An innovative electrostatic particle accelerator was developed by INFN and Padova University. The high voltage generation scheme is based on a recent technique which generates it through series connection of lower voltage stages made of independently stabilized generators, each one providing a remotely settable voltage, actively controlled at about 2.0 & times; 10-4 V/V stability. All the power needed for the operation is supplied to each stage by laser light fed to high efficiency photovoltaic cells through optical fibres. The all-optical feeding scheme decouples each stage from other stages and ground reference. The maximum attainable voltage is thus limited only by the insulation of the last stage with respect to the mechanical structure of the container. We tested electrical insulation provided both by a dielectric liquid and high-pressure gases, choosing the former one eventually. The accelerator, produced in a tandem scheme, with a stripping carousel for continuous operation, was fully engineered, assembled and tested for high voltage, yet without ion beam. The concept, the design, the realization and the experimental results will be discussed.
161Tb is a promising radionuclide for targeted beta therapy due to its favorable half-life, (3- emission, and coemission of Auger/conversion electrons. In this study, its production was systematically investigated via three neutron irradiation pathways: direct 159Tb irradiation, indirect irradiation of natural gadolinium, and enriched 160Gd targets. An integrated computational framework combining MATLAB-based analytical modeling using Bateman chain equations and MCNPX 2.6.0 Monte Carlo simulations was applied to predict time-dependent activity evolution, assess impurity formation, and evaluate radionuclidic purity under identical irradiation conditions. The analytical model accurately reproduced the overall trends of 161Tb and co-produced isotopes, while MCNPX provided detailed insights into neutron transport, spectral effects, and self-shielding. Among the routes, enriched 160Gd yielded the highest 161Tb activity with minimal long-lived impurities, natural gadolinium provided a balanced compromise between yield and purity, and direct 159Tb irradiation was limited by significant 160Tb co-production. This combined approach offers a robust, predictive, and efficient platform for optimizing 161Tb production, guiding experimental design, and supporting the development of high-purity therapeutic radiopharmaceuticals.
A TE211-mode Single Hybrid Cavity linear accelerator (TE211-mode SHC linac) is an ion linac with a 4-vane RFQ and a double IH-DTL in a single cavity. A double IH-DTL incorporates drift-tubes inside from alternating horizontal and vertical directions, excites the TE211-mode and provides gap voltage. A TE211-mode SHC linac excites the TE211-mode to accelerate ion beams in the low energy region (several tens of keV to about 3 MeV) with high efficiency. In this study, a TE211-mode SHC linac proof-of-principle machine was designed and its acceleration properties were evaluated using a beam simulation code. Specifically, the cell parameters of the RFQ electrode and the drift tube were designed. Furthermore, end-to-end beam simulations in the TE211-mode SHC linac were performed to evaluate beam acceleration characteristics.
Museum herbaria are collections of preserved, dried plants, bearing an exceptional value as archives of botanical history and biodiversity, an invaluable resource for modern research in several fields. The Museum of Natural History of the University of Florence (Italy) houses the Florentine Botanical Collections (FI), which include some of the most ancient and largest herbaria in the world, such as the Herbarium Centrale Italicum (FI-HCI). Like many herbaria worldwide, these collections are affected by Hg contamination resulting from the historical use of corrosive sublimate (HgCl2) as a pesticide for specimen preservation. Although this practice was discontinued over a century ago, elemental Hg degassing from the samples and residual Hg compounds on them prevent the full accessibility and valorisation of these collections. This work aims at characterizing the concentrations and in-depth distributions of Hg and other possibly related elements (Cl, and S) within contaminated samples from the Florentine collections using external beam ion beam analysis (IBA) techniques. Nine representative specimens-eight from the 19th century and a recent, untreated one (blank)-were selected for PIXE and EBS measurements, with a 3 MeV proton beam, at the INFN LABEC 3 MV Tandem accelerator. The study revealed that contamination variably affects both the plant matrix and the support paper: Hg concentrations measured on dark stains on paper, which were identified as superficial accumulations of Hg, were significantly higher than those measured on clear paper and on the plant matrix, where Hg penetrates deeply instead. It was also possible to make some hypotheses about the speciation of Hg in the samples.
