Low energy proton damage in silicon solar cells.
Proton irradiation effects on current degradation at fixed voltages of silicon solar cells with coverslips
Curtin, D. J.↗
SEARCH · Engineering Papers
Results for “irradiation damage”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Experimental Analysis of Proton-Induced Displacement and Ionization Damage Using Gate-Controlled Lateral PNP Bipolar Transistors
The electrical characteristics of proton-irradiated bipolar transistors are affected by ionization damage to the insulating oxide and displacement damage to the semiconductor bulk. While both types of damage degrade the transistor, it is important to understand the mechanisms individually and to be able to analyze them separately. In this paper, a method for analyzing the effects of ionization and displacement damage using gate-controlled lateral PNP bipolar junction transistors is described. This technique allows the effects of oxide charge, surface recombination velocity, and bulk traps to be measured independently.
Ball, D. R.↗
Self-Learning Kinetic Monte Carlo Simulations of Radiation Damage in Nuclear Fuels
Understanding how irradiation affects the thermo-physical and mechanical properties of nuclear materials, such as thermal conductivity degradation in fuels and embrittlement of structural components, is critical to the safety and efficiency of nuclear reactors. These effects are largely governed by the formation and evolution of atomic-scale point defects and defect clusters. Due to their small sizes, however, these defects are invisible under high-resolution scanning transmission electron microscopy. This project aims to fill this experimental knowledge gap by integrating density functional theory (DFT), machine learning interatomic potential (MLIP), and kinetic Monte Carlo (KMC) techniques to predict longtime evolution of irradiation-induced defects in nuclear fuels.
36 - MATERIALS SCIENCE↗
Radiation damage study of POCO ZXF-5Q graphite for neutrino production targets using 4.5 MeV helium ions
To address the challenges of increased beam power and target survivability associated with next-generation particle production beam lines, high dose, high-energy proton beam conditions are simulated using irradiation from low-energy ion beams. A low-energy ion irradiation study of POCO ZXF-5Q graphite under conditions similar to those of the NuMI NT-02 neutrino production target at the Fermi National Accelerator Laboratory is reported. Helium ion irradiation was performed at 100 ∘ C to a maximum damage level of 0.9 displacements per atom (DPA). Irradiation induced hardening, swelling of the irradiated region, inter-plane lattice expansion, and intraplane lattice contraction with increasing ion fluence was observed using micromechanical (nanoindentation, atomic force microscopy) and electron microscopy (high-resolution imaging, selected area diffraction) characterization. Similar changes were also observed in post irradiation examination of the NT-02 target indicating that ion irradiation can be a valuable tool for estimating radiation damage in proton beam targets. Caution must be exercised though, because the hardening, lattice alteration, and swelling occur to different magnitudes for a given damage level. The observed hardening and embrittlement were greater for ion irradiated graphite. For He ion irradiated samples the lattice spacing changes were smaller at low damage levels (78% less expansion and 71% less contraction at 0.1 DPA) and larger at high damage levels (38% more expansion and 5% more contraction at 0.9 DPA) relative to that observed in the NT-02 target. The magnitude of swelling was 8.5× greater under ion irradiation which is influenced by the differing damage gradients and inclusion of implanted He ions in the region of interest.
43 PARTICLE ACCELERATORS↗
A concurrent irradiation-mechanics multiscale coupling model
The vast majority of our current knowledge regarding the basic mechanisms controlling irradiation effect on mechanical properties is based almost entirely on the results of post-irradiation experiments or theoretical models. However, the concurrent effects of irradiation, mechanical stress, and thermal damage on the failure phenomena of materials and components remain largely unexplored due to its internal multiscale-multiphysics coupling nature. Here, we present here a concurrent irradiation-mechanics multiscale coupling model. The concurrent evolutions of nanoscale irradiation defect clusters, microscale dislocation configurations, and mechanical responses are well captured based on coupling cluster dynamics, discrete dislocation dynamics, and the finite element methods using an effective time marching scheme. Model predictions of defect densities and size are in general agreement with experimental observations. Irradiation hardening is shown to take place also in samples undergoing concurrent irradiation-mechanical loading, similar to samples tested post-irradiation. However, the occurrence of plastic flow localization and dislocation channel formation is not accompanied with apparent yield drop (softening) under concurrent irradiation-mechanical loading conditions, which is different from the post-irradiation case.
