Nuclear Analysis最新文献

The recent advancements in neutron scattering technologies in China, with the development of China's first Spin-Echo Small-Angle Neutron Scattering (SESANS) spectrometer at China Mianyang Research Reactor (CMRR) and the integration of a Very Small Angle Neutron Scattering (VSANS) instrument at China Spallation Neutron Source (CSNS), have significantly bolstered the nation's scientific capabilities. This review aims to highlight the distinctive features and applications of SESANS and SANS, and to offer a valuable contribution by demonstrating how SESANS and SANS can be leveraged for the study of soft matters and solid-state materials, with a particular emphasis on the benefits of techniques such as chain labeling, contrast variation, and contrast matching. We also aim to illustrate what types of information can be gleaned from these methods. The review is structured to first introduce the general concepts of SANS and SESANS, followed by a discussion on the information these techniques can provide. Then the applications of these techniques, in combination with other techniques, on various material investigations will be demonstrated. The review concludes with a summary and future perspectives, aiming to inspire further interdisciplinary research and collaboration, and beneficial to a broader audience.

This study uses Monte Carlo simulations to examine the dose enhancement effect of gold nanoparticles (AuNPs) in radiation therapy and its effects on DNA damage. Using the GATE- 9.0 and Geant4-DNA packages, Monte Carlo simulations were used to simulate a mathematical phantom and determine the energy deposition in the vicinity of AuNP. The simulations were conducted for various photon beam energies (50, 100, 250, and 6000 keV) with and without the presence of different-size AuNPs (10, 30, 50 and 100 nm). The dose enhancement factor (DER) was evaluated using Geant4-DNA to examine the effects AuNP sizes and photon beam energies on DNA damage. A multi-scale Monte Carlo simulation was conducted to evaluate enhanced DNA damage owing to nanoparticles in the proximity of cancer cells. The Monte Carlo simulations indicated that AuNPs boost the dose delivery, resulting in enhanced energy deposition and subsequent DNA damage. The DER analysis revealed a significant increase in the dose deposition within DNA, leading to single or double-strand breaks. Geant4-DNA simulations revealed information on the dosage enhancement factor for various AuNP sizes and photon beam intensities, enabling a deeper comprehension of the underlying mechanics. The outcomes of this study emphasize the potential of AuNPs as effective radiosensitizers in radiation therapy and contribute to the growing body of research on the use of nanotechnology in enhancing cancer treatment outcomes. Further investigations and experimental validations are necessary to optimize the usage of AuNPs for improved radiation therapy.

The objective of this study is to assess natural activity in soil to estimate potential radiological risks for the population. Given that soil is inherently radioactive and can reach hazardous levels, it is crucial to determine the activities of radionuclides such as Potassium-40 and Uranium-238 descendants at different depths and geographical positions. For this work, gamma spectrometry method was employed to analyze soil samples collected at three different positions in the Missour region. Each position was sampled at five different depths, spaced 5 cm apart, resulting in a total of 15 samples. The activity of Potassium-40 and Uranium238 descendants in the soil was accurately assessed using Lvis software, enabling the estimation of radiological doses.

With a suitable half-life and abundant radiolabeling strategy, ²²⁵Ac has become one of the most promising radionuclides in the area of targeted alpha therapy. However, limited radionuclide supply is threatening the development of ²²⁵Ac related endoradiotherapy dramatically. As the parent nuclide of ²²⁵Ac, ²²⁹Th can be produced via ²²⁶Ra(3n, 2β)²²⁹Th reaction in a nuclear reactor. However, related practice has not been conducted in large scale, since the nuclear reaction pathway for producing ²²⁹Th is complicated. In this work, the feasibility of producing ²²⁵Ac/²²⁹Th in a reactor was confirmed by systematic theoretical calculations, and a procedure that combines irradiation with separation process was proposed. The results show that 176 MBq of ²²⁹Th can be produced by irradiating 1.0 g of ²²⁶Ra with a neutron flux density of 1 × 10¹⁵ n cm⁻² s⁻¹ for 90 days. This will generate 150 MBq of ²²⁵Ac monthly from a radionuclide generator, which is sufficient for the single treatment cycle of 200 patients each year considering the radioactivity loss in radiochemical separation, transfer and radiolabeling process. In addition, this irradiation process will also produce 37.8 GBq ²²⁷Ac for the preparation of ²²⁷Ac-²²⁷Th-²²³Ra generator. In general, the production of ²²⁵Ac by neutron irradiation of ²²⁶Ra in reactor is practicable and holds potential to alleviate the shortage of current supply of ²²⁵Ac.

