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This paper focuses on the application of Compton cameras in nuclear decommissioning, aiming to develop efficient and affordable radiological characterization methods. Compton cameras offer advantages over traditional Anger cameras, including increased sensitivity and a larger field of view. We showcase the use of monolithic scintillation detectors in a Compton camera setup to compute two‐dimensional reconstructions of the source location of incident gamma rays. The presence of multiple scattering effects in the large, spatially non‐resolved detectors can lead to spatial artifacts in the reconstructed source activity. To address this, the paper proposes an extended forward model that accounts for double scattering interactions within a single detector element. Experimental and simulation results demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper studied the radiation shielding properties of new lead‐free telluride glass with different BaF2 content. The 65TeO2–15Bi2O3–(20 − x)ZnO–xBaF2 glass systems (where x = 1, 3, 5, 7, 9 mol%) were tested through the X‐ray diffraction, ultraviolet–visible spectrophotometer, and differential scanning calorimetry. The glass system exhibited good thermal stability and a uniform surface without surface crystallization. The linear attenuation coefficient of the TBZBF series glass was tested using five different gamma radiation sources (241Am, 133Ba, 57Co, 137Cs, and 60Co). They were calculated to the mass attenuation coefficient, half‐value layer, mean free path, and effective atomic number through numerical simulations with XCOM software. The maximum mass attenuation coefficient for TBZBF‐9 was calculated to be 5.3577 cm2/g. Comparisons were made between this glass system and other tellurite and leaded glasses reported in the literature. The glass system exhibited superior radiation shielding capability compared to leaded tellurite glass under the same testing conditions. The gamma radiation shielding capacity increased with BaF2 content in the glass system. These results show that TBZBF‐9 exhibited the best gamma radiation shielding effectiveness while maintaining glass transparency. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of a powerful gamma ray burst (GRB) that occurred on 9 October 2022, on the Earth's environment using a very low frequency receiver (VLF) to probe the lower ionospheric region (the D region). In addition to the VLF data analysis, we employ numerical simulation through the Long Wavelength Propagation Capability code (LWPC) to derive the increase in the D− region electron density. Our results revealed discernible perturbations in amplitude and phase across all transmitter paths (NAA, DHO, ICV, and NSC) to the Algiers receiver persisting for 40 min. At the maximum of the signal perturbation, the LWPC simulation results showed a decrease in the mean new reference height h′ from 74 to 65.71 km, along with an increase in the sharpness factor β from 0.3 to 0.4875 km−1. Under these new conditions, the electron density increased from its ambient value (216.10 cm−3) to 33.7 103 cm−3. Plain Language Summary: Gamma rays are good indicator of the activity that is taking place in the universe. As they travel freely in the space, these phenomena can cause strong disturbances in the Earth's environment. In 9 October 2022, a powerful burst of gamma rays was recorded by many satellites in the near Earth space. This radiation burst was responsible of the ionospheric disturbance resulting in a modification of the propagation conditions of the radio waves. The intensity of the disturbance as well as its spatial extent can be determined through the analysis of different radio signals propagation and the level of the ionization increases. These results give us insight about the coupling between the gamma rays and the ionized layer of the Earth atmosphere. Key Points: The impact of GRB221009A on the VLF transmitter signal dynamics captured by measurements from the Algiers VLF receiver is reportedA numerical simulation showcases the changes in electron density dynamics in the ionosphere's D‐region during the GRB221009A phenomenonThe model accurately replicates the variations in VLF signal parameters (amplitude and phase) recorded during the GRB221009A event [ABSTRACT FROM AUTHOR]

Development of shielding materials for 222Rn and γ radiation has crucial implications for ensuring the safety of individuals. This paper reports the synthesis of modified graphene nanosheets (MGNPs) via the reaction of KH560 with graphene nanosheets (GNPs), while melt blending and hot‐press molding technique were used to fabricate a multifunctional polymer composite shielding material, MGNP/WB/PMMA (polymethyl methacrylate). Successful synthesis of MGNP was confirmed by Fourier transform infrared spectroscopy, and scanning electron microscope (SEM) analysis was utilized to assess the distribution of functional fillers within the cross‐section of the polymer composite. Additionally, thermogravimetric analysis (TGA) demonstrated that MGNP and WB particles enhance the thermal stability of the polymer composite materials. Compared to pure PMMA, 98.7% decrease in the radon diffusion coefficient was observed for MGNP1.5 wt%/PMMA composite material. In addition to enhance the radon‐blocking characteristics of the polymer composites, inclusion of WB particles also boosts their shielding capacity against gamma radiation. The 222Rn diffusion coefficient of MGNP1.5 wt%/WB25wt%/PMMA polymer composite material decreased by 99.6% and at energies of 60 KeV, 80 KeV, 122 KeV, 365 KeV, the mass attenuation coefficient (MAC) for the composite material increased by 0.79, 1.97, 0.57, and 0.05 cm2/g, respectively, compared to pure PMMA. Highlights: The PMMA composite materials doped with graphene nanosheets demonstrate outstanding resistance to 222Rn.Graphene nanosheets modified by KH560 exhibit favorable dispersion within PMMA.WB can further enhance the radon resistance of MGNP/WB/PMMA composite materials.The polymer composites exhibit excellent 222Rn and gamma ray shielding properties. [ABSTRACT FROM AUTHOR]

Gamma‐ray glows are observational evidence of relativistic electron acceleration due to the electric field in thunderclouds. However, it is yet to be understood whether such relativistic electrons contribute to the initiation of lightning discharges. To tackle this question, we started the citizen science "Thundercloud Project," where we map radiation measurements of glows from winter thunderclouds along Japan's sea coast area. We developed and deployed 58 compact gamma‐ray monitors at the end of 2021. On 30 December 2021, five monitors simultaneously detected a glow with its radiation distribution horizontally extending for 2 km. The glow terminated coinciding with a lightning flash at 04:08:34 JST, which was recorded by the two radio‐band lightning mapping systems, FALMA and DALMA. The initial discharges during the preliminary breakdown started above the glow, that is, in vicinity of the electron acceleration site. This result provides one example of possible connections between electron acceleration and lightning initiation. Plain Language Summary: Thunderstorms are natural particle accelerators. The strong electric field inside thunderclouds accelerates relativistic electrons, which emit gamma rays via interaction with the atmosphere. High‐energy photons generated in this process have been observed as radiation enhancements called gamma‐ray glows. Winter thunderclouds along the sea of Japan are an ideal target for monitoring glows because their altitudes are usually sufficiently low for the generated gamma‐ray photons to reach the ground. We started a new citizen science "Thundercloud Project" in this area, where we distributed radiation detectors to citizen supporters to observe glows and to reveal their relationship with the aerological condition and lightning discharges. On 30 December 2021, five of those sensors detected a glow from a single thundercloud. Two of them recorded a sudden termination of the glow coinciding with a lightning flash, which was monitored by our two radio mapping systems of FALMA and DALMA. The initial discharges of the flash started at a location about 1.6 km above the glow region with an unusually fast downward progression. This paper is the first report of our citizen science project. We discuss the possibility that accelerated electrons contribute to the initiation of lightning discharges. Key Points: We started the citizen science "Thundercloud Project," a multi‐point observation campaign of gamma‐ray glows from thunderstormsOn 30 December 2021, five radiation monitors detected a 2‐km‐long size gamma‐ray glow, which suddenly terminated with a lightning flashTwo radio mapping systems of lightning identified the initiation of the discharges, which started at a location above the glow region [ABSTRACT FROM AUTHOR]

Radiochromic films composed of polymer matrices and organic dyes are widely used for routine dosimetry purposes in operation of various radiation facilities—gamma and X‐ray‐irradiation, electron accelerators, and so on. However, the sensitivity of these films rapidly decreases at doses exceeding 30–50 kGy due to a saturation of their optical response, making them unsuitable for accurate dosimetry in radiation processing of polymers and composites where doses up to 200 kGy are typically employed. To overcome this limitation, the use of inorganic substances as the coloring agents of polymer‐based radiochromic films was proposed in this paper, specifically, heteropolyacidacid H3PW12O40 (tungstophosphoric acid) in the matrix of poly(vinyl alcohol) (PVA). Nanocomposite PVA/H3PW12O40 films were prepared by solution casting and their optical responses toward 60Co gamma radiation and beams of 6 MeV electrons for a dose range of 10–200 kGy were investigated. It was established that upon exposure to gamma rays and electron beams, the films turn blue and a broad absorption band at 750 nm appears in their spectra. Importantly, the radiation‐induced optical absorption increases in a linear fashion up to the dose of 150 kGy and only slightly deviates from linearity at 200 kGy. Moreover, it was found that the PVA/H3PW12O40 films have a long shelf life, are dose‐rate independent within a wide range, and color‐stable after irradiation. All these features make the nanocomposite PVA/H3PW12O40 films promising for use as routine dosimeters and dose labels in a much wider range of high doses as compared to radiochromic films based on organic dyes. [ABSTRACT FROM AUTHOR]

