• Journal of radiological science and technology
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• v.11 no.2
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• pp.3-15
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• 1988

When X-rays were projected into a patient, there occured the phenomena such as penetration, absorption and scattering etc. The penetrating rays were recorded on films as X-ray image used for diagnosis but scattered rays caused the radiation hazard both to the patient, specialist and technicians. The soft tissue includes many organs which are sensitive to the radiation and in may occupy $40{\sim}50%$ of body weight. Therefore X-rays should be carefully projected to the patient and it is strongly recommended to analyse the distribution of X-rays, when ever the patient is exposed to X-rays. In this study, the distribution of X-ray according to the thickness, the radiation field and the tube voltages (kVp) in soft tissue, the following results were obtained: 1. Total transmitted rays which kept the step with X-ray tube voltage (kVp) increased in proportion to the increasing of X-ray tube voltage. 2. The scattered ray rate in the total transmitted ray was not significantly found with X-ray tube voltage. 3. The affecting factors of the scattered ray rate in total transmitted ray were shown through the radiation field and the thickness. 4. The dose of scattered ray by the angle was observed more in direction of primary ray ($0^{\circ}$) and back scattering ($160^{\circ}$) than in direction of $90^{\circ}$. 5. The more the distance from phantom to the patient should be less distribution of scattered ray.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.301-307
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• 2013

In the present study, space doses generated during X-ray radiography of hand, head, and abdomen, etc. were examined and whether the intensity of space doses of scattering rays is attenuated by the "inverse square law of distance" was figured out. First, the space doses of X-ray with small amounts of generated scattering rays such as hand radiography were mostly attenuated by the "inverse square law of distance" and were not detected at all at a distance of 2m. Second, the space doses of X-ray with large amounts of generated scattering rays such as head or abdomen radiography attenuated in higher rates than the rates under the "inverse square law of distance" at distances ranging from 30cm to 1m from the center of the irradiation field and were attenuated by the "inverse square law of distance" at distances ranging from 1m to 2m. Therefore, in X-ray rooms, the subject should be at least 2m away from the center of the irradiation field in the case of hand radiography and X-ray exposure prevention actions using protective devices are required in the entire spaces of the X-ray rooms in the case of head or abdomen radiography.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.181-181
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• 2013

Recently, nanostructure and the molecular orientation of organic thin films have been largely paid attention due to its importance in organic electronics such as organic thin film transistors (OTFTs), organic light emitting diodes (OLEDs), and organic photovoltaics (OPVs). Among various methods, the diffraction and scattering techniques based on synchrotron x-rays have shown powerful results in organic thin film systems. In this work, we introduce the in-situ annealing system installed at PLS-II (Pohang Light Source II) for organic thin films by simultaneously conducting various x-ray scattering measurements of x-ray reflectivity, conventional x-ray scattering, grazing incidence wide angle x-ray scattering (GI-WAXS) and so on. Using the in-situ measurement, we could obtain real time variation of nanostructure as well as molecular orientation during thermal annealing in metal-phthalocyanine thin films. The variation of surface and interface also could be simultaneously investigated by the x-ray reflectivity measurement.

• Journal of the Korean Ceramic Society
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• v.34 no.1
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• pp.109-113
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• 1997

When the intensity of X-rays scattered from amorphous materials (very weakly absorbing materials) is measured using standard diffractometric technique, the intensity caused by multiple scattering is obtained in the measured X-ray intensity. Computer programs have been developed to estimate the intensity of the mul-tiple scattering obtained in vitreous SiO2 and B2O3 with various X-rays. Using the above computer program, the intensity ratios of multiple scattering to single scattering in vitreous SiO2 were 0.10~0.16% at CuK$\alpha$, 0.98~5.87% at MoK$\alpha$, and 1.88~17.86% at AgK$\alpha$ in the range of 2$\theta$=0~180$^{\circ}$. Therefore, pri-or to the structural analysis of vitreous SiO2 and B2O3 performed experimentally using X-ray diffractometric technique, the intensity data measured in MoK$\alpha$ and AgK$\alpha$ radiations must be corrected for multiple scattering effect.

• Journal of The Korean Astronomical Society
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• v.27 no.1
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• pp.45-53
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• 1994

We present the calculation of X -ray spectra produced through Compton scattering of soft X-rays by hot electrons in the spherical shell geometry, using fully relativistic Monte Carlo simulation. With this model, we show that the power-law component, which has been observed in the low luminosity state of low-mass X-ray binaries (LMXBs), is explained physically. From a spectral. analysis, we find that spectral hardness is mainly due to the relative contribution of scattered component. In addition, we see that Wi en spectral features appear when the plasma is optically thick, especially in the high energy range, $E{\gtrsim}100keV$. We suggest that after a number of scattering the escape probability approaches an asymptotic form depending on the geometry of the scattering medium rather than on the initial photon spectrum.

