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Numbers of citations of outstanding conference papers (OCPs) of IEEE Nuclear and Space Radiation Effects Conferences (NSRECs) from 1966 to 2017 are compared with citations of the most highly cited papers (HCPs) of the corresponding special issues of the IEEE TRANSACTIONS ON NUCLEAR SCIENCE (TNS), as well as average numbers of citations and cumulative $h$ index, $h_{\mathrm {cum}}$ , for all TNS papers published in the same year. 85% of NSREC OCPs are cited at a higher rate than the average for all TNS articles in that year. 55% of NSREC OCP citation totals are higher than $h_{\mathrm {cum}}$ for TNS in that year; these rank among the ~8% most highly cited TNS papers for that year. In ~10% of cases, the NSREC OCP is also the most HCP. Similarly high citation impact is found for papers nominated as candidates for OCPs. Radiation effects papers published in annual NSREC special issues comprise a significant fraction of all TNS articles cited $h_{\mathrm {cum}}$ times or more. These results support the use of $h_{\mathrm {cum}}$ as a metric of citation impact in this work and show that the NSREC OCP process generally meets awards criteria guidelines for impact. Potential reasons for variations in citation rates are discussed, and recommendations are provided to enhance the awards process. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate the applicability of the data‐driven solar energetic particle (SEP) model, SOlar‐wind with FIeld‐lines and Energetic‐particles (SOFIE), to simulate the acceleration and transport processes of SEPs and make forecast of the energetic proton flux at energies ≥10 MeV that will be observed near 1 AU. The SOFIE model is built upon the Space Weather Modeling Framework developed at the University of Michigan. In SOFIE, the background solar wind plasma in the solar corona and interplanetary space is calculated by the Stream‐Aligned Aflvén Wave Solar‐atmosphere Model(‐Realtime) driven by the near‐real‐time hourly updated Global Oscillation Network Group solar magnetograms. In the background solar wind, coronal mass ejections (CMEs) are launched by placing an force‐imbalanced magnetic flux rope on top of the parent active region, using the Eruptive Event Generator using Gibson‐Low model. The acceleration and transport processes are modeled by the Multiple‐Field‐Line Advection Model for Particle Acceleration. In this work, nine SEP events (Solar Heliospheric and INterplanetary Environment challenge/campaign events) are modeled. The three modules in SOFIE are validated and evaluated by comparing with observations, including the steady‐state background solar wind properties, the white‐light image of the CMEs, and the flux of solar energetic protons, at energies of ≥10 MeV. Plain Language Summary: In this paper, we describe a physics‐based solar energetic particle (SEP) model, called Solar‐wind with FIeld‐lines and Energetic‐particles (SOFIE). This model is designed to simulate the acceleration and transport processes of SEPs in the solar atmosphere and interplanetary space. SOFIE is built on the Space Weather Modeling Framework developed at the University of Michigan. There are three modules in the SOFIE model, the background solar wind module, the coronal mass ejection (CME) initiation and propagation module, and the particle acceleration and transport module. The background solar wind plasma in the solar corona and interplanetary space is modeled by the Stream‐Aligned Aflvén Wave Solar‐atmosphere Model(‐Realtime) driven by the near‐real‐time hourly updated Global Oscillation Network Group solar magnetograms. In the background solar wind, the CMEs are launched by placing an force‐unbalanced magnetic flux rope on top of the active region, using the Eruptive Event Generator using Gibson‐Low configuration. The acceleration and transport processes are then modeled by the Multiple‐Field‐Line Advection Model for Particle Acceleration. Using SOFIE, we modeled nine historical SEP events. The performance of the model and its capability in making space radiation prediction is discussed. Key Points: The >10 MeV energetic protons can be predicted using the physics‐based model SOlar‐wind with FIeld‐lines and Energetic‐particles (SOFIE)The background of the acceleration and transport processes of energetic protons are resolved using data driven magnetohydrodynamic modelThe default and free parameters of the SOFIE model are evaluated [ABSTRACT FROM AUTHOR]

