Space Radiation Environment Research Articles

Lifetime evaluation of left ventricular structure and function in male ApoE null mice after gamma and space-type radiation exposure.

The space radiation (IR) environment contains high charge and energy (HZE) nuclei emitted from galactic cosmic rays with the ability to overcome current shielding strategies, posing increased IR-induced cardiovascular disease risks for astronauts on prolonged space missions. Little is known about the effect of 5-ion simplified galactic cosmic ray simulation (simGCRsim) exposure on left ventricular (LV) function. Three-month-old, age-matched male Apolipoprotein E (ApoE) null mice were irradiated with 137Cs gamma (γ; 100, 200, and 400cGy) and simGCRsim (50, 100, 150cGy all at 500 MeV/nucleon (n)). LV function was assessed using transthoracic echocardiography at early/acute (14 and 28days) and late/degenerative (365, 440, and 660days) times post-irradiation. As early as 14 and 28-days post IR, LV systolic function was reduced in both IR groups across all doses. At 14days post-IR, 150cGy simGCRsim-IR mice had decreased diastolic wall strain (DWS), suggesting increased myocardial stiffness. This was also observed later in 100cGy γ-IR mice at 28days. At later stages, a significant decrease in LV systolic function was observed in the 400cGy γ-IR mice. Otherwise, there was no difference in the LV systolic function or structure at the remaining time points across the IR groups. We evaluated the expression of genes involved in hemodynamic stress, cardiac remodeling, inflammation, and calcium handling in LVs harvested 28days post-IR. At 28days post-IR, there is increased expression of Bnp and Ncx in both IR groups at the lowest doses, suggesting impaired function contributes to hemodynamic stress and altered calcium handling. The expression of Gals3 and β-Mhc were increased in simGCRsim and γ-IR mice respectively, suggesting there may be IR-specific cardiac remodeling. IR groups were modeled to calculate the Relative Biological Effectiveness (RBE) and Radiation Effects Ratio (RER). No lower threshold was determined using the observed dose-response curves. These findings do not exclude the possibility of the existence of a lower IR threshold or the presence of IR-induced cardiovascular disease (CVD) when combined with additional space travel stressors, e.g., microgravity.

EXPERIMENTAL SIMULATION OF FAST ELECTRON BOMBARDMENT OF METHANOL ICE AND ITS IMPLICATIONS IN ASTROCHEMISTRY

In this work, we experimentally simulate the methanol (CH3OH) ice behavior (12 K) through the bombarded by fast electrons (4.9 keV) in an attempt to simulate radiation chemistry induced by radiation in space environments. The sample analysis by infrared spectroscopy reveals the appearance of new species, including CO2, CO, H2O, and CH4, during the sample bombardment. We have quantified the effective destruction cross-section of methanol (5.5 × 10-19 cm2) and determined the formation cross-section for these newly produced species. Additionally, we have characterized the chemical equilibrium (CE) phase, which becomes evident at higher fluences. We have also calculated molecular abundances and assessed the desorption yield induced by fast electrons within the same sample. Furthermore, we estimated the timescale required to achieve chemical equilibrium in specific astrophysical environments impacted by electrons. This study significantly contributes to our comprehension of electron bombardment behavior in astrophysical ices and allows for meaningful comparisons with organic-rich ices in space environments

Application of displacement damage dose approach to low-energy proton irradiated GaInP/GaAs/Ge solar cells

In this paper, a displacement damage simulation model for proton-irradiated GaInP/GaAs/Ge triple junction (TJ) solar cells is constructed in Geant4, and the problem of the displacement damage dose curve deviation for low-energy protons is analyzed. The modeling results show that energy loss effects and local displacement damage are important factors for the deviation of the displacement damage dose curve. The non-ionizing energy loss (NIEL) values of GaAs sub-cells calculated by Geant4 can effectively improve the deviation of the curve caused by energy loss effects. The NIEL should be constrained by the structure and size of the device rather than just the proton energy and material type. In addition, the isotropic radiation field numerical method proposed in this paper allows the displacement damage simulation model constructed in Geant4 to be expediently applied to the radiation environment in space.

