Simulation of Radiation Damage for Silicon Drift Detector

Silicon drift detector with high sensitivity and energy resolution is an advanced detector which is suitable to be used in deep space detection. To study and reveal the radiation damage of the silicon drift detector (SDD) in a deep-space environment, which will degrade the detector performance, in this paper, the SDD radiation damage effects and mechanics, including displacement damage and ionization damage, for irradiations of different energy of neutrons and gammas are investigated using Geant4 simulation. The results indicate the recoil atoms distribution generated by neutrons in SDD is uniform, and recoil atoms’ energy is mainly in the low energy region. For secondary particles produced by neutron irradiation, a large energy loss in inelastic scattering and fission reactions occur, and neutron has a significant nuclear reaction. The energy deposition caused by gammas irradiation is linear with the thickness of SDD; the secondary electron energy distribution produced by gamma irradiation is from several eV to incident particle energy. As the scattering angle of secondary electron increases, the number of secondary electrons decreases. Therefore, a reasonable detector epitaxial thickness should be set in the anti-irradiation design of SDD.

Choosing a substrate for the ion irradiation of two-dimensional materials

This study is dedicated to the common problem of how to choose a suitable substrate for ion irradiation of two-dimensional materials in order to achieve specific roles of certain defect formation mechanisms. The estimations include Monte Carlo simulations for He, Ar, Xe, C, N and Si ions, performed in the incident ion energy range from 100 eV to 250 MeV. Cu, SiO2, SiC and Al2O3 substrates were analyzed. The considered substrate-related defect formation mechanisms are sputtering, recoil atoms reaching the interface with a non-zero energy, and generation of hot electrons in close proximity of the interface. Additionally, the implantation of sputtered substrate atoms into the 2D material lattice is analyzed. This work is useful both for fundamental studies of irradiation of two-dimensional materials and as a practical guide on choosing the conditions necessary to obtain certain parameters of irradiated materials.

Контролируемый синтез графена на меди с использованием метода имплантации атомов отдачи углерода

A method of graphene synthesis on the surface of copper foil by cold implantation of carbon recoil atoms is considered. It is established that monolayer graphene films are formed on the surface of carbon-implanted copper foil under certain conditions (annealing temperature and duration, cooling rate) of postimplantation processing.

Расчетно-экспериментальное моделирование обратимых сбоев ячеек статической памяти субмикронных микросхем при воздействии потоков нейтронов

The simulation of reversible single events in test samples of static memory microcircuits with design norms of 0.5, 0.35, 0.25, and 0.1 μm under the effect of neutron fluxes with various energies is performed. It is shown theoretically and experimentally that reversible single events can occur in modern microelectronics and nanoelectronics products under the effect of a fission-spectrum neutron flux caused by the passage of primary recoil atoms and nuclear reaction products along the microcircuit surface perpendicularly to the electric current lines in the near-drain transistor area. A series of irradiation experiments of static memory circuits with design norms of 0.35 μm is interpreted based on the proposed model.

Образование радиационных дефектов в слабо легированных слоях n- и p-SiC при торможении протонов

Mathematical simulation of the cascade of displacements in SiC is used to consider the specific features of Frenkel-pair generation upon the scattering of 8- and 15-MeV protons. The distribution histograms of energies acquired not only by primary knocked-out atoms, but also by recoil atoms generated in displacement cascades, are calculated. An analysis of the histograms considers two energy ranges. In the first range of “low” energies, the spontaneous recombination of genetically related Frenkel pairs is dominant. Recoil atoms in the second range have a higher energy, which enables these atoms to leave the spontaneousrecombination zone and dissociate into isolated components. The compensation of lightly doped n - and p -4 H -SiC samples grown by gas-phase epitaxy is experimentally studied under irradiation with 8- and 15-MeV protons. The carrier removal rates are measured. The calculated and experimental data are compared and estimates are obtained for the size of the spontaneous-recombination zone.