Analytical calculation of the dose to a spherical target by an ion at almost all impact parameters, and calculation of the energy deposition spectra.

Assessment of indoor radon levels and annual effective dose across university campus: A case study from Kırşehir Province, Turkiye.

Urine is the best method for monitoring internal exposure to environmental pollutants such as heavy metals and radon gas. This may lead to human exposure to these environmental pollutants, which is associated with potential health risks. Therefore, this study aims to determine concentrations of heavy metals chromium (Cr), cadmium (Cd), and lead (Pb), and radon (222Rn) concentrations in 20 urine samples collected from male volunteer workers of car mechanics from Al-Najaf governorate, Iraq. Similarly, 5 urine samples from the non-car mechanics group were collected from several regions in the Al-Najaf governorate. Heavy metals and radon gas were measured using an atomic absorption spectroscopy (AAS) and a nuclear track detector type CR-39, respectively. The mean value of Cr, Cd, Pb, and Rn concentrations for workers was 0.018 ± 0.011mg/L, 0.083 ± 0.067mg/L, 0.004 ± 0.002mg/L, and 24.300 ± 20.906Bq/m3, respectively. In non-car mechanic individuals, the mean values of Cr, Cd, Pb, and Rn concentrations were 0.010 ± 0.006mg/L, 0.002 ± 0.001mg/L, 0.002 ± 0.0007mg/L, and 4.246 ± 0.489Bq/m³, respectively. Statistical analysis revealed that cadmium levels were significantly higher in car mechanics (0.083 ± 0.067mg/L) compared to non-car mechanics (0.002 ± 0.001mg/L, p < 0.001), while lead concentrations were also elevated in workers (0.004 ± 0.002mg/L vs. 0.002 ± 0.0007mg/L, p = 0.010). Radon levels showed a marked increase in car mechanics (24.30 ± 20.91Bq/m³) compared to controls (4.25 ± 0.49Bq/m³, p = 0.003). Spearman's correlation analysis demonstrated significant positive correlations between radon and lead (ρ = 0.511, p = 0.021), as well as a strong correlation between chromium and cadmium (ρ = 0.692, p = 0.001). Accordingly, the mean values of heavy metals and radon concentrations in the urine samples of workers were generally higher than those in the non-car mechanic group. Additionally, no statistically significant correlations were observed between Rn and Cr, Rn and Cd, Cr and Pb, or Cd and Pb among workers. Overall, this study indicates that Cr concentrations were within the commonly reported reference ranges, while Rn concentrations in urine lack well-established standard reference limits. Therefore, radon results should be interpreted with caution in terms of safety assessment, while Cd and Pb concentrations in most urine samples of workers exceeded the permissible limits. The limitations of the study are described, as the findings do not establish causality between radon and heavy metals exposure and the health of car mechanics and non-car mechanics. Due to the cross-sectional design of this study, the results reflect associations rather than causal relationships and cannot be generalized to populations with different environmental conditions and exposure levels.

This study investigated the seasonal variations of indoor radon concentrations in parts of cities across different climate zones of China. Using solid state nuclear track detectors (SSNTDs), radon measurements were conducted over a 12-month period in 171 dwellings located in 15 provincial capital cities. The annual average indoor radon concentration was 81Bqm-3, with the highest mean level recorded in the Severe Cold Area (99Bqm-3) and the lowest in the Hot Summer Warm Winter Area (52Bqm-3). A consistent seasonal pattern was observed across all zones, characterized by elevated concentrations in autumn and winter and lower levels in spring and summer. The mean winter-to-summer concentration ratio was 1.68, indicating a declining trend compared to earlier data from 1994 in China. This trend may be attributed to changes in ventilation practices associated with the widespread adoption of air conditioning. Seasonal correction factors were determined for different climate zones, ranging from 0.80 to 1.43. This study highlights the seasonal fluctuations of indoor radon and the necessity of applying appropriate correction factors when estimating annual average radon concentrations based on short-term measurements to reduce assessment bias. The findings provide critical data and a methodological foundation for accurately assessing and seasonally correcting indoor radon concentrations under diverse climatic conditions in China.

