• Title, Summary, Keyword: $\gamma$-ray

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Immunostimulating Effects of Angelica Gigas by Radio-Protective (당귀의 방사선 방호에 의한 생체면역 증진 효과)

  • Kim Kyung-Yoon;Jeong Hyun-Woo;Kim Gye-Yeop
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.19 no.5
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    • pp.1256-1260
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    • 2005
  • The purpose of this study was to investigate the effects of Angelica gigas on jejunal survival, endogenous spleen colony formation and jejunal crypt cells of mice irradiated with Gamma-ray irradiation. The subject of this study includes 42 mice which were divided into each 7 groups. Angelica gigas experiment groups were Angelica gigas + Gamma-ray(10Gy), Angelica gigas + Gamma-ray(3Gy), Angelica gigas. Gamma-ray(1 Gy), Gamma-ray control (10Gy), Gamma-ray control(3Gy), Gamma-ray control(1Gy), Normal groups. In the present study to evaluate the effect of Angelica gigas on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice Gamma-ray with each dose of Gamma-ray irradiation. The results of this study were as follows: In low-dose(1Gy) Gamma-ray radiation were treatment of Angelica gigas showed significantly increased(p<0.05) on the cell death apoptosis in crypt, intestine crypts survival of intestine after gamma-ray irradiation. High-dose(10Gy) Gamma-ray, treatment of Angelica gigas showed significantly increased(p<0.05) on the leukocyte. The above results suggest that Angelica gigas were immunostimulating effectively reduced Gamma-ray irradiation.

Immunostimulating Effects of Acanthopanax in mice following Gamma-ray irradiation (방사선 조사 마우스에서 오가피의 면역활성 효과)

  • Kim, Gye-Yeop;Jeong, Hyun-Woo;Kim, Kyung-Yoon
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.20 no.3
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    • pp.670-674
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    • 2006
  • This experimental study was carried out to investigate the immunostimulating effect of Acanthopanax, as Oriental rhizomata herbs, on jejunal survival, endogenous spleen colony formation, apoptosis in jejunal crypt cells and lipid peroxidation in the liver of mice following Gamma-ray irradiation. The subject of this study includes 72 mice which were divided into each 7 groups. Acanthopanax experiment groups were Acanthopanax. Gamma-ray(lOGy), Acanthopanax. Gamma-ray(3Gy), Acanthopnax. Gamma-ray(1Gy), Gamma-ray control(1OGy), Gamma-ray control(3Gy), Gamma-ray control(1Gy), Normal groups. The results of this study were as follows : Treatment with Acanthopanax showed significantly increased(p<0.05) on the cell death apoptosis in crypt, intestine crypts survival of intestine in mice following low-dose(1Gy) Gamma-ray radiation. And that significantly increased(p<0.05) on jejunal crypt survival and reduced(p<0.05) on lipid peroxidation in mice following high-dose(1OGy) Gamma-ray radiation. The above results suggest that Acathopanax were immunostimulating effectively reduced Gamma-ray irradiation.

Study of n/γ discrimination using 3He proportional chamber in high gamma-ray fields

  • Choi, Joonbum;Park, Junesic;Son, Jaebum;Kim, Yong Kyun
    • Nuclear Engineering and Technology
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    • v.51 no.1
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    • pp.263-268
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    • 2019
  • The $^3He$ proportional chamber is widely used for neutron measurement owing to its high neutron detection efficiency and simplicity for gamma-ray rejection. In general, the neutron and gamma-ray signals obtained from the $^3He$ proportional chamber can be easily separated by the difference in the pulse heights. However, for a high gamma-ray field, the gamma-ray signal cannot be precisely eliminated by the pulse height due to gamma-ray pulse pileup which causes the pulse height of gamma-ray pulse to increase and making the pulses due to neutrons and gamma rays indistinguishable. In this study, an improved algorithm for $n/{\gamma}$ discrimination using a parameter, which is the ratio of the rise time to the pulse height, is proposed. The $n/{\gamma}$ discrimination performance of the algorithm is evaluated by applying it to $^{252}Cf$ neutron signal separation from various gamma-ray exposure rate levels ranging 0.1-5 R/h. The performance is compared to that of the conventional pulse-height analysis method in terms of the gamma elimination ratio. The suggested algorithm shows better performance than the conventional one by 1.7% (at 0.1 R/h) to 70% (at 5 R/h) for gamma elimination.

