• Title/Summary/Keyword: HPGe검출기

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Development of Simulated HPGe Detector Spectrum for Education (교육용 모사 HPGe 검출기 스펙트럼 개발)

  • Seo, Kyung-Won;Lee, Mo-Sung
    • Journal of Radiation Protection and Research
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    • v.32 no.1
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    • pp.9-13
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    • 2007
  • From HPGe calibration spectrum of liquid mixed source in cylindrical vial, we developed simulated spectrum for spectrum analysis education. It is the spectrum that combine peaks separated from measured spectrum. After that, spectrum removed statistical variation of channel counts. Statistical fluctuation of the spectrum is made by Box-Muller function. The spectrum contains 18 peaks. The peak's centroid and area were defined exactly. Developed spectra are calibration spectrum, sample spectrum, background spectrum and spectra for efficiency correction for geometry and cascade coincidence.

Performance Test of Portable Hand-Held HPGe Detector Prototype for Safeguard Inspection (안전조치 사찰을 위한 휴대형 HPGe 검출기 시제품 성능평가 실험)

  • Kwak, Sung-Woo;Ahn, Gil Hoon;Park, Iljin;Ham, Young Soo;Dreyer, Jonathan
    • Journal of Radiation Protection and Research
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    • v.39 no.1
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    • pp.54-60
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    • 2014
  • IAEA has employed various types of radiation detectors - HPGe, NaI, CZT - for accountancy of nuclear material. Among them, HPGe has been mainly used in verification activities required for high accuracy. Due to its essential cooling component(a liquid-nitrogen cooling or a mechanical cooling system), it is large and heavy and needs long cooling time before use. New hand-held portable HPGe has been developed to address such problems. This paper deals with results of performance evaluation test of the new hand-held portable HPGe prototype which was used during IAEA's inspection activities. Radioactive spectra obtained with the new portable HPGe showed different characteristics depending on types and enrichments of nuclear materials inspected. Also, Gamma-rays from daughter radioisotopes in the decay series of $^{235}U$ and $^{238}U$ and characteristic x-rays from uranium were able to be remarkably separated from other peaks in the spectra. A relative error of enrichment measured by the new portable HPGe was in the range of 9 to 27%. The enrichment measurement results didn't meet partially requirement of IAEA because of a small size of a radiation sensing material. This problem might be solved through a further study. This paper discusses how to determine enrichment of nuclear material as well as how to apply the new hand-held portable HPGe to safeguard inspection. There have been few papers to deal with IAEA inspection activity in Korea to verify accountancy of nuclear material in national nuclear facilities. This paper would contribute to analyzing results of safeguards inspection. Also, it is expected that things discussed about further improvement of a radiation detector would make contribution to development of a radiation detector in the related field.

Study on the cascade summing correction for high efficiency HPGe detector (고효율 HPGe 검출기의 동시합성효과 보정 연구)

  • Lee, M.S.
    • Journal of Radiation Protection and Research
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    • v.30 no.3
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    • pp.107-112
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    • 2005
  • Cascade summing occurs when two gamma-rays emitted in the decay of a single nucleus both deposit energy in a detector. The effect may cause systematic errors that can reach levels of more than ten percent for some radionuclides. A method for estimation of the effect of these coincidences was developed. It is based on direct computation of the effect by means of peak to total ratio measured for the place around the detector. It has been shown that the P/T ratio for the given energy in the working space around the detector may not be a constant value and must use its mean value. Some results from a peak to total calibration study in the presence of scattering materials are also given.

Development of a simple laboratory-made radioactive source to check the integrity of a gamma spectrometry system with HPGe detector (HPGe 검출기를 사용한 감마분광분석계의 점검선원 개발)

  • Lee, Mo Sung
    • Journal of Radiation Protection and Research
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    • v.38 no.2
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    • pp.119-123
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    • 2013
  • A simple laboratory-made radioactive source to check the integrity of a gamma spectrometry system with HPGe detector was developed. The check source consists of radium-riched soil which was ground in size of less than 0.154mm and contained in air tight cylinderical vial, and provides photons with 12 distinct energies. The spectra of the check source were measured once a month during one year, analyzed the charactreictics of their peaks. When the gamma spectrometry system was in normal state, the areas and FWHMs of the gamma rays with more than 3% gamma emission rate in radium and its decay products was constant within standard deviation 2% and 3%, respectively, except 77 keV peak. And it was found that this check source can play a sufficient role to check the integrity of a gamma spectrometry system using 10 peaks in the range of 77 to 2202 keV.

