TRIM Simulation Research Articles

Development of nano-porous Au thin film at room temperature via ion irradiation in a-Ge/Au bilayer system followed by chemical etching of Ge

The development of nano-porous gold (NPG) via room temperature ion irradiation has been presented in detail. The bilayer thin films of a-Ge/c-Au have been irradiated by 100 MeV Ni ions with the fluence of 5 × 1013 ions cm−2 at room temperature. NPG is obtained by selectively etching Ge off from the Au matrix by dipping the Ge/Au thin film into 10 % H2O2 solution. Diffusion of Ge and Au across the interface under irradiation was confirmed by TRIM simulation and RBS spectra. The SEM image and EDX spectra confirms the formation of NPG with high purity. In addition, the statistical and fractal analysis of AFM image also confirms the formation of NPG. NPG system has been observed to show very good optical properties (low reflectance and high transmittance). The high quality NPG prepared by this method can be useful in the fields like optical sensors, transparent conductive electrodes, anti-reflective coatings, and photo-detector technology.

Influence of 700 keV O3+ ion implantation on current transport properties of Cr/p-GaN SBD’s

In the present study we show a detailed investigation into the influence of 700 keV O3+ ion implantation in Cr/p-GaN SBDs on electrical characteristics / current transport properties. Also the damage events along the trajectory of the ion beam were quantitatively estimated through SRIM and TRIM simulations. The Current-voltage (I-V) characteristics were analyzed using different methods such as Cheung and Cheung's method and Norde’s method to obtain different electrical parameters. The values of n and ϕB decrease up to a fluence of 1 × 1014 ions cm−2, and show a fractional increase at a fluence of 1 × 1015 ions cm−2. Further, a drastic increase in values of series resistance (RS ) of SBDs with an increase in fluence was observed. In the forward-bias voltage regions, the Cr/p-GaN SBDs conduction mechanism shows an increasingly ohmic behavior with an increase in fluence, which may be attributed to thermally generated carriers. At low voltage, the reverse current conduction mechanism is due to Poole-Frenkel emission. For the high voltage region, Schottky emission mechanism becomes more prominent. The changes in electrical parameters are closely related to the defect and damage profiles estimated through SRIM/TRIM simulations, which are strongly dependent on the dose of the 700 keV O3+ ion implantation. Additionally, we found that at high doses, the charge transport mechanism changes, with additional defects affecting not only the thermionic emission mechanism but also various current transport mechanisms.

Swift heavy ion irradiation effects on tungsten carbide films

Tungsten carbide (WC) is an important material to study for various applications in extreme environments due to its radiation-resistant properties and high mechanical strength. Due to its excellent properties such as high hardness, strength, and wear resistance, it is also being considered lately as a plasma facing component in nuclear fusion reactors. To study the response of this material in extreme radiation environments, WC films prepared using RF sputtering technique were irradiated with 100 MeV Ag8+ ions in the present work. The irradiation was carried out at three different fluences: 3 × 1012, 1 × 1013, and 3 × 1013 ions/cm2. Rutherford Backscattering Spectrometry (RBS) was performed to determine the stoichiometry and thickness of the pristine film. To study the irradiation-induced modifications, glancing angle X-ray diffraction (GAXRD), field emission scanning electron microscopy (FE-SEM), High Resolution Transmission Electron Microscopy (HRTEM), and Raman spectroscopy were performed on the pristine and irradiated samples. GAXRD of the pristine and irradiated samples revealed grain size reduction accompanied with reduced crystallinity with increasing ion fluence which was further manifested in HRTEM measurements and Raman spectroscopy measurements. Change in surface morphology due to the ion irradiation was observed in FE-SEM. These modifications have been explained using thermal-spike and TRIM simulations which showed that although the swift heavy ions irradiation did not result in track formation in the WC films, it caused radiation damage which may be attributed to the synergistic effect of electronic and nuclear energy loss mechanisms. These results might be crucial for a fundamental understanding of the radiation resistance of WC thin films and its application in different radiation environments.