Gamma‐ray glows associated with thunderclouds have been observed since the 1980s, however it remains unclear how, and at which thunderstorms gamma‐ray glows are generated in dense atmospheres. In this study, we report the first Compton camera imaging of a gamma‐ray glow from a winter thundercloud. On 14 January 2022, using two identical Bi4Ge3O12 scintillators in energy range of 0.05–5 MeV, we detected two gamma‐ray glows lasting ∼4 min in a mountain area 25 km from the Japan Sea and 410 m above sea level. The same events were also observed by the Compton camera, where the first glow we observed suggested statistically significant (4.0 and 5.9 σ level) signals of two enhanced concentrations in gamma‐ray photon images in a range of 0.15–1.5 MeV. These concentrations were most clearly observed in a time window of Δt = 50 s around the peak intensity of the gamma‐ray glow. Plain Language Summary: Observations of gamma rays from thunderclouds started in 1980s, leading to intensive studies in the last 40 years. However, the question of where and how such gamma rays are produced in thunderclouds remains unclear, as no gamma‐ray images have been obtained to date. This paper presents the first successful gamma‐ray imaging of a thundercloud in a winter of Japan. In particular, we installed a Compton camera of 10 × 10 cm2 in size, that is a compact but high sensitivity camera originally developed in the field of astronomy to observe gamma‐ray sky. At the peak of a gamma‐ray emission, we detected significant enhancements in the gamma‐ray photon image. The image provides the source position and beam pattern of the gamma‐ray emission, thus may be connected to highly electrified region and electron acceleration inside thunderclouds. Key Points: Gamma‐ray glows were observed in a mountainous area 25 km from the Japan Sea and 410 m above sea level on 14 January 2022, during winterOne of the glows suggested two enhanced concentrations in gamma‐ray images, which was taken for the first time with a Compton cameraThe first successful gamma‐ray imaging provides a new means of investigating radiation beam pattern of gamma‐ray glows in thunderclouds [ABSTRACT FROM AUTHOR]

In this paper, we present XStorm, a gamma ray spectrometer developed to detect gamma ray glows and terrestrial gamma ray flashes (TGFs) in close proximity. Measurements are mostly planned to take place on balloon campaigns but also on the ground using bigger detectors. The main aim in developing XStorm is to perform new in situ and close proximity measurements of those events to improve the understanding of the physical processes involved. For that, we ensured XStorm reached performances adapted to glow and TGF detections. It detects photons with energy between ∼400 keV and ∼20 MeV. Detected particles are timetagged with a 600 ns precision with respect to UTC. Using two types of scintillator, Bismuth Germanium Oxide and EJ‐276 plastic associated with SiPMs, the instrument is able to discriminate three types of particles involved in those events: photons, neutrons, and electrons. The behavior of the detector under high particle fluxes has been quantified through ground testing using a pulse generator. A triggered detection system has been developed, with different thresholds depending on the target of study. First measurements have been carried out with test flights in fair weather conditions and are presented here. Estimations of the configurations in which a gamma ray glow can be detected by XStorm and of the number of TGFs that could be detected in specific campaigns are also addressed. Plain Language Summary: Terrestrial gamma ray flashes (TGFs) are bursts of high‐energy photons generated in thunderstorms in less than 100 μs, whereas gamma ray glows are enhancement of the high‐energy radiation background in thunderstorms, lasting from seconds to minutes. We present a gamma ray spectrometer, XStorm, designed to detect terrestrial gamma ray flashes (TGFs) and gamma ray glows in close proximity. It is composed of two scintillators of different kinds to allow the detection of TGF and gamma ray glow photons (energies between 400 keV and 20 MeV, with a time precision of 600 ns UTC). XStorm measurements are mainly planned to take place on board balloons, but can also be performed at ground level using bigger scintillators. XStorm is able to discriminate photons, electrons and neutrons, that are particle types involved in TGFs. We show the first measurements in fair weather and configurations allowing the detection of gamma ray glows. We estimate that XStorm will detect ∼0.5 TGF on average over one balloon flight of Stratéole‐2 campaign presented in the scientific objectives. Key Points: Development of a gamma ray spectrometer to detect gamma ray glows and terrestrial gamma ray flashes (TGFs), able to discriminate photons, electrons, and neutronsResults from balloon test flights performed in fair weather conditions, detecting the background radiation level as a function of altitudeEstimation of the detectability of gamma ray glows and TGFs as a function of altitude with XStorm [ABSTRACT FROM AUTHOR]

The role of free passage distance (FPD: the distance between the avalanche region and surface detectors) in influencing the relative numbers of energetic electrons and gamma rays in Thunderstorm Ground Enhancements (TGEs) is reconsidered and focuses on the contrast between long (>100 m) versus short (<100 m) FPDs, respectively. Estimates of FPD are based on information from published balloon soundings of the electric field, from published profiles of radar reflectivity in TGEs, and from analyses of Japan winter storms. All these data sources support typical values of FPD >100 m. Neither the shortcomings of present particle detectors in distinguishing electrons from gamma rays, nor the dominance of gamma rays over electrons, are sufficient evidence to deny the robust presence of Compton electrons at FDP values greater than 100 m that have also been shown in earlier simulations as well as the present Comment. Problems with having sustained electric fields of breakeven magnitude within 100 m of the Earth's surface (in relatively rare TGEs) are identified. The resolution of these problems, and the prominent nocturnal presence of these rare events, may possibly be explained by the descent of a strong field region in a collapsing storm, and by a low cloud base that intercepts and immobilizes fast corona ions, thereby preserving the intense electric field. Plain Language Summary: Thunderstorms are capable of accelerating electrons to large energy by a process called electron runaway. This process is often confined to the cold portion of the thunderstorm at higher altitude where ice particles are available to separate electric charge to produce the necessary electric field, and where so‐called avalanche electrons are present. As a result, the high field region in the storm is removed from the ground where measurements of energetic radiation are usually undertaken to diagnose electron acceleration aloft. Gamma rays are produced when the energetic electrons are decelerated in coming in contact with heavy nuclei in a process called bremsstrahlung. Electrons unaided by strong field have short range in the atmosphere: tens of meters and less, whereas gamma rays have larger range (hundreds of meters). Accordingly, energetic electrons cannot be expected far (>200 m) below the high field region. One possible scenario for reducing this gap is the descent of strong field to near cloud base in a collapsing storm and the protection of field dissipation by the capture of small corona ions by cloud droplets. Evidence from several research areas in the literature is used to support the arguments in this paper. Key Points: Energetic Compton electrons are an inevitable accompaniment of the gamma ray flux of Thunderstorm Ground Enhancements (TGEs) but in numbers too small to be readily distinguished from the gamma rays with typical detectorsThe observations of avalanche electrons in TGEs is surprising, given the small free passage distance (FPD) (<50–100 m) requiredOne suggested scenario for creating small FPD is the lowering of negative charge in storm collapse and the capture of fast corona ions by cloud droplets [ABSTRACT FROM AUTHOR]

Purpose: This paper focused on the design and optimization of ridge filter–based intensity‐modulated proton therapy (IMPT), and its potential applications for FLASH. Differing from the standard pencil beam scanning (PBS) mode, no energy/layer switching is required and total treatment time can be shortened. Methods: Unique dose‐influence matrices were generated as a proton beam traverses through slabs of different thicknesses (i.e., modulation by different layers). To establish the references for comparison, conventional IMPT plans (single field) were created using a large‐scale nonlinear solver. The spot weights from the reference IMPT plans were used as inputs for optimizing the design of ridge filters. Two designs were evaluated: model A (static) and model B (dynamic). The ridge filter designs were first verified (by GEANT4 simulation) in a water phantom and then in an H&N case. A direct comparison was made between the GEANT4 simulation results of two models and their respective references, with regard to plan quality, dose‐averaged dose rate, and total treatment time. Results: In both the water phantom and the H&N case, two models are able to modulate dose distributions with high conformity, showing no significant difference relative to the reference plans. Dose rate–volume histograms suggest that in order to achieve a dose rate of 40 Gy/s over 90% PTV, the beam intensity needs to be 2.5 × 1011 protons/s for both models. For a fraction dose of 10 Gy, the total treatment time (including both irradiation time and dead time) can be shortened by a factor of 4.9 (model A) and 6.5 (model B), relative to the reference plans. Conclusion: Two proposed designs (both static and dynamic) can be used for PBS–IMPT requiring no layer switching. They are promising candidates for FLASH‐IMPT capable of reducing treatment time and achieving high dose rates while maintaining dose conformity simultaneously. [ABSTRACT FROM AUTHOR]

In this paper, some electrical properties of (polyethylene glycol [PEG]) which is dissolved in distal water after and before irradiation by (γ‐ray) (60Co) with dose of (8000 rad) and average radiation (320 rad min−1) for (25 min) have been studied. The study of electrical properties has included two lines; first the measurement of capacity, electrical conductivity of (PEG), and second the calculation of dielectric constant and molar conductivity. It has been founded that the capacitance, electrical dielectric constants, and conductivity are increased after irradiation and increased with increasing of concentration and also after irradiation but the molar conductivity is decreased with increasing of the concentration. The temperature is constant approximate to room temperature (25°C) in all calculated measurements. The cross linking of polymer chains is the main cause of the change in values of properties that may be resulted and then increased in the average viscosity molecular weight for material (PEG) used in research. [ABSTRACT FROM AUTHOR]

In this paper, three commercial polymers (polytetrafluoroethylene [PTFE], polyetheretherketone [PEEK], and polyimide [PI]) were irradiated by gamma rays in the ambient air. The changes in microstructure, mechanical, and tribological properties of these three polymers after irradiation were investigated comparatively. The results display that both the surface and internal structures of PTFE are degraded due to the irradiation chemical reaction, and the molecular chain scission at the surface is more severe than that at its internal as a result of the involvement of oxygen. The oxidative degradation also plays a dominant role in the PEEK surface, but the molecular chain crosslink is dominant in the PEEK internal. The top layer of PI also shows the characteristics of oxidative irradiation degradation, but its internal exhibits excellent irradiation resistance and no structure change occurs even at irradiation doses up to 20 MGy. The microhardness and scratch resistance of irradiated surfaces for all three polymers decrease but only the scratching damage mode of PTFE changes after irradiation. Friction experiments show that the friction coefficients of PTFE increase but that of PEEK decrease after irradiation. The wear rates on the irradiated surfaces of all three polymers increase compared with the unirradiated samples. Moreover, there is a depth gradient effect on the wear properties of both irradiated PTFE and PEEK polymers. The changes in wear rates of irradiated surfaces are consistent with the structural variations of all three polymers. [ABSTRACT FROM AUTHOR]