The Near-Earth space environment is impacted by various radiation sources like galactic cosmic rays, solar storms, geomagnetic storms, etc. In the present paper, we have estimated the impact of space radiation observed during the last four cycles. We have observed that during solar cycle 24, there were fewer solar radiation storms than during its three preceding solar cycles. In terms of solar radiation storm strength, solar cycle 22 recorded a maximum intensity of S4 (severe radiation storm) of ~ 43000 pfu. In comparison, the maximum intensity of solar cycle 24 was ~ 6530 pfu (S3 type). We have concluded that the intensity of an X-class flare did not predict the intensity of the ensuing geomagnetic activity. The flares with less intensity in X-rays, e.g. M-class and C-class flares, can give rise to stronger radiation storms. Using the NOAA scales, we have compared the data of intense radiation storms with geomagnetic storms of higher intensity. This analysis has revealed that there were only 11 days during solar cycles 23 and 24 where the maximum solar radiation storm (solar particle event) coincided with a period of severe geomagnetic storming. On comparison of monthly neutron count (cosmic ray intensity) relative to the average of the last 20 years, we also deduced that the neutron count was 7.12% greater than usual during the most recent solar low, which was nearly as high as the last solar cycle lowest (8.20%). We have observed the lower probability rate of Solar Particle Events during the 3 or so years cantered on solar minimum, and the probability does not necessarily peak within a few years of solar maximum. The intensity of relativistic electrons observed by GOES in geostationary orbit was relatively low during periods of low geomagnetic activity and low solar wind speed, and the outer belt 2 MeV electrons flux appears to be highly associated with the Dst index. [ABSTRACT FROM AUTHOR]

This review explores the convergence of clinical radiotherapy and space radiation therapeutics, focusing on ionizing radiation (IR)-generated reactive oxygen species (ROS). IR, with high-energy particles, induces precise cellular damage, particularly in cancer treatments. The paper discusses parallels between clinical and space IR, highlighting unique characteristics of high-charge and energy particles in space and potential health risks for astronauts. Emphasizing the parallel occurrence of ROS generation in both clinical and space contexts, the review identifies ROS as a crucial factor with dual roles in cellular responses and potential disease initiation. The analysis covers ROS generation mechanisms, variations, and similarities in terrestrial and extraterrestrial environments leading to innovative ROS-responsive delivery systems adaptable for both clinical and space applications. The paper concludes by discussing applications of personalized ROS-triggered therapeutic approaches and discussing the challenges and prospects of implementing these strategies in clinical radiotherapy and extraterrestrial missions. Overall, it underscores the potential of ROS-targeted delivery for advancing therapeutic strategies in terrestrial clinical settings and space exploration, contributing to human health improvement on Earth and beyond. [Display omitted] • Ionizing radiation within clinical radiotherapy parallels space exposure. • Ionizing radiation causes linear energy transfer-dependent biological effects. • Reactive oxygen species-triggered therapeutics can be applied on Earth and in space. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Chemistry is the property of Chinese Journal of Applied Chemistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Novel design techniques for efficient testability are developed and have been implemented in a 14-/16-nm bulk FinFET node technology characterization vehicle. The result of this paper was the measurement of over 300 000 SETs across 12 combinational logic variants and 415 000 SEUs in three D-flip-flop designs over a large test matrix of heavy-ion linear energy transfer, angle of incidence, and supply voltage in only 319 test runs with a total test time of 108 h. A similar-sized data set with equivalent technology coverage, using the traditional serial testing approach as used in previous work, would typically require thousands of test runs and a significant number of additional hours of testing. The methodologies developed in this paper are technology agnostic and have provided the capability to efficiently characterize the radiation-induced response of the 14-/16-nm FinFET technology generation and yielded insights for assessing the feasibility for incorporation in systems requiring radiation resiliency. [ABSTRACT FROM PUBLISHER]

Copyright of Journal of Aeronautical Materials is the property of Editorial Board of Journal of Aeronautical Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Aeronautical Materials is the property of Editorial Board of Journal of Aeronautical Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most of the astronauts experience visual illusions, apparent flashes of light (LF) in absence of light. The first reported observation of this phenomenon was in July 1969 by Buzz Aldrin, in the debriefing following the Apollo 11 mission. Several ground-based experiments in the 1970s tried to clarify the mechanisms behind these light flashes and to evaluate possible related risks. These works were supported by dedicated experiments in space on the following Apollo flights and in Low Earth Orbit (LEO). It was soon demonstrated that the LF could be caused by charged particles (present in the space radiation) traveling through the eye, and, possibly, some other visual cortical areas. In the 1990s the interest in these phenomena increased again and additional experiments in Low Earth Orbit and others ground-based were started. Recently patients undergoing proton and heavy ion therapy for eye or head and neck tumors have reported the perception of light flashes, opening a new channel to investigate these phenomena. In this paper the many LF studies will be reviewed, presenting an historical and scientific perspective consistent with the combined set of observations, offering a single comprehensive summary aimed to provide further insights on these phenomena. While the light flashes appear not to be a risk by themselves, they might provide information on the amount of radiation induced radicals in the astronauts' eyes. Understanding their generation mechanisms might also support radiation countermeasures development. However, even given the substantial progress outlined in this paper, many questions related to their generation are still under debate, so additional studies are suggested. Finally, it is also conceivable that further LF investigations could provide evidence about the possible interaction of single particles in space with brain function, impacting with the crew ability to optimally perform a mission. [ABSTRACT FROM AUTHOR]