Simulation of ranges and sputtering of low energy Helium and Argon ions irradiation on Tungsten surface

The interactions of low energy He and Ar ions with pure W target were simulated by a new Monte-Carlo (MC) based computer code which was designed to insure maximum accuracy. For these irradiation systems, incident ions projected ranges in the target material, sputtering yield, and the percentage of backscattered ions at various incident energies were studied. furthermore, the effect of the angle of incidence on sputtering yield and the percentage of backscattered ions were also simulated. Our simulation results were compared with experimental data and those calculated by the TRIM simulation program. Our code is based on an algorithm that uses detailed numerical solutions for the classical scattering integral for evaluating the binary collision process. This approach has provided sputtering yield data with a higher level of accuracy compared to TRIM's simulation results. Also, a new approach of using a reduced atomic displacement threshold in the top surface monolayer enhances the simulation results in the near sputtering threshold energy range and eliminates its dependence on the selected value of the displacement energy threshold Ed. Nonetheless, both simulation programs produced less contrasting results in terms of incident ions mean projected ranges. Furthermore, fundamental discrepancies in the percentage of backscattered ions between the results of both simulation programs were found.

Ionization and phonon production by $^{10}$B ions in radiotherapy applications

The therapeutic use of heavy ions has received much attention due to their physical and radiobiological properties. Thanks to these features of heavy ion radiotherapy, radiation in tissues close to critical tissues can reduce LET while allowing an increase in LET in tumors. Selection of biomaterials closest to the tissue is critical to measure the accuracy of this LET transfer. The accuracy of LET and radiological features measured in phantoms created from biomaterials selected according to the characteristics of the target tissue is very important for human life. For this reason, the research of polymeric materials, which is the closest biomaterial to soft tissue and therefore phantom material, has increased recently. In this study, ionization to the polymeric biomaterials closest to the soft tissue in boron therapy application, and phonon release from all interactions were investigated and analyzed. This analysis was performed using MC-based TRIM simulation. In the analysis, the Bragg peak range closest to the soft tissue was 7.2% and PMMA was the phonon release from all interactions. It has been observed that the phonon production in phantoms results from ions on average 30% and recoils interactions 70%. The main novelty that this study will provide to the literature is to consider the phonon interactions as well as the ionization interactions. Thus, apart from proton and carbon, the most ideal polymeric biomaterial to be used instead of soft tissue was evaluated by calculating all interactions. Thus, it is aimed to determine the most ideal phantom material.

TRIM Simulations Tool for µ + Stopping Fraction in Hydrostatic Pressure Cells

For quantum systems or materials, a common procedure for probing their behaviour is to tune electronic/magnetic properties using external parameters, e.g. temperature, magnetic field or pressure. Pressure application as an external stimuli is a widely used tool, where the sample in question is inserted into a pressure cell providing a hydrostatic pressure condition. Such device causes some practical problems when using in Muon Spin Rotation/Relaxation (µ +SR) experiments as a large proportion of the muons will be implanted in the pressure cell rather than in the sample, resulting in a higher background signal. This issue gets further amplified when the temperature dependent response from the sample is much smaller than that of the pressure cell,which may cause the sample response to be lost in the background and cause difficulties in aligning the sample within the beam. To tackle this issue, we have used pySRIM [1] to construct a practical and helpful simulation tool for calculating muon stopping fractions, specifically for the pressure cell setup at the µE1 beamline using the GPD spectrometer at the Paul Scherrer Institute, with the use of TRIM simulations. The program is used to estimate the number of muon stopping in both the sample and the pressure cell at a given momentum. The simultion tool is programmed into a GUI, making it accessible to user to approximate prior to their experiments at GPD what fractions will belong to the sample and the pressure cell in their fitting procedure.

α-SpecTrim: A new application designed for reproducing alpha-particle spectra

In this work, we introduce a new software application developed to reproduce α-particle spectra measured with silicon detectors. It takes into consideration the main physical processes involved in the interaction of alpha particles with the source and the detector. This application is considerably more user-friendly than multipurpose codes, being also the runtimes to obtain a spectrum much lower. It makes use of the TRIM simulation code for tracking alpha particles in the source and the detector entrance window. Concerning to the response function of a silicon detector, the contribution of electronic excitation and ionization produced by the alpha particles is also obtained by simulation, while the electron-hole pair statistics and the broadening produced by the amplifier system (electronic chain) are included as convolutions of theoretical functions. The code α-SpecTrim is written in Python 3 language using Flask framework, so it can be run in every PC or laptop. It is free and can be provided if requested to the authors.