Summary: This paper overcomes two key issues within radiation monitoring networks. Secure and accurate transmission of detected gamma radiation in remote areas is the first challenge. The second one is related to the robustness of transmitted signal under different fading scenarios. These issues are handled during signal transmission over worldwide interoperability for microwave access (WiMax) networks. The signals are experimentally captured using a 137Cs point source, a NaI (TI) detector, and an analog‐to‐digital converter with 16 MS/s. For the first issue, several algorithms are implemented for secure and efficient transmission of gamma‐based signals. These algorithms include encoding of captured signal, decoding, interleaving, and frequency transformation of modulated signal. Encoding and decoding of target signals are conducted using the Reed Solomon technique and convolutional encoding with a Viterbi decoder. A superior algorithm for channel interleaver using the combinational interleaving method is introduced. Fast lifting transform (FLT) is applied for transforming modulated signal into frequency domain. The results declare that CC = 1/2 with BPSK‐1/2 coding rate introduces a better BER of 0.00068. A higher SNR of 1.5 dB is accomplished by the combinational interleaving algorithm. For the second issue, several models are suggested for overcoming channel degradations under gamma, exponential, Poisson, and geometric fading. Closed‐form expressions that describe outage probability, bit error rate (BER), and symbol error rate (SER) are suggested. Geometric and gamma fading achieve respectively a lower BER of 0.18 and 0.48. These channels demonstrate similar channel performances at 3.6 dB. The proposed models are validated through comparison with published work. Finally, the proposed algorithms enable higher data rate transmission of detected 137Cs signals under higher robustness using WiMax networks. [ABSTRACT FROM AUTHOR]

Background: Neutron beams utilized for performing BNCT are composed of a mixture of neutrons and gamma rays. Although much of the dose delivered to the cancer cells comes from the high LET particles produced by the boron neutron capture reaction, the dose delivered to the healthy tissues from unwanted gamma rays cannot be ignored. With the increase in the number of accelerators for BNCT, a detector system that is capable of measuring gamma ray dose in a mixed neutron/gamma irradiation field is crucial. Currently, BeO TLDs encased in quartz glass are used to measure gamma ray dose in a BNCT irradiation field. However, this type of TLD is no longer commercially available. A replacement dosimetry system is required to perform the recommended ongoing quality assurance of gamma ray measurement for a clinical BNCT system. Purpose: The purpose of this study is to evaluate the characteristics of a BeO OSLD detector system under a mixed neutron and gamma ray irradiation field and to assess the suitability of the system for routine quality assurance measurements of an accelerator‐based BNCT facility. Methods: The myOSLD system by RadPro International GmbH was evaluated using the accelerator‐based neutron source designed for clinical BNCT (NeuCure BNCT system). The readout constancy, linearity, dose rate effect, and fading effect of the OSLD were evaluated. Free‐in‐air and water phantom measurements were performed and compared with the TLD results and Monte Carlo simulation results. The PHITS Monte Carlo code was used for this study. Results: The readout constancy was found to be stable over a month‐long period and similar to the TLD results. The OSLD readout signal was found to be linear, with a high coefficient of determination (R2 ≥ 0.999) up to a proton charge of 3.6 C. There was no significant signal fading or dose rate dependency. The central axis depth dose and off‐axis dose profile measurements agreed with both the TLD and Monte Carlo simulation results, within one standard deviation. Conclusion: The myOSLD system was characterized using an accelerator system designed for clinical BNCT. The experimental measurements confirmed the OSLD achieved similar, if not superior to, the currently utilized dosimetry system for routine QA of an accelerator‐based BNCT system. The OSLD system would be a suitable replacement for the current TLD system for performing routine QA of gamma ray dose measurement in a BNCT irradiation field. [ABSTRACT FROM AUTHOR]

Terrestrial gamma ray flashes (TGFs) are short bursts of gamma rays occurring during thunderstorms. They are believed to be produced by relativistic runaway electron avalanches (RREAs). It is usually admitted that the number of high‐energy electrons produced in the brightest TGFs remains mostly confined within a range from 1017 to 1019. To understand the constraints in the development of RREAs, we perform self‐consistent simulations using a newly developed model with a finite acceleration region and various injection rates. We find that RREAs should naturally self‐quench for a fixed total number of runaway electrons, and hence a fixed number of bremsstrahlung photons. From the idea that TGF sources quench themselves, we derive a simple equation controlling the total number of runaway electrons. In this framework, the existence of a saturation in the electron density discovered in a previous work places a lower limit on TGF durations. Plain Language Summary: Terrestrial gamma ray flashes (TGFs) are short bursts of high‐energy photons occurring during thunderstorms. They are believed to be produced by energetic electrons accelerating due to the intense electric field, forming a Relativistic Runaway Electron Avalanche (RREA). Discovered fairly recently, many of the TGF features remain unexplained. In this article, we aim to understand the constraint on the number of high‐energy electrons produced during TGFs, that always remains confined between 1017 and 1019. Using a newly developed simulation model, we find that RREAs naturally quench themselves when the number of high‐energy electrons and photons reach the range previously mentioned. Based on a limited number of fundamental processes, we were able to derive a simple equation controlling the total number of runaway electrons and deduce a lower limit for TGF durations. Key Points: There is a maximum low‐energy electron density reachable in Terrestrial Gamma Ray Flashe (TGF) sources when relativistic runaway electron avalanches (RREAs) reach saturation: nesat∼1015 ${n}_{e}^{\mathit{sat}}\sim 1{0}^{15}$ m−3There exists a minimum TGF timescale equal to the RREA timescale: τmin ∼ 1 μsThe self‐quenching of the TGF sources implies a maximum number of electrons Ne ∼ 1017 [ABSTRACT FROM AUTHOR]

Proton beam radiotherapy is a cancer treatment method that uses proton beams to irradiate cancerous tissue while simultaneously sparing doses to healthy tissue. In order to optimize radiational doses to the tumor and ensure that healthy tissue is spared, many researchers have suggested verifying the treatment delivery through real‐time imaging. One promising method of real‐time imaging is through a Compton camera, which can image prompt gamma rays emitted along the beam's path through the patient. However, the images reconstructed with modern reconstruction algorithms are often noisy and unusable for verifying proton treatment delivery due to limitations with the camera. This paper demonstrates the ability of deep learning for removing false prompt gamma couplings and correcting the improperly ordered gamma interactions within the data for the case of Triples and Doubles‐to‐Triple events. [ABSTRACT FROM AUTHOR]

We investigate sequential processes underlying the initial development of in‐cloud lightning flashes in the form of initial breakdown pulses (IBPs) between 7.4 and 9.0 km altitudes, using a 30–250 MHz VHF interferometer. When resolved, IBPs exhibit typical stepped leader features but are notably extensive (>500 m) and infrequent (∼1 millisecond intervals). Particularly, we observed four distinct phases within an IBP stepping cycle: the emergence of VHF sources forming edge structures at previous streamer zone edges (interpreted as space stem/leader development), the fast propagation of VHF along the edge structure (interpreted as the main leader connecting the space leader), the fast extension of VHF beyond the edge structure (interpreted as fast breakdown), and a decaying corona fan. These measurements illustrate clearly the processes involved in the initial development of in‐cloud lightning flashes, evidence the conducting main leader forming, and provide insights into other processes known to occur simultaneously, such as terrestrial gamma ray flashes. Plain Language Summary: The initial development of a lightning flash inside a cloud has long been a mystery. This study utilizes state‐of‐the‐art lightning imaging techniques with a 30–250 MHz VHF interferometer, providing clear images of the processes involved in the initial development of in‐cloud lightning flashes. New radio features suggest distinct development phases, including what we interpret as space stems, space leaders, connection between the main leader and the space leader, fast breakdown, and corona fan development within an initial breakdown pulse stepping cycle. This provides evidence of the conducting main leader in the initial breakdown stage. These observations showcase the intricate streamer discharge phenomena during initial lightning development, and shed light on other processes known to occur simultaneously, including Terrestrial Gamma ray Flashes. Key Points: We observed four distinct VHF processes in the development of 300–1,000 m long initial breakdown pulses (IBPs) in in‐cloud lightning flashesThese four processes appear to map to the known processes in a conventional stepped leader, including space stem and space leader formationDuring an initial breakdown step, fast extension over several hundred meters indicates that fast breakdown may be an essential part of in‐cloud flash [ABSTRACT FROM AUTHOR]

Thermal treatments, with and without co‐irradiation with gamma rays, were given to safety‐related cables insulated with silicone rubber for nuclear power plants (NPPs). To examine the effects of the above treatments on the insulation properties of the cables, DC voltages were applied to them and the induced changes in leakage current were measured by the current integration method. As a result, it has become clear that the leakage current is the largest in the pristine untreated cable. In addition, almost no leakage current flows in the cables heated at 200°C or 290°C for several hundred hours. The leakage current remains small when the co‐irradiation with gamma rays was given at 100°C or 200°C for relatively long periods exceeding 1000 h. The reason for these results seems to be that the silicone rubber insulation becomes hardened as a result of the thermal or concurrent treatment, and the transport of ionic carriers becomes difficult. The above results indicate experimentally that the degradation is not a matter of great concern for the insulation performance of silicone‐rubber‐insulated safety‐related cables in NPPs. [ABSTRACT FROM AUTHOR]

