Radiation Protection In Space Research Articles

Characterization of the FOOT neutron detectors for nuclear fragmentation measurements at the n_TOF facility

FOOT (FragmentatiOn Of Target) is an applied nuclear physics experiment with the aim of performing high precision cross section measurements for fragmentation reactions of interest in hadrontherapy and radiation protection in space. The physics program of the experiment foresees a set of measurements with light ion beams, such as C and O, in the energy range of 100–800 MeV/u interacting with tissue-like and shielding material targets. The setup was initially conceived for the detection of charged fragments and, in 2021, the Collaboration started the study of possible solutions for neutron detection. Two detection systems have been proposed: one based on BC-501A liquid scintillators with neutron/γ discrimination capabilities and a system based on BGO crystals operated in phoswich mode. In 2022, a dedicated data acquisition campaign was carried out at the n_TOF facility at CERN to evaluate the capabilities of the two systems. First, the neutron/γ discrimination efficiency of the BC-501A system was studied using radioactive sources. Then, the two systems were placed in the n_TOF experimental area to study their neutron detection efficiency under a well characterized neutron beam. In this work, the first preliminary results concerning the characterization of the two possible neutron detectors of FOOT are presented.

Optimisation of the Tripathi model using a nuclear reaction cross-section database

Nuclear reaction cross-sections are an essential ingredient to reliable deterministic and stochastic radiation transport codes used for radiation protection in space and heavy-ion therapy applications. A recent study compared the existing literature data compiled within the open-access GSI-ESA-NASA cross-section database to the models implemented in the transport codes most commonly used for radiation protection in space and heavy-ion therapy applications. The outcome of the comparison was that none of the models fit well the experimental data for all projectile-target systems at all energy ranges. Therefore, the literature data were exploited to optimise the Tripathi–Cucinotta–Wilson model as reported in this work. This model is used as default in FLUKA, TRiP, and SpaceTRiP, it is part of the hybrid-Kurotama (HK) model used in particle and heavy ion transport code (PHITS), and it is implemented in Geant4. The consequences of using the proposed Tripathi–Cucinotta–Wilson optimisation in the HK model are also analysed.

Nuclear fragmentation cross section measurements with the FOOT experiment

FOOT (FragmentatiOn Of Target) is an applied nuclear physics experiment that aims at a full characterization of the nuclear fragmentation processes of interest for Particle Therapy and Radiation Protection in Space. The physics program foresees a set of measurements in direct and inverse kinematics using particle beams and targets with composition similar to human tissues and spacecraft shielding materials. The final goal of the experiment is the measurement of double differential cross sections with respect to angle and fragment energy in the 100-800 MeV/u range with a precision better than 5%. The FOOT Collaboration is currently completing the development of the apparatus and data acquisition campaigns with partial setups have already started. In this paper, an overview of the current status of the experiment is given, together with a summary of the preliminary results obtained from the first measurements with 16O beams.

Dose Attenuation in Innovative Shielding Materials for Radiation Protection in Space: Measurements and Simulations.

Galactic cosmic rays (GCR) are among the main deterrents to manned space exploration. Currently, the most realistic way to reduce the dangers caused by GCR to acceptable levels is passive shielding. Light materials guarantee the strongest dose attenuation per unit mass. High-density polyethylene is considered the gold standard for radiation protection in space. Nevertheless, accelerator-based experimental campaigns already showed the advantages of more hydrogen-rich innovative shielding materials such as lithium hydride. The experimental campaigns of this work focused on the absorbed dose attenuation properties of lithium-based hydrides chemically stabilized with a paraffin matrix. Such materials were compared to pure lithium-based hydrides, polyethylene, structural materials such as spacecraft aluminum alloys and lithium batteries, and in situ shielding materials such as Moon regolith and its main components silicon and silicon dioxide. The experimental results were compared to simulations performed with PHITS, FLUKA, and Geant4, which are among the most used Monte Carlo codes for radiation protection in space. The simulations showed systematic differences and highlighted the pressing need for reliable nuclear cross-section models.

Lethal DNA damage caused by ion-induced shock waves in cells.