Favourable tuning of optical absorbance, bandgap and surface roughness of ZnO thin films by C ion implantation at the critical angle

Low energy ion implantation with exquisite control of angle allows manipulating the applications of thin films. Here we present a favourable and efficient strategy of 50 keV Carbon ion implantations on ZnO thin films at three different tilt angles 0°, 30° and 60°. This plays a significant role in tuning of optical absorbance, bandgap, grain size and surface roughness simultaneously. The TRIM simulations are performed to elucidate the theoretical understanding and to compare the modifications in the physical properties using different characterization tools. These experimental results demonstrate that the ion implantations at 30° result in a significant reduction of 89% in the grain size and 35% reduction in the optical transmittance along with an improvement of 25% in the surface roughness of these thin films. The optical bandgap is also tuned from 3.27 to 3.20 eV. These results establish a new approach in designing the exotic materials with lower grain size, lower bandgap and smoother surface along with higher absorbance of ultraviolet (UV) light that will help increasing the data storage capacity and getting higher energy efficiency with reduced UV light emissions.

Electrically Active Defects Induced by α‐Particle Irradiation in p‐Type Si Surface Barrier Detector

Herein, the investigation of radiation‐induced defects generated in the Al/SiO2/p‐type FZ Si surface barrier detector upon irradiation with α‐particles at room temperature using capacitance−voltage (C−V) and current deep‐level transient spectroscopy (IDLTS) methods is conducted. The carried out C−V measurements indicate the formation of at least 8 × 1012 cm−3 radiation‐induced acceptor traps at the depth fairly close to that where, according to TRIM simulations, the highest concentration of vacancy‐interstitial pairs is created by the incoming α‐particles. The studies conducted by the current DLTS technique allow to relate the observed increase in the acceptor concentration with the near‐midgap level at E V + 0.56 eV. This level can apparently be associated with V2O defects recognized previously to be responsible for the space−charge sign inversion in the irradiated n‐type Si detectors.

Toward energy-efficient physical vapor deposition: Routes for replacing substrate heating during magnetron sputter deposition by employing metal ion irradiation

In view of the increasing demand for achieving sustainable development, the quest for lowering energy consumption during thin film growth by magnetron sputtering becomes of particular importance. In addition, there is a demand for low-temperature growth of dense, hard coatings for protecting temperature-sensitive substrates. Here, we explore a method, in which thermally-driven adatom mobility, necessary to obtain high-quality fully-dense films, is replaced with that supplied by effective low-energy recoil creation resulting from high-mass metal ion irradiation of the growing film surface. This approach allows the growth of dense and hard films with no external heating at substrate temperatures Ts not exceeding 130 °C in a hybrid high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) setup involving a high mass (m > 180 amu) HiPIMS target and metal-ion-synchronized bias pulses. We specifically investigate the effect of the metal ion mass on the extent of densification, phase content, nanostructure, and mechanical properties of metastable cubic Ti0.50Al0.50N based thin films, which present outstanding challenges for phase stability control. Ti0.50Al0.50N based thin films are irradiated by group VIB transition metal (TM) target ions generated by Me-HiPIMS discharge, in which Me = Cr (mCr = 52.0 amu), Mo (mMo = 96.0 amu), and W (mW = 183.8 amu). Three series of (Ti1-yAly)1-xMexN films are grown with x = Me/(Me+Al+Ti) varied intentionally by adjusting the DCMS powers, while y = Al/(Al+Ti) also varies as a result of Me+ ion irradiation. Results reveal a strong dependence of film properties on the mass of the HiPIMS-generated metal ions. All layers deposited with Cr+ irradiation exhibit porous nanostructure, high oxygen content, and poor mechanical properties. In contrast, (Ti1-yAly)1-xWxN films are fully-dense even with the lowest W concentration, x = 0.09, show no evidence of hexagonal AlN precipitation, and exhibit state-of the-art mechanical properties typical of Ti0.50Al0.50N grown at 500 °C. The process energy consumption is lowered by 64% with no negative impact on the coating quality. TRIM simulations provide an insight into the densification mechanisms.

Research on Trim Simulation and Flight Test of a General Electric Aircraft

In order to study the stable flight of an electric aircraft in the whole flight speed range, taking the manned electric aircraft as an example, the method and principle of Longitudinal Trim for high aspect ratio aircraft are presented. Based on the wind tunnel test data, the torque produced by different gravity centers and tension lines as input parameters, and ignoring the influence of lateral and heading parameters, the three-degree-of-freedom motion equation of the aircraft is established, the difference of the performance parameters before and after the trim state is analyzed, which reflects the flight characteristics of the aircraft in a comprehensive way, and is compared with the flight test data. The simulative simulation data and the flight test data are in good agreement and have certain feasibility, it provides a reference for analyzing the performance parameter modification of other high aspect ratio electric aircraft in the future.

