Radiation Damage Research Articles (Page 1)

We present a theoretical and experimental study of proton radiation effects on the performance of InGaAs/InP single-photon avalanche diodes (SPADs), used in applications such as space communications and remote sensing, where single-photon detectors for the telecom-compatible near-infrared (NIR) wavelengths are required. The devices were exposed to 3 MeV protons at different fluences. At high fluences (above 10 10 protons/cm 2 ), we measured large variations in dark current, breakdown voltage, and dark count rate, while at lower fluences (below 10 9 protons/cm 2 ), minor variations in dark count rate, negligible variations in the dark current, and no shift in the breakdown voltage were observed. Combining experimental results with TRIM simulations, we determined the proton radiation hardness parameters, including the acceptable displacement damage dose (DDD) to avoid catastrophic failure of these types of photodiodes. Furthermore, we experimentally investigated the mitigation of the radiation damage through annealing by means of high-power lasers, and we observed a significant reduction in the dark count rate of the InGaAs/InP SPADs that were irradiated at low fluences. Our study provides important guidance on using telecom-wavelength compatible single-photon detectors in a space environment and shows that such devices are good candidates for satellite-based quantum communication nodes.

Abstract. Ultraviolet (UV) radiation can damage DNA and kill cells. We use laboratory and observational studies of the harmful effect of UV radiation on marine photosynthesizers to inform the implementation of a UV radiation damage function for phytoplankton photosynthesis in a modified version of the Community Earth System Model version 2 (CESM2-UVphyto). CESM2-UVphyto is capable of simulating UV inhibition of photosynthesis among modeled phytoplankton and ocean column penetration of UV-A, UV-B, and UV-C radiation. We conduct a series of simulations with CESM2-UVphyto using the Marine Biogeochemistry Library (MARBL) ecosystem model to understand the sensitivity of phytoplankton productivity to UV radiation. Results from the simulations indicate that increased UV radiation shifts the vertical distribution of phytoplankton biomass and productivity deeper into the column, causes a moderate decline in total global productivity, and changes phytoplankton community structure. Our new CESM2-UVphyto model configuration can be used to quantify the potential ocean biogeochemical and ecosystem impacts resulting from events that disturb the stratospheric ozone layer, such as an asteroid impact, a volcanic eruption, a nuclear war, and stratospheric-aerosol-injection-based geoengineering.

Degradation studies of the ASnX3 perovskites to the A2SnX6 vacancy-ordered double perovskite form have been well researched, but little is known about how A2SnX6 compounds degrade. Herein, a new double perovskite, FA2SnBr6 (FA = CH(NH2)2), is synthesized and characterized by using X-ray diffraction and X-ray photoelectron spectroscopy. FA2SnBr6 is found to crystallize in the P21/n monoclinic space group and shows the ability to form single-phase, solid solutions with another double perovskite (NH4)2SnBr6. Solid solutions of ((NH4)(1-x)FAx)2SnBr6, where x = 0.03, 0.04, 0.06, and 0.09, are produced, and X-ray radiation damage is investigated to qualitatively and quantitatively uncover degradation mechanisms. Correlation analysis, a new statistical analytical method for X-ray photoelectron spectra, is used to fortify peak fitting models. Comparing shifts in binding energies and relative atomic quantities between two elements constructs phase models from different spectral environments to understand the degradation of these compounds. In each radiation damage experiment, great consideration must be taken to combine the chemistry of the system and the physical process of photoelectron emission with the quantitative phase models formed. Overall, the presence of ammonium in the double perovskite enhances the stability of the compound to X-ray irradiation.

High‐entropy alloys (HEAs) represent a frontier in materials science, offering many promising features suitable for high‐demand applications in nuclear and space sectors, such as exceptional mechanical properties. However, a major challenge in these fields is accurately predicting the behavior of HEAs under extreme conditions, such as radiation exposure or elevated operating temperatures, in order to maintain the integrity of the materials. Machine learning (ML) provides powerful tools to address this challenge. ML techniques, including ML interatomic potentials (MLIP), enable the modeling and prediction of complex behaviors in HEAs. This review focuses on ML to enhance the understanding of phase stability, mechanical properties, and radiation damage prediction in these complex alloys. The potential of ML to accelerate the discovery/optimization of new HEA compositions with good performance under extreme conditions is also discussed. Ultimately, the aim is to highlight the transformative role of ML in the field of HEAs under extreme conditions, in light of developing novel materials suitable for harsh environments.

Abstract. Polishing mounted zircon crystals prior to bulk grain (U-Th)/He thermochronology analysis provides opportunities for characterizing and subsampling each grain via in situ methods to obtain additional information relevant for (U-Th)/He date interpretation and the broader geologic questions of interest. However, polishing introduces complications for classifying grain geometry and determining grain volume (V), on which many derived (U-Th)/He data partially depend. Derived data that depend on volume include isotope concentrations, effective uranium (eU; a proxy for radiation damage), and alpha-ejection correction factors (FT), which are used to correct (U-Th)/He dates. These derived data are integral to interpreting (U-Th)/He dates, and, without a way to accurately calculate these values for polished grains, a choice must be made between polishing zircon to provide robust in situ data at the expense of the thermochronologic data or not polishing and limiting in situ data to grain rims or one-dimensional depth profiles. To address this issue, this paper presents a comprehensive protocol for calculating volume and alpha-ejection surface area for polished zircon grain fragments, from which additional data, including eU and FT, are derived. This protocol is implemented after grains have been polished and in situ measurements have been made and can easily be integrated into existing workflows for characterizing and measuring grains for conventional (U-Th)/He analysis. An R script accompanying this paper can be used to perform the required calculations and assign uncertainties during analytical data reduction. Applying the new protocol to a synthetic dataset covering a range of zircon geometries, sizes, and grinding conditions shows that the method is an improvement over existing methods to calculate polished grain FT, which only apply to a small subset of possible grain geometries and grinding conditions. The new protocol also calculates all derived data and uncertainties necessary and recommended for (U-Th)/He data reporting, aside from the (U-Th)/He dates themselves, to facilitate integrations with existing data reporting, date interpretation, and thermal history modeling.