Background: Electron synchrotrons produce x‐ray beams with dose rates orders of magnitude greater than conventional x‐ray tubes and with beam sizes on the order of a few millimeters. These characteristics put severe challenges on current dosimeters to accurately realize absorbed dose or air kerma. Purpose: This work seeks to investigate the suitability of a novel aluminum‐based calorimeter to determine absorbed dose to water with an uncertainty significantly smaller than currently possible with conventional detectors. A lower uncertainty in the determination of absolute dose rate would impact both therapeutic applications of synchrotron‐produced x‐ray beams and research investigations. Methods: A vacuum‐based calorimeter prototype with an aluminum core was built, matching the beam profile of the 140 keV monochromatic x‐ray beam, produced by the Canadian Light Source Biomedical Imaging and Therapy beamline. The choice of material and overall calorimeter design was optimized using FEM thermal modeling software while Monte Carlo radiation transport simulations were used to model the impact of interactions of the radiation beam with the detector components. Results: Corrections for both the thermal conduction and radiation transport effects were of the order of 3% and the simplicity of the geometry, combined with the monochromatic nature of the incident x‐ray beam, meant that the uncertainty in each correction was ≤0.5%. The calorimeter performance was found to be repeatable over multiple irradiations of 1 Gy at the ± 0.6% level, and no systematic dependence on environmental effects or total dose was observed. Conclusion: The combined standard uncertainty in the determination of absorbed dose to aluminum was estimated to be 0.8%, indicating that absorbed dose to water, the ultimate quantity of interest, could be determined with an uncertainty on the order of 1%. This value is an improvement over current techniques used for synchrotron dosimetry and comparable with the state‐of‐the art for conventional kV x‐ray dosimetry. [ABSTRACT FROM AUTHOR]

We provide an updated analysis of the gamma ray signature of a terrestrial gamma ray flash (TGF) detected by the Fermi Gamma ray Burst Monitor first reported by Pu et al. (2020, https://doi.org/10.1029/2020GL089427). A TGF produced 3 ms prior to a negative cloud‐to‐ground return stroke was close to simultaneous with an isolated low‐frequency radio pulse during the leader's propagation, with a polarity indicating downward moving negative charge. In previous observations, this "slow" low‐frequency signal has been strongly correlated with upward‐directed (opposite polarity) TGF events (Pu et al., 2019, https://doi.org/10.1029/2019GL082743; Cummer et al., 2011, https://doi.org/10.1029/2011GL048099), leading the authors to conclude that the Fermi gamma ray observation is actually the result of a reverse positron beam generating upward‐directed gamma rays. We investigate the feasibility of this scenario and determine a lower limit on the luminosity of the downward TGF from the perspective of gamma ray timing uncertainties, TGF Monte Carlo simulations, and meteorological analysis of a model storm cell and its possible charge structure altitudes. We determined that the most likely source altitude of the TGF reverse beam was 7.5 km ± 2.6 km, just below an estimated negative charge center at 8 km. At that altitude, the Monte Carlo simulations indicate a lower luminosity limit of 2 × 1018 photons above 1 MeV for the main downward beam of the TGF, making the reverse beam detectable by the Fermi Gamma ray Burst Monitor. Plain Language Summary: Pu et al. (2020, https://doi.org/10.1029/2020GL089427) published an article on a terrestrial gamma ray flash (TGF) observation made by the Fermi satellite with a simultaneous radio wave observation of a lightning event almost directly below Fermi's position. The radio data unequivocally showed that the lightning event was negative cloud to ground (−CG). This implied that the electric field orientation of the lightning would have produced a downward TGF with a source altitude near 6 km. Fermi must have seen the reverse beam, which is the consequence of antimatter production within the strong electric fields that produce the TGF. Predictions of the reverse beam indicate that it is far less bright than the main forward beam. The scenario seems at first glance very unlikely, as it would require the TGF to be far brighter than any previous observation. It turns out that characteristics of the antimatter‐induced reverse beam, such as its higher average energy and narrower beaming, make the reverse beam more penetrating and thus more likely to be observed from lower altitudes at TGF intensities that are within the upper range of previous observations. Key Points: Multiwavelength observations and estimates of thunderstorm charging altitudes estimate the likely altitude of the terrestrial gamma ray flash (TGF) at 7.5 kmMinimum luminosity estimate for a downward TGF at 7.5 km detectable by Fermi via the reverse beam is 2 × 1018 photons above 1 MeVThe e‐folding attenuation length in grammage for the reverse beam component of a TGF was found to be 58 g/cm2 [ABSTRACT FROM AUTHOR]

Summary: Nuclear energy, already a practical solution for supplying energy on a scale similar to fossil fuels, will likely increase its footprint over the next several decades to meet current climate goals. Gamma radiation is produced during fission in existing nuclear reactors and thus the need to detect leakage from nuclear plants, and effects of such leakage on ecosystems will likely also increase. At present, gamma radiation is detected using mechanical sensors that have several drawbacks, including: (i) limited availability; (ii) reliance on power supply; and (iii) requirement of human presence in dangerous areas. To overcome these limitations, we have developed a plant biosensor (phytosensor) to detect low‐dose ionizing radiation. The system utilizes synthetic biology to engineer a dosimetric switch into potato utilizing the plant's native DNA damage response (DDR) machinery to produce a fluorescent output. In this work, the radiation phytosensor was shown to respond to a wide range of gamma radiation exposure (10–80 Grey) producing a reporter signal that was detectable at >3 m. Further, a pressure test of the top radiation phytosensor in a complex mesocosm demonstrated full function of the system in a 'real world' scenario. [ABSTRACT FROM AUTHOR]

In this study, the novel pH‐sensitive s‐IPN consist of sodium alginate integrated with poly(HEMA‐co‐MA) hydrogel matrix are prepared by using two‐step methodology. In the first step, 2‐hydroxyethyl methacrylate (HEMA)/maleic acid (MA) copolymeric hydrogels are prepared by gamma radiation polymerization. Then, poly(HEMA‐co‐MA) hydrogel was immersed in sodium alginate solution (SA) and finally gamma radiation polymerization was carried out. The swelling, pH‐sensivity and diffusion properties of the prepared s‐IPN gels in deionized water and in dye solutions were investigated. Methylene Blue (MB) was used as a model dye. MB adsorption capacities of the hydrogels were found to be 0.26, 0.40 and 13.77 mg MB/g dry gel in PHEMA, P(HEMA‐co‐MA) and s‐IPN SA/P(HEMA‐co‐MA) hydrogels, respectively. MB release data was fitted to various kinetic models to study the dye release behavior. The MB release from all the prepared hydrogels fitted the Korsmeyer‐Peppas model. Swelling, diffusion and MB adsorption properties of the new s‐IPN hydrogel were improved with the inclusion of SA and MA in the gel structure. [ABSTRACT FROM AUTHOR]

This research article aimed to assist the works conducted to save water resources, which are rapidly depleted as a result of climate change by eliminating toxic chromium ions Cr(VI) from simulated solution. In this regard, chitosan/Na‐alginate/polyacrylic acid (CS/Na‐Alg/PAAc) and Ni/chitosan/Na‐alginate/polyacrylic acid (Ni@CS/Na‐Alg/PAAc) were created as eco‐friendly hydrogel composites via gamma radiation. The hydrogel matrix served as a basin for the in‐situ formation of Ni nanoparticles. The prepared composites were characterized by the FTIR and XRD analyses. The surface morphology of the nanocomposite was also verified via the SEM. It exhibited a dense packing of the Ni nanoparticles representing about 2.5% of the atomic percentage depicted by the EDX analysis. The swelling performance was investigated versus different pH values and the maximum swelling percent was attained as a non‐Fickian character at pH = 13 and 5 for CS/Na‐Alg/PAAc and Ni@CS/Na‐Alg/PAAc, respectively. Furthermore, the surface topographies of CS/Na‐Alg/PAAc and Ni@CS/Na‐Alg/PAAc loaded with Cr(VI) were examined by AFM at different pH values. The maximum Cr(VI) removal was top achieved at pH 8 (58.06 and 74.5 mg/g for CS/Na‐Alg/PAAc and Ni@CS/Na‐Alg/PAAc, respectively) and best fit with the Freundlich isotherm model with calculated RL values indicated a favorable adsorption. [ABSTRACT FROM AUTHOR]

Citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), and European corn borer (ECB), Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), are two key pests of young citrus and maize plants in Iran, respectively. In this study, the effects of sub‐sterilizing doses of gamma radiation (100–250 Gy for CLM, 90–180 Gy for ECB) on the biological and reproductive parameters of F1 progeny from irradiated males were determined. The results indicated that males irradiated at doses of ≥200 and ≥150 Gy produced highly sterile F1 descents for CLM and ECB, respectively. No adverse effects of radiation doses applied to males were observed on the F1 pupal emergence for both species, nor on the adult longevity of male and female ECB moths. However, the life span of CLM F1 male and female adults decreased with increasing doses. The sex ratio of emerged adults of F1 progeny from irradiated males was skewed towards males with increasing doses; the proportion of males to all emerged adults reached 0.52 and 0.54 at doses of 250 and 150 Gy for CLM and ECB, compared to 0.44 and 0.49 in the controls, respectively. The competitiveness index of irradiated and F1 males of both species fluctuated in acceptable ranges and in general F1 males were stronger competitors than their irradiated male parents. The results of the field cage experiments showed that the larval infestation in all cages including the released irradiated CLM and ECB moths decreased compared to the control treatment – the percentage of damaged leaves and stems in the cages with ratios of 20:1 and 7:1 irradiated‐to‐normal insects (highest ratios assayed) reached half and one‐third of the control for CLM and ECB, respectively. [ABSTRACT FROM AUTHOR]