Proton irradiation effects on metal-YBCO interfaces

10 MeV proton-irradiation effects on a YBCO-based test structure were analyzed by measuring its current-voltage (IV) characteristics for different cumulated fluences. For fluences of up to ~ 80⋅109 p/cm2 no changes in the electrical behavior of the device were observed, while for a fluence of ~ 300⋅109 p/cm2 it becomes less conducting. A detailed analysis of the room temperature IV characteristics based on the γ power exponent parameter [γ = dLn(I)/dLn(V)] allowed us to reveal the main conduction mechanisms as well as to establish the equivalent circuit model of the device. The changes produced in the electrical behavior, in accordance with Monte Carlo TRIM simulations, suggest that the main effect induced by protons is the displacement of oxygen atoms within the YBCO lattice, particularly from oxygen-rich to oxygen-poor areas, where they become trapped.

Heavy ion track straggling effect in single event effect numerical simulation of 3D stacked devices

Numerical simulation of single event effect in 3D stacked NMOS transistor, inverter and 6T SRAM cell models were conducted using Geant4 and TCAD combined technology. Heavy ion track straggling effect was observed in 3D stacked transistor and inverter models by comparing the ion induced transient pulses and ion striking positions. TRIM simulation was carried out to study and verify the ion track straggling effect in 3D stacked models, which is much more significant for low energy heavy ions than high energy counterparts. Large scale simulation of upset sensitive area imaging in stacked 6T SRAM cell model showed that the upset areas (or cross sections) in each tier are very similar. It indicated that high energy heavy ions are beneficial to the SEE analysis of 3D stacked devices and almost can remove the ion track straggling effect, but which is only appropriate for the relatively thin devices. Finally, the problems on SEE evaluation and analysis in future 3D stacked devices were further discussed.

Mechanisms of alpha particle induced soft errors in nanoscale static random access memories

In this paper, the Am-241 is used as an alpha particle radioactive source to investigate the soft error mechanism in 65-nm and 90-nm static random accessmemory (SRAM). Combining reverse analysis, TRIM and CREME-MC Monte Carlo simulation, the energy transport process, deposited energy spectrum and cross-section characteristics of alpha particles in the device are revealed. The results show that the soft error sensitivity of the 65-nm device is much higher than that of the 90-nm device, and no flipping polarity is found. According to the real-time measured soft error rate at an altitude of 4300 m in Tibetan Yangbajing area, the thermal neutron sensitivity and alpha particle soft error rate, the overall soft error rate of 65-nm SRAM used at sea level of Beijing city is 429 FIT/Mb, and the contribution from alpha particles is 70.63%. Based on the results of reverse analysis, a three-dimensional simulation model of the device is constructed to study the influence of the incident angle of alpha particles on the single event upset characteristics. It is found that the corresponding deposition energy value at the peak of the number of particles in the sensitive region decreases by 40% with the incident angle increasing from 0° to 60°. While the single event upset cross sectionincreases by 79% due to the apparent single event upset edge effect in a sensitive region of the 65-nm device.

Issues of TRIM program as a tool for developing a silicon detectors radiation degradation scenario

The presented study is focused around the TRIM program issues and its applications for prediction of silicon detectors degradation under heavy ions of 40Ar. Results of the simulations of low-energy ion (53.4 MeV) and high-energy ion (1.62 GeV) irradiation are demonstrated. Experimental data for silicon p+-n-n+ detectors irradiated by the low energy are also presented. Reliability of TRIM simulations application for studying silicon detectors degradation under heavy ion irradiation is discussed.

Antibacterial Effect of Au Implantation in Ductile Nanocomposite Multilayer (TiAlSiY)N/CrN Coatings.

A multilayered nanocomposite designed for biomedical applications based on (TiAlSiY)N/CrN coating implanted by heavy Au- ions is studied. Ion irradiation produced formation in the upper-surface of local amorphous clusters. The obtained composite system was characterized by SEM-EDS, RBS, SIMS, HRTEM, STEM, and nanoindentation mechanical tests, inspecting microstructure, phase state, elemental composition and surface defectiveness. The range of ion impact with correlation to TRIM simulations amounted to 23.5 nm with visible dislocations and interstitial loops indicating the nanopores' creation up/lengthways to the interface boundary. Mechanical parameters remain stable with a slight decrease (less than 2%) in hardness along with an increase in ductility. The antibacterial effect was evaluated in vitro by agar-diffusion and time-kill (72 h) assessments to define both cell-killing mechanisms: dry surface-contact and cytotoxic golden ions-release into moist environment. The identified antibacterial activity within implantation was 2-2.5 times higher due to inhibition zone diameter and antibacterial rate increase. The Au- implanted composite exhibits excellent defense against Gram-negative and Gram-positive bacteria without appreciable surface contamination. Possible biophysical and chemical mechanisms of microorganisms' disruption and annihilation were proposed and analyzed. The present study shows that produced composite has large potential for use in biomedical areas.