42 ENGINEERING↗
mBAND Analysis of Early and Late Damages in the Chromosome of Human Lymphocytes after Exposures to Gamma Rays and Fe Ions
Stable type chromosome aberrations that survive multiple generations of cell division include translocation and inversions. An efficient method to detect an inversion is multi-color banding fluorescent in situ hybridization (mBAND) which allows identification of both inter- and intrachromosome aberrations simultaneously. Post irradiation, chromosome aberrations may also arise after multiple cell divisions as a result of genomic instability. To investigate the stable or late-arising chromosome aberrations induced after radiation exposure, we exposed human lymphocytes to gamma rays and Fe ions ex vivo, and cultured the cells for multiple generations. Chromosome aberrations were analyzed in cells collected at first mitosis and at several time intervals during the culture period post irradiation. With gamma irradiation, about half of the damages observed at first mitosis remained after 7 day- and 14 day- culture, suggesting the transmissibility of damages to the surviving progeny. At the doses that produced similar frequencies of gamma-induced chromosome aberrations as observed at first mitosis, a significantly lower yield of aberrations remained at the same population doublings after Fe ion exposure. At these equitoxic doses, more complex type aberrations were observed for Fe ions, indicating that Fe ion-induced initial chromosome damages are more severe and may lead to cell death. Detailed analysis of breaks participating in total chromosome exchanges within the first cell cycle post irradiation revealed a common hotspot located in the 3p21 region, which is a known fragile site corresponding to the band 6 in the mBand analysis. The breakpoint distribution in chromosomes collected at 7 days, but not at 14 days, post irradiation appeared similar to the distribution in cells collected within the first cell cycle post irradiation. The breakpoint distribution for human lymphocytes after radiation exposure was different from the previously published distribution for human mammary epithelial cells, indicating that interphase chromatin folding structures play a role in the distribution of radiation-induced breaks.
Sunagawa, Mayumi↗
Fluence Uniformity Measurements in an Electron Accelerator Used for Irradiation of Extended Area Solar Cells and Electronic Circuits for Space Applications
It is common to have liquid crystal displays and electronic circuit boards with area sizes of the order of 20x20 sq cm on board of satellites and space vehicles. Usually irradiating them at different fluence values assesses the radiation damage in these types of devices. As a result, there is a need for a radiation source with large spatial fluence uniformity for the study of the damage by radiation from space in those devices. Kent State University s Program on Electron Beam Technology has access to an electron accelerator used for both research and industrial applications. The electron accelerator produces electrons with energies in the interval from 1 to 5 MeV and a maximum beam power of 150 kW. At such high power levels, the electron beam is continuously scanned back and forth in one dimension in order to provide uniform irradiation and to prevent damage to the sample. This allows for the uniform irradiation of samples with an area of up to 1.32 sq m. This accelerator has been used in the past for the study of radiation damage in solar cells (1). However in order to irradiate extended area solar cells there was a need to measure the uniformity of the irradiation zone in terms of fluence. In this paper the methodology to measure the fluence uniformity on a sample handling system (linear motion system), used for the irradiation of research samples, along the irradiation zone of the above-mentioned facility is described and the results presented. We also illustrate the use of the electron accelerator for the irradiation of large area solar cells (of the order of 156 sq cm) and include in this paper the electrical characterization of these types of solar cells irradiated with 5 MeV electrons to a total fluence of 2.6 x 10(exp 15) e/sq cm.
Uribe, Roberto M.↗
Evidence of Morphological Change in Sulfur Cathodes upon Irradiation by Synchrotron X-rays
While the development of lithium–sulfur battery cathodes has benefited substantially from the use of in situ and ex situ X-ray absorption studies, the degree of undesired influence from synchrotron radiation has not been studied. In this study, we present evidence of severe beam damage on sulfur cathodes under irradiation by synchrotron X-rays. Specifically, X-ray fluorescence mapping with relatively low dosage was conducted to observe the morphological changes after conducting X-ray absorption spectroscopy (XAS). Under open-circuit conditions, the morphology of the sulfur spontaneously changes and tends to migrate out of the region of XAS sampling. Our work indicates that effort should be placed in first obtaining a no-change/stable open-circuit baseline when attempting to conduct in operando studies of lithium–sulfur batteries using synchrotron radiation with an energy of <7.7 keV and a flux of >6 × 10 12 photons s –1 .