Iontronic memristor in funnel-shaped Ångström channels.

Lung cancer is the most common malignancy among Iraqi males, yet comprehensive radon exposure data remain scarce. This matched case-control study investigated the cumulative burden of long-lived radon decay products (²¹⁰Pb/²¹⁰Po) in dried blood samples as a biological proxy for radon exposure in Babylon Governorate, Iraq. Blood samples were collected from 38 lung cancer patients and 38 age- and sex-matched healthy controls, lyophilized, and analyzed using CR-39 solid-state nuclear track detectors over a 120-day exposure period. Linear mixed-effects modelling, accounting for the matched design and potential confounders, revealed significantly higher radon decay product concentrations in cases compared to controls (adjusted mean difference: 67.95Bq/m³; 95% confidence interval (CI): 57.43-78.46; p < 0.001). Age was positively associated with concentration (7.56Bq/m³ per year; p < 0.001), reflecting cumulative environmental exposure. Male smokers showed significantly higher concentrations than male non-smokers (24.9Bq/m³; p = 0.039), while no significant smoking-related difference was observed in females. These findings validate dried blood samples with CR-39 detectors as a sensitive tool for assessing cumulative radon progeny burden and underscore the urgent need for targeted radon mitigation strategies in Iraq, particularly for smokers and older populations.

Ion track formation and porosity in InSb following 125 MeV and 150 MeV 107 Ag swift heavy-ion irradiation are investigated as a function of ion fluence and irradiation angle. Rutherford backscattering spectrometry in channelling geometry reveals track radii of approximately 5 nm and 8 nm for 125 MeV and 150 MeV ion energies, respectively. The results indicate that the damage fraction saturates at approximately 90% amorphization, suggesting partial recrystallization inhibits complete amorphization. In addition to track formation, a porous structure develops at a fluence of 8 . 8 × 1 0 12 ions/cm 2 , whereas no significant porosity is observed at lower fluences. Notably, the average pore diameter and pore density differ for the different irradiation parameters. • RBS/C reveals track radii of ≈ 5 nm and ≈ 8 nm for 125 MeV and 150 MeV, respectively. • Damage fraction saturates at 90% suggesting partial recrystallization. • For 5° and 30° irradiation angles, the average pore diameter is larger at 125 MeV than at 150 MeV. • For 60° irradiation angle, the average pore diameter is larger at 150 MeV than at 125 MeV.

In this work, the experimental results of the electrical discharge and output ion beam characteristics of the cold conical cathode ion source at different pressures are measured using nitrogen and argon gases. The optimum distance between the disc anode and the conical cathode, as well as the optimum inner diameters of two insulator confinement rings, are determined at different pressures using nitrogen gas. Also, the optimum distance between the ion exit aperture of the conical cathode and the ion collector plate is determined at a constant pressure and different discharge currents using nitrogen and argon gases. The ion source optimum efficiency at optimum operating conditions, constant pressure and discharge current is determined using nitrogen and argon gases. Also, the effect of negative voltage applied to the ion collector plate on the extracted ion beam current at optimum operating conditions and constant pressure is measured using nitrogen and argon gases. Additionally, the changes in optical properties of Makrofol nuclear track detector samples after exposure to different ion fluence from 5 × 1016 ions / cm2 up to 5 × 1018 ions / cm2 are determined using argon ions. The transmission of these samples in the wavelength range 200–2500 nm is measured. In addition, the color intensity, ΔE (the color difference between the non-exposure Makrofol sample and samples exposed to different argon ion fluence), is calculated. The color intensity increased with increasing argon ion fluence, indicating a significant color difference.