Tungsten-doped high-density carbon (HDC) target pellets have emerged as promising ablator materials for inertial confinement fusion (ICF) applications. However, ensuring a uniform distribution of dopants and accurately quantifying their concentration remains a challenge. In this study, we present a non-destructive approach for three-dimensional (3D) characterization of tungsten dopants within HDC pellets using Rutherford Backscattering Spectrometry Tomography (RBS-T). A scanning nuclear microprobe system was employed to simultaneously collect RBS and Particle-Induced X-ray Emission (PIXE) data. PIXE analysis revealed an average tungsten concentration of approximately 0.31 atomic percent with uniformity across the pellet. Depth-resolved RBS measurements, conducted with a 5-MeV C3+ ion beam, were segmented into multiple layers with an approximate thickness of 100 nm each. Two-dimensional distribution maps of tungsten at various depths were obtained and subsequently integrated to construct a 3D spatial distribution model. The results demonstrate that RBS-T enables 3D mapping and concentration measurement of the tungsten dopants within HDC pellets, effectively overcoming the limitations inherent in PIXE-based tomography for completely penetrating samples and providing enhanced depth resolution without spectral interference from the carbon matrix. This method offers a robust and alternative means for visualizing dopant homogeneity in ICF target materials.
Calcium oxide obtained from waste chicken eggshells was prepared through high-temperature calcination and its thermoluminescence characteristics under X-ray irradiation were systematically examined. X-ray diffraction analysis confirmed the successful formation of phase-pure cubic CaO with an average crystallite size of approximately 39 nm. Scanning electron microscopy revealed irregular and agglomerated particles with rough and porous surface features. The TL glow curves showed a pronounced dependence on annealing temperature, and the maximum TL intensity was achieved for samples annealed at 500 degrees C. Analysis based on the T-m-T-stop method combined with glow curve deconvolution indicated the presence of multiple trapping levels, including both shallow and deep traps with activation energies ranging from 0.91 to 1.32 eV. These trapping centers contribute to the material's high sensitivity as well as its long-term signal stability. Additionally, activation energies were determined using the Initial Rise Method based on the Ln(I) vs 1/T and E vs T-stop plots, revealing the temperature dependence of trapping centers in CaO. The TL dose-response exhibited approximately linear behavior up to similar to 2 Gy, with a slope of 0.98 on a log-log scale, followed by a slight sublinear deviation at higher doses. Fading measurements demonstrated that a considerable fraction of the TL signal was preserved after 35 days of storage, and reusability tests confirmed stable TL performance over repeated irradiation-readout cycles. Overall, the results suggest that eggshell-derived CaO represents a low-cost and environmentally friendly TL material with potential for low-dose X-ray dosimetry applications.
Treatment of yttria-stabilized zirconia (YSZ) ceramics by a pulsed low-energy (8 keV) electron beam in He or O2 at pressure of 8 Pa provides to change the surface properties of the YSZ ceramics. Tailored smoothing or roughening of the ceramic surface can be realized by variation of the energy density and power per pulse of the electron beam. A layer with columnar structure is observed when the e-beam energy density reaches threshold value (9 J/cm2), and rather high power per pulse (>= 338 kW per pulse) is required to form this layer. The thickness of the columnar structured layer increases with increasing beam energy density. Increased surface microhardness, from 11.1-11.2 GPa up to 18-20 GPa, is observed when the columnar structured layer is formed. Compared to helium, the e-beam treatment in oxygen maintains the original white color of YSZ ceramics at threshold energy density and slightly higher.
