• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3133-3139
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• 2023

Neutron imaging technology as a means of non-destructive detection of materials is complementary to X-ray imaging. Silicon photomultiplier (SiPM), a new type of optical readout device, has overcome some shortcomings of traditional photomultiplier tube (PMT), such as high-power consumption, large volume, high price, uneven gain response, and inability to work in strong magnetic fields. Its application in the field of neutron detection will be an irresistible general trend. In this paper, a thermal neutron imaging detector based on ⁶LiF/ZnS scintillation screen and SiPM array readout was developed. The design of the detector geometry was optimized by geant4 Monte Carlo simulation software. The optimized detector was evaluated with a step wedge sample. The results show that the detector prototype with a 48 mm × 48 mm sensitive area can achieve about 38% detection efficiency and 0.26 mm position resolution when using a 300 ㎛ thick ⁶LiF/ZnS scintillation screen and a 2 mm thick Bk7 optical guide coupled with SiPM array, and has good neutron imaging capability. It provides effective data support for developing high-performance imaging detectors applied to the China Spallation Neutron Source (CSNS).

• 대한의용생체공학회:의공학회지
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• 제18권3호
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• pp.267-272
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• 1997

3.6cm${\times}$2.0cm (지름 ${\times}$ 두께) 크기의 $BaF^2$ 섬광체로 검출기를 제작하여 감마 카메라등 의료용 진단장치에서 센서로 사용되고 있는 NaI(씨)검출기와 방사선 검출특성을 비교하여 보았다. 특정에 사용된 선원은 $^{22}Na,\;^{54}Mn,\;^{57}Co,\;^{137}Cs$의 ${\gamma}$선 방출선원으로 검출기와 선원간의 거리를 7cm로 유지하였다. 시간특성을 분석하기 위하여 511keV의 양전자 방출선원을 사용하여 NaI(Tl)(1" ${\times}$ 1"), NaI(Tl)(3" ${\times}$ 3")순으로 $BaF^2$가 가장 빠르게 나타났으며, $BaF^2$ 검출기의 효율은 500keV에서 가장 높게 측정되었다.

• 한국통신학회논문지
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• 제22권11호
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• pp.2470-2476
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• 1997

We propose a simle scheme for detecting tone signals narrowly spaced in the frequency by employing a nonlinear device called Teager's energy tracker. When the input signal is a tone signal, the output of Teager's energy tracker is proportional to the energy and tone frequency of the input signal. When the envelope of the input tone is varying, this tracker can also track the energy of the envelope. By employing Teager's algorithm as a preprocessor, the detector for narrowly spaced tone signals can be implemented without the use of sharp notch filters. As an example, the proposed detector is applied to distinguishing ITU-T V.8 and V.25 tone signals. The detector perfodrmance is analyszed and is verified by computer simulation.

• Nuclear Engineering and Technology
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• 제46권2호
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• pp.217-224
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• 2014

The present work used the efficiency transfer method used to calculate the full energy peak efficiency (FEPE) curves of the (2"*2" & 3"*3") NaI (Tl) detectors based on the effective solid angle subtended between the source and the detector. The study covered the effect of the self attenuation coefficient of the source matrix (with a radius greater than the detector's radius) on the detector efficiency. $^{152}$ An Eu aqueous radioactive source covering the energy range from 121.78 keV up to 1408.01 keV was used. In this study an empirical formula was deduced to calculate the difference between the measured and the calculated efficiencies [without self attenuation] at low and high energy regions. A proper balance between the measured and calculated efficiencies [with self attenuation] was achieved with discrepancies less than 3%, while reaching 39% for calculating values [without self attenuation] due to working with large sources, or for low photon energies.

• 조명전기설비학회논문지
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• 제24권12호
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• pp.201-207
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• 2010

This thesis studies development of a triple pyroelectric Infrared flame detector to have appropriate reaction characteristics with proper operational features in various and radiant energy characteristics of fire sources, and to contribute to minimize the losses of human lives and properties by detecting fire in very early stage to restrict the spread of fire.

• 조명전기설비학회논문지
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• 제30권1호
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• pp.49-54
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• 2016

There is needed the quard channel triple wave lengths pyroelectric infrared flame detector to recognize the unique characteristics of fire sources in various type. This system detects the triple wave lengths of infrared flame emitting maximum radient energy and scattering frequency of flame. The quard channel infrared flame detector detects the duplicate wave lengths of maximum radient energy to enhance the accuracy of detecting fire. Especially this paper focuss on development of the self diagnosis function system including contamination, temperature and input voltage. Therefore, the prevention and early suppression of fire is available.