A Copper Shield for the Reduction of X-γ True Coincidence Summing in Gamma-ray Spectrometry

  • Byun, Jong-In
    • Journal of Radiation Protection and Research
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    • v.43 no.4
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    • pp.137-142
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    • 2018
  • Background: Gamma-ray detectors having a thin window of a material with low atomic number can increase the true coincidence summing effects for radionuclides emitting X-rays or gamma-rays. This effect can make efficiency calibration or spectrum analysis more complicated. In this study, a Cu shield was tested as an X-ray filter to neglect the true coincidence summing effect by X-rays and gamma-rays in gamma-ray spectrometry, in order to simplify gamma-ray energy spectrum analysis. Materials and Methods: A Cu shield was designed and applied to an n-type high-purity germanium detector having an $X-{\gamma}$ summing effect during efficiency calibration. This was tested using a commercial, certified mixed gamma-ray source. The feasibility of a Cu shield was evaluated by comparing efficiency calibration results with and without the shield. Results and Discussion: In this study, the thickness of a Cu shield needed to avoid true coincidence summing effects due to $X-{\gamma}$ was tested and determined to be 1 mm, considering the detection efficiency desired for higher energy. As a result, the accuracy of the detection efficiency calibration was improved by more than 13% by reducing $X-{\gamma}$ summing. Conclusion: The $X-{\gamma}$ summing effect should be considered, along with ${\gamma}-{\gamma}$ summing, when a detection efficiency calibration is implemented and appropriate shielding material can be useful for simplifying analysis of the gamma-ray energy spectra.

GALAXY CLUSTERS IN GAMMA-RAYS: AN ASSESSMENT FROM OBSERVATIONS

  • REIMER OLAF
    • Journal of The Korean Astronomical Society
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    • v.37 no.5
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    • pp.307-313
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    • 2004
  • Clusters of galaxies are believed to constitute a population of astrophysical objects potentially able to emit electromagnetic radiation up to gamma-ray energies. Evidence of the existence of non-thermal radiation processes in galaxy clusters is indicated from observations of diffuse radio halos, hard X-ray and EUV excess emission. The presence of cosmic ray acceleration processes and its confinement on cosmological timescales nearly inevitably yields in predicting energetic gamma-ray emission, either directly deduceably from a cluster's multifreqency emission characteristics or indirectly during large-scale cosmological structure formation processes. This theoretical reasoning suggests several scenarios to actually detect galaxy clusters at gamma-ray wavelengths: Either resolved as individual sources of point-like or extended gamma-ray emission, by investigating spatial-statistical correlations with unidentified gamma-ray sources or, if unresolved, through their contribution to the extragalactic diffuse gamma-ray background. In the following I review the situation concerning the proposed relation between galaxy clusters and high-energy gamma-ray observations from an observational point-of-view.

A Study on Scattering Distribution in Metal of Ir-192 Gamma-Ray (Ir-192 $\gamma$선(線)의 금속(金屬)에 대(對)한 산란분포(散亂分布)에 관(關)한 연구(硏究))

  • Joo, Gwang-Tae
    • Journal of radiological science and technology
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    • v.4 no.1
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    • pp.63-71
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    • 1981
  • The metal-plates(Aluminium. Copper, Lead) of change the variation thickness have been penetrated by the collimated beam($450mm{\times}4mm{\phi}$) of Gamma-ray from $^{192}Ir$. Then, the scattered $\gamma$-ray dose in variable angle and the directly transmitted $\gamma$-ray dose were measured using the electrometer of ionization chamber. The results were summarized as follows: 1. Obtained the mass attenuation coefficients of $Al;0.0937cm^2g^{-1},\;Cu;0.0937cm^2g^{-1},\;pb;0.244cm^2g^{-1}$. 2. Total intensity of front scattered $\gamma$-ray follow the order of Al>Cu>pb. 3. The scattered $\gamma$-ray intensity with the lager angle of scattering was saturated after increase rapidly, and the scattering angle of the more larger was decreased. 4. The scattered $\gamma$-ray intensity through plates of aluminium or copper was saturated after increase with thicker scatterer, and the intensity was decreased at the more thicker. But the variation of scattered $\gamma$-ray dose in the lead plate made the fewest than Al and Cu. 5. The ratio of the scattered $\gamma$-ray dose and the directly transmitted $\gamma$-ray dose was saturated after increase with the thicker scatterer, and the scatterer of the more thicker was decreased. Degree of total intensity in these ratios was followed the order of Cu>Al>Pb.