In order to provide a scientific basis for a comprehensive understanding of the Zhanggongxiang kiln, the black and white porcelain unearthed from the Zhanggongxiang kiln was studied by modern analytical techniques. The research results show that the black and white porcelain unearthed from Zhanggongxiang kiln belonged to the daily life porcelain of people at that time. Most of the black and white porcelain glazes belong to calcium glazes. Limestone and plant ash were used as the glaze flux of white porcelain and black porcelain, respectively, while natural iron ore containing titanium impurities served as the colorant. The iron-rich crystals present in the glaze of the black porcelain sample are mainly magnetite and epsilon-Fe2O3 crystals. The firing temperature of black porcelain is generally higher than that of white porcelain, ranging from 1220 to 1310 degrees C.
High-transmission-efficiency, high-beam-current-density electron guns are pivotal components for breakthroughs in electron beam processing and characterization technologies. This work presents an electron-optics design method addressing two critical working modes: achieving a beam density > 1200 A/cm(2) with a spot size <= 10 mu m, and maintaining a transmission efficiency > 85% for spot sizes of 50-65 mu m. Guided by fundamental electron optics theory, a calculation framework for electron focusing and efficient transmission is established, enabling the optimization design of a high-brightness electron source and an electromagnetic focusing lens. The experimental results demonstrate that the discrepancy between simulation and measurement results is within 5% under the condition with an acceleration voltage of 20 kV and a working distance of 20 mm. This study lays a technical foundation for the development of electron guns featuring high transmission efficiency and high beam current density.
This work studies the main aspects of a simple and reliable gold determination in large-volume mineral samples by NAA. The irradiation source is a Linear Accelerator, and a single detector is the detection system. The report includes i) An experimental evaluation of geometric detection efficiency in big samples (20 to 30 cm3); ii) methods for the calculation of the gamma-ray self-attenuation in the sample, including some based on TOF techniques; iii) tests for gold inhomogeneity in the samples; iv) validation calculations obtained with the MCNP code. Although Linacs with TOF systems are used almost exclusively in materials science, this study demonstrates their potential for gold quantification in mineral samples, producing high-quality results. We conclude that gold analysis performed using this technique would surpass the precision of conventional reactor-based NAA for small samples-approximately 6-7%.
Monoenergetic neutron radiation fields based on the 7Li(p,n)7Be reaction require thin, uniform, and chemically stable lithium targets capable of sustained operation under proton beam irradiation. In this study, lithium fluoride (LiF) targets were designed, prepared, characterized, and tested in proton beam experiments. The target thickness was optimized by trading off neutron fluence and energy spread. The LiF layers were deposited onto silver backings by resistive thermal evaporation under high vacuum. The thickness measured on co-deposited silicon substrates was 455 +/- 3 nm, while gravimetric analysis gave an areal density of 98.24 mu g center dot cm-2. Characterization of the target's physicochemical properties indicated good uniformity and stoichiometry consistency. During the 8 h beam test, the target operated stably, yielding a neutron fluence of 225.8 cm-2 center dot mu C-1 at 0 degrees and 100 cm distance, which agrees with simulations within 10%. The prepared LiF target meets the basic requirements for establishing monoenergetic neutron radiation fields.
Artisanal mining has become a lucrative sector due to rising global demand and prices for rare and rare-earth elements. In Sudan, this informal industry supports rural livelihoods but lacks effective regulation and occupational safety. The absence of protective equipment exposes miners to mercury vapor, dust, and other toxic substances, posing serious health and environmental risks. This study applies Particle-Induced X-ray Emission (PIXE) and Laser-Induced Breakdown Spectroscopy (LIBS) to analyse toxic and essential trace elements in miners' hair, used as a non-invasive biological indicator of chronic exposure. Elements detected include S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Sr, and Pb. Multivariate analysis through Principal Component Analysis (PCA) and binarization reveals elemental correlations and exposure patterns. The integrated PIXE-LIBS approach offers a robust framework for biomonitoring, occupational safety improvement, and sustainable artisanal mining practices in Sudan.
