• Title/Summary/Keyword: Photomultiplier tube

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A Study on image noise removal of $2^{nd}$ electron detector for a E-Beam Lithography (전자빔 가공기를 위한 2 차 전자 검출기의 영상 노이즈 제거에 관한 연구)

  • Im Y.B.;Moon H.M.;Joe H.T.;Paek Y.J.;Lee C.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1741-1744
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    • 2005
  • The electron beam machining provides very high resolution up to nanometer scale, hence the E-Beam writing technology is rapidly growing in MEMS and nano-engineering areas. For E-Beam machining, $2^{nd}$ electron detector is required to see a machined sample at the stage. The $2^{nd}$ electron detector is composed of scintillator and photomultiplier with signal amplifier and high voltage power supplier. Since a photomultiplier tube is an extremely high-sensitivity photodetector, the signal light level to be detected is very low and therefore particular care must be exercised in shielding external light. In this paper, the design methodology of $2^{nd}$ electron detector and the image noise removal method are introduced.

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Development of a wireless radiation detection backpack using array silicon-photomultiplier (SiPM)

  • Kim, Jeong Ho;Back, Hee Kyun;Joo, Koan Sik
    • Nuclear Engineering and Technology
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    • v.52 no.2
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    • pp.456-460
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    • 2020
  • In this research, a radiation detection backpack to be used discreetly or by a wide range of users was developed using array silicon-photomultiplier (SiPM) and CsI (Tl), and its characteristics were evaluated. The R-squared value, which indicates the responsiveness of a detector based on the signal intensity, was determined to be 0.981, indicating a good linear responsivity. The energy resolutions for gamma radiation energies of Co-57 (122 keV), Ba-133 (356 keV), Cs-137 (662 keV), and Co-60 (1332 keV) were found to be 13.40, 10.50, 6.77, and 3.16%, respectively. These results confirm good energy resolution characteristics. Furthermore, in the case of mixed sources, the gamma radiation peaks were readily distinguishable, and the R-squared value for energy linearity was calculated to be 0.999, demonstrating an exceptional energy linearity. Further research based on the results of this study would enable the commercialization of lightweight SiPM-based wireless radiation detection backpacks that can be used for longer durations by replacing the photomultiplier tube, which is mainly used as the optical sensor in existing radiation detection backpacks.

Photomultiplier Tube Emission of Protein and fat specimens from the sirloin of a Chitosan-fed pig Comparison of meat quality (광전자증폭관에 의한 키토산 첨가 사료를 사용한 양돈 생체조직에서의 육질 품질 비교 측정)

  • Min, Je-Ho;Yoo, Jong-Su;Cheun, Byeung-Soo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.3
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    • pp.323-328
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    • 2014
  • Effect of chitosan with sirloin specimens from chitosan-fed and normal-fed pig. The specimens were observed by a optical microscope and their biophoton was measured by a photomultiplier(PMT)tube. Results of experiments showed that specimens of the chitosan-fed pig had lower biophoton rate than that of the normal-fed pig. As a result of the organization were also shown pictures Chitosan as a pork loin tissue and fat in the flesh less delicate and compactness is found that tastes good. Thus by PMT fleshy tissue biochemical measurements to measure the change of state to be one of the new method is to be expected.

Development of Portable Gamma Probe and Its Basic Performance Test (이동형 감마프로브 개발과 기본성능 평가)

  • Kim, H.J.;Kwark, C.;Choi, Y.;Yang, M.K.;Bong, J.K.;Lee, S.C.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.216-219
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    • 1997
  • We are developing a portable multipurpose gamma counting and imaging probe that will be useful for many applications in nuclear medicine including radioimmunoguided surgery in the detection and treatment of malignant tumors. Any diagnostic information provided by CT, MRI, PET, SPECT or gamma camera imaging prior to surgery obviously is very important, but current techniques are limited in many instances. To overcome some of these limitations, the portable multipurpose gamma probe is being developed. The gamma probe consists of NaI(Tl) crystal with 1" dia $\times$ 0.5" thick and singlechannel photomultiplier tube (SC-PMT) for counting, and 3" dia $\times$ 0.375" and multichannel photomultiplier tube (MC-PMT) for imaging, nuclear instrument module (NIM), position circuits, interface, and PC. The energy resolution using Tc-99m was measured as 14% and the spatial resolution using 3mm dia green LED was measured as 2.9mm. These priliminary results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine.

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Design and Manufacture of an Electron Detector for Scanning Electron Microscope (주사전자현미경용 전자검출기의 설계 및 제작)

  • Jeon, Jong-Up;Kim, Ji-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.4
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    • pp.53-60
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    • 2008
  • Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.

