Low-energy Irradiation Research Articles

Influence of Low-Level Laser Modification and Adhesive Application Mode on the Bonding Efficiency of Universal Adhesives to Er:YAG Laser-Ablated Dentin.

Introduction: Erbium laser ablation as a method of tooth preparation and conditioning has shown promising results. Although previous studies have adopted various combinations of different laser parameters and several dentin adhesive systems, very few have investigated combining high-level and low-level ER:YAG lasers with Universal adhesives. This study aimed to assess the impact of using low-energy irradiation on the surface micro-topography and shear bond strength (SBS) of universal adhesive (UA) to the erbium:yttrium-aluminum-garnet (Er:YAG) laser-ablated dentin substrate, bonded in etch-and-rinse or self-etch adhesive mode. Methods: Eighty-seven extracted molars were sectioned to expose flat occlusal dentin surface; 60 teeth were divided equally into three groups according to the surface treatment; bur-cutting (B), Er:YAG high-energy laser cutting (L1 - 200 mJ, 20 Hz, 50 μs pulse), or L1 followed by low-energy laser modification (L1 /L2 - 80 mJ, 10 Hz, 50 μs pulse). Then each group was equally divided into two groups (n=10) according to the mode of application of the universal adhesive; either etch-and-rinse (ER) or self-etching (SE). The samples were subjected to thermocycling (5000 cycle between 5°C and 55°C), and SBS was tested. Two-way ANOVA and Tukey post hoc test were used to analyze the results. The remaining 27 samples were used to investigate the effect of the treatment on the topography of the treated dentin surfaces using a scanning electron microscope (SEM). Results: B/SE recorded the highest SBS (25.48 ± 2.6 MPa) followed by B/ER (23.20 ± 6.8 MPa) and L1 /L2 /SE (22.94 ± 4.1 MPa) and with no statistically significant difference between these groups (P >0.05). The lowest SBS results (P <0.05) were recorded for L1/SE (12.22 ± 3 MPa). No statistical differences were found between the SBS of L1 /L2 /ER and L1 /ER groups or between the SBS of L1 /L2 / ER and L1 /L2 /SE groups. Conclusion: A subsequent treatment of the Er:YAG laser-ablated dentin with low-energy laser modification mode (LMM) enhances the SBS of the tested UA when applied in SE mode.

Nanopatterning of Weak Links in Superconducting Oxide Interfaces.

The interface between two wide band-gap insulators, LaAlO and SrTiO (LAO/STO), hosts a quasi-two-dimensional electron gas (q2DEG), two-dimensional superconductivity, ferromagnetism, and giant Rashba spin-orbit coupling. The co-existence of two-dimensional superconductivity with gate-tunable spin-orbit coupling and multiband occupation is of particular interest for the realization of unconventional superconducting pairing. To investigate the symmetry of the superconducting order parameter, phase sensitive measurements of the Josephson effect are required. We describe an approach for the fabrication of artificial superconducting weak links at the LAO/STO interface using direct high-resolution electron beam lithography and low-energy argon ion beam irradiation. The method does not require lift-off steps or sacrificial layers. Therefore, resolution is only limited by the electron beam lithography and pattern transfer. We have realized superconducting weak links with a barrier thickness of 30–100 nm. The barrier transparency of the weak links can be controlled by the irradiation dose and further tuned by a gate voltage. Our results open up new possibilities for the realization of quantum devices in oxide interfaces.

Study of the effect of ion irradiation on increasing the photocatalytic activity of WO3 microparticles

The work is devoted to the study of the possibility of using low-energy irradiation with helium ions to increase the photocatalytic activity of tungsten oxide (WO3) microparticles, if used as catalysts for the decomposition of Rhodamine B. The prospect of this study is to find new ways to solve the problem of increasing the catalytic activity of micro- and nano-particles. During the study, the dependences of changes in the structural and morphological properties of the studied microparticles exposed to irradiation were established, and the effect of irradiation on the increase in the efficiency of decomposition of the organic dye Rhodamine B in aqueous media under UV irradiation was studied. It was found that the use of irradiation with helium ions leads to an increase not only in the rate of photocatalytic reactions, but also in the degree of mineralization, as well as in the efficiency of removing COD from aqueous solutions. Cyclic tests have shown the resistance of the modified microparticles to degradation, as well as the retention of the decomposition efficiency, with a decrease in the degree of mineralization after ten test cycles by 30%. At the same time, unlike the initial microparticles, ionic modification leads to an increase in the resistance of the structure to temporary degradation during cyclic tests.