25 ENERGY STORAGE↗
Effects of radiation damage and precipitate distribution on micro-pillar compression testing of irradiated CuCrZr
The results of small-scale mechanical tests are convoluted by the so-called size effect, whereby materials appear stronger when the scale of the test is reduced to the order of microns or less. The dimensional range over which this occurs has been shown to be linked to a change in sample microstructure, such as the addition of defects induced by irradiation. To investigate this response, a CuCrZr alloy was subjected to proton irradiation and mechanically tested using micro compression of pillars with a range in size. It was found that irradiation defects dominate over the extrinsic size effect and the sensitivity to differences in precipitate microstructure was also somewhat reduced, suggesting that size-independent results could be obtained from much smaller test volumes in irradiated material compared to their non-irradiated counterparts. Lastly, comparison was made between the increase in yield strength predicted by models and the experimentally measured values to establish the key parameters driving the strengthening behaviour.
36 MATERIALS SCIENCE↗
Cytological analysis of the damage to the intestinal epithelium of mice which were subjected to irradiation by protons with an energy of 630 MeV
Proton irradiation effects on epithelial duodenum cells of mice
Mastryukova, V. M.↗
Dependence of the damage in optical metal/dielectric coatings on the energy of ions in irradiation experiments for space qualification
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Maria G. Pelizzo↗
Positron Emission Tomography Imaging of Functional Transforming Growth Factor β (TGFβ) Activity and Benefit of TGFβ Inhibition in Irradiated Intracranial Tumors
Transforming growth factor β (TGFβ) promotes cell survival by endorsing DNA damage repair and mediates an immunosuppressive tumor microenvironment. Thus, TGFβ activation in response to radiation therapy is potentially targetable because it opposes therapeutic control. Strategies to assess this potential in the clinic are needed.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Assessment of thermal and radiation induced creep in the dual cooled lead lithium blanket
The creep in recently designed blanket for the fusion nuclear science facility is described by decomposing it into thermal, irradiation and cavity swelling creep. Initial estimates of thermal creep using elastic high temperature rules showed that the recent heat transfer improvements at the first wall (FW) is feasible, and the FW can withstand heat flux of 0.35 MW/m 2 at 3000 hrs without rupture. A viscoplastic model that is based on Norton's power law and relies on Multiphysics coupling of solid mechanics and heat transfer modules is used to capture the inelastic deformation in the blanket. Results showed that the design peak heat flux of 0.25 MW/m 2 produced maximum thermal creep strain of 0.45 % and the relaxation of the thermal stress at the FW. Irradiation creep is prescribed to be proportional to the displacement damage dose and applied stress. The displacements from irradiation creep radially decrease from the FW to the back wall, but the maximum deformation is found at the back wall that is connected to the Helium manifold due to the high stresses at the region. In conclusion, cavity swelling creep is dominant at steady state and combined with radiation creep to produce displacement of about 8 mm at the FW.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Fusion Materials Semiannual Progress Report for the Period Ending December 31, 2020
Three ferritic/martensitic alloys; F82H, Fe8Cr2W and CNA3 were studied for the effect of H and He on swelling. Single ion beam (Fe 2+ ), dual ion beam (Fe 2+ +He 2+ ), and triple ion beam (Fe 2+ +He 2+ +H + ) irradiations were conducted at 500°C to a damage level of 50 dpa and dual and triple beam irradiation experiments were conducted at 450°C to 50 dpa. Cavity distribution and swelling were comparable in dual ion beam and triple ion beam irradiated F82H at 500°C, indicating that the role of hydrogen in swelling in triple beam irradiated F82H appeared to be insignificant compared to the role of helium. Swelling in Fe8Cr2W and CNA3 at 500°C was approximately 3-4X greater than that at 450°C. In F82H, the average cavity size and swelling were minimally larger at 500°C than at 450°C. The significant role of hydrogen in swelling has yet to be confirmed. Future efforts will focus on separate effects experiments to understand the role of hydrogen in cavity swelling.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
ZrN coating as diffusion barrier in U(Mo) dispersion fuel systems
The control of the interaction between the U(Mo) fuel phase and the Al matrix is one of the challenges of dispersion fuel plate development for research reactors. Given the specific properties of this interaction layer, larger amounts of it in the meat could lead to a reduction of the plate mechanical integrity and thermal conductivity, eventually leading to pillowing. The SELENIUM project showed that by depositing a ZrN coating on the surface of the U(Mo) fuel particles, the amount of formed U(Mo)-Al interaction layer is limited but still present. Microstructural analysis performed on the as fabricated coating and fresh fuel plates containing ZrN coated U(Mo) dispersed in an Al matrix, revealed that the coating gets damaged during plate production. The post irradiation examinations (PIE) of the ZrN coated U(Mo) fuel plates, from the SELENIUM and SEMPER FIDELIS experiments, show how the U(Mo)-Al interaction layer is formed -only at those locations where the coating is missing or damaged -and the evolution of coating microstructure during irradiation. Finally, as a remedy, to further reduce the amount of interaction layer formed, the use of an Al-Si matrix was proposed based on the higher affinity of Si for U compared to the affinity of Al for U. PIE of a fuel plate consisting of ZrN coated U(Mo) dispersed in an Al-Si matrix irradiated in the SEMPER FIDELIS experiment, clearly demonstrates the benefit of adding Si to the matrix.
