Low Radiation Environment Research Articles

Lung cell injury risks of PM2.5 exposure in the high humidity and low solar radiation environment of southwestern China

PM2.5 can cause lung cell injury. Due to the complexity and variation of the physical and chemical properties of PM2.5, the risk of lung cell injury may depend significantly on the type of atmospheric environment. With a population of 120 million, the Chengdu-Chongqing region in China is the most populated region in the world that experiences both high humidity and low solar radiation (HHLR). However, PM2.5-related lung cell injury and treatment strategies in this type of environment are still unclear. Thus, our study focuses on the relationships between the chemical components, lung cell injury effects, and pathogenic mechanisms of PM2.5 in HHLR (HHLR-PM2.5). In terms of mass, organic carbon (OC), NO3−, SO42−, and NH4+ are found to be the most significant components of HHLR-PM2.5. Extracts of HHLR-PM2.5 significantly inhibit cell viability, stimulate reactive oxygen species (ROS) levels, and trigger inflammation. Utilizing a combination of multi-omics, bioinformatics, and molecular biology, it is found that HHLR-PM2.5 extracts inhibit E3 ubiquitin-protein ligase (UHRF1) to suppress DNA methyltransferase 1 (DNMT1) and hamper DNA methylation, culminating in lung cell injury. Additionally, integrating transcriptomic data with human disease databases highlights chronic obstructive pulmonary disease (COPD) as a potential lung cell injury-related respiratory affliction induced by HHLR-PM2.5. This study expands the scientific comprehension of the health risks associated with HHLR-PM2.5, deciphers the molecular mechanism of lung cell injury, and provides precise treatment strategies for HHLR-PM2.5-induced lung cell injury.

Low-Energy Endgame Trajectory Design for Callisto Orbiter

Callisto is a promising target for future Jovian system exploration due to its high scientific value and low-radiation environment. This paper proposes a new low-energy endgame that can achieve a low-Δv transfer with short flight times for Callisto orbiting and landing missions. In contrast to the endgames designed for other Galilean moons, the proposed Callisto endgame would perform interior transfers from Ganymede in the low-energy region rather than exterior transfers. The definition and analysis of the Callisto endgame are completed using the Tisserand–Poincaré graph. Tisserand-leveraging transfers and isolating blocks techniques are used to search for different trajectory arcs in the endgame. The developed trajectory solver is able to find an optimal complete endgame trajectory with constraints on the initial state and the orbit around Callisto. In the designed scenarios, the spacecraft can complete the transfer from the Ganymede resonance orbit to the polar science orbit around Callisto with a minimum Δv of 712.3 m/s and a transfer time of about 140 days, which is a significant improvement compared to the high-energy endgame.

Effect of carbon dioxide application on tomato growth dynamics and yield within a low solar radiation environment in Akita (cold region), Japan

Effect of carbon dioxide application on tomato growth dynamics and yield within a low solar radiation environment in Akita (cold region), Japan

Canfranc biology platform: exploring life in cosmic silence

Deep underground laboratory infrastructures have extensively been used for exploring rare events, such as proton decay, dark matter searches or neutrino interactions, taking advantage of their large muon flux reduction. However, only very few investigations have evaluated the effects of low background radiation environments on living organisms. With this purpose, the Canfranc Underground Laboratory (LSC) launched the Biology Platform in 2021, which provides lab space for approved biology experiments. Two identical laboratories have been built (underground and on surface) to replicate biology experiments under the same conditions, with the main difference being the cosmic radiation background. The access protocol to use the LSC facilities includes two open calls per year and assigned time windows for executing the experimental program, which led to the first eight approved and already running experiments. We describe the scientific program of the Canfranc Biology Platform, which explores extremophiles, viral infection, immune system, multicellularity, development or aging in cosmic silence, and the first experimental results. The Platform also allows to observe the response of life to microgravity in absence of radiation, a key condition to explore life in space.