Encapsulated anion-dominated photocatalytic and adsorption performances for organic dye degradation and oxoanion pollutant capture over cationic Cu(i)-organic framework semiconductors.

Decontamination of industrial wastewater containing toxic organic dye molecules and oxoanions is urgently desirable for environmental sustainability and human health. Water-stable porous metal-organic frameworks (MOFs) have emerged as highly efficient photocatalysts and/or adsorbents for water purification through controllable integration of the constitutive requirements. To reveal the inclusion anion effect of microporous MOFs on wastewater treatment, two isostructural MOFs incorporating positive charge and semiconductive characteristics, {[Cu(tpt)]·3H2O·0.5SO4}n (1) and {[Cu(tpt)]·2H2O·ClO4}n (2, tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine), have been synthesized and employed as dual-functional materials for both dye photodegradation and oxoanion removal. The two MOFs possess the same 3-fold interpenetrating cationic backbones but are encapsulated by highly disordered sulfate or perchlorate in the open channels. These included anions have significantly tuned the hydrophilicity of the channels, extended the visible-light absorption, optimized the bandgap and decreased the conduction band potential. Under the low-energy irradiation of a 30 W LED lamp, MOF 1 has selectively and efficiently degraded rhodamine B compared to 2 with accelerated kinetics, resulting from the stronger reduction ability and less migration resistance of the photogenerated electrons. Instead, MOF 2 can quickly capture harmful MnO4- and Cr2O72- by exchanging with the entrapped ClO4-, with maximum adsorption amounts of 557 and 168 mg g-1, respectively, under ambient conditions. The improved decolorization of the aqueous solution over 2 benefits essentially from the shape and charge memory effect and the smaller hydration energy of ClO4- than SO42-. These interesting observations highlight the importance of the included anions inside the porous MOF semiconductors on wastewater treatment.

Ultrasonic-assisted chemical synthesis of activated carbon from low-quality subbituminous coal and its preliminary evaluation towards supercapacitor applications

An eco-friendly method consisting of ultrasonic-assisted chemical activation to synthesize the activated carbon (AC) with high specific surface area and high porosity from the low-quality subbituminous Indian coals is reported in this paper. There is a lack of studies on ultrasonic-assisted chemically synthesized ACs from precursor materials like coal. In this study, the adsorption properties, energy density, and power density of the ACs were improved by application of low-energy (40 kHz) ultrasonic irradiation via formation of high surface area and surface porosity. Physico-chemical properties, specific surface area (SSA), surface morphology, identification of surface functional groups, and other structural studies of synthesized activated carbon were evaluated by using proximate and ultimate analysis, Brunauer-–Emmett–Teller (BET) analysis, Field emission-scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Powder X-ray diffraction (XRD), and Raman spectroscopy, respectively. The maximum specific surface area (SSA) and total pore volume (VTotal) of the coal-derived activated carbon are 789.910 m2/g and 0.103cc/g, respectively. The preliminary electrochemical evaluation the coal-derived ACs showed reasonably good electrochemical properties with a maximum potential window of 2.5 V and more than 1000 cycles with considerable energy density and power density with the possibility of making low-cost supercapacitors for use in small/general electronics. In addition, the reported ultrasonic-assisted chemical activation method is observed to be more effective than other activation methods to synthesize the ACs from abundant coal resources on a large-scale.

Highly sensitive updatable green hologram recording polymer with photoisomerizable azobenzene with highly birefringent acetylene as the side chain