Reliable determination of radon adsorption properties in candidate adsorbents is essential for developing highly sensitive methods capable of measuring low 222Rn activity concentrations in air. Such measurements are increasingly important in environmental monitoring, climate research, and low-background experiments. Conventional approaches for determining the adsorption coefficient and heat of adsorption are labor- and time-intensive, limiting their suitability for comparative studies under identical conditions. Here, a recently proposed method is applied for the first time in a systematic comparative study. The approach couples solid-state nuclear track detectors (SSNTDs) with adsorbents that simultaneously act as radon collectors and alpha emitters, enabling fully parallel exposure and signal acquisition across multiple samples. Eight adsorbents—three activated carbon fabrics, two bulk activated carbons, and three synthetic zeolites—were evaluated simultaneously over a temperature range of 0–46.5 °C. Activated carbon fabrics exhibited the highest adsorption coefficients, with ACC-5092-10 reaching 11.8 ± 1.3 m3/kg at 20 °C. The heats of adsorption ranged from 24.8 ± 3.9 to 33.3 ± 5.0 kJ/mol, consistent with the literature values. For synthetic zeolites, the adsorption coefficient increased linearly with the Si:Al ratio. The influence of water content was further investigated for the five best-performing materials. The most hydrophobic material, zeolite SA-25 (Si:Al = 25), showed only a 25% reduction in adsorption coefficient under saturated humidity, whereas activated carbons exhibited strong suppression. These results demonstrate the practicality, sensitivity, and efficiency of the SSNTD–adsorbent method for comparative radon adsorption studies.

ABSTRACT The structural, optical, fluorescence, dielectric, and electrical changes that PM-355 nuclear track detector films undergo after being exposed to gamma-ray radiation dosages between 30 and 270 kGy are examined in this work. X-ray diffraction examination showed widening, a shift toward higher diffraction angles, and an increase in peak intensity, all of which were indicative of increased structural disorder and crosslinking together with chain scission. Through the weakening of distinctive C–H, C–O–C, and carbonate groups, as well as the creation of novel oxygenated species, FTIR spectra verified radiation-induced degradation. The creation of conjugated structures, color centers, and carbon-rich clusters was linked to a redshift in the absorption edge and a notable decrease in the direct bandgap (4.15 → 3.40 eV) and indirect bandgap (3.60 → 2.60 eV), according to UV – Vis research. Fluorescence analyses confirmed spectrum shifts linked to defect formation and improved non-radiative recombination pathways, as well as a dose-dependent drop in emission intensity (hypochromic impact). Dielectric tests revealed that as the dose rose, the dielectric constant, dielectric loss, and relaxation time increased. These findings were compatible with defect development, interfacial polarization, and increasing dipolar contributions. The associated barrier-hopping mechanism of charge transport was validated by the drop in the frequency exponent and the increase in AC conductivity with both frequency and radiation dose. Under gamma-ray irradiation, PM-355 films generally display variable structural and optoelectronic characteristics, underscoring their promise for sophisticated photonic, sensing, and radiation-dosimetry applications.

An effective technique for simulation of low-salinity waterflooding with detailed ion tracking

We present a phenomenological study demonstrating the feasibility of using olivine xenoliths from the Chaîne des Puys as a time-resolved paleo-detector array to probe the cosmic-ray flux over the last 40,000 years. This volcanic region provides a unique chronosequence of samples brought to the surface by well-dated eruptions. By modeling the expected density of nuclear recoil tracks induced by cosmic-ray muons in olivine, we show that the signal is detectable and above backgrounds from natural radioactivity. We demonstrate that by analyzing samples with different exposure ages, it is possible to construct a time-differential measurement of the cosmic-ray flux. This method shows sensitivity to historical variations, such as the enhanced flux expected during the Laschamp geomagnetic excursion (∼ 41 kyr) and the potential contribution from nearby supernovae, for which we use the Antlia supernova remnant precursor as a benchmark. This work establishes a new application of the paleo-detector technique for long-scale time-domain high-energy astrophysics and provides direct scientific motivation for experimental efforts to measure these track records.