Predicting the thermal protective performance of flame-retardant fabric based on machine learning

PurposeThe purpose of this study is to predict the thermal protective performance (TPP) of flame-retardant fabric more economically using machine learning and analyze the factors affecting the TPP using model visualization.Design/methodology/approachA total of 13 machine learning models were trained by collecting 414 datasets of typical flame-retardant fabric from current literature. The optimal performance model was used for feature importance ranking and correlation variable analysis through model visualization.FindingsFive models with better performance were screened, all of which showed R2 greater than 0.96 and root mean squared error less than 3.0. Heat map results revealed that the TPP of fabrics differed significantly under different types of thermal exposure. The effect of fabric weight was more apparent in the flame or low thermal radiation environment. The increase in fabric weight, fabric thickness, air gap width and relative humidity of the air gap improved the TPP of the fabric.Practical implicationsThe findings suggested that the visual analysis method of machine learning can intuitively understand the change trend and range of second-degree burn time under the influence of multiple variables. The established models can be used to predict the TPP of fabrics, providing a reference for researchers to carry out relevant research.Originality/valueThe findings of this study contribute directional insights for optimizing the structure of thermal protective clothing, and introduce innovative perspectives and methodologies for advancing heat transfer modeling in thermal protective clothing.

Sub-background radiation exposure at the LNGS underground laboratory: dosimetric characterization of the external and underground facilities

Radiobiological studies conducted in Deep Underground Laboratories allow to improve the knowledge of the biological effects induced by ionizing radiation at low doses/dose rates. At the Gran Sasso National Laboratory of the Italian Institute of Nuclear Physics we can study the possible differences in behavior between parallel biological systems, one maintained in a Reference-Radiation Environment (RRE, external) and the other maintained in an extremely Low-Radiation Environment (LRE, underground), in the absence of pressure changes, the RRE and LRE laboratories being at the same altitude. For these investigations, it is mandatory to evaluate the dose rate values at RRE and LRE. The aim of our work is to provide a comprehensive dosimetric analysis for external and underground laboratories. Measurements of the different low Linear Energy Transfer (LET) components at RRE and LRE were performed using different detectors. Gamma dose rates were 31 nSv/h at RRE and 27 nSv/h at LRE respectively. The muon dose rate was 47 nSv/h at RRE and negligible at LRE (less than pGy/h). Dosimetric measurements were also carried out to characterize the devices used to modulate the gamma dose rate, namely, a gamma source irradiator (to increase the dose rate by about 90 nSv/h) and shields (of iron at LRE and lead at RRE). Using the iron shield at LRE a dose reduction factor of about 20, compared to the RRE, was obtained for the low LET components; inside the lead shield at RRE the gamma component was negligible compared to the muonic component. Radon activity concentrations were approximately of 20 Bq/m3 at both LRE and RRE. The intrinsic contribution of radioactivity in the experimental set up was of 0.25 nGy/h, as evaluated with a GEANT4-simulation, using as input the measured activity concentrations. GEANT4 simulations were also performed to calculate the neutron dose rate at RRE, yielding a value of 1.4 nGy/h, much larger than that at LRE (which is less than pGy/h). In conclusion, RRE and LRE are currently characterized and equipped to perform radiobiological studies aimed at understanding the involvement of the different low LET components in determining the response of biological systems.

Overview of DISCOVER22 experiment in the framework of INFN-LNGS Cosmic Silence activity: challenges and improvements in underground radiobiology

