• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권11호
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• pp.490-492
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• 2005

A study on radiation hardening of infrared(IR) detector, the chief component of IR camera was performed. The radiation test on IR sensor passivated with the ZnS by Co$^{60}$ gamma-ray over 1 Mrads showed the reduction in Ro by 1/100 which was related to the noise level. This effect that was caused by carrier trapping in the ZnS passivation layer increased the leakage current and resulted in degradation in the device performance. For the radiation hardening of IR devices we suggested the ones with CdTe passivation layer which had a tendency to reluctant to carrier trapping in its layer and developed test patterns. Radiation test to the patterns showed that the our CdTe passivated device could survived over 1 Mrad gamma-ray dose.

• Journal of Radiation Protection and Research
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• 제35권2호
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• pp.81-84
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• 2010

A CSA(Charge Sensitive Amplifier) was designed and fabricated for application in a radiation detection system based on a semiconductor detector such as Si, SiC, CdZnTe and etc.. A fabricated hybrid.type CSA was evaluated by comparison with a commercially available CSA. A comparison was performed by using calculation of ENC (Equivalent Noise Charge) and by using energy resolutions of fabricated radiation detectors based on Si. In energy resolution comparison, a fabricated CSA showed almost the same performance compared with a commercial one. In this study, feasibility of a fabricated CSA was discussed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1371-1374
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• 1997

We had developed the on-line environmental monitoring system which has installed around Kori Nuclear Power Plants and will be taken the place of the existing system. The system consists of a main computer and 11 sets of radiation monitoring post equipments. Nal(Tl) scintillation detectro was adopted in addition to ion-chamber detector and implemented with DCU(Dose Conversion Unit) and SCA(Single Channel Analyzer). Compared with the existing system, it has revised feature in the radiation measurements which are detection of artificial radioactivity and 2-ways of the radiatiion detectors. The field test trsults show that the developed radiation detecting equipments can measure environmental radiation withn 5.0% of the theoretical value.

• 한국군사과학기술학회지
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• 제14권2호
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• pp.299-304
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• 2011

In this paper, we developed the semiconductor neutron radiation detector and the multi-purpose radiation detection technologies for the next generation military personal surveymeter. The PIN type semiconductor neutron detector and the prototype measure the neutron radiation dose upto 1,000cGy with ${\pm}20%$ error. It also have a good performance about the Gamma, Alpha and Beta radiation and MIL-STD-810F.

• 대한의용생체공학회:의공학회지
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• 제16권2호
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• pp.129-138
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• 1995

최근 방사선 치료에서 가속기를 이용한 고에너지, 고선량율 X-선과 전자선을 암환자 치료에 이용하고 있다. 치료시 방사선 조사선량의 5% 증감은 방사선 치료성적의 성패를 직접적으로 간여하고 있다고 국제 방사선 규정협회는 규정하고 있다. 본 논문에서는 방사선 치료에 영향을 미치는 빔 파라메터의 변동여부를 빠르고 간편하게 검출해 낼 수 있는 장치를 범용 실리콘 다이오드를 이용하여 제작한후 그 특성에 관해 고찰해 보았다. 13개 다이오드를 X-축 및 Y-축에 각각 7개씩 배열한 후 조사영역의 빔의 대칭도, 편평도, 안정성 등을 검출하여 보았고 방사선 손상에 대한 고찰, 일정기간 후의 변화량, 에너지 의존성 및 심부량 백분률등을 기존의 측정방법인 기체전리함을 이용한방법, 필름을 이용한 방법, 반도체 소자를 이용한 방법과의 값과 비교 분석하였다.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.300-305
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• 2007

In this study, we have studied the fabrication and the performance evaluation of digital radiation detector of the based on selenium (a-Se) prototype which is widely researched about recently. The detector was fabricated using amorphous selenium in the specification of active area size $7{\times}8.5"$, pixel pitch $139{\mu}m$, and 12 bit ADC. In order for the performance evaluation of the fabricated detector, we used radiation quality RQA 5 that is suggested by the International Electrotechnical Commission (IEC), and evaluated modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). Concerning MTF measurement, we used slit camera (Nuclear Associates, Model : 07-624-2222), and evaluated in the slit method. Also so as to compare the performance evaluation on the detector fabricated in this study, we used Hologic Direct-Ray (DR-1000) and GE Revolution XQ/I system, and evaluated and compared in the same method MTF, NPS, and DQE which are image quality factors. And as a result, the MTF of each detector In Nyquist frequency were evaluated to be 58% (at 3.5 lp/mm) in the case of DR-1000 and 65% (at 2.5 lp/mm) in the case of XQ/I, and that for the detector fabricated in this study was evaluated to be 36% (at 3.51 lp/mm). Also in the case of DQE(0), the detector fabricated in this study, DR-1000 of Hologic company, and XQ/I system of GE company respectively were evaluated as 36%, 32%, and 50%.

