China
Africa
Explore chapters and articles related to this topic
Nanofabrication Using Focused Ion Beam
Published in V. K. Jain, Advanced Machining Science, 2023
Bhaveshkumar Kamaliya, Rakesh G. Mote
During ion beam irradiation on the material, elastic ion–atom collision results in different mechanisms such as ion–solid collision cascades, sputtering of the atoms, and redeposition of sputtered atoms. These processes take place through the bulk of the solid, on the surface, and above the surface of the target. The ion–atom collision cascade due to ion–solid interactions in the bulk region of the substrate can be estimated by the binary collision approximation (BCA) model. According to the BCA model, ions undergo elastic collision with the target atoms in a manner which could be considered as hard-sphere collisions with an assumption that the ions and target atoms are classical perfect spheres colliding with each other. Interaction of irradiated ions and atomic nucleus in the material is considered to be an elastic collision in the BCA model, and the model has been widely used toward underlying kinetics during ion–atom collisions. Generally, based on the BCA model, the stopping and range of ions in matter (SRIM) can be estimated using the Monte Carlo simulations known as transport of ions in matter (TRIM) [5,6]. In these simulations, every incident ion and recoiled atom are traced, and their trajectories are stored up until their kinetic energy reduces to the cut-off value (i.e., stopping of ion or atom) or until they have escaped from the simulation region.
Helium Ion Microscopy
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Alex Belianinov, Olga S. Ovchinnikova, Artem A. Trofimov, Kyle T. Mahady, Philip D. Rack
Nuclear stopping process arises from elastic collisions between primary ions and atomic nuclei, and these collisions are the primary means by which ion bombardment leads to target damage. A useful approach to study elastic collisions is the binary collision approximation (BCA). In the BCA model, the nuclear stopping process is reduced to a series of binary collisions, taking place between the primary ion and the nearest atom in the target. During each binary collision, the energy transferred from the primary ion to the stationary target atom may be taken to be elastic, as illustrated by Eq. 9.2.
Cluster formation by the precise joining of iron oxide nanoparticles on low energy nitrogen ion irradiation
Published in Radiation Effects and Defects in Solids, 2023
Arpita Patro, Smruti Ranjan Nayak, Manoj Rajbhar, Shyamal Chatterjee, Satyanarayan Dhal
The cluster formation process by joining nanoparticles at this very low energy is also further examined by engaging TRI3DYN simulations. The effects due to collision can be well understood by TRI3DYN simulation while illustrating the progressions of the atomic percentages of the nanoparticles before and after the ion bombardment. The computer simulation TRI3DYN is based on the Binary Collision Approximation (BCA) in a Monte Carlo concept. For example, in Figure 8(a and b), the oxygen atomic percentage is revealed on two iron oxide nanoparticles oriented as if one particle is on top of the other. The dynamic evolution of a 3D structure with a pre-defined shape that predicts more precise post-collision changes. The target was comprised of volume elements of size 60 × 60 × 60 nm3 and a total of 80 × 60 × 60 voxels with periodic y–z boundaries. A uniform beam of N+ ions was used as the projectile at an energy of 5 keV at ion fluences of 1 × 1016 and 3 × 1016 ions per cm2, respectively. At an ion fluence from 3 × 1016 ions per cm2, a considerable decrease in the number of oxygen atoms arises due to recoils and sputtering. A very less amount of oxygen atoms indicated by green and cyan-colored dots are also found on the substrate (Figure 8(b)) representing a very little amount of sputtered-out oxygen atoms get deposited on the silicon substrate. The ion bombardment further makes dangling bonds (33) because of ion-induced defects (34) on the surface of each of the nanoparticles. These displaced atoms from their original configuration are forming the neck between two joined iron oxide nanoparticles which in turn became the primary reason behind the clusters of iron oxide nanoparticles. Silicon atoms from the substrate are not sputtered out by primary ions possibly due to their very low energy, because as TRIM simulation suggests the projected average range is about 9 nm. Furthermore, each iron atom absorbs 1.52 keV per ion whereas each oxygen atom absorbs 2.06 keV per ion. Most of the energetic ions might have lost all of their energies during the cascade collisions which can be confirmed from the ion distribution in the TRIM simulation.
An extensive study on nuclear shielding performance and mass stopping power (MSP)/projected ranges (PR) of some selected granite samples
Published in Radiation Effects and Defects in Solids, 2021
H. O. Tekin, E. Kavaz, M. I. Sayyed, O. Agar, M. Kamislioglu, E. E. Altunsoy Guclu, C. Eke
Stopping and Range of Ions in Matter (SRIM), which was improved by Ziegler and Biersack is based on a Monte Carlo simulation method of the binary collision approximation with a random selection of the impact parameter of the next colliding ion (35,36). It contains quick calculations that generate knowledge on stopping power and range distributions for any ion at any energy over a wide range 10 eV–2 GeV and in any elemental target. More detailed simulations contain absorbers with complex multi-layer configurations (37). SRIM tables depending on particle energy are very useful to compute the particle transport in various simulation applications. Using the neutron radiation damage profile, this code calculates the amount of code and damage to the unit. The results show the number of atom displacements. SRIM has been carried out in simulation with the energy of 2 × 105 sputtered particles (38). Radiation effects in a specific substance depend on more than the amount of exposure to the absorption dose and energy. The influence of radiation on living organism is related to the energy density. The rate of energy loss of charged particles passing through an absorber is defined as the stopping power. It is due to the interaction of the charged particle with the atomic electrons in the material. Nuclear stopping power is the interaction of the charged particle with the nucleus of the atom. where and denote the electronic stopping power and the nuclear stopping power, respectively. The stopping power of the medium for a charged particle is related to the mass charge and velocity of the ion. The electron stopping power is similar to the interaction of charged particles with orbital electrons. Nuclear stopping power is specific to electron radiation. Typical energies of beta particles released from radioactive sources are in the range of 1–10 MeV. As the wavelength increases, the energy decreases as the energy decreases. As the atomic number increases, the coefficient of mass reduction at the specific wavelength increases with increasing Z because the stopping power increases. There is a relation between ion implantation, radiation detectors, ion beam irradiation due to irradiation of materials, Balmoral Red (G1), Capao Bonita (G2), Verde Guatemala (G3), Verde Butterfly (G4), Bianco Extra (G5), Bluea Peark (G6), Porto Rosa (G7), Rosy Pink (G8), Star Galaxy (G9) structure formation, redistribution of ion-derived mass and increased spray efficiency and in the understanding of basic ion interaction processes.