To develop highly sensitive updatable hologram materials, an azobenzene monomer was synthesized herein that supports effective photoisomerization under visible green beam irradiation. Furthermore, an acetylene group was introduced via Sonogashira coupling for higher birefringence. Polymerization was performed on the synthesized azobenzene monomer and on the methyl methacrylate (MMA) monomer, which serves as the skeleton of the film. The structures of all molecules were characterized by nuclear magnetic resonance (NMR) spectroscopy, and UV-Visible absorption spectroscopy was performed to analyze their optical properties. The holographic writing and rewriting capabilities of the newly synthesized azobenzene side-chain polymer were characterized by using a green laser as a writing beam, which showed that a high diffraction efficiency was reliably achievable under low-energy laser irradiation when evaluated with a four-wave-mixing optical scheme. In this study, high birefringent acetylene group containing azobenzene-based polymers were synthesized as materials for rewritable green-laser holograms, and their properties were evaluated. Birefringence change of polymer, which has an absorption wavelength suitable for green laser (532 nm), is 0.018. The diffraction efficiency of polymer was 72% under low-energy irradiation (7 J/cm2). These results show that the hologram recording material made in this study with high birefringent azobenzene are stable, without undergoing decomposition even when repeated recording and rewriting were performed.

Coherent Atomic-Scale Ripples on Metallic Glasses Patterned by Low-Energy Ion Irradiation for Large-Area Surface Structuring

Periodic surface structures at the nanometer or micrometer scale have been achieved by various methods, while atomic-scale surface structures over large areas are unavailable. Herein, we report the...

Effects of surface damage on critical current density in MgB2 thin films

We investigated the influence of surface damage on the critical current density (Jc) of MgB2 thin films via 140-keV Co-ion irradiation. The Jc(H) of the surface-damaged MgB2 films was remarkably improved in comparison with that of pristine films. The strong enhancement of Jc(H) caused by a surface damage in MgB2 films can be ascribed to additional point defects along with an atomic lattice displacement introduced through low-energy Co-ion irradiation, which is consistent with the change in the pinning mechanism, from weak collective pinning to strong plastic pinning. The irreversible magnetic field (Hirr) at 5 K for surface-damaged MgB2 films with a thickness of 850 and 1300 nm was increased by a factor of approximately 2 compared with that of a pristine film. These results show that the surface damage produced by low energy ion irradiation can serve as an effective pinning source to improve Jc(H) in a MgB2 superconductor.

Deep level transient spectroscopy investigation of ultra-wide bandgap (2̄01) and (001) β-Ga2O3

This work reports on a comprehensive examination of the electrical and thermal properties of vertical Schottky diodes fabricated on (2¯01)- and (001)-oriented samples of β-Ga2O3. The temperature-dependent current–voltage (I–V) and capacitance–voltage (C–V) data were gathered and analyzed down to 60 K. Deep level transient spectroscopy (DLTS) was used to study bulk and interface defects in the two materials from approx. 325 K down to 60 K. In the bulk (2¯01) material, an electron trap was observed at EC−0.46 eV, with a capture cross section of 1.6 × 10−14 cm2 and a lambda-corrected maximum trap density of 9.08 × 1015 cm−3. These results and others indicate that the electron trap is a strong candidate for the well-known E1 defect in β-Ga2O3 based on recent investigations. Additionally, in the (2¯01) material, the smooth modulation typical of interface states is evident at temperatures below 275 K. The (001) samples manifested what is likely the E2* electron trap at EC−0.68 eV, with a capture cross section of 1.64 × 10−15 cm2 and a lambda-corrected maximum trap density of 8.85 × 1015 cm−3. The presence of the E2* defect, in particular, is a contrast to the findings of recent DLTS investigations on β-Ga2O3, which report that E2* emerged only after low-energy proton irradiation. These results help to further map out the defect signatures found in β-Ga2O3 materials, which are of vital importance in the design and fabrication of future β-Ga2O3 devices.

High Flux Helium Irradiation of Dispersion-Strengthened Tungsten Alloys and Effects of Heavy Metal Impurity Layer Deposition

Tungsten has been chosen as the plasma-facing material (PFM) for the divertor region in ITER and also a candidate PFM for future plasma-burning nuclear fusion reactors. During fusion device operation, PFMs will be exposed to low-energy He irradiation at high temperatures, resulting in sub-surface bubbles and surface morphology changes such as pores and fuzz. Carbide dispersion-strengthened W materials may enhance the ductility of W, but their behavior under high flux He irradiation remains unclear. In this work, the response of dispersion-strengthened tungsten materials to high flux, low energy He irradiation at high temperature is examined. Tungsten alloyed with 1, 5, or 10 wt. % tantalum carbide or titanium carbide exposed to these conditions result in surface pores, coral-like feature growth and sub-surface helium bubbles. Reactor-relevant helium irradiation (5x1026 m-2 fluence) combined with high powered laser pulses to simulate off-normal reactor events does not significantly alter the surface morphology, as the surface nanostructures appear stable and cracks are only observed on a localized region of one sample. However, specimens show the development of an impurity layer on the surface, likely impurity deposition from the sample holder during irradiation, resulting in a mixed material layer on the surface. Helium bubbles exist in this impurity layer, and obscure conclusions about helium interactions with the carbide dispersoids. Nonetheless, it is clear that the dispersoid microstructure limits He bubble formation and subsequent surface nanostructuring, attributed to the dispersoid composition.