Structural materials in fusion reactors simultaneously experience transmutation helium production and displacement damage; while the synergistic effects on the evolution of irradiation-induced defects and the resulting hardening remains incompletely understood. In this work, T91 steel was implanted with 2000 or 6000 appm He at 450 degrees C followed by 3.25 MeV Fe13+ irradiation. Under subsequent Fe irradiation, helium bubbles at 2000 appm exhibited larger average size but lower density, whereas those at 6000 appm were significantly refined with a 3.4-fold increase in number density. Notably, irradiation hardening in the 2000 appm sample was slightly lower than in the Fe-only reference. In contrast, 6000 appm helium led to pronounced hardening, far exceeding both Fe-only and 2000 appm cases. This non-monotonic hardening stems from He-dependent vacancy trapping and defect coupling: at 2000 appm, bubbles mainly mitigate loop-controlled hardening, whereas at 6000 appm dense bubbles and bubble-loop complexes dominate the obstacle field and enhance hardening.
The China Institute of Atomic Energy (CIAE) is developing a proton cyclotron with an energy of 9.5 MeV and a current of 100 mu A. To evaluate the performance of the cyclotron, the beam dynamics study has been conducted. Static and dynamic orbit analyses combined with phase-space matching were used to assess its beam acceptance and acceleration capability. Particle tracking simulations were employed to calculate characteristics such as radial centering and axial focusing, and the structure was optimized accordingly. The extracted beam parameters were controlled by adjusting the tilt angle of the stripping foil. The phase acceptance of this cyclotron exceeds 60 degrees, and the beam size at the liquid target is 1.35 mm & times; 2.01 mm. The cyclotron has entered the beam commissioning stage, with measured beam currents of 107 mu A at the internal target and 65 & micro;A of extracted beam current at the Faraday cup after stripping.
Carbon ion therapy offers substantial advantages over conventional radiotherapy; however, the uncertainty in range verification remains a major barrier to its broader deployment. To address this limitation, we propose a miniaturized monitoring system based on a cross-strip CdZnTe (CZT) detector that measures secondary particles during carbon ion irradiation to provide range feedback. A channel-compression circuit was integrated into the detection system to reduce the number of readout channels and overall system complexity. Experiments performed at the Heavy Ion Medical Machine (HIMM) terminal showed that carbon-ion irradiation of polymethyl methacrylate (PMMA) produced abundant secondary particles that interacted with the detector and generated electrical signals. For carbon ion energies ranging from 160.86 to 221.48 MeV/u, we monitored the relationship between monitor units (MU) over beam-cycle timescales and the total secondary particle counts and quantified the dependence of Ratio epsilon (total counts per MU) on the measured range. The results show a linear dependence of total secondary particle counts on MU over a few beam cycles and a linear relationship between Ratio epsilon and beam range. At MU = 3.1 & times; 106, the proposed method achieved an average range deviation of 0.80 mm relative to film measurements, with a maximum deviation of 1.61 mm. The relationship between the reconstructed count distribution at the CZT detector anodes and carbon beam range was further investigated using small energy increments. At 184.59 and 190.19 MeV/u, the response curve of the CZT detector anode count yielded deviations of 1.58 mm and 0.52 mm for the Bragg-peak and maximum-count positions, respectively. These findings demonstrate the feasibility of combining channel compression with a strip CZT detector for compact dose and range monitoring. By measuring secondary particle counts, the MU could be estimated over fewer beam cycles and converted to a relative dose, and the range was determined with millimeter-level accuracy, thereby reducing the uncertainty associated with both parameters.
A design scheme for an electron-driven intense slow positron source has been proposed based on a low-energy, high-power accelerator. Considering the heating in the target and extraction and focusing of slow positron, the parameters of the electron linear accelerator, positron target, moderator and electrostatic lens are chosen to obtain the high positron flux. In this paper, the simulation and evaluation of energy deposition on the target, heat of the water-cooling system and slow positron flux, shows the feasibility of the compact and intense positron source based on the low-energy, high-power accelerator.