Tamoxifen‐induced hepatotoxicity is an inevitable side effect during breast cancer treatment. Low‐dose gamma irradiation (IRR) shows many beneficial effects by stimulating various biological processes. This study evaluates the possible effect of sildenafil and low‐dose gamma radiation on liver damages as new treatment strategies. Group I (control), group II: (tamoxifen), group III: (tamoxifen + Sildenafil), group IV: (tamoxifen+ irradiation) and group V: (tamoxifen +Sildenafil + irradiation). Rats were sacrificed after 5 h from tamoxifen injection. Results showed that tamoxifen caused elevation in serum AST, ALT and ALP as well hepatic ROS, iNOS, MDA, Keap‐1 and NF‐Kb, in addition to diminution in hepatic Nrf2 and HO‐1. Exposure to low‐dose gamma radiation and sildenafil amended the alterations in the measured parameters in serum and tissue. Moreover, all results were confirmed by histopathological examination. In conclusion, sildenafil and low‐dose gamma radiation can mitigate the toxicity induced by tamoxifen in liver tissues. Hence, this treatment could be further evaluated as a new approach for alleviating various liver disorders. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Due to changes in climate and the estimation of fossil fuel exploitation in the future, there is a great demand for green energy. Therefore, hydrogen production was studied by water splitting using Al2O3 nanoparticles as a radiation catalyst with gamma rays irradiation EXPERIMENTAL: The effects of different particle sizes, surface area, amounts of radiation catalyst and the time of gamma rays irradiation were studied. The kinetics of hydrogen generated by the water decomposition of the water system with Al2O3 nanoparticles were also studied. It was determined that the hydrogen produced by water splitting with smaller‐sized nanoparticles was 1.4–1.6 times greater than the large‐sized catalysts. RESULTS AND DISCUSSION: The best conditions were 5 nm particle size, 250 mm2/g surface area, 0.25 g amount and 10 h time (5.97 molecules/100 eV). The equivalent dispersal of radiation nanocatalyst (alumina) in water and greatly more sorption of water on the catalyst surface caused more effective radiolysis. The mechanism of water splitting and radiolysis was also established. CONCLUSION: The reported method may be used in the future for hydrogen production on an industrial scale. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Terrestrial gamma‐ray flashes are linked to growth of long bidirectional lightning leader system consisting of positive and stepping negative leaders. The spatial extent of streamer zones of a typical lightning leader with tip potential exceeding several tens of megavolts is on the order of 10–100 m. The photoelectric absorption of bremsstrahlung radiation generated by avalanching relativistic runaway electrons occurs efficiently on the same spatial scales. The intense multiplication of these electrons is triggered when the size of the negative leader streamer zone crosses a threshold of approximately 100 m (for sea‐level air pressure conditions) allowing self‐replication of these avalanches due to the upstream relativistic electron seeds generated by the photoelectric absorption. The model results also highlight importance of electrode effects in interpretation of X‐ray emissions from centimeter to meter long laboratory discharges, in particular, a similar feedback effect produced by generation of runaway electrons from the cathode material. Plain Language Summary: We propose a physical mechanism that explains spectacular naturally occurring bursts of X‐rays that are observed in association with lightning activity in the Earth's atmosphere. These events are commonly referred to as terrestrial gamma ray flashes (TGFs). The mechanism is based on a feedback process allowing amplification of relativistic electron avalanches when X‐rays emitted by these electrons travel backwards with respect to the electron motion and generate new relativistic electron seeds due to the photoelectric absorption in air. The presented model results agree with the observational and experimental evidence indicating that TGFs are associated with steps of negative lightning leaders and originate from relatively compact regions of space with spatial extent on the order of 10–100 m. The mechanism is not sensitive to the origin and amount of the initial runaway electrons and identical results are obtained whether the initial seeds are provided by the natural background as cosmic ray secondaries or generated by the streamer discharges. We also provide quantitative evidence that in the presence of electrodes the same amplification mechanism and X‐ray production may involve generation of runaway electrons from the cathode material. These effects may be relevant to development of new X‐ray sources. Key Points: The onset of terrestrial gamma ray flashes is linked to the spatial extent of the lightning leader streamer zoneThe photoelectric absorption is the dominant feedback factor defining inception of relativistic runaway discharges in airThe photoelectric absorption generated runaway electrons from the cathode facilitate X‐rays from laboratory sparks [ABSTRACT FROM AUTHOR]

The Late Miocene‐Early Pliocene Biogenic Bloom (∼9–3.5 Ma) was a paleoceanographic phenomenon defined by anomalously high accumulations of biological components at multiple open ocean sites, especially in certain regions of the Indian, and Pacific oceans. Its temporal and spatial extent with available information leaves fundamental questions about driving forces and responses unanswered. In this work, we focus on the middle part of the Biogenic Bloom (7.4–4.5 Ma) at International Ocean Discovery Program Site U1506 in the Tasman Sea, where we provide an integrated age model based on orbital tuning of the Natural Gamma Radiation, benthic foraminiferal oxygen isotopes, and calcareous nannofossil biostratigraphy. Benthic foraminiferal assemblages suggest changes in deep water oxygen concentration and seafloor nutrient supply during generally high export productivity conditions. From 7.4 to 6.7 Ma, seafloor conditions were characterized by episodic nutrient supply, perhaps related to seasonal phytoplankton blooms. From 6.7 to 4.5 Ma, the regime shifted to a more stable interval characterized by eutrophic and dysoxic conditions. Combined with seismic data, a regional change in paleoceanography is inferred at around 6.7 Ma, from stronger and well‐oxygenated bottom currents to weaker, oxygen‐depleted bottom currents. Our results support the hypothesis that the Biogenic Bloom was a complex, multiphase phenomenon driven by changes in ocean currents, rather than a single uniform period of sustained sea surface water productivity. Highly resolved studies are thus fundamental to its understanding and the disentanglement of local, regional, and global imprints. Key Points: We construct an integrated age model (7.4–4.5 Ma) for Site U1506 beneath the subtropical return flow of the South Pacific GyreBenthic foraminifera reveal high productivity and a local change in oceanography during the Late Miocene to Early Pliocene Biogenic BloomStronger intermediate depth bottom currents before 6.7 Ma suggest a weakening of shallow wind driven Pacific Ocean circulation at 6.7 Ma [ABSTRACT FROM AUTHOR]

Terrestrial gamma ray flashes (TGFs) are bursts of high‐energy photons produced in thunderstorms. Photons are produced by bremsstrahlung from high‐energy electrons, gaining energy through the electric field in the thunderstorm. Both electrons and photons are ionizing radiation and could have an impact on the radiation exposure of commercial aircrews and passengers. Previous works from Dwyer et al. (2010) and Pallu et al. (2021) have quantified doses possibly delivered by TGFs. They showed that the photon doses are sufficiently low so as not to be taken into account in the calculation of the radiation doses received during flights. However, electrons could deliver high doses up to 1 Sv, though in a compact area around the TGF source. In this work, we estimate an upper bound of the probability for a commercial flight to find itself in the electron beam of a TGF. Using the first Fermi‐Gamma ray Burst Monitor TGF catalog and both simulated routes between airports as a first step and real flight routes from Air France airline for 2.5 years as a second step, we show that the probability is lower than one aircraft hit every 2 years for the total air traffic. Knowing that we did not take into account altitudes and the fact that pilots usually avoid thunderstorms, it is likely that no aircraft would have been hit by the source of a TGF since the beginning of the commercial aviation. Plain Language Summary: Terrestrial gamma ray flashes (TGFs) are bursts of high‐energy photons produced in common thunderstorms. Generated by bremsstrahlung from relativistic electrons, they have been estimated to be able to deliver high radiation doses, though in very compact areas (<200‐m radius around the source). This work presents a statistical study to estimate the probability for a commercial flight to be hit by a TGF. We show that this probability is low, estimated to be less than one aircraft hit by a TGF every 2 years for the total air traffic. Key Points: The probability for a commercial flight to be hit by a terrestrial gamma ray flash (TGF) is estimated by two methodsEstimation of an upper bound of the probability: one flight hit by a TGF every 2 years over the total air trafficEstimation of one flight hit by a TGF every 390 years over the whole Air France fleet [ABSTRACT FROM AUTHOR]

Nanocomposites based on poly (vinyl alcohol) (PVA) filled with different types of nanometal oxides named MgO, Al2O3, and CuO were attained from an aqueous solution of PVA. PVA/nanometal oxide films were achieved by the solution casting procedure. The prepared nanocomposites were subjected to a gamma radiation dose at 50 kGy to study the impact of ionizing radiation on the various properties of the prepared samples. In this context, this work was mainly concerned with the differences in the behavior of various metal oxides, as well as the effect of ionizing radiation on the tensile strength (TS), elongation at break (E%), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction, and optical characteristics of the fabricated specimens. Furthermore, Fourier transform infrared (FTIR), SEM, and thermodynamic factors (Ea, ΔH, ΔG, and ΔS) were considered. FTIR and the suggested reaction mechanism supported that the hydroxyl groups of PVA have a really strong affinity to form charge‐transfer complexes with different nanometal oxides done chelation. In general, the interference of 0.1% of all studied nanometal oxides improved TS, thermal stability, melting temperature, and optical properties of PVA, whereas PVA/0.1 CuO was the best. Moreover, gamma radiation exposure enhanced the different properties of native PVA and displayed anisotropic behavior toward its nanocomposites. [ABSTRACT FROM AUTHOR]