36 MATERIALS SCIENCE↗
Heavy ion irradiation induced failure of gallium nitride high electron mobility transistors: effects of in-situ biasing
Abstract While radiation is known to degrade AlGaN/GaN high-electron-mobility transistors (HEMTs), the question remains on the extent of damage governed by the presence of an electrical field in the device. In this study, we induced displacement damage in HEMTs in both ON and OFF states by irradiating with 2.8 MeV Au 4+ ion to fluence levels ranging from 1.72 × 10 10 to 3.745 × 10 13 ions cm −2 , or 0.001–2 displacement per atom (dpa). Electrical measurement is done in situ , and high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray (EDX), geometrical phase analysis (GPA), and micro-Raman are performed on the highest fluence of Au 4+ irradiated devices. The selected heavy ion irradiation causes cascade damage in the passivation, AlGaN, and GaN layers and at all associated interfaces. After just 0.1 dpa, the current density in the ON-mode device deteriorates by two orders of magnitude, whereas the OFF-mode device totally ceases to operate. Moreover, six orders of magnitude increase in leakage current and loss of gate control over the 2-dimensional electron gas channel are observed. GPA and Raman analysis reveal strain relaxation after a 2 dpa damage level in devices. Significant defects and intermixing of atoms near AlGaN/GaN interfaces and GaN layer are found from HRTEM and EDX analyses, which can substantially alter device characteristics and result in complete failure.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Helium effects and bubbles formation in irradiated Ti 3 SiC 2
Ti 3 SiC 2 is a potential structural material for nuclear reactor applications. However, He irradiation effects in this material are not well understood, especially at high temperatures. Here, we compare the effects of He irradiation in Ti 3 SiC 2 at room temperature (RT) and at 750 °C. Irradiation at 750 °C was found to lead to extremely elongated He bubbles that are concentrated in the nano-laminate layers of Ti 3 SiC 2 , whereas the overall crystal structure of the material remained intact. In contrast, at RT, the layered structure was significantly damaged and highly disordered after irradiation. Our study reveals that at elevated temperatures, the unique structure of Ti 3 SiC 2 can accommodate large amounts of He atoms in the nano-laminate layer, without compromising the structural stability of the material. The structure and the mechanical tests results show that the irradiation induced swelling and hardening at 750 °C are much smaller than those at RT. Overall, these results indicate that Ti 3 SiC 2 has an excellent resistance to accumulation of radiation-induced He impurities and that it has a considerable tolerance to irradiation-induced degradation of mechanical properties at high temperatures.
36 MATERIALS SCIENCE↗
Modulating Oxide‐Based Quantum Materials by Ion Implantation
Ion implantation has emerged as a powerful tool for manipulating and investigating oxide quantum materials, where strong electron correlations give rise to exotic phases and functionalities. This Review examines how controlled ion bombardment enables targeted modulation of structural, electronic, and magnetic properties in complex oxides. Recent advances in ion beam techniques is analyzed that provide unprecedented control over defect profiles, from point defects to extended damage cascades. In application, ion irradiation has demonstrated the ability to tune quantum phenomena including metal‐insulator transitions, magnetism, and superconductivity through selective doping, defect creation, and lattice strain. The ability to write quantum states with nanoscale precision using focused ion beams is opening new paths for quantum device fabrication. Challenges in understanding radiation damage mechanisms in strongly correlated systems is discussed, and identify opportunities for designing quantum functionality through defect‐engineering approaches. The technique's demonstrated capability to write quantum states with nanoscale precision, combined with its compatibility with existing semiconductor processing infrastructure, suggests a clear pathway for translating fundamental discoveries in quantum materials into practical technological applications.
defect engineering↗