Space radiation environment adaptability of the domestic 5056 high-performance aluminum honeycomb

In order to investigate the influence of space radiation environment on the performance of domestic 5056 high-performance aluminum honeycomb core, the effects of different irradiation effects and different radiation doses on the nodal strength and mechanical properties of domestic 5056 high-performance aluminum honeycomb core were studied through space radiation environmental tests and mechanical property tests such as high-energy electron irradiation, γ-ray irradiation, ultraviolet irradiation, hot and cold shock test, vacuum volatilization test. The results show that under multiple environmental conditions such as high-energy electron irradiation γ-ray irradiation, ultraviolet irradiation, and hot and cold shock environment, the domestic high-performance aluminum honeycomb core shows excellent adaptability to the irradiation environment and can be used for a long time in the extravehicular environment. However, when the radiation dose is greater than 2 × 109rad, the strength of honeycomb core nodes decreased significantly. The vacuum volatilization test results sindicate that the material meets the gas requirements of aerospace raw materials and has extremely low vacuum pollution characteristics.

Study of displacement damage effects in InGaAs PIN photodiode under 10 MeV proton irradiation

The displacement damage effect of 10 MeV proton radiation on a high-speed InGaAs PIN photodiode has been experimentally investigated to evaluate the stability of the device in a space radiation environment. The results show that the dark current and low-frequency noise of the device increase significantly after irradiation, while the capacitance of the device decreases slightly after irradiation, where the spectral response parameters are less affected by irradiation. The increase in dark current is essentially linear with the displacement damage dose. Finally, the effect of proton irradiation on the optical communication system is simulated and the results show that the bit error rate of the system increases with the increase in irradiation fluence, which seriously affects the sensitivity of the optical communication system.

Radium deposition in human brain tissue: A Geant4-DNA Monte Carlo toolkit study

NASA has encouraged studies on 226Ra deposition in the human brain to investigate the effects of exposure to alpha particles with high linear energy transfer, which could mimic some of the exposure astronauts face during space travel. However, this approach was criticized, noting that radium is a bone-seeker and accumulates in the skull, which means that the radiation dose from alpha particles emitted by 226Ra would be heavily concentrated in areas close to cranial bones rather than uniformly distributed throughout the brain. In the high background radiation areas of Ramsar, Iran, extremely high levels of 226Ra in soil contribute to a large proportion of the inhabitants' radiation exposure. A prospective study on Ramsar residents with a calcium-rich diet was conducted to improve the dose uniformity due to 226Ra throughout the cerebral and cerebellar parenchyma. The study found that exposure of the human brain to alpha particles did not significantly affect working memory but was significantly associated with increased reaction times. This finding is crucial because astronauts on deep space missions may face similar cognitive impairments due to exposure to high charge and energy particles. The current study was aimed to evaluate the validity of the terrestrial model using the Geant4 Monte Carlo toolkit to simulate the interactions of alpha particles and representative cosmic ray particles, acknowledging that these radiation types are only a subset of the complete space radiation environment.

Analysis of Difference in Areal Density Aluminum Equivalent Method in Ionizing Total Dose Shielding Analysis of Semiconductor Devices

The space radiation environment has a radiation effect on electronic devices, especially the total ionizing dose effect, which seriously affects the service life of spacecraft on-orbit electronic devices and electronic equipment. Therefore, it is particularly important to enhance the radiation resistance of electronic devices. At present, many scientific research institutions still use the areal density equivalent aluminum method to calculate the shielding dose. This paper sets five common metal materials in aerospace through the GEANT4 Monte-Carlo simulation tool MULASSIS, individually calculating the absorption dose caused by single-energy electrons and protons in the silicon detector after shielding of five different materials, which have the same areal density of 0.8097 g/cm2. By comparing the above data, it was found that depending on the particle energy, the areal density aluminum equivalent method would overestimate or underestimate the absorbed dose in the shielded silicon detector, especially for the ionization total dose shielding effect of low-energy electrons. The areal density aluminum equivalent method will greatly overestimate the shielding dose, so this difference needs to be taken into account when evaluating the ionizing dose of the electronics on a spacecraft to make the assessment more accurate.

Toward the Use of Electronic Commercial Off-the-Shelf Devices in Space: Assessment of the True Radiation Environment in Low Earth Orbit (LEO)

Low Earth orbit missions have become crucial for a variety of applications, from scientific research to commercial purposes. Exposure to ionizing radiation in Low Earth Orbit (LEO) poses a significant risk to both spacecraft and astronauts. In this article, we analyze radiation data obtained from different LEO missions to evaluate the potential of using electronic commercial off-the-shelf (COTS) devices in space missions. This study is focused on the total ionizing dose (TID). Our results demonstrate that COTS technology can effectively provide cost-effective and reliable solutions for space applications. Furthermore, we compare the data obtained from actual missions with computational models and tools, such as SPENVIS, to evaluate the accuracy of these models and enhance radiation exposure prediction. This comparison provides valuable insights into the true radiation environment in space and helps us to better understand the potential of COTS technology in reducing costs and development times by utilizing technology previously used in other areas. In light of the results, we can see that the radiation values observed experimentally in space missions versus the computer simulations used present variations up to a factor of 30 depending on the model used in the analysis.

