• Title/Summary/Keyword: Neutron sensor

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A Study On Hardware Design for High Speed High Precision Neutron Measurement (고속 고정밀 중성자 측정을 위한 하드웨어 설계에 관한 연구)

  • Jang, Kyeong-Uk;Lee, Joo-Hyun;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.20 no.1
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    • pp.61-67
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    • 2016
  • In this paper, a hardware design method is proposed for high speed high precision neutron radiation measurements. Our system is fabricated to use a high performance A/D Converter for digital data conversion of high precision and high speed analog signals. Using a neutron sensor, incident neutron radiation particles are detected; a precision microcurrent measurement module is also included: this module allows for more precise and rapid neutron radiation measurement design. The high speed high precision neutron measurement hardware system is composed of the neutron sensor, variable high voltage generator, microcurrent precision measurement component, embedded system, and display screen. The neutron sensor detects neutron radiation using high density polyethylene. The variable high voltage generator functions as a 0 ~ 2KV variable high voltage generator that is robust against heat and noise; this generator allows the neutron sensor to perform normally. The microcurrent precision measurement component employs a high performance A/D Converter to precisely and swiftly measure the high precision high speed microcurrent signal from the neutron sensor and to convert this analog signal into a digital one. The embedded system component performs multiple functions including neutron radiation measurement for high speed high precision neutron measurements, variable high voltage generator control, wired and wireless communications control, and data recording. Experiments using the proposed high speed high precision neutron measurement hardware shows that the hardware exhibits superior performance compared to that of conventional equipment with regard to measurement uncertainty, neutron measurement rate, accuracy, and neutron measurement range.

Measurements of thermal neutron distribution of nuclear fuel using a plastic fiber-optic sensor (플라스틱 광섬유 센서를 이용한 핵 연료의 열중성자 분포도 측정)

  • Jang, Kyoung-Won;Cho, Dong-Hyun;Yoo, Wook-Jae;Seo, Jeong-Ki;Heo, Ji-Yeon;Lee, Bong-Soo;Moon, Joo-Hyun;Park, Byung-Gi;Kim, Sin;Cho, Young-Ho
    • Journal of Sensor Science and Technology
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    • v.18 no.5
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    • pp.402-407
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    • 2009
  • In this study, plastic optical fiber sensors which can measure thermal neutron dose in a mixed neutron-gamma field are developed and characterized. Using $^{252}Cf$ and $^{60}Co$ sources, the scintillators suitable for thermal neutron detection, are tested and the scintillating lights generated from a plastic optical fiber sensor in the Kyoto University Critical Assembly (kuca) core are measured. Also, the distributions of thermal neutron and gamma-ray are measured in a mixed field as a function of the distance from the center of the reactor core at KUCA and the distribution of thermal neutron is obtained using a subtraction method. Sensitivity of the fiber-optic radiation sensor system is about 0.49 V/mW according to power of the KUCA core and its relative error is about 1.2 %.

Measurement of the Shape of the Cold Neutron Source Vertical Hole by Ultrasonic Wave Sensor (초음파센서를 이용한 냉중성자원 수직공 형상측정)

  • Park, Guk-Nam;Choe, Chang-Ung;Sim, Cheol-Mu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.9 s.180
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    • pp.2167-2173
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    • 2000
  • The HANARO (High-flux Advanced Neutron Application Reactor) has operated since 1995. The Cold Neutron(CN) hole was implanted in the reflector tank from the design stage. Before a vacuum chamber and a moderator cell for the cold neutron source are installed into the CN hole, it is necessary to measure the exact size of the inside diameter and thickness of the CN hole to prevent the interference problem. Due to inaccessibility and high radiation field in the CN hole, a mechanical measurement method is not permitted. The immersion ultrasonic technique is considered as the best method to measure the thickness and the diameter. The 4 axis manipulator of the 2 channel of a sensor module was fabricated. The transducer of 10 MHz results in 0.03 nun of resolution. The inside diameter and thickness for 550 points of the CN hole were measured using 2 channel ultrasonic sensors. The results showed that the thickness is in the range of 13-6.7 mm and inside diameter is in the range of o 156-165. These data will be a good reference in the design of a cold neutron source facility.

