• Title/Summary/Keyword: IR Detector

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Measurement of Rectal Rodiation dose in the Patients with Uterine Cervix fencer using In Vivo Dosimetry(Diode Detector) (자궁경부암 환자에서 In vivo dosimetry(Diode detector)를 이용할 직장선량의 측정)

  • Kim, Sung-Kee;Kim, Wan-Sun
    • The Journal of Korean Society for Radiation Therapy
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    • v.16 no.1
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    • pp.29-37
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    • 2004
  • Purpose : A rectum and a bladder should be carefully considered in order to decrease side effects when HDR patient of uterine cervix cancer. Generally speaking, the value of dosimeter at a rectum and a bladder only depends on the value of a planning equipment, while some analyses of the value of dosimetry at rectum with TLD has been reported Or the contrary, it is hardly to find a report with in vivo dosimetry(diode detector). On this thesis, we would like to suggest the following. When a patient of uterine cervix cancer is in therapy, it is helpful to put a diode detector inside of a rectum in order to measure the rectal dose Based upon the result of the dosimetry, the result can be used as basic data at decreasing side effects. Materials and Methods : Six patients of uterine cervix cancer(four with tandem and ovoid, one with cylinder, and the other one with tandem and cylinder) who had been irradiated with HDR. Ir-192 totally 28 times from February 2003 to June 2003. We irradiated twice in the same distant spots with anterior film and lateral film whenever we measured with a diode detector. Then we did planning and compared each film. Results : The result of the measurement 4 patients with a diode detector is the following. The average and deviation from 3 patients with tandem and ovoid were $274.1{\pm}13.4cGy$, from 1 patient with tandem and ovoid were $126.1{\pm}7.2cGy$, from 1 patient with cylinder were $99.7{\pm}7.1cGy$, and from 1 patient with tandem and cylinder were $77.7{\pm}11.5cGy$. Conclusion : It is difficult to predict how the side effect of a rectum since the result of measurement with a diode detector depends on the state of a rectum. According to the result of the study, it is effective to use a TLD or an in vivo dosimetry and measure a rectum in order to consider the side effect. It is very necessary to decrease the amount of irradiation by controlling properly the duration of the irradiation and gauze packing, and by using shield equipments especially when side effects can be expected.

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The Study on Design of Semiconductor Detector for Checking the Position of a Radioactive Source in an NDT (비파괴검사 분야에서 방사선원의 위치 확인을 위한 반도체 검출기 설계에 관한 연구)

  • Kim, Kyo-Tae;Kim, Joo-Hee;Han, Moo-Jae;Heo, Ye-Ji;Ahn, Ki-Jung;Park, Sung-Kwang
    • Journal of the Korean Society of Radiology
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    • v.11 no.3
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    • pp.171-175
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    • 2017
  • In the non-destructive inspection field, we invest a lot of time and resources in developing the radiation source system to ensure the safety of the workers. However, the probability of accidents is still high. In order to prevent potential radiation accidents in advance, it is necessary to directly verify the position of the radiation source, but the research is still insufficient. In this study, we developed a monitoring system that can detect the position of the radiation source in the source guide tube in the gamma-ray irradiator. The characteristics of the radiation detector are estimated by monte carlo simulation. As a result, the radiation detector for Ir-192 gamma-ray energy was analyzed to have secondary electron equilibrium at $150{\mu}m$ regardless of the semiconductor material. Also, it is expected that the gamma ray response characteristic is the best in $HgI_2$. These results are expected to be used as a basis for determining the optimal thickness of the radiation detector located in the detection part of the future monitoring system. In addition, when developing a monitoring system based on this, radiation workers can easily recognize the danger and secure safety, as well as prevent and preemptively respond to potential radiation accidents.