The division of geological time is of general interest as this allows a better understanding of the geological processes and Earth's evolutionary history. Astrochronology provides a way to evaluate high‐resolution timescales of Earth's climate changes. Astronomical tuning of orbitally forced stratigraphic records to construct astronomical‐calibrated timescales has led to a progressive refinement of the geological timescale over the last decades. However, the Triassic remains a relatively weak link. A large lake with an area of 370 000 square kilometres formed in the Ordos Basin in North China during the Triassic Period. It has been demonstrated that the sedimentary deposits of the seventh Oil Member (Chang 7 Member) of the Triassic Yanchang Formation in the southern Ordos Basin responded to astronomically forced climate changes. However, the constructed astronomical‐calibrated timescales failed to reach an agreement. This study presents natural gamma ray logs and geochemical climate record of Fe and Al concentrations from the southern Ordos Basin margin that are dated precisely from 239 to 229 Ma by combined U–Pb dating and astrochronology. Therefore, the Chang 7 Member was deposited during the Ladinian and Carnian (late Middle through to earliest Late Triassic), this knowledge will refine the Triassic astronomical scale. The distribution of detrital zircon dates shows that the Chang 7 Member in the southern Ordos Basin has multiple provenance characteristics. The southern Ordos Basin is far from this provenance area, which is reflected in the low sediment accumulation rate (0.5 to 2.0 cm/kyr). In contrast to the lower part of Yanchang Formation underlying the Chang 7 Member, the large tuffs and seismites from the bottom of Chang 7 Member indicate the initiation of tectonic collision between North Qinling orogenic belt and the southern margin of the Ordos Basin. [ABSTRACT FROM AUTHOR]

Based on the broad clinical utility of the immunosuppressant mycophenolic acid (MPA), this article aims to intensify the biosynthetic potential of Penicillium roqueforti for more effective hyperproduction of the drug. Several mutants were generated from irradiation mutagenesis and screened. Two strains (GM1013 and GM1093) presented an elevated MPA productivity with significant yield constancy over 10 subsequent generations. By investigating the effect of some phosphorous sources and mineral salts on MPA production by the two mutants, KH2PO4 and FeSO4·7H2O were most preferred by the two mutants for higher MPA production rates. Statistics‐dependent experimental designs were also employed for optimizing medium components for maximum MPA production. Medium components were primarily screened using the Plackett–Burman model to demonstrate the most important components that most significantly affect MPA production. The concentrations of these significant components were then optimized through a central composite rotatable model. In conclusion, gamma‐radiation mutation and response surface optimization resulted in a promising MPA productivity by P. roqueforti GM1013. To our knowledge, the MPA‐yield achieved in this study (2933.32 mg L–1) is the highest reported by academic laboratories from P. roqueforti cultures, which could be of economic value for a prospective large industrialized application. [ABSTRACT FROM AUTHOR]

Understanding residual radioactive contamination state and the resulting radiation environment is vital before reconstructing the lives of residents in areas affected by nuclear power plant accidents. In this study, we surveyed the depth profiles of Cs‐137 in three artificially paved ground surfaces: impermeable asphalt, permeable asphalt, and concrete, in areas affected by the Fukushima Daiichi Nuclear Power Plant accident after a period of 10 years and analyzed the gamma‐ray air dose rate distribution in a two‐story wooden house model surrounded by different ground surfaces using the Particle and Heavy Ion Transport code System of the Japan Atomic Energy Agency. The air dose rate distribution tendencies within the building for different surrounding ground surfaces were clarified by analyzing the transport of gamma rays emitted from the Cs‐137 in the ground. Moreover, the shielding effect of an ordinal concrete fence on the indoor air dose rate was analyzed. The analysis showed that the indoor air dose rate was higher in an environment with artificial pavement than in that with a soil surface, and even a simple measure, such as installing an ordinal concrete fence, could significantly reduce indoor radiation dose rates. [ABSTRACT FROM AUTHOR]

Delirium occurs in as many as 80% of critically ill older adults and is associated with increased long‐term cognitive impairment, institutionalization, and mortality. Less than half of delirium cases are identified using currently available subjective assessment tools. Electroencephalogram (EEG) has been identified as a reliable objective measure but has not been feasible. This study was a prospective pilot proof‐of‐concept study, to examine the use of machine learning methods evaluating the use of gamma band to predict delirium from EEG data derived from a limited lead rapid response handheld device. Data from 13 critically ill participants aged 50 or older requiring mechanical ventilation for more than 12 h were enrolled. Across the three models, accuracy of predicting delirium was 70 or greater. Stepwise discriminant analysis provided the best overall method. While additional research is needed to determine the best cut points and efficacy, use of a handheld limited lead rapid response EEG device capable of monitoring all five cerebral lobes of the brain for predicting delirium hold promise. [ABSTRACT FROM AUTHOR]

The Permian Fengcheng Formation of the Mahu Sag in the Jungar Basin is one of the most important hydrocarbon source rocks in Xinjiang oil field. The preservation of the geological records of Milankovitch cycles can be studied to understand the history of the Earth's evolution and sedimentary processes, and high‐resolution astronomical time scales (ATS) can be obtained by analysing (quasi) periodic sedimentary signals in geological records. In this study, the natural gamma ray (GR) and density (DEN) logging data are used to carry out a detailed spectrum analysis, including 2π‐Multi‐taper Method (MTM), Evolutive Harmonic Analysis (EHA), Correlation coefficient method (COCO) and DYNOT simulation. GR and DEN data analysis results show sedimentary cycles of 39.3, 9.1 m, 3.6–2.7 m and 2.1–1.7 m, 37.5, 9.7, 3.7 m and 2.4–1.9 m in MY‐1 well; MH‐15 well recorded the significant peaks at 81, 20, 8.6 m and 3.6–3.4 m and 66, 17.6, 6.8 m and 3.3–2.7 m; FN‐14 well revealed high‐confidence level frequencies with wavelength of 97, 23, 8.8 and 3.9 m and 88, 22, 8.5 m and 4–3.4 m respectively. The average sediment accumulation rates (SAR) are estimated at 9–9.7 cm/kyr for MY‐1, 14.5–19 cm/kyr for MH‐15, 13.5–14.5 cm/kyr for FN‐14 by using the COCO. In addition, we construct a continuous time scale for Fengcheng Formation, yielding a deposition duration of about 3.5 ± 0.2 Myr for these three drilling cores. Finally, we used the DYNOT sea‐level change model to analyse the GR and DEN logging series of three wells, for reconstructing the lake‐level changes of the Fengcheng Formation in the Junggar Basin. [ABSTRACT FROM AUTHOR]

Background: In proton therapy dose calculation, Monte Carlo (MC) simulations are superior in accuracy but more time consuming, compared to analytical calculations. Graphic processing units (GPUs) are effective in accelerating MC simulations but may suffer thread divergence and racing condition in GPU threads that degrades the computing performance due to the generation of secondary particles during nuclear reactions. Purpose: A novel concept of virtual particle (VP) MC (VPMC) is proposed to avoid simulating secondary particles in GPU‐accelerated proton MC dose calculation and take full advantage of the computing power of GPU. Methods: Neutrons and gamma rays were ignored as escaping from the human body; doses of electrons, heavy ions, and nuclear fragments were locally deposited; the tracks of deuterons were converted into tracks of protons. These particles, together with primary and secondary protons, are considered to be the realistic particles. Histories of primary and secondary protons were replaced by histories of multiple VPs. Each VP corresponded to one proton (either primary or secondary). A continuous‐slowing‐down‐approximation model, an ionization model, and a large angle scattering event model corresponding to nuclear interactions were developed for VPs by generating probability distribution functions (PDFs) based on simulation results of realistic particles using MCsquare. For efficient calculations, these PDFs were stored in the Compute Unified Device Architecture textures. VPMC was benchmarked with TOPAS and MCsquare in phantoms and with MCsquare in 13 representative patient geometries. Comparisons between the VPMC calculated dose and dose measured in water during patient‐specific quality assurance (PSQA) of the selected 13 patients were also carried out. Gamma analysis was used to compare the doses derived from different methods and calculation efficiencies were also compared. Results: Integrated depth dose and lateral dose profiles in both homogeneous and inhomogeneous phantoms all matched well among VPMC, TOPAS, and MCsquare calculations. The 3D–3D gamma passing rates with a criterion of 2%/2 mm and a threshold of 10% was 98.49% between MCsquare and TOPAS and 98.31% between VPMC and TOPAS in homogeneous phantoms, and 99.18% between MCsquare and TOPAS and 98.49% between VPMC and TOPAS in inhomogeneous phantoms, respectively. In patient geometries, the 3D–3D gamma passing rates with 2%/2 mm/10% between dose distributions from VPMC and MCsquare were 98.56 ± 1.09% in patient geometries. The 2D–3D gamma analysis with 3%/2 mm/10% between the VPMC calculated dose distributions and the 2D measured planar dose distributions during PSQA was 98.91 ± 0.88%. VPMC calculation was highly efficient and took 2.84 ± 2.44 s to finish for the selected 13 patients running on four NVIDIA Ampere GPUs in patient geometries. Conclusion: VPMC was found to achieve high accuracy and efficiency in proton therapy dose calculation. [ABSTRACT FROM AUTHOR]