Dosimetry of the PIM1 Pion Beam at the Paul Scherrer Institute for Radiobiological Studies of Mice.

Significant past work has identified unexpected risks of central nervous system (CNS) exposure to the space radiation environment, where long-lasting functional decrements have been associated with multiple ion species delivered at low doses and dose rates. As shielding is the only established intervention capable of limiting exposure to the dangerous radiation fields in space, the recent discovery that pions, emanating from regions of enhanced shielding, can contribute significantly to the total absorbed dose on a deep space mission poses additional concerns. As a prerequisite to biological studies evaluating pion dose equivalents for various CNS exposure scenarios of mice, a careful dosimetric validation study is required. Within our ultimate goal of evaluating the functional consequences of defined pion exposures to CNS functionality, we report in this article the detailed dosimetry of the PiMI pion beam line at the Paul Scherrer Institute, which was developed in support of radiobiological experiments. Beam profiles and contamination of the beam by protons, electrons, positrons and muons were characterized prior to the mice irradiations. The dose to the back and top of the mice was measured using thermoluminescent dosimeters (TLD) and optically simulated luminescence (OSL) to cross-validate the dosimetry results. Geant4 Monte Carlo simulations of radiation exposure of a mouse phantom in water by charged pions were also performed to quantify the difference between the absorbed dose from the OSL and TLD and the absorbed dose to water, using a simple model of the mouse brain. The absorbed dose measured by the OSL dosimeters and TLDs agreed within 5-10%. A 30% difference between the measured absorbed dose and the dose calculated by Geant4 in the dosimeters was obtained, probably due to the approximated Monte Carlo configuration compared to the experiment. A difference of 15-20% between the calculated absorbed dose to water at a 5 mm depth and in the passive dosimeters was obtained, suggesting the need for a correction factor of the measured dose to obtain the absorbed dose in the mouse brain. Finally, based on the comparison of the experimental data and the Monte Carlo calculations, we consider the dose measurement to be accurate to within 15-20%.

Spektr–UF Mission Spectrograph Space Qualified CCD Detector Subsystem

Spektr–UF (World Space Observatory Ultraviolet, WSO-UV) is a Russian-led international collaboration aiming to develop a large space-borne 1.7 m Ritchey–Chretién telescope with science instruments to study the Universe in ultraviolet wavelengths. The WSO-UV spectrograph (WUVS) consists of three channels: two high-resolution channels (R = 50,000) with spectral ranges of 115–176 nm and 174–310 nm, and a low-resolution (R = 1000) channel with a spectral range of 115–305 nm. Each of the three channels has an almost identical custom detector consisting of a CCD inside a vacuum enclosure, and drive electronics. The main challenges of the WUVS detectors are to achieve high quantum efficiency in the FUV-NUV range, to provide low readout noise (3 e− at 50 kHz) and low dark current (<12 e−/pixel/hour), to operate with integral exposures of up to 10 h and to provide good photometric accuracy. A custom vacuum enclosure and three variants of a custom CCD272-64 sensor with different UV AR coatings optimised for each WUVS channel were designed. The enclosure prevents contamination and maintains the CCD at the operating temperature of −100 ∘C, while the temperature of the WUVS optical bench is +20 ∘C. A camera electronics box (CEB) that houses the CCD drive electronics was developed. Digital correlated double sampling technology allows for extremely low readout noise and flexible frequency for normal and binned pixel readout modes. This paper presents the WUVS detector design drivers, methods for extending the service life of the CCD sensors working with low signals in a space radiation environment and the key calculated parameters and results of the engineering qualification model qualification campaign.

Nuclear data for space exploration

Understanding the harmful effects of galactic cosmic rays (GCRs) on space exploration requires a substantial amount of nuclear data. Specifically, the interaction of energetic GCR charged particles with spacecraft materials generates secondary radiations that, through energy deposition, can harm astronauts and electronic systems. By identifying the gaps in our knowledge of the relevant nuclear data—such as interaction cross sections—and identifying ways to fill those gaps—with measurements, compilations, evaluations, dissemination, reaction modeling, sensitivity studies, and uncertainty quantification—the safety and viability of space exploration can be improved. This work surveys the state of the art in this interdisciplinary field and identifies promising collaborative research topics that have significant potential to advance our understanding of the effects of the space radiation environment on space exploration.