The sputtering yield of crystalline Si(1 0 0) surface by monoatomic and diatomic nitrogen ions impact

We have investigated the sputtering rate of thin crystalline silicon film forming silicon-on-insulator structure impinged by atomic and molecular nitrogen ions with medium energies of 25, 50, and 100 keV/(N atom) at several incident angles of 0, 30, 45, and 60°. The thickness of the surface silicon layer after ion irradiation was quantitatively estimated by Rutherford backscattering spectroscopy using 2.56-MeV 10B2+ ions with a grazing angle geometry to accurately analyze the thickness decrement in several nanometers for ultrathin Si layers. The sputtering rates were compared with a full-cascade TRIM simulation based on a binary collision approximation. We found that the sputtering yields of monoatomic N ion with higher energies (>50 keV/N) took significantly higher than that of diatomic N2 ion, probably suggesting that a wake-like effect of relatively fast NN molecular ions surviving for a long period due to a considerably strong triple bond. In addition, the observed sputtering yields for all present conditions were a few times smaller than that estimated by the full-cascade TRIM calculation using typical lattice parameters. We quantitatively discuss the details of sputtering phenomenon of crystalline silicon by nitrogen ions at medium energy region.

Effect of oral β-blocker treatment on mortality in contemporary post-myocardial infarction patients: a systematic review and meta-analysis.

AimsGuidelines concerning β-blocker treatment following acute myocardial infarction (AMI) are based on studies undertaken before the implementation of reperfusion and secondary prevention therapies. We aimed to estimate the effect of oral β-blockers on mortality in contemporary post-AMI patients with low prevalence of heart failure and/or reduced left ventricular ejection fraction.Methods and resultsA random effects model was used to synthetize results of 16 observational studies published between 1 January 2000 and 30 October 2017. Publication bias was evaluated, and heterogeneity between studies examined by subgroup and random effects meta-regression analyses considering patient-related and study-level variables. The pooled estimate showed that β-blocker treatment [among 164 408 (86.8%) patients, with median follow-up time of 2.7 years] was associated with a 26% reduction in all-cause mortality [rate ratio (RR) 0.74, 95% confidence interval (CI) 0.64–0.85] with moderate heterogeneity (I2 = 67.4%). The patient-level variable mean age of the cohort explained 31.5% of between study heterogeneity. There was presence of publication bias, or small study effect, and when controlling for bias by the trim and fill simulation method, the effect disappeared (adjusted RR 0.90, 95% CI 0.77–1.04). Also, small study effect was demonstrated by a cumulative meta-analysis starting with the largest study showing no effect, with increasing effect as the smaller studies were accumulated.ConclusionEvidence from this study suggests that there is no association between β-blockers and all-cause mortality. A possible beneficial effect in AMI survivors needs to be tested by large randomized clinical trials.

Energy loss due to defect formation from 206Pb recoils in SuperCDMS germanium detectors

The Super Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory studied energy loss associated with defect formation in germanium crystals at mK temperatures using in situ 210Pb sources. We examine the spectrum of 206Pb nuclear recoils near its expected 103 keV endpoint energy and determine an energy loss of (6:08 ± 0:18)%, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of 19.7−0.5+0.6 eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter searches.

Dynamic maneuver loads calculations for a sailplane and comparison with flight test

This work presents the results of dynamic maneuver simulations of a sailplane and the comparison with flight test data. The goal of the effort is to extend and validate an in-house toolbox used for loads analysis of free-flying flexible aircraft in the time domain. The underlying aerodynamic theories are the steady vortex lattice and the doublet lattice method with a rational function approximation for the unsteady simulations in the time domain. The structural model comprises a beam model to represent the stiffness properties and a lumped mass model, both are developed using preliminary design methods. Steady aeroelastic trim simulations are performed and used as initial condition for the time simulation of the unsteady maneuvers in which the pilot’s commands, which were recorded during flight test, are prescribed at the control surfaces. Two vertical maneuvers with elevator excitation, two rolling maneuvers with aileron excitation and three aileron sweeps are simulated. The validation focuses on the comparison of interesting quantities such as section loads, structural accelerations and the rigid body motion. Good agreement between simulation and flight test data is demonstrated for all three kinds of maneuvers, confirming the quality of the models developed by the preliminary design methods.