Shear wave velocity information is valuable in many aspects of seismic exploration and characterization of reservoirs. However, shear wave logs are not always available in the interval of interest due to cost and time‐saving purposes. In this study, we present a tailored supervised learning approach to estimate shear wave velocity from well‐log measurements in the Lower Cretaceous succession of the Valdemar and Boje fields in the Danish North Sea. Our objective is to investigate the performance of four supervised learning regression models (linear, random forest, support vector and multi‐layer perceptron). A limited well‐log data set from six wells is used for training and testing the supervised learning models. A set of well data containing normalized gamma ray, compressional wave velocity, neutron porosity and medium resistivity logs gave reasonable shear wave velocity estimates in the test wells with root‐mean‐square error scores within the range of other published studies. Based on limited input data and complex geology, the multi‐layer perceptron was the most successful model in predicting the reservoir sections of the test wells. However, all models lacked stability in the overburden zones. Lastly, re‐training the multi‐layer perceptron on the six wells to predict missing shear wave velocity in a nearby well showed promising results for further reservoir characterization. The obtained results can yield useful input into, for example, seismic pre‐stack inversion, amplitude versus offset analysis and rock physics analysis. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of gamma radiation (3 kGy) on the quality of post‐rigor beef (M. longissimus lumborum) aged for up to 21 days at different temperatures (1, 7, and 15°C). Irradiation reduced the mesophilic and lactic acid bacteria counts, which were higher in the non‐irradiated samples aged at 7 and 15°C. The water retention capacity was lower in the irradiated beef, resulting in higher values of exudation and cooking losses. High aging temperatures increased the exudation loss and myofibrillar proteolysis (lower fragmentation index; FI) and reduced the total and insoluble collagen contents and the beef Warner‐Bratzler square Shear Force (WBsSF). However, irradiated beef had higher FI and SF than non‐irradiated ones, increasing the time required for the beef tenderizing. Gamma irradiation (3 kGy) can be used to ensure the microbiological safety during short storage at high temperatures (up to 15°C) in order to accelerate the process of beef tenderizing. [ABSTRACT FROM AUTHOR]

Ni (II) and Co (II) complexes of thiosemicarbazide ligand (2‐(anilinoacetyl)‐N‐(3‐methylphenyl)hydrazine‐1‐carbothioamide(H2LB) have been prepared and characterized by 1HNMR, IR, elemental analyses, molar conductance, UV–visible spectra, magnetic susceptibility measurements, thermogravimetric analysis (TGA/DTG), and X‐ray differaction pattern before and after irradiation. The results confirmed that gamma rays enhanced the stability of irradiated compounds compared with those non‐irradiated. Density functional theory (DFT) calculations of synthesized compounds were completely optimized with respect to the energy using B3LYP level. DNA binding of compounds before and after gamma irradiation has been studied. Inhibitory effect on the growth of bacteria against gram‐positive (Streptococcus pyogenes) and gram‐negative (Escherichia coli) of synthesized compounds have been investigated. The results revealed that Ni (II) complex after gamma irradiation showed a higher antibacterial activity against gram positive and gram negative bacteria more than all investigated compounds. The ability of scavenging 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical by our synthesized compounds was investigated on the basis of the determination of IC50 values. [ABSTRACT FROM AUTHOR]

The Southern Ocean is supposed to play a crucial role in influencing atmospheric CO2 concentrations. However, the dynamic relationships among the rate of Southern Ocean upwelling, atmospheric CO2 concentration, and Antarctic climate at millennial timescales remain unclear. Here, we present high‐resolution color reflectance component b* and natural gamma radiation from the southern Scotia Sea sector of the Southern Ocean to reconstruct productivity over the past 160 ka. We find that these two independent productivity proxies, reflecting the signal of nutrient supply in this region, captured millennial‐scale upwelling that covaried in timing with Heinrich Stadials and Antarctic warming events, supporting the bipolar seesaw mechanism. The one‐to‐one coupling of variability between productivity and atmospheric CO2 concentrations reveals that the upwelling is closely linked to atmospheric CO2 and climate change. Plain Language Summary: The Southern Ocean's physical and associated biogeochemical processes play important roles in influencing atmospheric CO2 and climate change. In this study, we investigate temporal changes in productivity in the Antarctic Zone of the Southern Ocean by color reflectance component b* and natural gamma radiation data over the past 160 ka. We find that millennial‐scale productivity variability, which reflects the rate of upwelling in this region, corresponds to millennial‐scale variations in Antarctic temperature and atmospheric CO2 concentration over the past 160 ka. These tight couplings could imply that Southern Ocean upwelling is involved in atmospheric CO2 fluctuation and climate change. Key Points: Change in productivity at Site U1537 reflects the degree of upwelling in the Antarctic Zone of the Southern OceanThe millennial‐scale productivity peaks correspond to the Antarctic Isotope Maximum events that coincided with the Heinrich Stadials or Dansgaard‐Oeschger events in GreenlandThe rate of upwelling and atmospheric CO2 concentrations are positively correlated during the Heinrich Stadials [ABSTRACT FROM AUTHOR]

Several studies have suggested the potential value in applying gamma radiation surveys to support identification of buried archaeological features. However, the number of previous studies is very small and has yielded mixed results. The true efficacy of the technique is therefore unclear. Here, we report on an alternative survey method that uses Groundhog®, a portable gamma radiation system with spectrometric capability, to achieve high spatial density monitoring of archaeological sites. The system, which is used extensively in the nuclear industry, was used to carry out preliminary surveys at four different locations within the Silchester Roman Town. Targeting a site for which an extensive amount of archaeological data is available facilitated testing of the method on a range of known target types. Surveys were carried out along 1‐m transects at an approximate walking speed of 1 m per second, resulting in the capture of one radiation measurement per square metre. Total gamma radiation, recorded in counts per second, was presented in the form of surface radiation (contour) maps and compared against existing geophysical data. Total gamma counting consists of counting gamma rays, without energy discrimination, that are spontaneously emitted by the material under investigation. The obtained counts represent the total, or gross, gamma contribution from all radionuclides, both natural background series and anthropogenic. Radiation anomalies were identified in two of the four survey sites. These anomalies correlated with features present in the geophysical data and can be attributed to a Temenos wall bounding the temple complex and an infilled clay pit. Early results suggest that this may be a complementary technique to existing geophysical methods to aid characterization of archaeological sites. However, it is believed that data quality could be significantly improved by further increasing spatial resolution. This will be explored as part of future fieldwork. [ABSTRACT FROM AUTHOR]

Microbeam radiotherapy could help to cure malignant tumours which are currently still considered therapy-resistant. With an irradiation target in the thoracic cavity, the heart would be one of the most important organs at risk. To assess the acute adverse effects of microbeam irradiation in the heart, a powerful ex vivo tool was created by combining the Langendorff model of the isolated beating mammalian heart with X-Tream dosimetry. In a first pilot experiment conducted at the Biomedical and Imaging Beamline of the Australian Synchrotron, the system was tested at a microbeam peak dose approximately ten times higher than the anticipated future microbeam irradiation treatment doses. The entire heart was irradiated with a dose of 4000 Gy at a dose rate of >6000 Gy s'1, using an array of 50 mm-wide microbeams spaced at a centre-tocentre distance of 400 mm. Although temporary arrhythmias were seen, they reverted spontaneously to a stable rhythm and no cardiac arrest occurred. This amazing preservation of cardiac function is promising for future therapeutic approaches. [ABSTRACT FROM AUTHOR]

Balázs et al. discovered a gigaparsec‐scale ring‐like cluster of gamma‐ray bursts (GRBs) at redshift z∼0.8$$ z\sim 0.8 $$, the so‐called Giant GRB Ring (GGR), and claimed that the existence of such a gigantic structure challenges the standard cosmological paradigm. We show that the kth nearest neighbor analysis of Balázs et al., by which they estimated the probability of finding by chance a GRB cluster comparable to the GGR to be only 0.05%, has several flaws in the statistical reasoning. After correcting these flaws, the above probability becomes 5–20%, considerably higher than the original estimate and large enough to discard the hypothesis that the GGR has a physical origin. Moreover, this probability is even higher, 60–90%, when using the most recent compilation of GRB data whose redshifts have been measured. We conclude that the GGR is merely a pattern that occurred by chance in the random distribution of GRBs. [ABSTRACT FROM AUTHOR]

Thunderstorm Ground Enhancements (TGEs) refer to correlated enhancements in surface electric field and gamma ray flux that are manifestations of electron runaway in the storm overhead. The electric field enhancements can be of positive or negative polarity. In this study, altitude‐resolved S‐band radar observations of graupel are used to demonstrate distinct differences in storm structure linked with these "positive" and "negative" TGEs. The physical interpretation rests on the well‐established temperature‐dependent tripole structure of thunderstorms, with the main negative charge of the tripole acting as an electron repeller. This interpretation is supported by case studies showing altitude‐stable convection, with shallow (deep) development linked with "positive" ("negative") TGEs, and by case studies of collapsing storms that show upper dipole dominance early and lower inverted dipole dominance later when graupel particles descend from a colder to warmer temperature domain. In the case of many TGEs on Mt Aragats (3.2 km MSL), the temperature‐dependent altitude of downward electron acceleration and avalanching may be sufficiently distant (>500 m) from surface detectors that the energetic electrons (1–10 MeV) are not likely avalanche/runaway electrons. Instead, they are Compton‐scattered and pair‐produced electrons from bremsstrahlung gamma radiation emanating from the high‐field avalanche region aloft. These inferences are consistent with GEANT4 calculations that identify the physical origins of energetic electrons at the surface. Key Points: Thunderstorm Ground Enhancements (TGEs) are indicative of downward electron acceleration within the storm and are manifest with both polarities of the electric fieldVertical development disclosed by RADAR is uniquely linked with "positive" and "negative" TGEsThese different vertical developments are attributed to a temperature‐dependent tripole structure of thunderclouds [ABSTRACT FROM AUTHOR]