Inactivation of Salmonella Typhimurium, Escherichia coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes in cardamom using 150 KeV low-energy X-ray

This study aimed to investigate the inactivation effect of 150 KeV low-energy X-ray on Salmonella Typhimurium, Escherichia coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes that were inoculated in dry cardamom. The D10 value for E. coli O157:H7 was 71.43 Gy and the tR values for S. Typhimurium, L. monocytogenes, and S. aureus were 53.57, 87.74, and 114.64 Gy, respectively. The irradiation did not significantly affect the amount of mono-unsaturated fatty acids (MUFAs) in cardamom; however, the content of poly-unsaturated fatty acids (PUFAs) decreased by approximate 20%. No 2-alkylcyclobutanones (2-ACBs), dimethyl disulfide and 3-methyl-thiophene were detected in the irradiated dry cardamom. These findings indicated that 150 KeV low-energy X-ray could be applied to effectively inactivate pathogens in dry cardamom. Industrial relevanceIt was shown that low-energy X-ray irradiation up to 350 Gy did not generate 2-ACBs, dimethyl disulfide and 3-methyl-thiophene in dry cardamom, which are among the major concerns with the application of food irradiation. The outcomes of this research highlight the potential of low-energy X-ray for the preservation of low moisture foods.

Low-energy X-ray inactivation of Salmonella Enteritidis on shell eggs in mono-/co-culture biofilms with Pseudomonas fluorescens

This study investigated the bactericidal effect of low-energy X-ray on mono-culture biofilms of Salmonella Enteritidis and Pseudomonas fluorescens biofilm as well as co-culture biofilms of S. Enteritidis and P. fluorescens at the ratio of 1:1 and 1:100 (S. Enteritidis: P. fluorescens) on shell eggs. The results showed that the low-energy X-ray irradiation could effectively inactivate the mono-culture biofilm cells of S. Enteritidis and P. fluorescens with the tR values of 63.19 Gy and 66.53 Gy, respectively. The low-energy X-ray irradiation could also effectively inactivate co-culture biofilm cells with tR values of 80.03 Gy and 47.97 Gy for S. Enteritidis biofilm cells in the 1:1 and 1:100 ratios of co-culture, respectively, and 61.87 Gy and 30.16 Gy for P. fluorescens biofilm cells in the two ratios of co-co-culture, respectively. Apart from inactivating biofilm cells, extracellular polysaccharide (EPS) was markedly reduced at increasing dosage of irradiation. Based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and texture profile analysis (TPA) results, egg white proteins and the puncture force of eggshell remained unchanged after the irradiation at up to 225 Gy. No 2-alkylcyclobutanones (2-ACBs) were detected in the irradiated eggs. These findings demonstrated that low-energy X-ray has potential as an effective method to inactivate the mono- and co-culture biofilms of S. Enteritidis and P. fluorescens on shell eggs.

Comparison of different methods of nitrogen-vacancy layer formation in diamond for wide-field quantum microscopy