A novel radiation-dependence model of InP HBTs including gamma radiation effects

In order to predict the lifetime of InP Heterojunction Bipolar Transistor (HBT) devices and related circuits in the space radiation environment, a novel model including gamma radiation effects is proposed in this paper. Based on the analysis of radiation-induced device degradation effects including both DC and AC characteristics, a set of empirical expressions describing the device degradation trend are presented and incorporated into the Keysight model. To validate the effective of the proposed model, a series of radiation experiments are performed. The correctness of the novel model is validated by comparing experimental and simulated results before and after radiation.

Radiation damage of [formula omitted] pixelated CdZnTe due to high-energy protons

Pixelated CdZnTe detectors are a promising imaging-spectrometer for gamma-ray astrophysics due to their combination of relatively high energy resolution with room temperature operation negating the need for cryogenic cooling. This reduces the size, weight, and power requirements for telescope-based radiation detectors. Nevertheless, operating CdZnTe in orbit will expose it to the harsh radiation environment of space. This work, therefore, studies the effects of 61MeV protons on 2×2×1cm3 pixelated CdZnTe and quantifies proton-induced radiation damage of fluences up to 2.6×108p/cm2. In addition, we studied the effects of irradiation on two separate instruments: one was biased and operational during irradiation while the other remained unbiased. Following final irradiation, the 662keV centroid and nominal 1% resolution of the detectors were degraded to 642.7keV,4.9%(FWHM) and 653.8keV,1.75%(FWHM) for the biased and unbiased systems respectively. We therefore observe a possible bias dependency on proton-induced radiation damage in CdZnTe. This work also reports on the resulting activation and recovery of the instrument following room temperature and 60°C annealing.

LOW COST DOSIMETER MODULE FOR MVA LUNAR LANDER MISSION

Understanding the lunar radiation environment is crucial for future space exploration missions, as the lack of atmospheric and magnetic shielding allows charged particles of varying energies and origins to penetrate the surface of the moon. In space radiation environments, it is common practice to use radiation dosimeters to measure absorbed dose and dose rate. In this study, the payload will include a radiation dosimeter capable of measuring the radiation intensity at the landing site’s surface. The design concept and implementation of a radiation readout system for the real-time measurement of gamma absorbed dose and dose rate at the surface of the landing area for the MVA mission are based on a photodiode sensor that is commercially available and will be used as a gamma radiation sensor. The module experienced low levels of activity (Cs137, Co60, and Sr90). The performance of the photodiode-based module has been demonstrated by the Giger counter. Due to its low cost and high sensitivity, this radiation module would be clearly advantageous.

Total ionizing dose effects of 60Co-γ ray radiation on SiC MOSFETs with different gate oxide thickness

The application of SiC power devices in the space radiation environment not only requires good resistance to Single Event Effect (SEE) but also requires certain resistance to Total Ionizing Dose (TID) and long-term reliability. Increasing the thickness of the gate oxide layer (tox) can effectively improve the ability of SiC VDMOS to resist SEE. However, it will mainly impact its resistance to TID and Gate Oxide Integrity (GOI). Therefore, this paper compares the influence of tox on the radiation resistance and long-term reliability of SiC VDMOS under the same process and irradiation conditions. The experimental results show that after being irradiated by Cobalt-60 γ-rays, the static parameters of SiC VDMOS devices degrade severely with the increase of the tox; at the same time, the thick gate oxide process will also cause more defects in the gate oxide, leading to the decrease of the gate oxide long-term reliability, but it can be significantly improved after high temperature (HT) accelerated annealing. The research results suggest that the method of increasing tox should take into account the requirements of TID resistance and long-term reliability when improving the SEE radiation resistance of SiC VDMOS. This study is based on the improvement of electrical parameters and the analysis of reliability degradation of SiC VDMOS, providing experimental data support for determining the balance point of tox.

Parametric Evaluation of the See Rate on the SEU and SEL Monitors Aboard the Alphasat Using the IRPP Model

Calculating Single Event Effect (SEE) rates is essential to ensure space mission reliability. Standard methods rely on ground-data which is not fully representative of the space radiation environment. In this paper, we evaluate these methods using SEE data collected during 5.5 years from the Single Event Upset and Single Event Latch-up Monitors aboard the Alphasat spacecraft in Geostationary orbit.

