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To validate radiation safety of the ionization source being designed, the results of numerical simulation of dose fields using certified software are used. In this work, an algorithm to assess the radiation environment near a newly designed intense fusion neutron source (MIN facility, Troitsk) is designed and applied. The CORIDA software was used to develop a 3D detailed model of the facility and perform variant calculations of the dose rate fields during pulses and after them taking into account gamma radiation from activated materials. The results obtained made it possible to specify radiation shield parameters and determine the forbidden time intervals after pulses for staff access. [ABSTRACT FROM AUTHOR]

Since the beginning of research into radiation and protection against it, the importance of searching for proper materials against radiation hazards has been recognized. Gamma radiation protection materials usually deal with heavy elements with high prices, which are hard to maintain. Polyurethane-based (PU) materials are popular in sound and thermal insulation due to, their low-weight properties and, most importantly, fast and convenient construction ingredients. PU foams (PUF) can be used as radiation shield and noise and heat resistance due to their approachability, light-weight, high resistance, and comfortable construction. This study involved simulation and an experiment to construct and investigate the properties of Polyurethane material doped with lead oxide as a gamma shield. The shield was considered in several weight fractions of lead, yielding several samples. The MCNPX 2.6 Monte Carlo code has been utilized for simulation procedure, and 137Cs was employed as the gamma source in both simulation and experiment. The results offer a promising response against the gamma radiation and are suitable for attenuating gamma rays. [ABSTRACT FROM AUTHOR]

Background: Radiation shielding in radiology has historically been achieved with lead; however, there has been an increasing demand for radiation shielding to be more environmentally friendly. Barium has shown promise as a substitute in many radiology applications. This study aims to investigate a barium sulphate shield in protecting the thyroid and the eye lens during panoramic radiography. Methods: During a simulated panoramic examination, an anthropomorphic phantom and a solid-state detector measured the radiation dose to the surface thyroid and the eye lens. The measurements were taken using no shield and a barium sulphate shield. A Welch's T-test was employed to compute the shield's effect on radiation. Two radiologists assessed the image quality with and without the thyroid shields. Results: The dose reduction was between 66 and 75% for the barium shield at the thyroid. The dose reduction ranged between 15 and 61% in the eye region. Images using a barium shield were deemed adequate for diagnostic interpretation. Conclusions: Barium shields effectively reduce the radiation dose in the thyroid region during panoramic radiography without degrading image quality. The dose reduction depends on the tube voltage and the area of interest. [ABSTRACT FROM AUTHOR]

A novel material bismuth–copper–boron nanocomposite has been synthesized in the present study using the solution combustion technique. The microstructure of the compound has been studied using SEM, XRD and FTIR techniques which are used to explore the physical and chemical structure of the novel material. The optical properties are studied using a UV–visible analysis. The radiation shielding efficiency has been investigated in detail theoretically and experimentally. Several gamma shielding parameters, neutron and bremsstrahlung shielding parameters have been estimated for the novel material in the present study. The linear and mass attenuation coefficient decreases with an increase in energy whereas the tenth value layer thickness increases with an increase in energy. The radiation protection efficiency is found to be high in the lower energy range when compared to the higher energy range. Crystalline size is determined by PXRD studies which proves the crystalline nature of the novel material. The chemical structure and functional groups are determined by the FTIR analysis and energy gap is found out to be 2.87 eV from UV visible studies. The studied sample has shown good gamma shielding ability in the lower energy range. EDX spectrum confirms the presence of bismuth, boron and copper nanocomposites. In addition, the said material is found to possess good absorption ability for neutrons and bremsstrahlung radiations. [ABSTRACT FROM AUTHOR]