Photoneutron cross sections were extracted for isotopes of ruthenium and molybdenum on natural abundance targets via a reduced chi-squared analysis on excitation functions, or activation yields, as function of electron beam energy. Bremsstrahlung photons were produced via an electron linear accelerator and a tungsten radiator at the Idaho Accelerator Center. A total of 16 irradiations were performed with electron beam energies ranging from approximately 8 MeV to 23 MeV. Induced radioactivity was measured using a high purity germanium detector. The cross sections were extracted assuming a three parameter Lorentzian fit with a smooth truncated rise at reaction threshold.
Although particle accelerators support adjusting the energy of the charged particles directly, a finer energy resolution can be achieved with passive elements (degraders). However, this method disperses the energy distribution.Using a simplified stopping power law valid over part of the Bethe-Bloch regime at the lower end, we developed an analytical model for the energy distribution as function of traversed distance. We show the model’s predictive capabilities using simulation data from Gate/Geant4. Among other results, 10 energy distributions (mean energies from >170MeV to <25MeV) were predicted with r2>0.98 when using only the initial distribution (no degrader) and literature data as input. From the predicted distributions, the fraction of remaining primaries was estimated with r2>0.998. This quantity is essential for many applications, e.g. single event effect testing using the variable-depth Bragg peak method.
This study proposes a physics-informed Deep Fully-Connected Neural Network (Deep FC-NN) to rapidly predict radial electron-hole pair density distributions induced by heavy ions in silicon. The model, featuring an encoderdecoder architecture with six hidden layers, is trained on Geant4 simulations covering atomic numbers 3-70, energies 10-2000 MeV/n, and silicon thicknesses 2-30 mu m. Benchmarking against ResNet, SVR, and KNN demonstrates superior Deep FC-NN performance, achieving Coefficient of Determination (R2) of 0.9366 and Mean Squared Error (MSE) of 0.1014 in logarithmic space-significantly outperforming alternatives. The framework provides an efficient tool for ionization track structure analysis in radiation effects research.
This study investigated the distribution, biogeochemical behavior, and radiological impact of I-129 in seawater and rockfish (Sebastes cheni) off southern Fukushima during 2014-2015, three to four years after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Seawater I-129 concentrations exhibited pronounced surface enrichment, decreasing from 158 & times; 10(7) atoms L-1 at the near-surface (similar to 0 m depth) to (8.65-8.78) & times; 10(7) atoms L-1 at 15.0-17.4 m depth. The mean I-129 concentration (52 +/- 36) & times; 10(7) atoms L-1 (n = 4; mean +/- standard error of the mean, SEM), remained one to two orders of magnitude higher than the pre-accident levels. In rockfish, I-129 concentrations ranged from 386 to 915 & times; 10(7) atoms kg(-1)-wet weight (w.w.) (5.40-12.8 & micro;Bq kg(-1)-w.w.), with concentration factors (CFs) of 7.4-18 L kg(-1). These CFs were approximately one order of magnitude higher than those of stable I-127 CFs (1.12-2.36 L kg(-1)) but notably lower than the equilibrium CFs for stable Cs. The I-129/Cs-137 activity ratio in the whole-body sample (2.58 & times; 10(-7)) was consistent with the FDNPP reactor inventory, while the muscle samples exhibited lower ratios ((1.21-1.53) & times; 10(-7)) due to tissue-specific accumulation of Cs-137. The committed effective dose from I-129 ingestion via rockfish muscle (the edible part) was estimated at 14-33 pSv y(-1), confirming that the radiological risk is negligible compared to natural dietary radiation. These results highlight the persistence of I-129 in the coastal surface layer and provide the first field-based evidence of its bioaccumulation in rockfish off Fukushima during the mid-term recovery phase.