Thin layers of near-surface nitrogen-vacancy (NV) defects in diamond substrates are the workhorse of NV-based widefield magnetic microscopy, which has applications in physics, geology and biology. Several methods exist to create such NV layers, which generally involve incorporating nitrogen atoms (N) and vacancies (V) into the diamond through growth and/or irradiation. While there have been detailed studies of individual methods, a direct side-by-side experimental comparison of the resulting magnetic sensitivities is still missing. Here we characterise, at room and cryogenic temperatures, $\approx100$ nm thick NV layers fabricated via three different methods: 1) low-energy carbon irradiation of N-rich high-pressure high-temperature (HPHT) diamond, 2) carbon irradiation of $\delta$-doped chemical vapour deposition (CVD) diamond, 3) low-energy N$^+$ or CN$^-$ implantation into N-free CVD diamond. Despite significant variability within each method, we find that the best HPHT samples yield similar magnetic sensitivities (within a factor 2 on average) to our $\delta$-doped samples, of $<2$~$\mu$T Hz$^{-1/2}$ for DC magnetic fields and $<100$~nT Hz$^{-1/2}$ for AC fields (for a $400$~nm~$\times~400$~nm pixel), while the N$^+$ and CN$^-$ implanted samples exhibit an inferior sensitivity by a factor 2-5, at both room and low temperature. We also examine the crystal lattice strain caused by the respective methods and discuss the implications this has for widefield NV imaging. The pros and cons of each method, and potential future improvements, are discussed. This study highlights that low-energy irradiation of HPHT diamond, despite its relative simplicity and low cost, is a competitive method to create thin NV layers for widefield magnetic imaging.

Nanopatterning of the (001) surface of crystalline Ge by ion irradiation at off-normal incidence: Experiment and simulation

Intricate topographical patterns can form on the surface of crystalline Ge(001) subject to low-energy ion irradiation in the reverse epitaxy regime, i.e., at elevated temperatures which enable dynamic recrystallization. We compare such nanoscale patterns produced by irradiation from varied polar and azimuthal ion incidence angles with corresponding calculated surface topographies. To this end, we propose a continuum equation including both anisotropic erosive and anisotropic diffusive effects. Molecular dynamics simulations provide the coefficients of angle-dependent sputter erosion for the calculations. By merely changing these coefficients accordingly, the experimentally observed surface morphologies can be reproduced, except for extreme ion incidence angles. Angle-dependent sputter erosion is thereby identified as a dominant mechanism in ion-induced pattern formation on crystalline surfaces under irradiation from off-normal incidence angles.

Theoretical study of the formation of C18H and C18H2 molecules by low energy irradiation with atomic and molecular hydrogen

We study the formation of C18H and C18H2 by irradiating a cyclo [18]carbon molecule with atomic and molecular hydrogen at impact energy, E, in the range of 0.5–25 eV. We utilize the density-functional tight-binding method to perform molecular dynamics simulations to emulate the interaction of a carbon ring when colliding with atomic or molecular hydrogen. From our results, the formation of the C18H molecules is likely to occur upon irradiating by H atoms at E<10 eV and by H2 molecules at 2<E<15 eV center of mass energy. Formation of C18H2 molecules is only observed at around E=2 eV. Our results show that the absorption of hydrogen is more prone in atomic than in molecular hydrogen atmosphere. Thus, we find that the probability of physio-absorption reaches up to 80% for atomic projectiles with E<5 eV but only up to 10% for the molecular ones. Our analysis shows that the deformation of the carbon ring due to the hydrogen bonding produces transition from sp to sp2 hybridization. The angle between the carbon atoms at the locations near to the H bond in the resulting ring is not 120° but instead 110° degrees. No molecular fragmentation of the C18 ring is observed.

Study of the Effect of Low-Energy Irradiation with O2+ Ions on Radiation Hardening and Modification of the Properties of Thin TiO2 Films

The paper presents the results of a systematic study of the effect of exposure to low-energy O2+ ions on the structural, optical, mechanical properties, as well as resistance to degradation and aging of thin TiO2 films. The studied samples were obtained using the magnetron sputtering method; the film thickness was 600 nm. Atomic force and scanning electron microscopy, energy dispersive analysis, X-ray diffraction, and UV–Vis spectroscopy were used as the main research methods. In the course of the results, dose dependences of changes in the properties of thin films were established, and it was also shown that irradiation leads to an increase in hardness and resistance to cracking due to radiation hardening. A decrease in the band gap from 3.61 to 3.43 eV not only changes the optical properties, but also has a significant effect on the change in the conductivity. The novelty and relevance of this study lies not only in obtaining new data on the effect of ionizing radiation on the properties of thin films, but also in expanding the prospects for the use of ion irradiation for the purpose of radiation hardening and modification of new materials.

Etching Behavior of Tungsten under Irradiation of Low Energy and High Flux Hydrogen Ions

Etching Behavior of Tungsten under Irradiation of Low Energy and High Flux Hydrogen Ions

Bacterial Envelope Damage Inflicted by Bioinspired Nanostructures Grown in a Hydrogel.