The level of knowledge accumulated to date in the physics and technologies of controlled thermonuclear fusion (CTF) makes it possible to begin designing fusion-fission hybrid systems that would involve a fusion neutron source (FNS) and which would admit employment for the production of fissile materials and for the transmutation of spent nuclear fuel. Modern Russian strategies for CTF development plan the construction to 2023 of tokamak-based demonstration hybrid FNS for implementing steady-state plasma burning, testing hybrid blankets, and evolving nuclear technologies. Work on designing the DEMO-FNS facility is still in its infancy. The Efremov Institute began designing its magnet system and vacuum chamber, while the Kurchatov Institute developed plasma-physics design aspects and determined basic parameters of the facility. The major radius of the plasma in the DEMO-FNS facility is R = 2.75 m, while its minor radius is a = 1 m; the plasma elongation is k = 2. The fusion power is P = 40 MW. The toroidal magnetic field on the plasma-filament axis is B = 5 T. The plasma current is I = 5 MA. The application of superconductors in the magnet system permits drastically reducing the power consumed by its magnets but requires arranging a thick radiation shield between the plasma and magnet system. The central solenoid, toroidal-field coils, and poloidal-field coils are manufactured from, respectively, NbSn, NbTi and NbSn, and NbTi. The vacuum chamber is a double-wall vessel. The space between the walls manufactured from 316L austenitic steel is filled with an iron-water radiation shield (70% of stainless steel and 30% of water). [ABSTRACT FROM AUTHOR]

The variation of air temperature measurement errors using two different radiation shields (DTR502B Vaisala, Finland, and HYTFZ01, Huayun Tongda Satcom, China) was studied. Datasets were collected in the field at the Daxing weather station in Beijing from June 2011 to May 2012. Most air temperature values obtained with these two commonly used radiation shields were lower than the reference records obtained with the new Fiber Reinforced Polymers (FRP) Stevenson screen. In most cases, the air temperature errors when using the two devices were smaller on overcast and rainy days than on sunny days; and smaller when using the imported rather than the Chinese shield. The measured errors changed sharply at sunrise and sunset, and reached maxima at noon. Their diurnal variation characteristics were, naturally, related to changes in solar radiation. The relationships between the record errors, global radiation, and wind speed were nonlinear. An improved correction method was proposed based on the approach described by Nakamura and Mahrt (2005) (NM05), in which the impact of the solar zenith angle (SZA) on the temperature error is considered and extreme errors due to changes in SZA can be corrected effectively. Measurement errors were reduced significantly after correction by either method for both shields. The error reduction rate using the improved correction method for the Chinese and imported shields were 3.3% and 40.4% higher than those using the NM05 method, respectively. [ABSTRACT FROM AUTHOR]

Experiments and calculations were conducted with a 0.13 mm fine wire thermocouple within a naturally-aspirated Gill radiation shield to assess and improve the accuracy of air temperature measurements without the use of mechanical aspiration, wind speed or radiation measurements. It was found that this thermocouple measured the air temperature with root-mean-square errors of 0.35 K within the Gill shield without correction. A linear temperature correction was evaluated based on the difference between the interior plate and thermocouple temperatures. This correction was found to be relatively insensitive to shield design and yielded an error of 0.16 K for combined day and night observations. The correction was reliable in the daytime when the wind speed usually exceeds 1 m s−1 but occasionally performed poorly at night during very light winds. Inspection of the standard deviation in the thermocouple wire temperature identified these periods but did not unambiguously locate the most serious events. However, estimates of sensor accuracy during these periods is complicated by the much larger sampling volume of the mechanically-aspirated sensor compared with the naturally-aspirated sensor and the presence of significant near-surface temperature gradients. The root-mean-square errors therefore are upper limits to the aspiration error since they include intrinsic sensor differences and intermittent volume sampling differences. [ABSTRACT FROM AUTHOR]

Experts expect that even though peaceful use of nuclear power including nuclear power plant is less likely to contribute to average annual radiation exposure level, once accidents occur, it will spell a disaster. This paper is to manufacture a bismuth eco-friendly radiation shield which does not contain lead for providing medical support when national disaster and radioactive accident occur and compare and evaluate the characteristics of the shield and the definition of image by using glass dosimeter and finally to assess its usability. The fact that bismuth radiation shield with 0.5 mm and lead radiation shield with 0.5 mm showed an equal percentage of efficiency is showing that bismuth is suitable as a eco-friendly material replacing lead in the field of medical radiation. This result implies that the eco-friendly radiation shield which is lighter than lead radiation shield can be utilized in the field of medical radiation as a radiation shield decreasing radiation exposure level. It is advised to develop a light weight and eco-friendly radiation shield to reduce radiation exposure level in the field of medical radiation and to obtain optimal medical image. [ABSTRACT FROM AUTHOR]