One of the most intriguing and still pending questions in radiobiology is to understand whether and how natural environmental background radiation has shaped Life over millions of years of evolution on Earth. Deep Underground Laboratories (DULs) represent the ideal below-background exposure facilities where to address such a question. Among the few worldwide DULs, INFN-Laboratorio Nazionale del Gran Sasso (LNGS) is one of the largest in terms of size and infrastructure. Designed and built to host neutrino and dark matter experiments, since the 1990 s the LNGS has been one of the first DULs to systematically host radiobiology experiments. Here we present the DISCOVER22 (DNA Damage and Immune System Cooperation in VEry low Radiation environment 2022) experiment recently started at LNGS. DISCOVER22 aims at investigating how the low radiation background modulates the Immune System (IS) response in in vitro and in vivo models. Underground radiobiology experiments are particularly complex and tricky to design and perform. In these studies, the accurate characterization of exposure scenarios is mandatory, but a challenging aspect is to understand how the very few ionizing tracks in the ultra-Low Radiation Environment (LRE) interact with the living matter in space and time in order to trigger different biological responses. In this Perspective, we describe these challenges and how we address them through a microdosimetric and a radiobiological approaches. We aim at linking physical microdosimetric measurements and the corresponding biological radiation responses by using radiation biophysical models that could shed light on many as yet unresolved questions.

Compact, portable, automatic sample changer stick for cryostats and closed-cycle refrigerators

Beamlines are facilities that produce and deliver highly focused and intense beams of radiation, typically x rays, synchrotron radiation, or neutrons, for scientific research purposes. Millions of dollars are spent annually to maintain and operate these scientific beamlines, oftentimes running continuously between cycles. To reduce human intervention and improve productivity, mechanical sample changers are often commissioned for use. Designing sample changers is difficult because mechanical parts can be bulky, expensive, and challenging to design for instruments with low volume access, high radiation, and cryogenic environments. We present a portable and inexpensive sample changer stick that can hold and manipulate up to four samples, specifically designed for use with cryogenic closed-cycle refrigerators. The sample changer stick enables rapid and efficient exchange of samples without manual intervention, and is compatible with standard sample mounts such as vanadium cans. The sample changer stick includes a motorized rotation and lancing mechanism, which enables the precise positioning of each sample in the neutron beam, while ensuring compatibility with the operating temperatures and vacuum conditions required for closed-cycle refrigerators. The design has been successfully tested at the VISION beamline at the Spallation Neutron Source. The mechanical action and software controls are detailed. The sample changer stick is a valuable tool for scientists working with cryogenic closed-cycle refrigerators.

Latest developments and characterisation results of DMAPS in TowerJazz 180nm for High Luminosity LHC

The last couple of years have seen the development of Depleted Monolithic Active Pixel Sensors (DMAPS) fabricated in TowerJazz 180nm with a process modification to increase the radiation tolerance. While many of MAPS developments focus on low radiation environment, we have taken the development to high radiation environment like pp-experiments at High Luminosity LHC. DMAPS are a cost effective and lightweight alternative to state-of-the-art hybrid detectors if they can fulfil the given requirements for radiation hardness, signal response time and hit rate capability. The MALTA and Mini-MALTA sensors have shown excellent detection efficiency after irradiation to the life time dose expected at the outer layers of the ATLAS pixel tracker Upgrade. Our development focuses on providing large pixel matrixes with excellent time resolution (<2ns) and tracking. This publication will discuss characterisation results of the DMAPS devices with special focus on the new MALTA2 sensor and will show the path of future developments

Evolutionary adaptation highlights the interconnection of fatty acids, sunlight, inflammation and epithelial adhesion.

Gene variants that influence human biology today reflect thousands of years of evolution. Genetic effects on infant health are a major point of selective pressure, given that childhood survival is essential to evolutionary success. Knowledge of this evolutionary history can have implications for paediatric research.ConclusionAn episode of human adaptation to the extremely low ultraviolet radiation environment of the Arctic 20,000 years ago implicates the Ectodysplasin A Receptor (EDAR) and the Fatty Acid Desaturases (FADS) in human lactation and epithelial inflammation.