The elucidation of fundamental mechanisms underlying ion-induced radiation damage of biological systems is crucial for advancing radiotherapy with ion beams and for radiation protection in space. The study of ion-induced biodamage using the phenomenon-based multiscale approach (MSA) to the physics of radiation damage with ions has led to the prediction of nanoscale shock waves created by ions in a biological medium at the high linear energy transfer (LET). The high-LET regime corresponds to the keV and higher-energy losses by ions per nanometer, which is typical for ions heavier than carbon at the Bragg peak region in biological media. This paper reveals that the thermomechanical stress of the DNA molecule caused by the ion-induced shock wave becomes the dominant mechanism of complex DNA damage at the high-LET ion irradiation. Damage of the DNA molecule in water caused by a projectile-ion-induced shock wave is studied by means of reactive molecular dynamics simulations. Five projectile ions (carbon, oxygen, silicon, argon, and iron) at the Bragg peak energies are considered. For the chosen segment of the DNA molecule and the collision geometry, the number of DNA strand breaks is evaluated for each projectile ion as a function of the bond dissociation energy and the distance from the ion's path to the DNA strands. Simulations reveal that argon and especially iron ions induce the breakage of multiple bonds in a DNA double convolution containing 20 DNA base pairs. The DNA damage produced in segments of such size leads to complex irreparable lesions in a cell. This makes the shock-wave-induced thermomechanical stress the dominant mechanism of complex DNA damage at the high-LET ion irradiation. A detailed theory for evaluating the DNA damage caused by ions at high-LET is formulated and integrated into the MSA formalism. The theoretical analysis reveals that a single ion hitting a cell nucleus at high-LET is sufficient to produce highly complex, lethal damages to a cell by the shock-wave-induced thermomechanical stress. Accounting for the shock-wave-induced thermomechanical mechanism of DNA damage provides an explanation for the "overkill" effect observed experimentally in the dependence of cell survival probabilities on the radiation dose delivered with iron ions. This important observation provides strong experimental evidence of the ion-induced shock-wave effect and the related mechanism of radiation damage in cells.

Charge identification of nuclear fragments with the FOOT Time-Of-Flight system

FOOT (FragmentatiOn Of Target) is an applied nuclear physics experiment conceived to conduct high-precision cross section measurements of nuclear fragmentation processes relevant for particle therapy and radiation protection in space. These measurements are important to estimate the physical and biological effects of nuclear fragments, which are produced when energetic particle beams penetrate human tissue.A component of the FOOT experiment is the ΔE-TOF system. It is designed to measure energy loss and time-of-flight of nuclear fragments produced in particle collisions in thin targets in order to extract their charge and velocity. The ΔE-TOF system is composed of a start counter, providing the start time for the time-of-flight, and a 40 × 40 cm2 wall of thin plastic scintillator bars, providing the arrival time and energy loss of the fragments passing through the detector. Particle charge discrimination can be achieved by correlating the energy loss in the scintillator bars with the measured time-of-flight.Recently, we have built a full-size ΔE-TOF detector. In this work, we describe the energy and time-of-flight calibration procedure and assess the performance of this system. We use data acquired during beam tests at CNAO with proton and 12C beams and at GSI with 16O beams in the energy range relevant for particle therapy, i.e., from 60 to 400 MeV/u. For heavy fragments (C and O), we obtain energy and time resolutions ranging from 4.0 to 5.2% and from 54 to 76 ps, respectively. The procedure is also applied to a fragmentation measurement of a 400 MeV/u 16O beam on a 5 mm carbon target, showing that the system is able to discriminate the charges of impinging fragments.

Cancer incidence risks above and below 1 Gy for radiation protection in space

The risk assessment quantities called lifetime attributable risk (LAR) and risk of exposure-induced cancer (REIC) are used to calculate the cumulative cancer incidence risks for astronauts, attributable to radiation exposure accumulated during long term lunar and Mars missions. These risk quantities are based on the most recently published epidemiological data on the Life Span Study (LSS) of Japanese A-bomb survivors, who were exposed to γ-rays and neutrons. In order to analyze the impact of a different neutron RBE on the risk quantities, a model for the neutron relative biological effectiveness (RBE) relative to gammas in the LSS is developed based on an older dataset with less follow-up time. Since both risk quantities are based on uncertain quantities, such as survival curves, and REIC includes deterministic radiation induced non-cancer mortality risks, modelled with data based on the general population, the risks for astronauts may not be optimally estimated. The suitability of these risk assessment measures for the use of cancer risk calculation for astronauts is discussed. The work presented here shows that the use of a higher neutron RBE than the value of 10, traditionally used in the LSS risk models, can reduce the risks up to almost 50%. Additionally, including an excess absolute risk (EAR) baseline scaling also increases the risks by between 0.4% and 8.1% for the space missions considered in this study. Using just an EAR model instead of an equally weighted EAR and excess relative risk (ERR) model can decrease the cumulative risks for the considered missions by between 0.4% and 4.1% if no EAR baseline scaling is applied. If EAR baseline scaling is included, the calculated risks with the EAR- and the mixed model, as well as the risks calculated with just the ERR model are almost identical and only small differences in the uncertainties are visible.