Well water quality has been characterized with constant and continuous changes via the interaction of rock, soil and natural nano-filters which terminates at the aquiferous layer for clean well-water collection. The continuous exploration and production of crude oil has resulted significant increase of unwanted elements such as naturally occurring radionuclides in the water-bed which necessitates this study. The study determines the radionuclides based health impact or hazards associated with drinking water from crude oil exploration/production release in Ughievwen and Udu communities of Delta State, Nigeria. Sixty well water samples (three samples from each community) were collected and analyzed using sodium iodide (Nal (Tl)) detector. The obtained mean values of ²³⁸U, ²³²Th and ⁴⁰K are 6.91 $\pm$ 1.62BqL⁻¹, 4.39 $\pm$ 1.47 BqL⁻¹ and 24.54 $\pm$ 1.59 BqL⁻¹ respectively. The ²³⁸U, ²³²Th and ⁴⁰K results showed that the measured values are higher than the world standard (UNSCEAR; WHO) and the control values The mean values of total annual effective dose of different age groups are: 11.08 mSvy⁻¹, 2.54 mSvy⁻¹, 1.93 mSvy⁻¹, 2.52 mSvy⁻¹, 7.03 mSvy⁻¹ and 1.12 mSvy⁻¹ respectively. While the mean committed effective dose of adult is 55.94 mSvy⁻¹. The total annual effective dose, committed effective dose, cancer risks and hereditary effects are all lower than recommended limit (WHO; ICRP; USEPA) and reported scientific values except 11.08 mSvy⁻¹ and 7.03 mSvy⁻¹ that are higher than limit. It is evident from obtained results that the drinking water may not be radiologically safe for use by the public, which necessitates routine monitoring and caution to circumvent increase in radiation and the radiological of the studied communities’ drinking water. This is to avoid long term radiological risk arising from accumulation of such release in the studied communities.

This article examines the impact of temperature on the steel collimator cap and the primary beam shutter. These components will be used to implement the Prompt Gamma Activation Analysis (PGAA) technique in the Moroccan TRIGA Mark-II research reactor. The steel collimator plug is essential for forming the neutron beam, while the main role of the shutter is to stop the beam when the channel is inactive. This study analyzes the effect of temperature on the collimator and shutter system, particularly focusing on the variation in maximum temperature over a month of operation with 8-h cycles per day, the behavior of temperature over 24 h, the total heat flux as a function of the length of the experimental device, the temperature distribution in mild steel (E235) and 304L stainless steel materials, and the total displacement and strain gradient as a function of temperature. All calculations were performed using COMSOL Multiphysics simulation software, based on the finite element method.

This study investigates the critical significance of anode material selection in defining the energy spectrum and properties of X-ray photons in medical physics applications. Using the GATE platform and Monte Carlo simulations, a direct relationship between anode material atomic number and photon fluence is demonstrated. As the atomic number increases from Z = 29 (Copper) to Z = 74 (Tungsten), photon fluence rises by 62 %, indicating a substantial impact on X-ray production. Furthermore, the X-ray spectrum is affected by this material-driven changes, revealing a noticeable shift towards higher energy values: the mean energy of the continuous spectrum rises from 46.97 keV for Copper to 49.0 keV for Tungsten. The thermal properties of the material affect the temperature increase at the focal point. Rhodium and Molybdenum have a higher temperature rise than Copper (Cu) and Tungsten (W), because Cu and W have a greater thermal diffusion compared to other materials. These findings underscore the significance of anode material choice in optimizing X-ray systems which may enhance diagnostic accuracy and efficiency in diverse applications.

This study delves into the thermal dynamics induced by an electron beam sourced from the CIRCE III accelerator, focusing on a lead target previously employed at the National Centre for Nuclear Science and Technology (CNSTN) in Tunisia for neutron and photon production. Leveraging FLUKA software, we simulate the intricate interplay between electrons and the target surface, analyzing variations in deposited energy across different target thicknesses. Beyond elucidating the electron-target interaction, our investigation extends to predicting crucial parameters such as the maximum operational threshold and surface temperature distribution of the target. To achieve this, a computational model harnessing the finite volume method is employed, offering insights into the thermal response dynamics and paving the way for optimized operational protocols and target design refinements. Through this comprehensive analysis, we aim to advance the understanding of thermal phenomena in electron-target interactions, thereby bolstering the efficiency and safety of particle accelerator operations in diverse scientific applications.