• 대한방사선기술학회지:방사선기술과학
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• 제45권4호
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• pp.305-312
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• 2022

The proportion and testing of portable radiation tests, which are limited at the request of the doctor, are gradually increasing only for patients in emergency situations and difficulties in moving. However, as there are many limiting factors compared to fixed devices, this study intends to measure and analyze the distortion of images according to the angle of the detector and the change in dose according to the position of the subject. For distortion experiments using a mobile radiation generator used in Hospital A, the SID was tilted by 110 cm, 14"×17" wireless FPD detector to 0°, -5°, -10°, -15°, -20°, and -35° to measure the change in area. The dose according to the location of the detector was analyzed on average by measuring the central dose at 110 cm of the SID and measuring the dose of 9 locations three times each. The analysis result of distortion by location according to the angle of the detector showed a statistically significant difference (f=58.74, p<0.000). Therefore, it can be seen that the angle of the detector and the tube is closely related to the distortion of the image. The difference in dose by location of the detector increased with respect to the center - pole, and decreased with the + pole. Tests using mobile radiation generators will require careful efforts by clinicians to position patients in the center of the detector for accurate diagnosis, and efforts will be made to level the angle between the mobile radiation generators and the detector.

• 전기전자학회논문지
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• 제21권2호
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• pp.146-149
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• 2017

본 논문에서는 GM Tube 및 NaI(TI) 검출기를 사용한 Wide-Range 방사선 측정 시스템을 제안한다. 제안하는 시스템은 NaI(Tl) 검출기 및 GM Tube의 검출기 신호를 제어, 계수할 수 있게 최적화한 하나의 소형 모듈로 설계한 다. 방사선량은 2개의 검출기를 연동하여 Wide-range인 0.1uSv/h~10mSv/h 구간에서 측정되고, 측정구간이 중복되는 지점인 10uSv/h~100uSv/h에서는 2개의 검출기가 동시에 동작한다. 방사선량은 중첩된 방사선 측정 가능 구간에 대해 적정한 구간에서 해당 검출기 기능의 On/Off를 제어하는 Wide-Range 방사선 측정 알고리즘을 이용하여 선택 적용하였다. 제안된 시스템의 성능을 평가하기 위하여 공인시험기관에서 실험한 결과, 각 구간별로 측정 불확도가 ${\pm}7.5%$로 측정되어 국제 표준인 ${\pm}15%$ 이하에서 정상동작 됨이 확인되었다.

• Journal of Radiation Protection and Research
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• 제42권4호
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• pp.212-221
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• 2017

Background: This study aims to calculate detector positions as a design of a radioactive source localizing radiation portal monitor (RPM) system using an improved genetic algorithm. Materials and Methods: To calculate of detector positions for a source localizing RPM system optimization problem is defined. To solve the problem, a modified iterative genetic algorithm (MIGA) is developed. In general, a genetic algorithm (GA) finds a globally optimal solution with a high probability, but it is not perfect at all times. To increase the probability to find globally optimal solution rather, a MIGA is designed by supplementing the iteration, competition, and verification with GA. For an optimization problem that is defined to find detector positions that maximizes differences of detector signals, a localization method is derived by modifying the inverse radiation transport model, and realistic parameter information is suggested. Results and Discussion: To compare the MIGA and GA, both algorithms are implemented in a MATLAB environment. The performance of the GA and MIGA and that of the procedures supplemented in the MIGA are analyzed by computer simulations. The results show that the iteration, competition, and verification procedures help to search for globally optimal solutions. Further, the MIGA is more robust against falling into local minima and finds a more reliably optimal result than the GA. Conclusion: The positions of the detectors on an RPM for radioactive source localization are optimized using the MIGA. To increase the contrast of the measurements from each detector, a relationship between the source and the detectors is derived by modifying the inverse transport model. Realistic parameters are utilized for accurate simulations. Furthermore, the MIGA is developed to achieve a reliable solution. By utilizing results of this study, an RPM for radioactive source localization has been designed and will be fabricated soon.

• 대한방사선기술학회지:방사선기술과학
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• 제27권2호
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• pp.21-27
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• 2004

본 연구에서는 현재 국내에서 사용되고 있는 여러 기종의 CT장치를 대상으로 하여 CT검사로 인한 방사선피폭 정도를 실험을 통하여 알아보고, 외국의 사례와 비교함으로써 CT장치의 성능관리의 하나인 피폭선량 기준 설정에 필요한 기초 데이터를 제시하고자 서울시 및 경기도에 위치한 병의원 및 종합병원에서 가동 중인 32대의 CT장치를 대상으로 CTDI값을 측정한 결과 다음과 같았다. 1) Head phantom의 100 mAs 당 $CTDI_W$값은 $8.1{\sim}19.1\;mGy$ 범위였고, 평균 $13.5{\pm}3.2\;mGy$였다. 그리고 body phantom의 $CTDI_W$값은 $3.7{\sim}10.9\;mGy$ 범위였고, 평균 $7.1{\pm}2.0\;mGy$였다. 2) Single detector CT와 multi detector CT의 $CTDI_W$값을 비교해 보면, multi detector CT가 single detector CT에 비해 head phantom에서는 평균 3.2 mGy(약 1.26배), body phantom에서는 평균 2.1 mGy(약 1.34배) 높았다. 3) Channel 수에 따른 $CTDI_W$값 비교에서는 head pahantom에서는 4 channel CT가 가장 높았으며, 8 channel CT, 16 channel CT, single detector CT순이었으며, body phantom에서는 역시 4 channel CT와 8 channel CT, 16 channel CT, single detector CT순이었다.