Simulation and design of individual neutron dosimeter and optimization of energy response using an array of semiconductor sensors

  • Noushinmehr, R.;Moussavi zarandi, A.;Hassanzadeh, M.;Payervand, F.
    • Nuclear Engineering and Technology
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    • v.51 no.1
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    • pp.293-302
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    • 2019
  • Many researches have been done to develop and improve the performance of personal (individual) dosimeter response to cover a wide of neutron energy range (from thermal to fast). Depending on the individual category of the dosimeter, the semiconductor sensor has been used to simplify and lightweight. In this plan, it's very important to have a fairly accurate counting of doses rate in different energies. With a general design and single-sensor simulations, all optimal thicknesses have been extracted. The performance of the simulation scheme has been compared with the commercial and laboratory samples in the world. Due to the deviation of all dosimeters with a flat energy response, in this paper, has been used an idea of one semi-conductor sensor to have the flat energy-response in the entire neutron energy range. Finally, by analyzing of the sensors data as arrays for the first time, we have reached a nearly flat and acceptable energy-response. Also a comparison has been made between Lucite-PMMA ($H_5C_5O_2$) and polyethylene-PE ($CH_2$) as a radiator and $B_4C$ has been studied as absorbent. Moreover, in this paper, the effect of gamma dose in the dosimeter has been investigated and shown around the standard has not been exceeded.

Digital power range neutron monitoring system

  • Endo, Yorimasa;Itoh,Toshiaki;Tai, Ichiro
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10b
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    • pp.804-809
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    • 1988
  • PRNM(Power Range Neutron Monitoring) of BWR (Boiling Water Reactor) is a system that processes signals from about two hundred LPRM (Local Power Range Monitor) sensors in the nuclear reactor and this system monitors the neutron flux level during the plant operating region. Development has been made by employing a special technique for multiplexing neutron sensor signals and the recent advanced microelectronics technology. It is applicable to the total plant digital control system for a nuclear power plant.

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The development of a thermal neutron dosimetry using a semiconductor (반도체형 열중성자 선량 측정센서 개발)

  • Lee, Nam-Ho;Kim, Yang-Mo
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.789-792
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    • 2003
  • pMOSFET having 10 ${\mu}um$ thickness Gd layer has been tested to be used as a slow neutron sensor. The total thermal neutron cross section for the Gd is 47,000 barns and the cross section value drops rapidly with increasing neutron energy. When slow neutrons are incident to the Gd layer, the conversion electrons are emitted by the neutron absorption process. The conversion electrons generate electron-hole pairs in the $SiO_2$ layer of the pMOSFET. The holes are easily trapped in Oxide and act as positive charge centers in the $SiO_2$ layer. Due to the induced positive charges, the threshold turn-on voltage of the pMOSFET is changed. We have found that the voltage change is proportional to the accumulated slow neutron dose, therefore the pMOSFET having a Gd nuclear reaction layer can be used for a slow neutron dosimeter. The Gd-pMOSFET were tested at HANARO neutron beam port and $^{60}CO$ irradiation facility to investigate slow neutron response and gamma response respectively. Also the pMOSFET without Gd layer were tested at same conditions to compare the characteristics to the Gd-pMOSFET. From the result, we have concluded that the Gd-pMOSFET is very sensitive to the slow neutron and can be used as a slow neutron dosimeter. It can also be used in a mixed radiation field by subtracting the voltage change value of a pMOSFET without Gd from the value of the Gd-pMOSFET.

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Measurement of the Shape in the Radioactive Area by Ultrasonic Wave Sensor

  • Park, Koon-Nam;Sim, Chuel-Muu;Park, Chang-Oong;Lee, Chang-Hee;Park, Jong-Hark
    • Journal of Mechanical Science and Technology
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    • v.16 no.7
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    • pp.927-934
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    • 2002
  • The HANARO ( High-flux Advanced Neutron Application Reactor) has been operated since 1995. The Cold Neutron (CN) hole was implanted in the reflector tank from the design stage. Before a vacuum chamber and a moderator cell for the cold neutron source are installed into the CN hole, it is necessary to measure exactly the size of the inside diameter and thickness of the CN hole to prevent the interference problem. Due to inaccessibility and high radiation field in the CN hole, a mechanical measurement method is not permitted. The immersed ultrasonic technique is considered as the best way to measure the thickness and the diameter of the CN hole. The 4-Axis manipulator was designed and fabricated for locating the ultrasonic sensors. The transducer of an ultrasonic sensor having 10 MHz frequency leads to high resolution as much as 0.03mm. The inside diameter and thickness of 550 points of the CN hole were measured using 2 channel ultrasonic sensors. The results show that the thickness and inside diameter of the CN hole is in the range of 3.3∼6.7mm and 156∼ 165mm, respectively. This data will be a good reference for the design of the cold neutron source facility.

