattering and synchrotron radiation, respectively, they propagate in a short length. We adopt nearby pulsar data in the distance of 1 kpc from the Australia Telescope National Facility (ATNF) pulsar catalogue. By using a Green’s function of an electron propagation model, we then fit pulsar parameters (i.e. the spectral index, the fraction of the total spin-down energy and the cutoff energy) for several cases of a single pulsar. With a combination of the electron background model, several cases of pulsar spectrum are able to explain the electron excess.

1d3v PIC/MCC simulation of dielectric barrier discharge dynamics in hydrogen sulfide

The products of hydrogen sulfide decomposition by dielectric barrier discharge are hydrogen and sulfur. This process can successfully recover hydrogen from a hazardous by product of fossil fuel extraction, and it has thus been attracting increasing attention. In this study, we computationally examined the dynamics of dielectric barrier discharge in hydrogen sulfide. The simulations were performed with a 1d3v particle-in-cell/Monte Carlo collision model in which a parallel-plate electrode geometry with dielectrics was used. Particle recombination process is represented in the model. The discharge mode was found to be initially Townsend discharge developing from the cathode to the anode, and at the peak of the current, a more stable glow discharge develops from the anode to the cathode. A higher applied voltage results in sufficient secondary electrons to trigger a second current peak, and then the current amplitude increases. As the frequency is increased, it leads to the advance of the phase and an increase in the amplitude of the current peak. A higher dielectric permittivity also makes the discharge occur earlier and more violently in the gap.

Surface effects in a capacitive argon discharge in the intermediate pressure regime

One-dimensional particle-in-cell/Monte Carlo collisional (PIC/MCC) simulations are performed on a capacitive 2.54 cm gap, 1.6 Torr argon discharge driven by a sinusoidal rf current density amplitude of 50 A/m2 at 13.56 MHz. The excited argon states (metastable levels, resonance levels, and the 4p manifold) are modeled self-consistently with the particle dynamics as space- and time-varying fluids. Four cases are examined, including and neglecting excited states, and using either a fixed or energy-dependent secondary electron emission yield due to ion and/or neutral impact on the electrodes. The results for all cases show that most of the ionization occurs near the plasma-sheath interfaces, with little ionization within the plasma bulk region. Without excited states, secondary electrons emitted from the electrodes are found to play a strong role in the ionization process. When the excited states, secondary electron emission due to neutral and ion impact on the electrodes are included in the discharge model, the discharge operation transitions from α-mode to γ-mode, in which nearly all the ionization is due to secondary electrons. Excited states are very effective in producing secondary electrons, with approximately 14.7 times the contribution of ion bombardment. Electron impact of ground state argon atoms by secondary electrons contributes about 76 % of the total ionization; primary electrons, about 11 %; metastable Penning ionization, about 13 %; and multi-step ionization, about 0.3 %.

Simulation of charged particle beam dynamics extracted from a plasma source

This paper presents the results of computer simulation in COMSOL Multiphysics of the hydrogen isotopes beam dynamics extracted from a plasma source of small linear accelerator. The beam energy was 100 keV. The simulation was carried out taking into account the charge exchange of ions on neutral gas molecules in the accelerating system. At the same time, the calculations took into account the process of secondary ion-electron emission from the surfaces of the accelerating system that are bombarded with both fast and slow ions. Consideration of this process made it possible to determine that the value of the electronic load is at least 50% of the main beam current of 100 μA. The inclusion in the trajectory analysis the magnetic field simulation in the secondary electrons generation area made it possible to determine the magnetic field strength, which effectively blocks secondary electrons on the target (3000 Gauss). Then it has been experimentally demonstrated that the discharge current in a plasma source automatically increases by 20% when using the magnetic suppression system on the target node (magnetic field strength is 3000 Gauss).

Teliospore mucilage of Puccinia miscanthi revealed through the axial imaging of secondary electrons

Puccinia miscanthi teliospores were observed on the leaf surface of Miscanthus sinensis using a field emission scanning electron microscope. Details of teliospore mucilage could be visualized through the axial imaging of secondary electrons for a better understanding of pathogen behavior in rust diseases.

The Role of Low-Energy Electron Interactions in cis-Pt(CO)2Br2 Fragmentation

Platinum coordination complexes have found wide applications as chemotherapeutic anticancer drugs in synchronous combination with radiation (chemoradiation) as well as precursors in focused electron beam induced deposition (FEBID) for nano-scale fabrication. In both applications, low-energy electrons (LEE) play an important role with regard to the fragmentation pathways. In the former case, the high-energy radiation applied creates an abundance of reactive photo- and secondary electrons that determine the reaction paths of the respective radiation sensitizers. In the latter case, low-energy secondary electrons determine the deposition chemistry. In this contribution, we present a combined experimental and theoretical study on the role of LEE interactions in the fragmentation of the Pt(II) coordination compound cis-PtBr2(CO)2. We discuss our results in conjunction with the widely used cancer therapeutic Pt(II) coordination compound cis-Pt(NH3)2Cl2 (cisplatin) and the carbonyl analog Pt(CO)2Cl2, and we show that efficient CO loss through dissociative electron attachment dominates the reactivity of these carbonyl complexes with low-energy electrons, while halogen loss through DEA dominates the reactivity of cis-Pt(NH3)2Cl2.