The Biophysics Collaboration for research at FAIR and other new accelerator facilities

Applied nuclear physics is ubiquitous in our lives, and is a field in fast and exponential growth. Biomedical application at particle accelerators are particular important, and many current accelerators in Europe built for nuclear physics (e.g. GSI in Germany, KVI in The Netherlands, GANIL in France, INFN-LNS in Italy) have intense and productive biomedical programs covering topics such as radiotherapy with charged particles and radiation protection in space [1].

High-performance piezoelectric nanogenerator based on microstructured P(VDF-TrFE)/BNNTs composite for energy harvesting and radiation protection in space

Stable and durable piezoelectric nanogenerators (PENGs) with good flexibility, high performance and superior radiation resistance under harsh environments are promising for space exploration. Here, a novel PENG based on P(VDF-TrFE)/boron nitride nanotubes (BNNTs) nanocomposite micropillar arrays with enhanced performance and excellent neutron radiation shielding is prepared by a reliable nanoimprint lithography. The PENG comprised of a microstructured P(VDF-TrFE)/0.3 wt% BNNTs nanocomposite demonstrates an outstanding output voltage of 22 V and a sensitivity of 55 V/MPa under the pressure of 0.4 MPa, which are 11-fold higher than those of pristine P(VDF-TrFE) film. This dramatic enhancement in performance is ascribed to synergistic contributions from strong piezoelectric BNNTs and a strain confinement effect of the nanocomposite microstructure. In practice, the PENG is capable of scavenging various mechanical and biomechanical energy for lighting up commercial LEDs, an LCD screen and a digital watch. More importantly, the as-obtained PENG exhibited 9% neutron radiation shielding with neutron cross section increase reaching 260% when compared to the film without BNNTs. Moreover, the high output is retained after 2 h of neutron radiation exposure. Overall, the as-prepared microstructured nanocomposites look promising for high-efficiency piezoelectric nanogenerators for the self-powered and wearable electronic devices, in particularly, under the extreme space environments.

The extension of the INCL model for simulation of shielding in space

Radiation hazard for space missions is mainly due to cosmic ray protons, helium nuclei and light ions, whose energy spectrum is maximum around 1 GeV per nucleon but remains non-negligible for energies up to 15 GeV per nucleon. Nuclear reactions induced by high energy protons are often described by intranuclear cascade plus evaporation models. The attention is focused here on the Liège Intranuclear Cascade model (INCL), which has been shown to reproduce fairly well a great deal of experimental data for nucleon-induced reactions in the 200 MeV to 2 GeV range, when coupled with the ABLA evaporation-fission code. In order to extend the model to other conditions relevant for space radiation, three improvements of INCL are under development. They are reported on here. First, the reaction model has been extended to nucleon–nucleus reactions at incident energies up to 15 GeV, mainly by the inclusion of additional pion production channels in nucleon–nucleon collisions during the cascade. Second, a coalescence mechanism for the emission of light charged particles has been implemented recently. Finally, the model has been modified in order to accommodate light ions as projectiles. First results are shown and compared with illustrative experimental data. Implications for issues concerning radiation protection in space are discussed.

Tests of shielding effectiveness of Kevlar and Nextel onboard the International Space Station and the Foton-M3 capsule

Radiation assessment and protection in space is the first step in planning future missions to the Moon and Mars, where mission and number of space travelers will increase and the protection of the geomagnetic shielding against the cosmic radiation will be absent. In this framework, the shielding effectiveness of two flexible materials, Kevlar and Nextel, were tested, which are largely used in the construction of spacecrafts. Accelerator-based tests clearly demonstrated that Kevlar is an excellent shield for heavy ions, close to polyethylene, whereas Nextel shows poor shielding characteristics. Measurements on flight performed onboard of the International Space Station and of the Foton-M3 capsule have been carried out with special attention to the neutron component; shielded and unshielded detectors (thermoluminescence dosemeters, bubble detectors) were exposed to a real radiation environment to test the shielding properties of the materials under study. The results indicate no significant effects of shielding, suggesting that thin shields in low-Earth Orbit have little effect on absorbed dose.