Surface-associated bacterial communities, known as biofilms, are responsible for a broad spectrum of infections in humans. Recent studies have indicated that surfaces containing nanoscale protrusions, like those in dragonfly wings, create a hostile niche for bacterial colonization and biofilm growth. This functionality has been mimicked on metals and semiconductors by creating nanopillars and other high aspect ratio nanostructures at the interface of these materials. However, bactericidal topographies have not been reported on clinically relevant hydrogels and highly compliant polymers, mostly because of the complexity of fabricating nanopatterns in hydrogels with precise control of the size that can also resist aqueous immersion. Here, we report the fabrication of bioinspired bactericidal nanostructures in bacterial cellulose (BC) hydrogels using low-energy ion beam irradiation. By challenging the currently accepted view, we show that the nanostructures grown in BC affect preferentially stiff membranes like those of the Gram-positive bacteria Bacillus subtilis in a time-dependent manner and, to a lesser extent, the more deformable and softer membrane of Escherichia coli. Moreover, the nanostructures in BC did not affect the viability of murine preosteoblasts. Using single-cell analysis, we demonstrate that indeed B. subtilis requires less force than E. coli to be penetrated by nanoprobes with dimensions comparable to those of the nanostructured BC, providing the first direct experimental evidence validating a mechanical model of membrane rupture via a tension-induced mechanism within the activation energy theory. Our findings bridge the gap between mechano-bactericidal surfaces and low-dimensional materials, including single-walled carbon nanotubes and graphene nanosheets, in which a higher bactericidal activity toward Gram-positive bacteria has been extensively reported. Our results also demonstrate the ability to confer bactericidal properties to a hydrogel by only altering its topography at the nanoscale and contribute to a better understanding of the bacterial mechanobiology, which is fundamental for the rational design bactericidal topographies.

Fabrication of single crystalline LiNbO3 thin films for wideband bulk acoustic wave filters

Single crystalline lithium niobate (LN) thin films with a Y43-cut are fabricated by crystal-ion-slicing technique, and the B-staged benzocyclobutene (BCB) polymer is used as the bonding medium for the transferring of the LN thin film on to a homogeneous LN substrate. The thickness of the LN film is about 910 nm, and low energy ion irradiation is used to treat the surface of the film, which reduces the roughness from 12.4 nm down to 3.6 nm. Bulk acoustic wave (BAW) resonator is fabricated based on the thin LN layer, and the electromechanical coefficient (k2t) of the LN film reaches 16.3%. A 3-stage BAW filter is obtained, and the 3 dB bandwidth of the filter is 8.5%, demonstrating the single crystalline LN thin film with large k2t is promising for wide band filter.

137Cs γ Ray and 28Si Irradiation Induced Murine Hepatocellular Carcinoma Lipid Changes in Liver Assessed by MALDI-MSI Combined with Spatial Shrunken Centroid Clustering Algorithm: A Pilot Study.

Characterization of lipids by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is of great interest because not only are lipids important structural molecules in both the cell and internal organelle membranes, but they are also important signaling molecules. MALDI-MSI combined with spatial image segmentation has been previously used to identify tumor heterogeneities within tissues with distinct anatomical regions such as the brain. However, there has been no systematic study utilizing MALDI-MSI combined with spatial image segmentation to assess the tumor microenvironment in the liver. Here, we present that image segmentation can be used to evaluate the tumor microenvironment in the liver. In particular, to better understand the molecular mechanisms of irradiation-induced hepatic carcinogenesis, we used MALDI-MSI in the negative ion mode to identify lipid changes 12 months post exposure to low dose 28Si and 137Cs γ ray irradiation. We report here the changes in the lipid profiles of male C3H/HeNCrl mice liver tissues after exposure to irradiation and analyzed using the spatial shrunken centroid clustering algorithm. These findings provide valuable information as astronauts will be exposed to high-charge high-energy (HZE) particles and low-energy γ-ray irradiation during deep space travel. Even at low doses, exposure to these irradiations can lead to cancer. Previous studies infer that irradiation of mice with low-dose HZE particles induces oxidative damage and microenvironmental changes that are thought to play roles in the pathophysiology of hepatocellular carcinoma.