Dependence Evaluation of the Self-Absorption Correction Factor for p-type High Purity Germanium Detector Characteristics (p-type HPGe 검출기 특성에 따른 밀도 보정인자 의존도 평가)

  • Jang, Mee;Ji, Young-Yong;Kim, Chang-Jong;Lee, Wanno;Kang, Mun Ja
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.13 no.4
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    • pp.295-300
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    • 2015
  • The precise determination of the activity for each radionuclide in environmental samples requires the self-absorption correction factor. In this research, we derived the self-absorption correction factor for three p-type high purity germanium detectors using the Monte Carlo code MCNPX. These detectors have different characteristics such as crystal diameter, height and size of the core. We compared the calculated full-energy peak efficiency with the experimental value using a standard sample with $1g/m^3$ density and verified the modeling. We simulated the dependency of the full-energy peak efficiency on the 0.3, 0.6, 0.9, 1.0, 1.2 and $1.5g/m^3$ samples and obtained the corresponding self-absorption correction factor. The self-absorption correction factors calculated for the three detectors differ by less than 1% over most of the energy range and sample densities considered. This indicates that the self-absorption correction factors are independent of the crystal characteristics of HPGe detector.

A Study on the Improvement of Gamma Ray Energy Spectrum Resolution through Electrical Noise Reduction of High Purity Ge Detector (고순도 Ge 검출기의 전기적 노이즈 감소를 통한 감마선 에너지 스펙트럼의 분해능 향상에 관한 연구)

  • Lee, Samyol
    • Journal of the Korean Society of Radiology
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    • v.14 no.7
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    • pp.849-856
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    • 2020
  • In the gamma-ray energy spectrum study, nuclide analysis through energy analysis is very important. High-purity Ge detectors, which are commonly used for gamma-ray energy measurements, are commonly used because of their high energy resolution and relatively high detection efficiency. However, in order to maintain a high energy resolution, the semiconductor detector has a problem in that it is difficult to maintain the original performance if the noise generated from the surrounding environment is not effectively blocked, and the effect of the expensive device is not achieved. Therefore, in this study, ground loop isolator (NEXT-001HDGL) was used to remove the electrical noise generated from the detector. In order to test the effect of improving energy resolution, HPGe detection device newly installed in the proton accelerator KOMAC was used. In the case of gamma-ray energy 2614 keV, the energy resolution was improved from (0.16 ± 0.02) % to (0.11 ± 0.01) %, and in the case of gamma-ray energy 662 keV of 137Cs isotope, the energy resolution was improved from (0.72 ± 0.07) % to (0.27 ± 0.03) %. This result is considered to be very useful for the gamma ray spectrum study using the HPGe detection equipment of KOMAC(Korea Multi-Purpose Accelerator Complex).

Response Function of HPGe Detector using $^{23}Na$(p, $\gamma$)$^{24}Mg$ and $^{27}Al$(p, $\gamma$)$^{28}Si$ Reaction ($^{23}Na$(p, $\gamma$)$^{24}Mg$$^{27}Al$(p, $\gamma$)$^{28}Si$반응을 이용한 HPGe 검출기의 응답함수)

  • Park, Sang-Tae
    • Journal of Radiation Protection and Research
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    • v.35 no.2
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    • pp.85-90
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    • 2010
  • In the present work, peak relative efficiency for the energy was obtained and response function was worked out. This study was carried out using the high resolution high efficiency HPGe detector(diameter 78.7 mm, length 86.5 mm) and NaI(Tl) detector for anti-compton. The anti-coincidence of the signals from the two detectors could be used to lessen the Compton effect signal; thus, the $\gamma$-ray energy resolution could be improved. The $\gamma$-ray spectrum was measured at $55^{\circ}$ to the direction of the incident proton beam. Reaction spectrum was obtained from the $^{23}Na$(p, $\gamma$)$^{24}Mg$ reaction at $E_p$ = 1424 keV and $^{27}Al$(p, $\gamma$)$^{28}Si$ reaction at $E_p$ = 992 keV. To accelerate the incident proton which creates the (p, $\gamma$) capture reaction, the 3 MeV Pelletron accelerator at the Tokyo Institute of Technology was used. Response function was worked out by a noble technique. We worked out a response function from 1.2 to 9.4 MeV at intervals of 0.75 MeV.