Neutron-induced single event upsets (SEUs) have become a significant reliability concern for advanced electronics. Ever-shrinking device sizes and the introduction of new elements in state-of-the-art integrated circuits (ICs) have increased device neutron SEU susceptibility. Various elements found in ICs each have a role in producing SEUs from low-energy neutrons (sub-10 MeV). This paper explores the role these elements play in a case study of a state-of-the-art 3-D NAND flash. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Space radiobiology is an interdisciplinary science that examines the biological effects of ionizing radiation on humans involved in aerospace missions. The knowledge of the risk assessment of the health hazard related to human space exploration is crucial to reducing damages induced to astronauts from Galactic Cosmic Rays (GCRs) and sun-generated radiation. GCRs have been identified as one of the primary sources of radiation exposure in space. In this context, an accurate characterization of the possible risk of carcinogenesis induced by exposure to GCRs particles is mandatory for safe human space exploration, and one of the most crucial open problems is the contribution to carcinogenesis due to the effects on the cells directly and not directly irradiated, indicated as Target Effects (TEs) and Non-Target Effects (NTEs), respectively. It is accepted that the detrimental effects of ionizing radiation are not restricted only to the irradiated cells but also to non-irradiated distant cells manifesting various biological effects. Tumor Prevalence (TP) is often used to investigate the effects of NTEs in predictions of chronic GCR exposure risk. This paper reports the status of the research on this topic at the INFN Roma Sapienza Alpha Magnetic Spectrometer (AMS) research group, where is in progress an extensive study about the risk evaluation of the NTEs that the GCRs radiation will imply when added to the TE. A theoretical framework is presented for TP-induced NTEs modeling, ready to be used with the data collected from the AMS02 detector. Finally, a possible example of the use of the tool is shown for an accurate estimate of the tumor prevalence function of the exposure period for different typical space protons energies. [ABSTRACT FROM AUTHOR]

The May 2021 Special Issue of the IEEE Transactions on Nuclear Science (TNS) contains selected papers from the 57th annual IEEE International Nuclear and Space Radiation Effects Conference (NSREC), which was held virtually from November 29 through December 30, 2020. The 2020 IEEE NSREC was sponsored by the IEEE Nuclear and Plasma Sciences Society. More than 60 of the papers presented during NSREC are included in this year’s Special Issue. This issue is neither a conference proceedings nor a conference record. The papers that appear in this Special Issue successfully completed the regular journal review process before the special issue deadline. Several more papers presented during the conference are likely to appear in subsequent issues of the TNS. [ABSTRACT FROM AUTHOR]

During deep space missions, astronauts are exposed to highly ionizing radiation, incl. neutrons, protons and heavy ions from galactic cosmic rays (GCR), solar wind (SW) and solar energetic particles (SEP). This increase the risks for cancerogenisis, damages in central nervous system (CNS), cardiovascular diseases, etc. Large SEP events can even cause acute radiation syndrome (ARS). Long term manned deep space missions will therefor require unique radiation protection strategies. Since it has been shown that physical shielding alone is not sufficient, this paper propose pre-flight screening of the aspirants for evaluation of their level of adaptive responses. Methods for boosting their immune system, should also be further investigated, and the possibility of using radiation effect modulators are discussed. In this paper, especially, the use of vitamin C as a promising non-toxic, cost-effective, easily available radiation mitigator (which can be used hours after irradiation), is described. Although it has previously been shown that vitamin C can decrease radiation-induced chromosomal damage in rodents, it must be further investigated before any conclusions about its radiation mitigating properties in humans can be concluded. [ABSTRACT FROM AUTHOR]