Mimic microgravity effect on muscle transcriptome under ionizing radiation

Spaceflight imposes the risk of skeletal muscle atrophy for astronauts. Two main factors of a spaceflight that results in deleterious effects are microgravity and cosmic rays in outer space. To study spaceflight-induced muscle atrophy with ground-based models, we performed two models of microgravity, tail suspension and denervation, in a low dose radiation environment and studied transcriptional changes in rat soleus muscle using microarrays. Soleus muscle from rats in the denervation group had greater expression changes compared to that found in rats from the tail suspension group. However, there was a very similar pattern of expression of differentially expressed genes (DEGs) in both models. In total, we identified 144 differentially expressed genes common in both models. Our study yielded two main findings. First, a large number of genes involved in energy metabolism were transcriptionally suppressed including those involved in fatty acid transport and beta-oxidation, and oxidative phosphorylation. Second, slow-twitch contractile protein encoding genes were down-regulated while there was an up-regulation in the fast-twitch type transcription. These results were consistent with other spaceflight studies on the effects on muscle cells, hence showed the potential of our ground-based models in studying spaceflight effects. The genes that might be involved in spaceflight effects will serve as candidate genes for future studies in understanding the mechanism of spaceflight-induced muscle atrophy and result in the development of effective countermeasures.

Exploring the possibility of Peter Pan discs across stellar mass

ABSTRACT Recently, several accreting M dwarf stars have been discovered with ages far exceeding the typical protoplanetary disc lifetime. These ‘Peter Pan discs’ can be explained as primordial discs that evolve in a low-radiation environment. The persistently low masses of the host stars raise the question whether primordial discs can survive up to these ages around stars of higher mass. In this work we explore the way in which different mass loss processes in protoplanetary discs limit their maximum lifetimes, and how this depends on host star mass. We find that stars with masses ≲0.6 M⊙ can retain primordial discs for ∼50 Myr. At stellar masses ≳0.8 M⊙, the maximum disc lifetime decreases strongly to below 50 Myr due to relatively more efficient accretion and photoevaporation by the host star. Lifetimes up to 15 Myr are still possible for all host star masses up to ∼2 M⊙. For host star masses between 0.6 and 0.8 M⊙, accretion ceases and an inner gap forms before 50 Myr in our models. Observations suggest that such a configuration is rapidly dispersed. We conclude that Peter Pan discs can only occur around M dwarf stars.

Sampling Plume Deposits on Enceladus’ Surface to Explore Ocean Materials and Search for Traces of Life or Biosignatures

Abstract Enceladus is unique as an astrobiology target in that it hosts an active plume sourced directly from its habitable subsurface ocean. Ice particles from the plume contain geochemical constituents that are diagnostic of the ocean conditions, and may hold traces of life and/or biosignatures, if they exist. Up to 93% of the plume particles fall back onto the surface of Enceladus. The low radiation environment and present-day activity are favorable to the preservation of any complex organics and putative biosignatures contained within these particles. Laboratory experiments and modeling suggest that plume deposits would likely be weakly consolidated and relatively easy to sample. Sampling systems like a dual rasp, under development to achieve technology readiness level (TRL) 5 in 2021, would enable a landed mission on Enceladus’ surface to acquire large amounts of surface materials, a requirement for analysis of trace constituents. A landed mission on Enceladus could greatly enhance our understanding of the chemical makeup of plume particles and the subsurface ocean, and seek traces of life and/or biosignatures.

Low Radiation Environment Switches the Overgrowth-Induced Cell Apoptosis Toward Autophagy