Radiation hardened 12T SRAM cell with improved writing capability for space applications

This paper presents an inventive and extremely dependable radiation-hardened by-design (RHBD) 12T SRAM Cell with enhanced writing capability (RHWC-12T) for a space radiation environment. The Proposed RHWC-12T SRAM is designed on Cadence Virtuoso with quad-storage nodes and simulated in 45-nm CMOS technology with the supply voltage of 1.1 V and 27∘C operating temperature. The proposed cell is tolerant to both 0 to 1 and 1 to 0 SEUs (Single event upsets). Also, it provides better speed and stability compared to the other considered SRAM cells such as 6T, 10T Dohar, Quatro, We-Quatro, QUCCE-12T, and NQuatro. According to simulation findings, the proposed SRAM cell provides 1.053× better writing stability than the 10T Dohar SRAM cell. In addition, the write access time improves by 3.56× with 1.36× area overhead than 10T Dohar SRAM cell.

Interaction between astrocytes and neurons in simulated space radiation-induced CNS injury

Purpose Astronauts exhibit neurological dysfunction during long-duration spaceflight, and the specific mechanisms may be closely related to the cumulative effects of these neurological injuries in the space radiation environment. Here, we investigated the interaction between astrocytes and neuronal cells exposed to simulated space radiation. Materials and methods we selected human astrocytes (U87 MG) and neuronal cells (SH-SY5Y) to establish an experimental model to explore the interaction between astrocytes and neuronal cells in the CNS under simulated space radiation environment and the role of exosomes in the interactions. Results We found that γ-ray caused oxidative and inflammatory damage in human U87 MG and SH-SY5Y. The results of the conditioned medium transfer experiments showed that astrocytes exhibited a protective effect on neuronal cells, and neuronal cells influenced the activation of astrocytes in oxidative and inflammatory injury of CNS. We demonstrated that the number and size distribution of exosomes derived from U87 MG and SH-SY5Y cells were changed in response to H2O2, TNF-α or γ-ray treatment. Furthermore, we found that exosome derived from treated nerve cells influenced the cell viability and gene expression of untreated nerve cells, and the effect of exosomes was partly consistent with that of the conditioned medium. Conclusion Our findings demonstrated that astrocytes showed a protective effect on neuronal cells, and neuronal cells influenced the activation of astrocytes in oxidative and inflammatory damage of CNS induced by simulated space radiation. Exosomes played an essential role in the interaction between astrocytes and neuronal cells exposed to simulated space radiation.

Additive Manufacturing of Multimaterial Composites for Radiation Shielding and Thermal Management.

The harsh radiation environment of space induces the degradation and malfunctioning of electronic systems. Current approaches for protecting these microelectronic devices are generally limited to attenuating a single type of radiation or require only selecting components that have undergone the intensive and expensive process to be radiation-hardened by design. Herein, we describe an alternative fabrication strategy to manufacture multimaterial radiation shielding via direct ink writing of custom tungsten and boron nitride composites. The additively manufactured shields were shown to be capable of attenuating multiple species of radiation by tailoring the composition and architecture of the printed composite materials. The shear-induced alignment during the printing process of the anisotropic boron nitride flakes provided a facile method for introducing favorable thermal management characteristics to the shields. This generalized method offers a promising approach for protecting commercially available microelectronic systems from radiation damage and we anticipate this will vastly enhance the capabilities of future satellites and space systems.

Total Ionizing Dose Effects of 60Co γ-Ray Radiation on Split-Gate SiC MOSFETs

SiC power devices require resistance to both single-event effects (SEEs) and total ionizing dose effects (TIDs) in a space radiation environment. The split-gate-enhanced VDMOSFET (SGE-VDMOSFET) process can effectively enhance the radiation resistance of SiC VDMOS, but it has a certain impact on the gate oxide reliability of SiC VDMOS. This paper investigates the impact mechanism and regularity of using the SGE process to determine the radiation resistance and long-term reliability of SiC VDMOS under other identical processes and radiation conditions. Our experimental results show that after 60Co γ-ray irradiation, the degradation degrees of the static parameters of SGE-VDMOSFET and planar gate VDMOSFET (PG-VDMOSFET) are similar. The use of the new process leads to more defects in the oxide layer, reducing the long-term reliability of the device, but its stability can recover after high-temperature (HT) accelerated annealing. This research indicates that enhancing the resistance of SEEs using an SGE-VDMOSFET structure requires simultaneously considering the demand for TIDs and long-term reliability.