Fluorescent Nuclear Track Detectors (FNTDs) provide high spatial resolution, wide linear energy transfer coverage, and reusability, making them well-suited for high-energy neutron dosimetry. When neutrons traverse a polyethylene converter, recoil protons are generated, and their tracks are stored inside the FNTDs and visualised through optical readout. Traditional analysis of FNTD images relies on deterministic algorithms or machine learning methods with explicit feature definition, limiting their general extension. In contrast, deep learning networks can extract image features enabling generalisation across different neutron energy spectra and dose values. In this study, a deep learning network was trained on images of FNTDs irradiated at six mono-energetic neutron energies and tested on images of FNTDs exposed to a broad-spectrum 241 Am-Be neutron source. Using raw images of irradiated FNTDs as input, the network predicted the proton tracks which were later counted. For the 241 Am-Be test dataset, a dose–response curve of identified tracks over ambient dose equivalent was fitted, and the sensitivity in terms of H ∗ ( 10 ) was extracted from the slope. When the fit was applied on the whole H ∗ ( 10 ) range, from 0 mSv up to 100 mSv, the predicted sensitivity for 241 Am-Be was S p r e d = ( 2280 ± 20 ) tracks mSv − 1 cm − 2 . The relative deviation of this predicted sensitivity from the reference sensitivity was 5.8%. When the fit considered only the H ∗ ( 10 ) range of the training dataset, namely from 5 mSv to 15 mSv, the predicted sensitivity for 241 Am-Be was S p r e d = ( 2500 ± 60 ) tracks mSv − 1 cm − 2 . This led to a relative deviation from the reference sensitivity of only 1.2%. Despite being trained solely on mono-energetic data, the model successfully generalised to the 241 Am-Be energy spectrum. • Fluorescent Nuclear Track Detector (FNTD) images segmented with deep learning. • The self-configuring nnU-Net framework was used for FNTDs. • FNTDs irradiated with mono-energetic neutrons were used as the training dataset. • Successful track identification of recoil protons. • FNTDs irradiated with broad spectrum 241 Am-Be properly predicted.

Exposure to natural radioactivity from building materials, particularly granites, poses significant health risks through gamma radiation and radon emissions. This study investigated eighteen commercially available Turkish granite samples to characterize their radiological properties and assess associated health risks. Activity concentrations of 226Ra, 232Th and 40K were measured using high-purity germanium (HPGe) gamma spectrometry following 30-day secular equilibrium, while radon exhalation rates were determined using LR-115 Type II solid-state nuclear track detectors with a four-week exposure period. The measured activity concentrations ranged from 11 ± 3 to 202 ± 12 Bq kg−1 for 226Ra, 15 ± 3 to 198 ± 11 Bq kg−1 for 232Th and 357 ± 38 to 1655 ± 124 Bq kg−1 for 40K. Radon concentrations varied between 120 ± 40 and 2840 ± 300 Bq m−3. Radiological hazard indices revealed that five granite types (Rosa Porino, Carmen Red, Giresun Mink, Balıkesir Gray and Kozak Granite) exceeded the recommended safety limit for radium equivalent activity (Raeq > 370 Bq kg−1), external hazard index (Hex > 1) and internal hazard index (Hin > 1). The annual effective dose rate (AEDR) ranged from 0.27 to 2.63 mSv y−1, with seventeen samples exceeding the UNSCEAR reference level of 0.41 mSv y−1. Furthermore, eleven samples (61%) exceeded Turkey's indoor radon reference level of 400 Bq m−3. These findings indicate that several Turkish granite varieties pose significant radiological risks when used in indoor environments. The study highlights the need for mandatory radiological screening of building materials and implementation of mitigation strategies to ensure public health protection.