Space missions with humans expose the crews to ionizing radiation, mainly due to the galactic cosmic radiation (GCR). All radiation protection programs in space aim to minimize crews' exposure to radiation. The radiation protection of astronauts can be achieved through the use of shields. The shields could serve as a suit to reduce GCR exposure and, in an emergency, as a radiation shelter to perform necessary interventions outside the space habitat in case of a solar proton event (SPE). A space radiation shielding that is suitable for exploration during space missions requires particular features and a proper knowledge of the radiation type. This study shows the results of numerical simulations performed with the Geant4 toolkit-based code DOSE. Calculations to evaluate the performance of Nomex, an aramidic fiber with high mechanical resistance, in terms of dose reduction to crews, were performed considering the interaction between protons with an energy spectrum ranging from 50 to 1100 MeV and a target slab of 20 g/cm2. This paper shows the properties of secondary products obtained as a result of the interaction between space radiation and a Nomex target and the properties of the secondary particles that come out the shield. The results of this study show that Nomex can be considered a good shield candidate material in terms of dose reductions. We also note that the secondary particles that provide the greatest contribution to the dose are protons, neutrons and, in a very small percentage, α-particles and Li ions. [ABSTRACT FROM AUTHOR]

The radiation environment in deep space, where astronauts are behind the shelter provided by the Earth's magnetosphere, is a major health concern. Galactic cosmic rays (GCR) and solar particle events (SPE) are two basic sources of space radiation in the solar system. The health risks of exposure to high levels of space radiation can be observed either as acute and delayed effects. Zhang et al. in their recently published paper entitled "γ-H2AX responds to DNA damage induced by long-term exposure to combined low-dose-rate neutron and γ-ray radiation" have addressed the effects of different cumulative radiation doses on peripheral blood cell, subsets of T cells of peripheral blood lymphocytes and DNA damage repair. These researchers exposed animals to low dose rate 60Co-rays at 0.0167 Gy h-1for 2 h/d and 252Cf neutrons at 0.028 mGy h-1for 20 h/d for 15, 30, or 60 consecutive days. They reported that the mRNA of H2AX increased significantly, and showed a positive correlation with dose. Despite strengths, this paper has several shortcomings such as poor definition of low dose radiation as well as space and reactor radiation environments. Another shortcoming of this paper comes from this point that blood cell studies do not represent the biological effects of ionizing radiation on the total body. Moreover, the effects of the human immune system and DNA repair mechanisms are not included in the study. The role of pre-exposures and induction of adaptive response phenomena in decreasing the risk of radiation in deep space missions are also ignored. [ABSTRACT FROM AUTHOR]

Most of the astronauts experience visual illusions, apparent flashes of light (LF) in absence of light. The first reported observation of this phenomenon was in July 1969 by Buzz Aldrin, in the debriefing following the Apollo 11 mission. Several ground-based experiments in the 1970s tried to clarify the mechanisms behind these light flashes and to evaluate possible related risks. These works were supported by dedicated experiments in space on the following Apollo flights and in Low Earth Orbit (LEO). It was soon demonstrated that the LF could be caused by charged particles (present in the space radiation) traveling through the eye, and, possibly, some other visual cortical areas. In the 1990s the interest in these phenomena increased again and additional experiments in Low Earth Orbit and others ground-based were started. Recently patients undergoing proton and heavy ion therapy for eye or head and neck tumors have reported the perception of light flashes, opening a new channel to investigate these phenomena.In this paper the many LF studies will be reviewed, presenting an historical and scientific perspective consistent with the combined set of observations, offering a single comprehensive summary aimed to provide further insights on these phenomena.While the light flashes appear not to be a risk by themselves, they might provide information on the amount of radiation induced radicals in the astronauts’ eyes. Understanding their generation mechanisms might also support radiation countermeasures development. However, even given the substantial progress outlined in this paper, many questions related to their generation are still under debate, so additional studies are suggested. Finally, it is also conceivable that further LF investigations could provide evidence about the possible interaction of single particles in space with brain function, impacting with the crew ability to optimally perform a mission.