Solid state nuclear track detectors in hadrontherapy and radiation protection in space

The recent widespread of carbon-therapy for cancer treatment and the long duration manned exploration planned by NASA require the knowledge of nuclear data both for assessing the correct dose distribution in the target volume and surrounding healthy tissue (radiation therapy), and for a better knowledge of the mixed radiation field to which astronauts will be exposed (radiation protection in space). Nuclear fragmentation taking place in traversed material, even human body itself, is indeed responsible for a beam quality change whose biological effects have to be evaluated. Solid state nuclear track detectors (SSNTD) provide accurate measurements of fluence and fragmentation of heavy ions needed for hadrontherapy and space radiation-protection purposes.

Nanodosimetry-based quality factors for radiation protection in space

Evaluation and monitoring of the cancer risk from space radiation exposure is a crucial requirement for the success of long-term space missions. One important task in the risk calculation is to properly weigh the various components of space radiation dose according to their assumed contribution to the cancer risk relative to the risk associated with radiation of low ionization density. Currently, quality factors of radiation both on the ground and in space are defined by national and international commissions based on existing radiobiological data and presumed knowledge of the ionization density distribution of the radiation field at a given point of interest. This approach makes the determination of the average quality factor of a given radiation field a rather complex task. In this contribution, we investigate the possibility to define quality factors of space radiation exposure based on nanodosimetric data. The underlying formalism of the determination of quality factors on the basis of nanodosimetric data is described, and quality factors for protons and ions (helium and carbon) of different energies based on simulated nanodosimetric data are presented. The value and limitations of this approach are discussed.

Optically stimulated luminescence fluence response of [formula omitted] dosimeters exposed to different types of radiation

This paper presents the optically stimulated luminescence (OSL) fluence response of carbon-doped aluminum oxide ( Al 2 O 3 : C ) dosimeters irradiated with heavy charged particles (HCPs) of energies relevant to radiation protection in space. The dosimeters were exposed to seven HCP beams with linear energy transfer in water from 0.223 keV/μm to 431.8 keV / μ m , and fluences from 2.9 × 10 3 cm - 2 to 2.8 × 10 10 cm - 2 . Irradiations with a 90 Sr / 90 Y beta source were also performed for comparison. The results show that the dosimeters’ response to high-energy protons is similar to that for the 90 Sr / 90 Y beta source. The supralinearity in the dose response curve of dosimeters exposed to the 90 Sr / 90 Y beta source and high-energy protons can be avoided by appropriate choice of optical filters. For HCPs from He to Fe no supralinearity was observed in the OSL dose response. We interpret the results in the framework of track structure model.

Radiation protection in space

Radiation protection in space

Fluence-Based and Microdosimetric Event-Based Methods for Radiation Protection in Space

Fluence-Based and Microdosimetric Event-Based Methods for Radiation Protection in Space

Radiation protection in space.

The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in our knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared with previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers, including space travelers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space.

Radiation protection in space

Radiation environment, basic concepts of radiation protection, and specific aspects of the space radiation field are reviewed. The discussion of physico-chemical and subcellular radiation effects includes mechanisms of radiation action and cellular consequences. The discussion of radiobiological effects includes unique aspects of HZE particle effects, space flight findings, terrestrial findings, analysis of somatic radiation effects and effects on critical organs, and early and delayed effects. Other topics include the impact of the space flight environment, measurement of radiation exposure, establishing radiation protection limits, limitations in establishing space-based radiation exposure limits, radiation protection measures, and recommendations.

The NASA space radiation health program

The NASA Space Radiation Health Program is a part of the Life Sciences Division in the Office of Space Science and Applications (OSSA). The goal of the Space Radiation Health Program is development of scientific bases for assuring adequate radiation protection in space. A proposed research program will determine long-term health risks from exposure to cosmic rays and other radiation. Ground-based animal models will be used to predict risk of exposures at varying levels from various sources and the safe levels for manned space flight.

RADIATION PROTECTION IN SPACE MAY COME FROM EXTREME COLD

School Science and MathematicsVolume 62, Issue 8 p. 627-627 RADIATION PROTECTION IN SPACE MAY COME FROM EXTREME COLD First published: November 1962 https://doi.org/10.1111/j.1949-8594.1962.tb13200.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume62, Issue8November 1962Pages 627-627 RelatedInformation