A Study of the Scene-based NUC Using Image-patch Homogeneity for an Airborne Focal-plane-array IR Camera (영상 패치 균질도를 이용한 항공 탑재 초점면배열 중적외선 카메라 영상 기반 불균일 보정 기법 연구)

  • Kang, Myung-Ho;Yoon, Eun-Suk;Park, Ka-Young;Koh, Yeong Jun
    • Korean Journal of Optics and Photonics
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    • v.33 no.4
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    • pp.146-158
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    • 2022
  • The detector of a focal-plane-array mid-wave infrared (MWIR) camera has different response characteristics for each detector pixel, resulting in nonuniformity between detector pixels. In addition, image nonuniformity occurs due to heat generation inside the camera during operation. To solve this problem, in the process of camera manufacturing it is common to use a gain-and-offset table generated from a blackbody to correct the difference between detector pixels. One method of correcting nonuniformity due to internal heat generation during the operation of the camera generates a new offset value based on input frame images. This paper proposes a technique for dividing an input image into block image patches and generating offset values using only homogeneous patches, to correct the nonuniformity that occurs during camera operation. The proposed technique may not only generate a nonuniformity-correction offset that can prevent motion marks due to camera-gaze movement of the acquired image, but may also improve nonuniformity-correction performance with a small number of input images. Experimental results show that distortion such as flow marks does not occur, and good correction performance can be confirmed even with half the number of input images or fewer, compared to the traditional method.

Automatic Registration Method for EO/IR Satellite Image Using Modified SIFT and Block-Processing (Modified SIFT와 블록프로세싱을 이용한 적외선과 광학 위성영상의 자동정합기법)

  • Lee, Kang-Hoon;Choi, Tae-Sun
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.4 no.3
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    • pp.174-181
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    • 2011
  • A new registration method for IR image and EO image is proposed in this paper. IR sensor is applicable to many area because it absorbs thermal radiation energy unlike EO sensor does. However, IR sensor has difficulty to extract and match features due to low contrast compared to EO image. In order to register both images, we used modified SIFT(Scale Invariant Feature Transform) and block processing to increase feature distinctiveness. To remove outlier, we applied RANSAC(RANdom SAample Concensus) for each block. Finally, we unified matching features into single coordinate system and remove outlier again. We used 3~5um range IR image, and our experiment result showed good robustness in registration with IR image.

Variation of Supersonic Aircraft Skin Temperature under Different Mach number and Structure (비행마하수와 형상에 따른 초음속 항공기 표면온도 변화)

  • Cha, Jong Hyun;Kim, Taehwan;Bae, Ji-Yeul;Kim, Taeil;Jung, Daeyoon;Cho, Hyung Hee
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.4
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    • pp.463-470
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    • 2014
  • Stealth technology of combat aircraft is most significant capability in recent air battlefield. As the detector of IR missiles is being developed, IR stealth capability which is evaluated by IR signature level become more important than it was in previous generation. Among IR signature of aircraft from various sources, aerodynamic heating dominates in long-wavelength IR spectrum of $8{\sim}12{\mu}m$. Skin temperature change by aerodynamic heating which is derived by effects of Mach number and structure. The 4th and 5th generation aircraft are selected for calculation of the skin temperature, and its height and velocity in numerical conditions are 10,000 m and Ma 0.9~1.9 respectively. Aircraft skin temperature is calculated by computing convection of fluid and conduction, convection and radiation of surface. As the aircraft accelerates to higher Mach number, maximum skin temperature increases more rapidly than average temperature and temperature distribution changes in more sharp, interactive ways. The 4th generation aircraft whose shape is more complex than that of the 5th generation aircraft have complicated temperature distribution. On the other hand, the 5th generation aircraft whose shape is relatively simple shows plain temperature distribution and lower skin temperature in terms of both average and maximum value.

Compiler triggered C level error check (컴파일러에 의한 C레벨 에러 체크)

  • Zheng, Zhiwen;Youn, Jong-Hee M.;Lee, Jong-Won;Paek, Yun-Heung
    • The KIPS Transactions:PartA
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    • v.18A no.3
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    • pp.109-114
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    • 2011
  • We describe a technique for automatically proving compiler optimizations sound, meaning that their transformations are always semantics-preserving. As is well known, IR (Intermediate Representation) optimization is an important step in a compiler backend. But unfortunately, it is difficult to detect and debug the IR optimization errors for compiler developers. So, we introduce a C level error check system for detecting the correctness of these IR transformation techniques. In our system, we first create an IR-to-C converter to translate IR to C code before and after each compiler optimization phase, respectively, since our technique is based on the Memory Comparison-based Clone(MeCC) detector which is a tool of detecting semantic equivalency in C level. MeCC accepts only C codes as its input and it uses a path-sensitive semantic-based static analyzer to estimate the memory states at exit point of each procedure, and compares memory states to determine whether the procedures are equal or not. But MeCC cannot guarantee two semantic-equivalency codes always have 100% similarity or two codes with different semantics does not get the result of 100% similarity. To increase the reliability of the results, we describe a technique which comprises how to generate C codes in IR-to-C transformation phase and how to send the optimization information to MeCC to avoid the occurrence of these unexpected problems. Our methodology is illustrated by three familiar optimizations, dead code elimination, instruction scheduling and common sub-expression elimination and our experimental results show that the C level error check system is highly reliable.