This paper describes a circuit called dynamic and applicative measurement of single events in logic (DAMSEL), which can individually measure the impact of single event upsets and single-event transients (SETs) in realistic, synchronous digital circuits. Heavy-ion and pulsed laser test results are presented. Both a simple digital and an analog simulation methodology are demonstrated to provide similar cross sections to those observed during the tests. Overall, the DAMSEL structure has many advantages over current circuits used for measuring SETs, including the ease with which test results can be extrapolated to real designs. [ABSTRACT FROM PUBLISHER]

Solar Energetic Particle (SEP) events are interesting from a scientific perspective as they are the product of a broad set of physical processes from the corona out through the extent of the heliosphere, and provide insight into processes of particle acceleration and transport that are widely applicable in astrophysics. From the operations perspective, SEP events pose a radiation hazard for aviation, electronics in space, and human space exploration, in particular for missions outside of the Earth's protective magnetosphere including to the Moon and Mars. Thus, it is critical to improve the scientific understanding of SEP events and use this understanding to develop and improve SEP forecasting capabilities to support operations. Many SEP models exist or are in development using a wide variety of approaches and with differing goals. These include computationally intensive physics-based models, fast and light empirical models, machine learning-based models, and mixed-model approaches. The aim of this paper is to summarize all of the SEP models currently developed in the scientific community, including a description of model approach, inputs and outputs, free parameters, and any published validations or comparisons with data. [ABSTRACT FROM AUTHOR]

NASA's planned mission to Mars will result in astronauts being exposed to ~350 mSv/yr of Galactic Cosmic Radiation (GCR). A growing body of data from ground-based experiments indicates that exposure to space radiation doses (approximating those that astronauts will be exposed to on a mission to Mars) impairs a variety of cognitive processes, including cognitive flexibility tasks. Some studies report that 33% of individuals may experience severe cognitive impairment. Translating the results from ground-based rodent studies into tangible risk estimates for astronauts is an enormous challenge, but it would be germane for NASA to use the vast body of data from the rodent studies to start developing appropriate countermeasures, in the expectation that some level of space radiation (SR) -induced cognitive impairment could occur in astronauts. While some targeted studies have reported radiation-induced changes in the neurotransmission properties and/or increased neuroinflammation within space radiation exposed brains, there remains little information that can be used to start the development of a mechanism-based countermeasure strategy. In this study, we have employed a robust label-free mass spectrometry (MS)-based untargeted quantitative proteomic profiling approach to characterize the composition of the medial prefrontal cortex (mPFC) proteome in rats that have been exposed to 15 cGy of 600 MeV/n28Si ions. A variety of analytical techniques were used to mine the generated expression data, which in such studies is typically hampered by low and variable sample size. We have identified several pathways and proteins whose expression alters as a result of space radiation exposure, including decreased mitochondrial function, and a further subset of proteins differs in rats that have a high level of cognitive performance after SR exposure in comparison with those that have low performance levels. While this study has provided further insight into how SR impacts upon neurophysiology, and what adaptive responses can be invoked to prevent the emergence of SR-induced cognitive impairment, the main objective of this paper is to outline strategies that can be used by others to analyze sub-optimal data sets and to identify new information. [ABSTRACT FROM AUTHOR]

Space assets are continuously bathed by charged particles making their components susceptible to the effects of spacecraft charging. While their orbits are not embedded within the radiation belts, low earth orbiting assets with high inclinations do pass through the horns of these belts during each polar crossing, transiting through potentially dangerous charged particle populations many times per day. Occasionally, these low altitude horns include significant populations of energetic ~1 MeV electrons, which can penetrate typical spacecraft shielding and accumulate within dielectric materials and on ungrounded conductors, a process known as internal charging. The National Oceanic and Atmospheric Administration Polar Operational Environmental Satellites (POES) have experienced on-orbit anomalies in the boost voltage regulator (BVR) that is suspected to be associated with the accumulation and discharge of ~800 keV electrons. We have used observations from the Medium Energy Proton and Electron Detector (MEPED) instrument and a first principles model of charge accumulation [11] to develop estimates of electron internal charge (IC) accumulation over the lifetime of each POES and Metop spacecraft for a range of typical discharge time constants. With the advantage afforded by a larger database of anomalies, we are able to show that these BVR anomalies are generally not attributable in a simple way to the accumulation and subsequent discharge from >800 keV nor a higher fluence of lower energy >300 keV electrons. To the best of our knowledge, this paper presents the first long-term estimates of IC for spacecraft in highly inclined low earth orbits. [ABSTRACT FROM PUBLISHER]