Plastic scintillators (PS) allow design of portative lightweight devices for quantification of low‐activity radiation sources. We have recently suggested a new type of organic fluorophores based on triphenyl pyrazoline (PZ) derivatives with high fluorescence quantum yield showing high radioluminescence when combined with a polyvinyltoluene (PVT) matrix. In this publication we report on radioluminescence properties of the PZ−X family with various halogen substitution (X=F, Cl, Br, I), or having vinyl functional group (vPZ, X=vinyl). PS based on such fluorophores and PVT matrix can be prepared as bulk samples, micrometer size beads or cladding on optical fibers. Application of fluorophores with vinyl functional groups enabled their enhanced interaction with the matrix due to covalent bonding between the components. We demonstrate high performance of PZ−X fluorophores and especially vPZ fluorophore in fabrication of nanocomposites for detection of various types of radiation. Scintillators have enhanced gamma ray detection capabilities with an addition of triphenyl Bi, or Gd2O3 nanoparticles. High fluorescence quantum yield and luminosity of PZ fluorophores allows dramatical reduction of their content in PS systems. Mechanisms of energy transfer and conversion during scintillation process are discussed. Special consideration is given to enhancement of α/β and neutron/gamma (n/γ) pulse shape discrimination (PSD) function of the developed scintillators. [ABSTRACT FROM AUTHOR]

The Permian‐Triassic alluvial rift succession in the Horda Platform area is analysed to construct a refined depositional model. The study demonstrates how subsurface continental rift successions may be stratigraphically subdivided and correlated by integrating seismic and well‐log data in concert with conceptual models. Regional unconformities mark the top and base of the Permian‐Triassic succession, which is sub‐divided into six seismic stratigraphic sequences, delineated by erosional‐ and non‐depositional surfaces. The definition of seismic stratigraphic sequences is based on seismic facies trends and Gamma Ray log signatures. Time‐thickness maps combined with geometries in cross‐section display the depocentre development. During the Permian‐Triassic, the Horda Platform experienced faulting, shaping the Caledonian pre‐rift landscape into a series of N–S trending half‐graben basins, contemporaneous to a gradual climate change from arid in the Permian to humid in the latest Triassic. The basin underwent three phases of rifting during the Late Permian‐Middle Triassic: (1) disconnected heterogeneous depocentres with strain concentrated in the west; (2) depocentres expanded northward; and (3) mature half graben development with widely distributed strain. Vertical lithological changes in mudstone/sandstone dominance reflect varying rates of accommodation and sediment supply (A/S). Systematic A/S variation reflects strong climatic fluctuations, which controlled facies patterns during both tectonic quiescence in the Middle‐Late Triassic, and during syn‐rift sedimentation. The Permian‐Triassic tectono‐sedimentary development in the Horda Platform area provides valuable lessons on the influence of faulting on depocentre development, how the interplay between tectonic and climatic forcing is expressed in subsurface continental deposits, and aid the characterisation of reservoirs. [ABSTRACT FROM AUTHOR]

Radiation technology has been recognized as a potential tool to modify starches in order to enhance their solubility and enzymatic digestion, hence improving their applicability in food industry. In the present study, the local cassava starch was irradiated under 60Co gamma source with the absorbed dose ranging from 1 to 10 kGy, and the obtained radiation‐modified starches were characterized. The microstructure of the initial cassava starch was not much changed although several starch granules were deformed or even fragmented by gamma irradiation as observed in the scanning electron microscopy images. Water solubility of the irradiated starch was significantly increased, and their viscosity was much reduced by radiation degradation. Gamma radiation broke glycosidic bonds in starch chains into smaller molecules with lower molecular weight, whereby increased the water solubility of cassava starch. Radiation scission also partly decreased the crystallinity of the starches irradiated with dose higher than 5 kGy as indicated in their X‐ray diffraction patterns. The Fourier transform infrared spectra of irradiated starches revealed the reduction in intensities of stretching vibration characterized for OH, CH, and COC groups of starch molecules. Thus, gamma irradiation can be used to modify cassava starch for further applications. [ABSTRACT FROM AUTHOR]

Winter thunderstorms in Japan have been recognized as an ideal target to observe high‐energy atmospheric phenomena thanks to low‐charge‐center cloud structures. During four winter seasons in Japan (from 2016 October to 2020 March), seven downward terrestrial gamma‐ray flashes (TGFs) were detected by gamma‐ray and broadband low‐frequency (LF: 0.8–500 kHz) monitors. All the detected TGFs took place at the initial stage of lightning flashes. Based on the LF observation, the seven downward TGFs in the present study can be classified into two types: energetic‐bipolar and small‐bipolar types. Three of them are energetic‐bipolar events, coincident with a high peak‐current LF pulse that originates from a negative return stroke with a peak current larger than 100 kA. The others are small‐bipolar events, followed by a negative bipolar LF pulse with a moderate peak current. Three of the four small‐bipolar events are multi‐pulse TGFs, while all of the energetic‐bipolar events in this study are single‐pulse TGFs. Plain Language Summary: Terrestrial gamma‐ray flashes (TGFs) are a transient high‐energy emission from lightning discharges. While a lot of upward TGFs have been detected by satellites, a few downward TGF have been detected by ground‐based experiments. Our detection network in Japan has detected seven downward TGFs in winter thunderstorms for 4 years. Lightning discharges associated with the downward TGFs were also monitored in the low‐frequency radio band. The low‐frequency pulses associated with the downward TGFs can be classified into two types. Correlation analysis of downward TGFs with gamma‐ray and low‐frequency observations is a powerful approach to reveal the production mechanism of TGFs. Key Points: Downward terrestrial gamma‐ray flashes (TGFs) in winter thunderstorms of Japan can be classified into two types based on low‐frequency (LF) observationsThree events were single‐pulse TGFs coincident with high peak‐current LF pulses of return strokesFour events were followed by moderate peak‐current LF pulses, and three of them are multi‐pulse TGFs [ABSTRACT FROM AUTHOR]

Background: Avian influenza virus (AIV) subtype H9N2 is a low pathogenic avian influenza virus (LPAIV). Objective: This study aims to evaluate the humoral and cellular immunity in vaccinated mice and broiler chicken by irradiated AIV antigen plus carboxymethyl chitosan bounded iron oxide nanoparticles (CMC‐IO NPs) as an adjuvant. Methods: AIV subtype H9N2 with 108.5 EID50/ml and haemagglutinin antigen assay about 10 log2 was irradiated by 30 kGy gamma radiation dose. Then, the gamma‐irradiated AIV was used as an inactivated vaccine and conjugated with CMC‐IO NPs to improve immune responses on mice. IO NPs must be applied in all activated tests using 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC) and N‐hydroxysulfosuccinimide sodium salt (sulfo‐NHS), and then functionalized by CMC as IO‐CMC. Fourier transform infrared (FTIR) spectra on functionalized IO‐CMC showed a peak of 638 cm−1 which is a band between metal and O (Fe‐O). Results: Based on the comparison between the two X‐ray diffraction (XRD) patterns on Fe2O3‐NPs and IO‐CMC, the characteristics of IO‐NPs did not change after carboxymethylation. A CHN Analyzer was applied to measure the molecular weight of IO‐CMC that was calculated as 1045 g. IO‐CMC, irradiated AIV‐IO‐CMC and formalin AIV‐IO‐CMC were injected into 42 BALB/c mice in six groups. The fourth group was the negative control, and the fifth and sixth groups were inoculated by irradiated AIV‐ISA70 and formalin AIV‐ISA70 vaccines. An increase in haemagglutination inhibition (HI) antibody titration was observed in the irradiated AIV‐IO‐CMC and formalin AIV‐IO‐CMC groups (p < 0.05). In addition, increases in the lymphoproliferative activity of re‐stimulated splenic lymphocytes, interfron‐γ (IFN‐γ) and interleukin‐2 (IL‐2) concentration in the irradiated AIV‐IO‐CMC group demonstrated the activation of Type 1 helper cells. The concentration of IL‐4 was without any significant increases in non‐group. Conclusions: Accordingly, Th2 activation represented no increase. Finally, the finding showed that AIV‐IO‐CMC was effective on enhancing immunogenicity as irradiated AIV antigen administered with a clinically acceptable adjuvant (i.e. IO‐CMC). [ABSTRACT FROM AUTHOR]

Cosmic‐ray shower, hitting the atmosphere all the time, includes high‐energy electrons. Electric fields in thunderstorms accelerate these electrons so that they can reach farther distances with producing secondary electrons. The strong field above 0.284 MV m−1 causes the Relativistic Runaway Electron Avalanches (RREA) process with an exponential increase of electrons. Even with lower electric fields below this RREA threshold which are usually measured in thunderstorms, an increase in electrons' kinetic energy and production of secondary electrons can occur without avalanche processes, known as Modification Of Spectra (MOS) of the cosmic‐ray shower. Both phenomena are related to observed gamma ray glow, which is bremsstrahlung emission from accelerated electrons in thunderstorms. We calculate an extended range and kinetic energy of electrons below the RREA threshold using an analytical evaluation and Geant4 Monte Carlo simulations. For example, at 0.280 MV m−1 slightly below the RREA threshold, 3 MeV electrons gain 100% of their original kinetic energy through the passage of the continuous slowing down approximation (CSDA) range defined at the null electric field, which is consistent with results in previous studies as the transition to the RREA process. Even at a lower field of 0.260 MV m−1, the energy recovery by the field allows an injected 20 MeV electron beam to extend its average electron range from 73 m, in the null field configuration, to 562 m. We have performed analytical calculation and Geant4 simulations of atmospheric electron behavior for initial electron energy of 0.1–100 MeV and an electric field below 0.290 MV m−1. Key Points: We develop calculations for e− spatial range with electric fields up to the avalanche threshold, 0.284 MV/m, related to gamma ray glowOur particle simulation shows that thunderstorm fields below avalanche level extend the range of 1–100 MeV electrons by a factor of 2–10The calculations indicate a transition to avalanche regime with 3 MeV electron under 0.280 MV/m that extends the spatial range to infinity [ABSTRACT FROM AUTHOR]