Low radiation doses can affect and modulate cell responses to various stress stimuli, resulting in perturbations leading to resistance or sensitivity to damage. To explore possible mechanisms taking place at an environmental radiation exposure, we set-up twin biological models, one growing in a low radiation environment (LRE) laboratory at the Gran Sasso National Laboratory, and one growing in a reference radiation environment (RRE) laboratory at the Italian National Health Institute (Istituto Superiore di Sanità, ISS). Studies were performed on pKZ1 A11 mouse hybridoma cells, which are derived from the pKZ1 transgenic mouse model used to study the effects of low dose radiation, and focused on the analysis of cellular/molecular end-points, such as proliferation and expression of key proteins involved in stress response, apoptosis, and autophagy. Cells cultured up to 4 weeks in LRE showed no significant differences in proliferation rate compared to cells cultured in RRE. However, caspase-3 activation and PARP1 cleavage were observed in cells entering to an overgrowth state in RRE, indicating a triggering of apoptosis due to growth-stress conditions. Notably, in LRE conditions, cells responded to growth stress by switching toward autophagy. Interestingly, autophagic signaling induced by overgrowth in LRE correlated with activation of p53. Finally, the gamma component of environmental radiation did not significantly influence these biological responses since cells grown in LRE either in incubators with or without an iron shield did not modify their responses. Overall, in vitro data presented here suggest the hypothesis that environmental radiation contributes to the development and maintenance of balance and defense response in organisms.

The Response of Living Organisms to Low Radiation Environment and Its Implications in Radiation Protection

Life has evolved on Earth for about 4 billion years in the presence of the natural background of ionizing radiation. It is extremely likely that it contributed, and still contributes, to shaping present form of life. Today the natural background radiation is extremely small (few mSv/y), however it may be significant enough for living organisms to respond to it, perhaps keeping memory of this exposure. A better understanding of this response is relevant not only for improving our knowledge on life evolution, but also for assessing the robustness of the present radiation protection system at low doses, such as those typically encountered in everyday life. Given the large uncertainties in epidemiological data below 100 mSv, quantitative evaluation of these health risk is currently obtained with the aid of radiobiological models. These predict a health detriment, caused by radiation-induced genetic mutations, linearly related to the dose. However a number of studies challenged this paradigm by demonstrating the occurrence of non-linear responses at low doses, and of radioinduced epigenetic effects, i.e., heritable changes in genes expression not related to changes in DNA sequence. This review is focused on the role that epigenetic mechanisms, besides the genetic ones, can have in the responses to low dose and protracted exposures, particularly to natural background radiation. Many lines of evidence show that epigenetic modifications are involved in non-linear responses relevant to low doses, such as non-targeted effects and adaptive response, and that genetic and epigenetic effects share, in part, a common origin: the reactive oxygen species generated by ionizing radiation. Cell response to low doses of ionizing radiation appears more complex than that assumed for radiation protection purposes and that it is not always detrimental. Experiments conducted in underground laboratories with very low background radiation have even suggested positive effects of this background. Studying the changes occurring in various living organisms at reduced radiation background, besides giving information on the life evolution, have opened a new avenue to answer whether low doses are detrimental or beneficial, and to understand the relevance of radiobiological results to radiation protection.

Calorimetry in Particle Physics, and the CMS High-Granularity Calorimeter

An overview of electromagnetic and hadronic shower development is presented, including how they lead to the design of modern calorimeters for energy measurements of high-energy particles. The differences between sampling and homogeneous calorimeters are explored, with the pros and cons of each being presented. Some real-world examples are given, focusing on state-of-the-art detectors designed and operating at the Large Hadron Collider. Methods to increase the information content from future calorimeters are given, and the challenges that these new calorimeters pose to detector physicists and engineers are discussed. Advances in large-area highly-segmented detectors are providing possibilities for high-granu-larity calorimetry. The CMS HGCAL, being designed to replace the existing CMS endcap calorimeters for the HL-LHC era, is one example. It is a sampling calorimeter, featuring unprecedented transverse and longitudinal readout segmentation for both electromagnetic (CE-E) and hadronic (CE-H) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The CE-E and a large fraction of CE-H will use hexagonal silicon sensors as active detector material. The lower-radiation environment will be instrumented with scintillator tiles with on-tile SiPM readout. These concepts borrow heavily from designs produced by the CALICE collaboration but the design of such a detector at a hadron collider is considerably more challenging than at the linear colliders.

