• Nuclear Engineering and Technology
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• 제32권5호
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• pp.457-464
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• 2000

In this paper, we describe the results of various calculations performed for a design of the thickness gauges that use the gamma-ray backscattering method. The radiation source is assumed to be the $_{24}$1Am(60keV gamma-ray) and the detector is a single crystal scintillator in a cylindrical form. The source is located at the center of the detector with the collimator of a cylindrical shape. First, when gamma-rays are incident on a material with a constant angle, we compute the variations of the spectrum for the photons scattered into different angular intervals. Next, we compute for an optimal size for the collimator cylinder for a fixed detector size and an optimal distance from the detector to the material. Finally, we compute the number of observed photons for different thickness of two different materials, a plastic film and an Al foil.

• 전자공학회논문지D
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• 제34D권4호
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• pp.47-53
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• 1997

We fabricated gamma radiation detector using high resistive p-Cd$_{80}$Zn$_{20}$Te grown by high pressure bridgman method and forming au thin film electrode by chemically electroless deposition method. The device of Au/Cd$_{80}$Zn$_{20}$Te/Au is a typical MIM structure. The characteristic of current-voltage showed good linearity to 3kV/cm but it depend on the square of electric field over 3kV/cm. As the results of rutherford backscattering spectroscope(RBS) and auger spectroscope on the Au/Cd$_{80}$Zn$_{20}$Te, Au penetrated to the surface of Cd$_{80}$Zn$_{20}$Te detector absorbed slightly high energy radiation like a few hundred keV and showed good performance to detect low energy gamma ray.mma ray.

• Nuclear Engineering and Technology
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• 제43권1호
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• pp.13-18
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• 2011

In this study, simulations were done of a 661.6 keV line from a point source of $^{137}Cs$ housed in a lead shield. When increasing the scattering angle from 60 to 120 degrees with a 6061 aluminum alloy target placed at angles of 30 and 45 degrees to the incident beam, the spectra showed that the single scattering component increases and that the multiple scattering component decreases. The investigation of the single and multiple scattering components was carried out using a MCNP5 simulation code. The component of the single Compton scattering photons is proportional to the target electron density at the point where the scattering occurs. The single scattering peak increases according to the thickness of the target and saturates at a certain thickness. The signal-to-noise ratio was found to decrease according to the target thickness. The simulation was experimentally validated by measurements. These results will be used to determine the best conditions under which this method can be applied to testing electron densities or to assess the thickness of samples to locate defects in them.

• Nuclear Engineering and Technology
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• 제49권7호
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• pp.1571-1574
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• 2017

In the present work, the gamma ray backscattering technique was used to determine the effective atomic numbers for certain binary alloys. With the help of a muffle furnace, the binary alloys were synthesized using the melt quenching technique with different compositions of $_{82}Pb$, $_{50}Sn$, and $_{30}Zn$. The intensity distribution of backscattered photons from radioactive isotope $^{22}Na$ (511 keV) was recorded with the help of GAMMARAD5 [$76mm{\times}76mm$ NaI(Tl) scintillator detector] and analyzed as a function of both atomic number and thickness of the target material. The effective atomic numbers for the same binary alloys were also computed theoretically using the atomic to electronic cross-section method with the help of the mass attenuation coefficient database of WinXCom (2001). Good agreement was observed between theoretical and experimental results for the effective atomic numbers of all the selected alloys.

• 대한전자공학회논문지
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• 제3권1호
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• pp.18-23
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• 1966

동철종으로 부터 후방 산란되는 감마선을 측정하므로써 그의 두께를 수정할 수 있는 두께계의 실용성에 관하여 실험적인 검토를 하였다. 본 두께계의 특징은 선원으로부터 반사되는 1 차방사선과 철판으로 부터 후방 산란되는 2차 방사선을 적시에 동일한 씬티레이숀 검출기로 검출하며 사용되는 선원의 방사선 강도도 20μc 정도로 적으므로 일절의 방사선 차폐물이 불필요하므로 가반형 두께계로서 적당하다. 씬티레이숀 검출기로 부터의 출력 펄스는 프리암프, 메인암프, 및 단채널 파고분석기를 거쳐 후방 산란 감마선만을 선별한 다음 계수률계상에서 두께로 직독하도록 할 수 있다. 광판의 두께 변화에 대한 지시감도를 크게 하기 위한 선원의 위치 파고분석기의 window width, 사용될 선원의 에너지와 강도등의 최적치를 구하기 위한 실험을 행하였다. 이 두께계로서 강철판 또는 파이프의 내벽상의 작은 흠이나 부식처를 용이하게 발견할 수 있다. 실측결과 3∼8mm 두께 범위에서 약 ±3%의 정밀도를 얻었고 20mm 두께에서는 약 ±10%로 저하되었다.

• Radiation Oncology Journal
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• 제1권1호
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• pp.21-24
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• 1983

Co ${\gamma}$선과 10MV x선으로 폴리스티렌 팬톰에 조사하여 이온함으로 배면과 배면근처의 선량을 측정한 결과는 아래와 같다. 1. 측정점 이하의 팬톰의 두께가 증가함에 따라 선량율과 선량보정계수가 증가하였으며 그 두께가 20cm 이상인 경우에는 일정하였다. 선량보정계수는 1 이하였다. 2. 조사면의 크기가 클수록, 측정점의 깊이가 깊을 수록 선량보정계수는 감소하였다. 3. 선량에 후방산란선량의 기여도는 조사면이 클수록, 깊이가 얕을수록, 그 깊이 이하의 물질의 두께가 두꺼울수록 증가하였다. 4. 10MV x선의 경우에도 선량보정계수는 같은 유형으로 변하기는 했지만 그 값이 0.995~1.000이었다. 5. $^{60}Co$에 경우에 치료부위의 두께가 10cm 이상이면 조사시간을 보정하지 않아도 좋을 것이다.