Effects of dislocation network on radiation damage in iron investigated by molecular dynamics method

This study aims to investigate the atomic-scale mechanisms of irradiation damage in hexagonal boron nitride (h-BN) and the effects of neutron irradiation on its microstructure under various conditions. Molecular dynamics simulations are employed to analyze the impact of the neutron incident energy, direction, and flux on the h-BN structure. These results indicate that the aforementioned factors influence both the type and distribution of defects in h-BN. Lower energy neutrons can generate N-vacancies due to the lower displacement threshold energy of the N atoms. The maximum kinetic energy in the collision cascades and lattice-atom displacement are crucial for defect formation. Moreover, increasing flux gradually leads to the formation of an amorphous surface layer, while the deeper regions maintain crystalline order. This observation is consistent with recent experimental results, suggesting that thermal neutron irradiation promotes a transition from sp2 to sp3 hybridization and leads to surface amorphization. These insights provide guidance for the development of radiation resistant neutron detection devices.

Characterization and applications of MSS pigment isolated from Streptomyces ardesiacus.

The influence of alloying elements on the He ion irradiation damage behavior of Ni0.9M0.1 alloys (M=Cr, Mo, W)

Determination of neutron and gamma ray shielding properties, secondary radiation formations and neutron damage of composites containing polyester/pyrite/titanium diboride.

Geranylgeranyl transferase inhibitors mitigate intestinal radiation toxicity.

Study of radiation damage of 28 MeV protons to the Lassena Monolithic Active Pixel Sensor.

Nitrile gloves enhanced with nanofibers: Comparing integrated reinforcement vs. surface coating for superior radiation resistance in medical and nuclear applications.

Study of mechanisms of stabilization and increase of resistance to accumulation of radiation damage by varying the composition of components in composite ceramics ZrO2 - WO3

Combined effects of radiation damage and He accumulation in Y2Ti2O7 borosilicate glass-ceramic composites

Orientation-dependent surface radiation damage in β-Ga2O3 explored by atomistic simulations

Enhanced He irradiation damage resistance at 850 °C of Ni-based alloy via W substitution for Mo: Experiments and DFT calculations

Mycosporine-like amino acids (MAAs) are secondary metabolites of interest for the development of natural sunscreens, owing to their antioxidant activity and ultraviolet radiation (UVR)-absorbing properties. MAA-rich aqueous extracts obtained from the Chilean red alga Mazzaella laminarioides (locally known as luga cuchara) were analyzed by HPLC and loaded into chitosan nanoparticles (CSNPs), with an encapsulation efficiency of 90.1%. The resulting CS nanoformulations (CSNFs) were characterized by FTIR spectroscopy, DLS and TEM microscopy, confirming the presence of nanoparticles with a core diameter of 94 ± 11 nm and FTIR absorption bands accounting for CS functional groups. Pre-treatment of HaCaT keratinocytes with CSNFs conferred complete protection against low-to-moderate UVA doses (5, 10, 15, and 30 J/cm2). Remarkably, cells still retained a protection efficacy of 64.7% under lethal UVA exposure (60 J/cm2), with gene expression evidence suggesting the activation of a compensatory stress response to photo-oxidative damage. CSNFs were also capable of restoring cell viability in post-treatment experiments at UVA doses of 30 J/cm2 (100% cell viability) and 60 J/cm2 (~43% cell viability). This is the first demonstration that nanoencapsulation of an MAA-rich algal extract yields superior UVA photoprotection in human keratinocytes compared with non-encapsulated MAA-based formulations, contributing to the effort of developing eco-friendly sunscreens.

Radiation therapy (LT) is one of the main methods of treating malignant tumors. LT is recommended for all patients with breast cancer (BC) to achieve optimal local control of the disease. Postradiation lesions of the lungs and heart are serious complications of LT in these patients. In the presented clinical case of a patient with breast cancer after LT, a rare lung lesion was diagnosed — radiation-induced developing pneumonia in combination with post-radiation heart damage in the form of cardiac arrhythmias and effusion pericarditis.

Diamond's exceptional radiation tolerance makes it ideal for aerospace electronics, yet the atomistic mechanisms governing its electronic stopping power (Se) remain elusive. Using real-time time-dependent density functional theory (rt-TDDFT), we simulate hydrogen irradiation in bulk diamond along channeling (<100>, <110>, <111>) and off-channeling trajectories. Our results reveal striking anisotropy in Se, with the <110> channel showing 35% lower stopping power at the Bragg peak (v = 1.8a.u.) than the <100>/<111> channels, correlated with reduced radial charge density. Off-channeling simulations further uncover nonlinear Se scaling at low velocities (v < 0.5a.u.), defying free electron gas predictions. We attribute this to hydrogen-induced impurity states that facilitate bandgap bridging via Zener-like tunneling, enabling electron excitation even at ultralow velocities. Electronic structure analysis confirms orbital-selective contributions: 2p electrons dominate below v = 0.4a.u., while deeper 2s electrons activate above v = 0.5a.u., driving nonlinear energy loss. These insights establish diamond's unique electronic stopping behavior, critical for predicting radiation damage in extreme environments.