Ultra-high dose-rate (FLASH) irradiation can transiently deplete oxygen and modulate radical-mediated chemistry in irradiated cells. Cellular antioxidants also contribute to mitigating oxidative damage in a manner dependent on linear energy transfer (LET), as suggested by recent experimental studies. In this work, we employed our multi-track Monte Carlo simulation framework (IONLYS-IRT) to investigate how LET influences transient radiation-induced oxygen depletion (ROD) in a cell-like aqueous environment under FLASH irradiation conditions. FLASH exposures were modeled as single, instantaneous pulses of protons with energies from 300 MeV to 150 keV, corresponding to LET values of ~0.3 to 71 keV/μm. Our simulations revealed a marked decline in oxygen depletion with increasing LET, in agreement with experimental observations. For an intracellular O2 concentration of 30 μM, the oxygen consumption yield, G(-O2), decreased from ~4.0 molecules/100 eV at low LET (~0.3 keV/μm) to ~1.6 molecules/100 eV at high LET (~71 keV/μm), representing a ~60% reduction. To assess whether ROD depends solely on LET or is also governed by ion track structure, we systematically compared multiple ion species (protons, 4He2+, 10B5+, 12C6+, 16O8+, 20Ne10+, 28Si14+, 32S16+, and 40Ar18+) at comparable LET values. At ~70 keV/μm, heavier ions produced significantly higher G(-O2) values than protons-though still below those at low LET-suggesting that track structure plays a key role beyond LET alone. These findings highlight the dual importance of LET and ion-specific track structure in modulating ROD under FLASH conditions. Notably, enhanced ROD in surrounding normal tissues (low-LET plateau regions) may contribute to radioprotective effects, whereas reduced ROD in tumor tissues (high-LET Bragg peak regions) would be expected to preserve tumoricidal efficacy. Together, these results provide a mechanistic framework for optimizing proton and heavy-ion approaches in FLASH radiotherapy.

Boron nitride coatings for the enhanced detection of neutrons in CR-39

Nuclear track detectors evaluation for radon activity concentration measurements.

Evaluating the health impact of indoor radon concentration in laboratory environments: a focus on lung cancer risk

In this study, samples were collected from three areas of the Iraqi marine environment, where fish are caught to be marketed to local markets for use as food. The study area includes coral reef, Khor Abdallah, as well as Um Qaser Port. Using the closed cylinder technique with Solid State Nuclear Track Detector (SSNTDs) CR-39. The concentration of Radon-222 was measured, as well as the radium equivalent, in addition to the emission per unit area and the emission per unit mass. The results are arranged by region as follows: In the Coral Reef, the lowest value was found in the bivalve Corbicula and was 14.01±4.68 Bq.m-3, while the highest concentration of Radon-222 gas isotope value was in the shrimps; 69.52±19.33 Bq.m-3 , with an average value of 28.69±9.1 Bq.m-3. In Kohr Abdallah, the lowest concentration of Radon-222 gas isotope value was found in the Laevicardium sample, it was 16 Bq.m-3 , while the highest value was in the Shrimps too, which was 61 Bq.m-3. This value is close to the value of the shrimps in the coral reef area, with the average value 37±11.2 Bq.m-3. In the Um Qaser area, the lowest concentration of Radon-222 9.93±3.76 Bq.m-3 was found in Cerithium scabridum whereas the highest value was 29.03±8.84 Bq.m-3 and found in the Anemones sample. Based on the measurements taken in this study, in which the concentration of radioactive Radon-222 isotope was calculated, it appears that the measured concentration values are within the acceptable range, and therefore the use of these samples does not pose a risk if used.

Abstract We report formation of ion tracks in amorphous and crystalline silicon by swift heavy ions of 100 MeV Au ions. These tracks contained new allotropes of amorphous silicon, namely high-density (HD) Q-silicon and low-density (LD) α -Silicon, providing evidence for polyamorphism in amorphous silicon. These ion tracks exhibited room-temperature ferromagnetism with tremendous potential for integrating spintronics with microelectronics for novel quantum devices. Using HR STEM-Z (HAADF), we determined that the tracks contained HD Q-Si and LD α -Si in both amorphous and crystalline silicon. The tracks were wider in amorphous silicon compared to crystalline silicon. Thermal properties of silicon played a critical role in the formation and the size of tracks. We discuss a model based upon melting along the tracks and rapid quenching to explain the formation of Q-Si and α -Si based upon undercooling. The Q-Si with nanostructuring as rings and strings showed robust ferromagnetism with a Curie temperature over 500 K. Graphical abstract