Design of Geiger Muller detector system for searching lost γ-ray source

Abstract If a radiation source is lost, it will do harm to human being, especially for the searching person. In order to find the lost radiation source easily, a detector system, including 3 detectors, was designed to search the lost c-ray radiation source autonomously in any environment. First, based on GEANT4 simulation, the radiation dose rates in 3 Geiger Muller (GM) counters were simulated at the different source-detector distances, distances between detectors and angles. Various analyses were performed by experimentally and verified the simulated detector designed system. A Mono-energetic 137Cs c-ray source with energy 662 keV and activity of 1.11 GBq was used for the observation. The simulated results were compared with the experimental dose rate values and obtained good agreements for various cases. Only based on the dose rates in three detectors, the radiation source was searched in a different location at a specific source activity and angle. The corresponding angles of deviation and detection limit were calculated for sensitivity and ability of detector designed system. The proposed detector designed system can be used to navigate radiation sources in the low level and high radiation environments.

R&D for the CLIC vertex and tracking detectors

Significant progress has been made to develop silicon pixel technologies for use in the vertex and tracker regions of the proposed Compact Linear Collider (CLIC) detector design. The electron-positron collisions generated by this linear accelerator provide a clean, low-radiation environment for the inner detectors. However, physics-driven performance targets, the CLIC beam structure, and occupancies from beam-induced backgrounds place challenging requirements on detector technologies for this region. A pixel pitch down to 25×25 μm2, material budget ⩽ 0.2–2%X0 per layer, average power dissipation of down to 50 mW cm−2, position resolution of 3–7μm, and timing resolution as low as 5 ns are called for in the vertex and tracking detectors. To this aim, a comprehensive R&D programme is ongoing to design and test silicon pixel detectors to fulfil these specifications, including both monolithic and hybrid devices. These studies involve Allpix2 Monte Carlo and TCAD simulations, advanced 65 nm ASIC and sensor design, laboratory testing, and beam tests of individual modules to determine the required performance parameters. The characterisation and simulation modelling of these devices has also lead to the development of a set of tools and software within the CLIC detector and physics (CLICdp) collaboration. This publication will present recent results from the technologies being developed and tested in view of the CLIC vertex and tracking detector requirements, such as various monolithic CMOS sensors, and fine pitch hybrid assemblies with planar sensors.

The SNOLAB underground laboratory

The SNOLAB laboratory is 2 kilometers undeground in Sudbury, Ontario, Canada. The depth of this location results in a reduction of cosmic-radiation induced muons to the negligible level of one muon per square meter per day. The laboratory maintains cleanliness standards to control the radioactivity from dust falling out of the air, from human activity, and from research equipment brought into the lab. The resulting low-radiation environment enables a variety of research, and SNOLAB is focused on rare-event searches such as dark matter searches and nuclear decay studies. In order to enable and advance these research topics, SNOLAB is conducting research and development into cleanliness, low-level assay, radioactive gasses and cryogenics. SNOLAB collaborates, and competes, with other underground laboratories on these research and development topics, as well as operational topics, to support the global research community.

A detector system for searching lost γ-ray source

The aim of this work is to develop a Geiger-Muller (GM) detector system for robot to look for a radioactive source in case of a nuclear emergency or in a high radiation environment. In order to find a radiation source easily, a detector system, including 3 detectors, was designed to search γ-ray radiation sources autonomously. First, based on GEANT4 simulation, radiation dose rates in 3 Geiger-Muller (GM) counters were simulated at different source-detector distances, distances between detectors and angles. Various sensitivity analyses were performed experimentally to verify the simulated designed detector system. A mono-energetic C137s γ-ray source with energy 662 keV and activity of 1.11 GBq was used for the observation. The simulated results were compared with the experimental dose rate values and good agreements were obtained for various cases. Only based on the dose rates in three detectors, the radiation source with a specific source activity and angle was localized in the different location. A method was adopted with the measured dose rates and differences of distances to find the actual location of the lost γ-ray source. The corresponding angles of deviation and detection limits were calculated to determine the sensitivity and abilities of our designed detector system. The proposed system can be used to locate radiation sources in low and high radiation environments.