Depletion Sensitivity Evaluation of Rhodium and Vanadium Self-Powered Neutron Detector (SPND) using Monte Carlo Method (Monte Carlo 방법을 이용한 로듐 및 바나듐 자발 중성자계측기의 연소에 따른 민감도 평가)

  • CHA, Kyoon Ho;PARK, Young Woo
    • Journal of Sensor Science and Technology
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    • v.25 no.4
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    • pp.264-270
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    • 2016
  • Self-powered neutron detector (SPND) is a sensor to monitor a neutron flux proportional to a reactor power of the nuclear power plants. Since an SPND is usually installed in the reactor core and does not require additional outside power, it generates electrons itself from interaction between neutrons and a neutron-sensitive material called an emitter, such as rhodium and vanadium. This paper presents the simulations of the depletion sensitivity evaluations based on MCNP models of rhodium and vanadium SPNDs and light water reactor fuel assembly. The evaluations include the detail geometries of the detectors and fuel assembly, and the modeling of rhodium and vanadium emitter depletion using MCNP and ORIGEN-S codes, and the realistic energy spectrum of beta rays using BETA-S code. The results of the simulations show that the lifetime of an SPND can be prolonged by using vanadium SPND than rhodium SPND. Also, the methods presented here can be used to analyze a life-time of those SPNDs using various emitter materials.

Estimation of Neutron Energy Spectrum of Cf-252 using Single Bonner Sphere with TLD-600 and TLD-700 (단일 보너구와 TLD-600 및 TLD-700을 이용한 Cf-252의 중성자 에너지 스펙트럼 평가)

  • Kim, Sunghwan;Cheon, Jongkyu;Lee, Jae Jin;Nam, Uk-Won
    • Journal of Sensor Science and Technology
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    • v.22 no.3
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    • pp.223-226
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    • 2013
  • We designed a single polyethylene bonner sphere with several thermo-luminescence dosimeters (TLD), for measurement of neutron energy spectrum. For the separation of the neutron dosage in the neutron-gamma mixed field, we used 21 ea TLD-600s and TLD-700s, respectively. Because, TLD-600 is sensitive to neutron and gamma rays, and, TLD-700 is sensitive only to gamma-rays, we could determine the each dose by neutron and gamma rays. The neutron response function of the bonner sphere with TLDs was calculated by MCNPX (ver. 2.5.0) Monte Carlo simulation in the energy range from $10^{-1}$ to 20 MeV. For the Cf-252 standard neutron source in KRISS, we could estimate the neutron energy spectrum by unfolding method using the response function.

Development of Neutron, Gamma ray, X-ray Radiation Measurement and Integrated Control System (중성자, 감마선, 엑스선 방사선 측정 및 통합 제어 시스템 개발)

  • Ko, Tae-Young;Lee, Joo-Hyun;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.21 no.4
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    • pp.408-411
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    • 2017
  • In this paper, we propose an integrated control system that measures neutrons, gamma ray, and x-ray. The proposed system is able to monitor and control the data measured and analyzed on the remote or network, and can monitor and control the status of each part of the system remotely without remote control. The proposed system consists of a gamma ray/x-ray sensor part, a neutron sensor part, a main control embedded system part, a dedicated display device and GUI part, and a remote UI part. The gamma ray/x-ray sensor part measures gamma ray and x-ray of low level by using NaI(Tl) scintillation detector. The neutron sensor part measures neutrons using Proportional Counter Detector(low-level neutron) and Ion Chamber Type Detector(high-level neutron). The main control embedded system part detects radiation, samples it in seconds, and converts it into radiation dose for accumulated pulse and current values. The dedicated display device and the GUI part output the radiation measurement result and the converted radiation amount and radiation amount measurement value and provide the user with the control condition setting and the calibration function for the detection part. The remote UI unit collects and stores the measured values and transmits them to the remote monitoring system. In order to evaluate the performance of the proposed system, the measurement uncertainty of the neutron detector was measured to less than ${\pm}8.2%$ and the gamma ray and x-ray detector had the uncertainty of less than 7.5%. It was confirmed that the normal operation was not less than ${\pm}15$ percent of the international standard.