• Applied Microscopy
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• v.33 no.4
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• pp.251-259
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• 2003

In this review, the sources and the characteristics of X-rays and electrons and their interactions with matters were described in terms of the atomic scattering factors. The geometrical diffraction conditions were taken into account in terms of Ewald spheres in reciprocal lattice spaces. The effects of the finite size of sources and detectors on diffractions were also considered.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.404-406
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• 2002

We have investigated the contribution of the scattered x rays to the signal imaging in the radiographs acquired with anti-scatter grids of several grid ratios by separating the line spread functions (LSFs) derived from the signal edge image into the primary and the scatter components. By using a 1.0-mm lead plate in the scattering material, the blurred signal edge images were acquired by use of an imaging plate at a tube voltage of 80 kV with the anti-scatter grids of grid ratios for 5:1, 6:1, 8:1, 10:1 and 12:1. The edge profiles of the signal images were scanned and those in relative exposure were differentiated to obtain the LSFs. To investigate the contribution of the scattered x rays to the signal imaging, we proposed a method for separating the LSFs derived from the signal images into the primary and the scatter components, where the scatter component was approximated with exponential function. Our basic approach is to separate the area of the LSFs by ratios of the scattered x-ray exposure to the primary x-ray exposure, which were obtained for the grid ratios by use of a lead disk method. The LSFs and the two components were Fourier transformed to obtain the modulation transfer functions (MTFs) and their two components. As the result, we found that, by using the anti-scatter grids, the scattered x rays were reduced, but the shape of the LSFs of the scatter component hardly changed. The contributions of the scatter component to the MTFs were not negligible (more than 10 %) for spatial frequencies lower than about 1.0 mm$\^$-l/ and that was greater as the grid ratio decreasing. On the other hand, for higher frequencies, the primary component was dominant compared with the scatter component.

• Journal of the Korean Vacuum Society
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• v.14 no.3
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• pp.143-146
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• 2005

A new method of x-ray photon correlation spectroscopy (XPCS) using coherent x-rays is developed recently for probing the dynamics of surface height fluctuations as a function of lateral length scale. This emerging technique applies the principles of dynamic light scattering in the x-ray regime. The short wavelength and slow time scales characteristic of XPCS extend the phase space accessible to scattering studies beyond some restrictions by light and neutron. In this paper, we demonstrate XPCS to study the dynamics of surface fluctuations in thin supported polymer films. We present experimental verification of the theoretical predictions for the wave vector and temperature dependence of the capillary wave relaxation times for the supported polymer films at melt for the film thicknesses thicker than 4 times of the radius of gyration of polymer. We observed a deviation from the conventional capillary wave predictions in thinner films. The analysis will be discussed in terms of surface tension, viscosity and effective interactions with the substrate.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1783-1790
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• 2023

Barium Bismuth Oxide Borate (BBOB) has been synthesized for the first time using solution combustion technique. SEM analysis reveal flower shape of the nanoparticles. The formation of the nanoparticles has been confirmed through XRD & FTIR studies which gives the physical and chemical structure of the novel material. The UV light absorption is observed in the range 200-300 nm. The present study highlights the radiation shielding ability of BBOB for different radiations like X/Gamma rays, Bremsstrauhlung and neutrons. The gamma shielding efficiency is comparable to that of lead in lower energy range and lesser than lead in the higher energy range. The bremsstrauhlung exposure constant is comparably larger for BBOB NPs than that of concrete and steel however it is lesser than that of lead. The beauty of BBOB nanoparticles lies in, high absorption of radiations and low emission of secondary radiations when compared to lead. In addition, the neutron shielding parameters like scattering length, absorption and scattering cross sections of BBOB are found to be much better than lead, steel and concrete. Thus, BBOB nanoparticles are highly efficient in absorbing X/Gamma rays, neutrons and bremsstrauhlung radiations.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.367-373
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• 2020

Most of the spatial scattered dose caused by the scattered rays generated by the collision between the object and X-rays is relatively easily absorbed by the human body as electromagnetic waves in the low energy region, thereby increasing the degree of radiation exposure. Such spatial scattering dose is also used as an indicator of the degree of radiation exposure of radiation workers and patients, and there is a need for a method to reduce exposure by reducing the spatial scattered dose that occurs indirectly. Therefore, in this study, a lead-free radiation shielding sheet was proposed as a way to reduce the spatial scattering dose, and a Monte Carlo (MC) simulation was performed based on a chest X-ray examination. The absorbed dose was calculated and the measured value and the shielding rate were compared and evaluated.