Autocollimation Type Automatic Spectrorefractometer for Solid and Liquids (자동시준형 분광굴절률 측정장치)

  • 이윤우;조현모;이인원
    • Korean Journal of Optics and Photonics
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    • v.5 no.3
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    • pp.431-436
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    • 1994
  • An automatic spectrorefractometer with a Littrow spectrometer arrangement has been designed and fabricated to measure the refractive indices of solids and liquids from the visible to the near IR. The achievable accuracy is numericaly analyzed by varying the measuring parameters and the electromechanical system for measuring the prism angle with a rotary encoder and a position sensitive detector is fabricated. The performance of the instrument is discussed in detail and the results of measurements are given. given.

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An analytical model considering temperature effects in self-signal processing infrared detectors (자기신호처리 적외선 감지소자의 온도효과를 고려한 해석적 모델)

  • 조병섭;곽계달
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.3
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    • pp.124-133
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    • 1995
  • A theoretical self-consistent thermoelectric model has been developed for optimal thermal design in the self-signal processing infraed detectors. The model is achived by employing the coupled thermoelectric equation which allows which allows the simultaneous investigation of the termal and electrical aspects of device behavior. The thermal limitation of detectivity and responsivity are determined by the enegy gap, carrier concentration, lifetime, and mobility as a function of the temperature. The calculated results indicate that the detectivity is decreased at bias fields above about 50 V/cm, because the performence is limiting by temperature when the bias voltage reached the level associated with Joule heating. It has been also found that the improvement in the mid-band modulation transfer function(MTF) may be restricted by increasing the bias fields. Further, the important paramerers in the thermal optimization of SPIR detector, such as temperature in the device, ambipolar velocity, element thickness and length, are also considered. The analytical study provides a mathematical basis for optimal design of such a photoconductive IR detector and the agreement between the experimental and theoretical results are seen to be good.

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Numerical Analysis on the Transient Cooling Characteristics of an Infrared Detector Cryochamber (적외선 센서 냉각용 극저온 용기의 과도 냉각 특성에 관한 수치해석)

  • 이정훈;김호영;강병하
    • Progress in Superconductivity and Cryogenics
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    • v.4 no.2
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    • pp.68-72
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    • 2002
  • This work investigates the transient cooling characteristics of an Infrared (IR) detector cryochamber, which has a critical effect on the cooling load. The current thermal modeling considers the conduction heat transfer through a cold well. the gaseous conduction due to outgassing. and the radiation heat transfer. The transient cooling Performance. i.e. the penetration depth and cooling load, is determined using a finite difference method. It is found that the penetration depth increases as the bore conductivity increases. Gaseous conduction and radiation hardly affect the penetration depth. The transient cooling load increases as the bore conductivity increases. The effects of gaseous conduction and radiation on transient heat transfer are weak at initial stages of cooling. However, their effects become significant as the cooling Process Proceeds.

Synthesis of Diamond films for Radiation Detector (방사선 검출기용 다이아몬드 막의 합성)

  • 박상현;김정달;박재윤;김경환;구효근;이덕출
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.366-369
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    • 1999
  • Synthetic diamond films have been deposited on the silicon(100) surface and molybdenum substrates using an microwave plasma enhanced vapor deposition (MWPECVD) method. The effect of deposition time, surface morphology, X-ray diffraction pattrm, infrared transmittance and Raman Scattering have been studied, The diamond film deposited on Mo substrate for (100) hours at 40 torr H$_2$-CH$_4$O$_2$ gas system have been shown 1${\mu}{\textrm}{m}$/h of growth rate and good crystallization

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