• Journal of Radiation Protection and Research
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• 제13권2호
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• pp.29-40
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• 1988

환경방사선 측정에 이용되는 휴대형 고순도 게르마늄검출기에 대한 스펙트럼-조사선량율 변환연산자를 원판형선원의 공간분포함수와 검출기의 평면에 대한 측정효율식을 적용하여 이론적으로 유도했다. 이와 같이 구한 변환연산자와 휴대형 고순도 게르마늄검출기를 이용해 한국에너지연구소내에서 방사선 조사선량율을 측정했다. 측정한 조사선량율을 이미 알려진 3'${\phi}\;{\times}$3'NaI(Tl) 섬광검출기에 대한 변환연산자를 적용해 NaI(Tl)검출기로 측정한 조사선량율과 가압형 이온전리함으로 측정한 값과 비교했다. 고순도 게르마늄 검출기로 얻은 결과는 NaI(Tl) 검출기와 가압형 이온전리함으로 얻은 값보다 약 17-29% 낮음을 보여주었다. 이 차이는 다른 문헌에서 보인 차이와 거의 같았다. 본 논문에서 제시한 스펙트럼-조사선량율 변환연산자는 탁상용 계산기로 쉽게 계산할 수 있으며 환경방사선의 측정에 사용되는 여러 검출기에 대해서도 쉽게 적용할 수 있는 장점이 있고 지각에서 방출되는 각 핵종별로 조사선량율을 구할 수 있는 장점이 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.420-423
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• 2002

In recent years, there has been keen interest in developing f1at panel detectors for all modalities of radiology, including gerneral radiology, fluoroscopy(angiography and cardiology), electronic portal imaging, and mammography. In this paper, we report the new hybrid x-ray detector consisted of CsI(Tl) photoemission layer and a-Se photoconductor layer to resolve conventional x-ray detector such as the direct detector using a-Se and the indirect detector using CsI(Tl)/a-Si. To design the structure of CsI(Tl)/a-Se detector, the penetrated energy spectrum and absorption fraction was estimated using MCNP 4C code. Experimental results showed that the absorption fraction of $500{\mu}m-Se$ film and $150{\mu}m-CsI\left(Tl \right)/a-Se\left( 30{\mu}m \right)$ film is 70% at 70 kVp. The absorption energy is 90% at $350{\mu}m-CsI(Tl)$.

• Journal of Radiation Protection and Research
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• 제49권2호
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• pp.85-90
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• 2024

Background: This study focuses on the fabrication and characterization of quasi-hemispherical Cd_0.9Zn_0.1Te (CZT) detector for gamma-ray spectroscopy applications, aiming to contribute to advancements in radiation measurement and research. Materials and Methods: A CZT ingot was grown using the vertical Bridgman technique, followed by proper fabrication processes including wafering, polishing, chemical etching, electrode deposition, and passivation. Response properties were evaluated under various external bias voltages using gamma-ray sources such as Co-57, Ba-133, and Cs-137. Results and Discussion: The fabricated quasi-hemispherical CZT detector demonstrated sufficient response properties across a wide range of gamma-ray energies, with sufficient energy resolution and peak distinguishability. Higher external bias voltages led to improved performance in terms of energy resolution and peak shape. However, further improvements in defect properties are necessary to enhance detector performance under low bias conditions. Conclusion: This study underscores the efficacy of quasi-hemispherical CZT detector for gamma-ray spectroscopy, providing valuable insights for enhancing their capabilities in radiation research field.

• Tribology and Lubricants
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• 제24권3호
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• pp.111-121
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• 2008

An integrated in-line oil monitoring detector assigned for continuous in situ monitoring multiple parameters of oil performance for predicting economically optimal oil change intervals and equipment condition control is presented in this study. The detector estimates oil deterioration based on the information about chemical degradation, total contamination, water content of oil and oil temperature. The oil oxidation is estimated by "chromatic ratio", total contamination is measured by the changes in optical intensity of oil in three optical wavebands ("Red", "Green" and "Blue") and water content is evaluated as Relative Saturation of oil by water. The detector is able to monitor oils with low light absorption (hydraulic, transformer, turbine, compressor and etc. oils) as well as oils with rather high light absorption in visible waveband (diesel and etc. oils). In a case study that the detector is applied to a diesel engine oil, it is found that the detector provides good results on oil chemical degradation as well as soot concentration.