Maximizing in situ resource utilization (ISRU) will be a necessary precept for all space faring nations wishing to establish a sustainable habitat on the Moon and Mars. As off-world infrastructure development advances and longer sustainable habitats are produced, what determines ISRU will also need to evolve. In this paper we explore a period in lunar colonization following the NASA Artemis program, where the available energy for manufacturing is still limited, where lunar chemical processing plants have not yet been constructed, and where the mass/weight of material transport from Earth is still confined to super heavy rockets. We present a multilayer construct, called a Regishell, that utilizes surface regolith mixed with a binder material. The Regishell is a robotic-build system that lands intact and is utilized multiple times. The focus of this paper is not the robot system but the binder materials that could be taken from the Artemis landers or produced in situ that when mixed with the regolith form a hardened structure under lunar solar radiation. The hardened material when integrated into the Regishell forms a protective structural support for a human habitat. We present examples of fused material along with measured hardness values for a polymer and a geopolymer binder. Moreover, we have conducted Monte Carlo simulations using the Regishell construct with the regolith mixture that includes a water layer to prove viability as a radiation shield. We find that the lunar regolith layer alone is adequate to substantially reduce astronaut space radiation dose due to solar particle events and galactic cosmic rays for a 14-day lunar surface mission. [ABSTRACT FROM AUTHOR]

This paper presents a new approach for analyzing the effect of single-event transient (SET) in SRAM-based field-programmable gate array (FPGA) devices, which are widely used in the space environment. New SET characterizing and mitigation techniques, including continuous monitoring and controlling of the test, are proposed to ensure proper operation of the device under test. This is vital for verifying the proper functioning of the design and performing online reconfiguration if required, since the effect of a single-event upset (SEU) on the device configuration bits may disrupt the SET detection and mitigation design. While many studies focus on SEU, latch-up, and cumulative radiation [total ionizing dose (TID)] effects on SRAM-based FPGAs, only a few published works refer to the SET effect. Moreover, in contrast to previous SET studies, this paper presents a quantitative assessment for SET probability under the real radiation environment and provides cross-sectional analysis for both SET and SEU effects at low linear energy transfers (LETs) (up to 0.925 MeV $\cdot$ cm2/mg). The SET experiments have been carried out at UCL Cyclotron (Belgium) accelerator using heavy ions and under alpha source irradiation. Experimental results indicate that SET examinations on SRAM-based FPGAs should be performed only at low LETs due to the high SEU rate compared to the SET rate. Several kinds of filters have been implemented and proposed for SET mitigation demonstrating a significant reduction of the SET transient effects. The proposed methodology may provide a basic model for future research studies on SET radiation effects on SRAM-based FPGAs, and assisting in selecting an immune FPGA-based platform for satellites applications. [ABSTRACT FROM AUTHOR]

In this paper, we test Si vertical-junction disk modulators and waveguide-integrated Ge p-i-n photodiodes (PDs) to see how the key performance metrics are affected by 60Co gamma radiation (total ionizing dose), a common proxy for simulating a mix of high-energy ion particle flux. It is found that reverse bias dark current increases significantly for both devices after 1-Mrad(Si) exposure. As the bandwidth of the Si disk modulator decreases by 6.5% after 1-Mrad(Si) dose, the bandwidth of the Ge p-i-n PD appears to be unaffected. The increased sensitivity of the Si disk modulator bandwidth to gamma radiation is hypothesized to be caused by a decrease in the carrier concentration of the junction with a resulting increase in the p-n junction RC time constant. The Ge p-i-n PD is relatively insensitive to the surface effects, because the absorption happens away from the SiO2–Ge interface and the gamma radiation has a minimal effect on carrier mobility. [ABSTRACT FROM AUTHOR]

In this paper, we examine the history of detection efficiency measurements of photons (soft to hard X-rays and beyond) with microchannel plates (MCPs). We investigate the detection efficiency as a function of photon energy over a wide energy range, from a few hundred eVs up to 20 MeV. We also investigate detection efficiency as a function of incident angle onto the MCP. We interpreted the published efficiency data measured with a variety of MCPs and the use of MCP coatings for enhancement of X-ray quantum detection efficiency, and discuss theoretical expectations based on the main photon interactions with matter: the photoelectric effect, Compton scattering, and pair production. Contributing to the published literature at the highest end of the energy range, we also discuss our photon detection efficiency experiments from 2.5 to 20 MeV and theoretical implications. [ABSTRACT FROM AUTHOR]