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The Study for the Method of Fast and Efficient Gamma-ray Detection for the Stereo Gamma-ray Ddetection System (스테레오 감마선 탐지장치의 고속 방사선 탐지기법에 관한 연구)

  • Hwang, Young-Gwan;Lee, Nam-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.9
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    • pp.1253-1258
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    • 2014
  • In this paper, we propose the fast and efficient detection method using the continuous measurement technique for the gamma-ray signal acquisition. This method is improved than the conventional method for the getting information of the radiation distribution. First, we implement the stereo radiation detection system using gamma-ray sensors and the motion controller. We apply continuous measurement technique to the gamma-ray detector and conduct gamma-ray irradiation test for the comparison of detection techniques. The results show that the continuous measurement technique has the high efficient performance than the conventional method.

A Study of Gamma-ray Weapon (Gamma-ray 무기 연구)

  • Han, Dong Yoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.1
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    • pp.72-80
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    • 2017
  • Gamma-ray has some advantages as a weapon: it has the ability to transmutate matter, high penetrability through materials, and it is very harmful to living things. So it is worth to study the features of gamma-ray weapon in order to utilize it. Such abilities were simulated on the basis of Monte Carlo simulation program GEANT4. For the simulation conceptual design of gamma-ray weapon was conducted. High energy electrons, which were necessary for the high energy gamma-rays, were produced by linear electron accelerator, of which the parameters were derived from the Pohang Light Source(PLS-II). Gamma-rays were get by bremsstrahlung mechanism. The spectra of gamma-rays, that were measured at distances of 500 m, 1000 m, 1500 m and 2000 m, were gained by GEANT4.

Effect of the Gamma-Ray Irradiation on the Electric and Optical Properties of SrTiO3 Single Crystals

  • Lee, Y.S.;Lim, Junhwi;Kim, E.Y.;Bu, Sang Don
    • Journal of the Korean Physical Society
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    • v.73 no.10
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    • pp.1566-1570
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    • 2018
  • We investigated the visible emission property of $SrTiO_3$ (STO) single crystals irradiated with gammy-ray (${\gamma}$-ray) at various total doses up to 900 kGy. The electric and optical absorption properties of the irradiated STO samples were hardly changed with the ${\gamma}$-ray irradiation, compared with those of un-irradiated STO. In contrast, the visible emission near 550 nm increased with the ${\gamma}$-ray dose increasing. While the development of the visible emission was indicative of the increase of oxygen vacancies inside STO by the ${\gamma}$-ray irradiation, the newly generated oxygen vacancies were not significantly harmful to the electric and optical properties of STO. We concluded that the STO single crystal should have a good tolerance against the damage by the ${\gamma}$-ray irradiation.

Measurement of Gamma-ray Yield from Thick Carbon Target Irradiated by 5 and 9 MeV Deuterons

  • Araki, Shouhei;Kondo, Kazuhiro;Kin, Tadahiro;Watanabe, Yukinobu;Shigyo, Nobuhiro;Sagara, Kenshi
    • Journal of Radiation Protection and Research
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    • v.42 no.1
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    • pp.16-20
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    • 2017
  • Background: The design of deuteron accelerator neutron source facilities requires reliable yield estimation of gamma-rays as well as neutrons from deuteron-induced reactions. We have so foar measured systematically double-differential thick target neutron yields (DDTTNYs) for carbon, aluminum, titanium, copper, niobium, and SUS304 targets. In the neutron data analysis, the events of gamma-rays taken simultaneously were treated as backgrounds. In the present work, we have re-analyzed the experimental data for a thick carbon target with particular attention to gamma-ray events. Materials and Methods: Double-differential thick target gamma-ray yields from carbon irradiated by 5 and 9 MeV deuterons were measured using an NE213 liquid organic scintillator at the Kyushu University Tandem accelerator Laboratory. The gamma-ray energy spectra were obtained by an unfolding method using FORIST code. The response functions of the NE213 detector were calculated by EGS5 incorporated in PHITS code. Results and Discussion: The measured gamma-ray spectra show some pronounced peaks corresponding to gamma-ray transitions between discrete levels in residual nuclei, and the measured angular distributions are almost isotropic for both the incident energies. Conclusion: PHITS calculations using INCL, GEM, and EBITEM models reproduce the spectral shapes and the angular distributions generally well, although they underestimate the absolute gamma-ray yields by about 20%.