Experiments at the NASA Space Radiation Laboratory were performed to develop a benchmark dataset relevant to space radiation shielding scenarios by bombarding aluminum and polyethylene targets with galactic cosmic ray-like ion beams. Unique to this experiment, a dual-target configuration was used to emulate an enclosed environment in space in which the radiation environment must be characterized. Neutrons produced by interactions in both thick targets were detected and characterized; this paper discusses the neutrons produced in the most upstream of the two thick targets, detailing the role of source ion and target configuration on neutron yield. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3) has recently gained attention as an alternative power electronics semiconductor for aerospace applications. Irradiation damage studies are needed to characterize the radiation tolerance of this material. This paper presents coupled neutronics and primary knock-on atom transport simulations that have been performed to estimate the neutron displacement damage cross section for Ga2O3 as a function of neutron energy. This functional dependence will allow for improved comparisons between irradiation experiments of Ga2O3 using a variety of neutron fields. The methodology presented uses MCNP and transport of ions in matter to determine the displacement damage cross section, which has been calculated in a multigroup neutron energy structure. The calculational method was also validated against the ASTM standard damage cross section for silicon. [ABSTRACT FROM PUBLISHER]

This paper describes a framework for incorporating linear radiation effects into the statistical machinery of the AE9/AP9 radiation climatology model software via “kernel” files. Users can provide their own kernels without modification of the software. Kernels can be applied to a variety of radiation effects such as proton single-event effect rate, internal charging current, ionizing dose, and nonionizing dose. Kernels can be generated for custom shielding geometry and materials and for custom parts or material susceptibilities. [ABSTRACT FROM PUBLISHER]

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) has been orbiting the Moon since 2009 aboard the Lunar Reconnaissance Orbiter (LRO). From this vantage point, it samples the interplanetary energetic particle population outside the shielding of the Earth's magnetosphere. We report the sensor's observations of galactic cosmic rays (GCRs) over a complete solar activity cycle. CRaTER is designed primarily to measure not the spectra of GCR particles outside the sensor but rather their effects on matter, and in particular, it measures the linear energy transfer (LET) or energy‐deposit spectrum in its silicon detectors. We have used the Geant4 radiation‐transport code to devise a background‐rejection algorithm to improve these measurements of LET under 9.9 g/cm2 of shielding, and the resulting observations show the changing radiation effects of GCRs as their intensity and spectrum vary with solar modulation. As of 2020 this intensity, after declining during solar maximum activity, has recovered to a level that exceeds by a few percent the historically high values seen during the deep solar minimum at the start of the LRO mission in 2009. Plain Language Summary: Energetic particle radiation consists of fast‐moving atomic fragments traveling in space. The particles with the highest energy, called cosmic rays, can penetrate even thick shielding and deposit their energy into astronauts or electronics, causing radiation damage. A sensor aboard the Lunar Reconnaissance Orbiter satellite has been measuring cosmic rays in orbit around the Moon since 2009, monitoring the varying intensity of their radiation effects, and this paper reports improvements we have made to these measurements. The Sun's output of energetic particles, magnetic fields, and so forth varies on an 11‐year cycle, and this activity affects the intensity of cosmic rays coming into the solar system. Our measurements of cosmic ray radiation effects show that, after a decline during the middle of the solar activity cycle, as of 2020 their intensity has risen back to exceed the historically high levels seen at the start of the mission. Key Points: The Cosmic Ray Telescope for the Effects of Radiation has measured galactic cosmic rays at the Moon over a full solar activity cycleWe have used the Geant4 radiation‐transport code to improve background rejection in measurements of Linear Energy Transfer spectraThe intensity of galactic cosmic rays, as of early 2020, has recovered and now slightly exceeds the historically high levels of 2009 [ABSTRACT FROM AUTHOR]

This paper reports on in situ measurements of the linear energy transfer spectra of galactic cosmic rays and their progeny and of trapped Van Allen belt protons as recorded by a pulse height analyzer (PHA) radiation spectrometer which flew on the STS-95 DISCOVERY mission on the Hubble Orbital Systems Test cradle. The shuttle was launched on October 29, 1998 and had a mission duration of 8.5 days during the minimum phase of the solar activity cycle. The orbit of the STS-95 was about 550 km altitude and 28.5° inclination. Close agreement was seen between radiation environment model predictions and the measurements of the PHA. Agreement is obtained by considering the directionality of the radiation interacting with the shuttle structure. [ABSTRACT FROM PUBLISHER]

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This paper presents a design philosophy for protecting spacecraft avionics from the effects of single-event transients caused by high-energetic charged particles in the space environment. The design philosophy has resulted in a proven concept over the many years of actual implementation in real avionics in real space missions. Only an overview of this design philosophy is presented. The paper first addresses the science of the space environment as it relates to high-energy charged particles. It includes the derivations of important parameters in high-energy particle physics as it applies to interactions with semiconductor electronic in component integrated circuits. The paper then transitions to explore some general methodologies widely used in the industry to control the damaging effects of single-event transients caused by the space environment. The paper then shifts emphasis to the main subject of design methods and philosophies, with examples of how spacecraft avionics can be designed and built with a certain level of immunity against the possible catastrophic effects of single-event transients. These design principles are presented briefly, but with enough detail to provide a general overview. [ABSTRACT FROM AUTHOR]

While humans have made enormous progress in the exploration and exploitation of Earth, exploration of outer space remains beyond current human capabilities. The principal challenges lie in current space technology and engineering which includes the protection of astronauts from the hazards of working and living in the space environment. These challenges may lead to a paradoxical situation where progress in space technology and the ability to ensure acceptable risk/benefit for human space exploration becomes dissociated and the rate of scientific discovery declines. In this paper, we discuss the predominant challenges of the space environment for human health and argue that development and deployment of a human enhancement policy, initially confined to astronauts – for the purpose of future human space programmes is a rational solution to these challenges. [ABSTRACT FROM AUTHOR]

In recent decades, the opportunity to introduce self-healing materials within space structures has drawn the attention of scientists and companies. Autonomous repair following damage caused by impacts with micrometeoroids and orbital debris (MMOD) would lead to safer human activity in space and would increase spacecraft operational life and autonomy, thus reducing replacement costs and possibly relieving astronauts from maintenance activities. In particular, integrating self-healing materials into structures to protect humans from the space environment is a fundamental step in the realization of long-lasting space exploration missions. Nevertheless, the way these materials interact with the environmental factors in space still needs to be properly analyzed and understood; in particular, space radiation is a serious threat to human health and material integrity. The proposed work hence investigates the shielding ability of candidate self-healing materials with the specific purpose of human protection in crewed missions. The NASA HZETRN2015 (High Z and Energy TRaNsport, 2015 version) software is used to simulate galactic cosmic rays (GCR) and low Earth orbit (LEO) environment. A comparison between a standard habitat layup proposed by NASA and a set of configurations containing self-healing polymers is performed to verify that the substitution of conventional bladder materials with the proposed self-healing solutions does not decrease the overall habitat shielding performance. A self-healing nanocomposite option with single-walled carbon nanotubes (SWCNTs) is also analyzed to determine whether the insertion of nanofillers can increase the overall shielding performance. In the second phase, the comparison of puncture tests on blank and irradiated samples under conditions reproducing a space suit example is presented to assess the possible effects of radiation on the self-healing performance. [ABSTRACT FROM AUTHOR]

This study examines the effects of microgravity and space radiation on astronauts' muscle and bone health during space missions. Microgravity leads to muscle atrophy and alterations in muscle tissue composition, whereas space radiation impacts bone cells by increasing osteoclast activity and decreasing osteoblast activity. The findings underscore the critical need for preventive measures, post-mission rehabilitation, and the use of specialized equipment and technology--such as microgravity-adapted treadmills and nutritional supplements--to sustain astronaut health. This study lays the groundwork for developing effective protection and intervention strategies for long-duration space exploration, highlighting the necessity of a thorough understanding of how the space environment affects the human body to ensure optimal health and performance in space. [ABSTRACT FROM AUTHOR]

During deep space missions, astronauts are exposed to highly ionizing radiation, incl. neutrons, protons and heavy ions from galactic cosmic rays (GCR), solar wind (SW) and solar energetic particles (SEP). This increase the risks for cancerogenisis, damages in central nervous system (CNS), cardiovascular diseases, etc. Large SEP events can even cause acute radiation syndrome (ARS). Long term manned deep space missions will therefor require unique radiation protection strategies. Since it has been shown that physical shielding alone is not sufficient, this paper propose pre-flight screening of the aspirants for evaluation of their level of adaptive responses. Methods for boosting their immune system, should also be further investigated, and the possibility of using radiation effect modulators are discussed. In this paper, especially, the use of vitamin C as a promising non-toxic, cost-effective, easily available radiation mitigator (which can be used hours after irradiation), is described. Although it has previously been shown that vitamin C can decrease radiation-induced chromosomal damage in rodents, it must be further investigated before any conclusions about its radiation mitigating properties in humans can be concluded.