REPLACEMENT OF A PHOTOMULTIPLIER TUBE IN A 2-INCH THALLIUM-DOPED SODIUM IODIDE GAMMA SPECTROMETER WITH SILICON PHOTOMULTIPLIERS AND A LIGHT GUIDE

  • KIM, CHANKYU;KIM, HYOUNGTAEK;KIM, JONGYUL;LEE, CHAEHUN;YOO, HYUNJUN;KANG, DONG UK;CHO, MINSIK;KIM, MYUNG SOO;LEE, DAEHEE;KIM, YEWON;LIM, KYUNG TAEK;YANG, SHIYOUNG;CHO, GYUSEONG
    • Nuclear Engineering and Technology
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    • v.47 no.4
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    • pp.479-487
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    • 2015
  • The thallium-doped sodium iodide [NaI(Tl)] scintillation detector is preferred as a gamma spectrometer in many fields because of its general advantages. A silicon photomultiplier (SiPM) has recently been developed and its application area has been expanded as an alternative to photomultiplier tubes (PMTs). It has merits such as a low operating voltage, compact size, cheap production cost, and magnetic resonance compatibility. In this study, an array of SiPMs is used to develop an NaI(Tl) gamma spectrometer. To maintain detection efficiency, a commercial NaI(Tl) $2^{\prime}{\times}2^{\prime}$ scintillator is used, and a light guide is used for the transport and collection of generated photons from the scintillator to the SiPMs without loss. The test light guides were fabricated with polymethyl methacrylate and reflective materials. The gamma spectrometer systems were set up and included light guides. Through a series of measurements, the characteristics of the light guides and the proposed gamma spectrometer were evaluated. Simulation of the light collection was accomplished using the DETECT 97 code (A. Levin, E. Hoskinson, and C. Moison, University of Michigan, USA) to analyze the measurement results. The system, which included SiPMs and the light guide, achieved 14.11% full width at half maximum energy resolution at 662 keV.

Self-Excited Noise Generation from Laminar Methane/Air Premixed Flames in Thin Annular JetsPut (환형제트에서의 메탄과 공기의 층류 예혼합 화염에서 발생되는 자발적인 소음에 대한 실험적 연구)

  • Jin, S.H.;Joung, J.H.;Kwon, S.J.;Chung, S.H.
    • 한국연소학회:학술대회논문집
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    • 2003.05a
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    • pp.159-165
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    • 2003
  • Self-excited noise generation from laminar flames in thin annular jets of methane/air premixture has been investigated experimentally. Various flames were observed in this flow configuration, including conical shape flames, ring shape flames, steady crown shape flames, and oscillating crown shape flames. Self-excited noise with the total sound pressure level of about 70dB was generated from the oscillating crown shape flames for the equivalence ratio larger than 0.95. Sound pressure and $CH^{\ast}$ chemiluminescence were measured by using a microphone and a photomultiplier tube. The frequency of generated noise was measured as functions of equivalence ratio and premixture velocity. A frequency doubling phenomena have also been observed. The measured $CH^{\ast}$ chemiluminescence data were analyzed from which the corresponding sound pressure has been calculated. By comparing the data with those of measured ones, the noise source can be attributed to the flame front fluctuation near the edge of the oscillating crown-shape flames. The flame stability regime was influenced sensitively to the supplying air through the inner tube.

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Evaluation of the 256ch Flat Panel PS-PMT on Positioning Image Histogram for PET

  • Orita, Narimichi;Murayama, Hideo;Kawai, Hideyuki;Inadama, Naoko;Umehara, Takaya;Kasahara, Takehiro;Tsuda, Tomoaki
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.324-327
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    • 2002
  • For a next generation PET that realizes high sensitivity and high resolution, we proposed a design of a depth of interaction detector. A unit of the detector is constructed of four stages rectangular blocks of 2 by 2 Gd$_2$SiO$\sub$5/: Ce (GSO) crystal array optically coupled to position sensitive photomultiplier tube (PS-PMT). The 256ch flat panel PS-PMT is under development by Hamamatsu Photonics K.K., JAPAN. It has large cathode area, 51.7 by 51.7 mm$^2$, and the ratio of the effective area to external size is about 90%. The feature will contribute high packing fraction, accordingly high sensitivity. The 256 anodes are arranged in 16 by 16 at intervals of 3.0 mm. So as to evaluate the detector capability for identifying crystal of interaction, we got positioning image histograms with coupling a 16 by 5 array of GSO crystals, 2.9 by 2.9 by 7.5 mm$^3$, to the PS-PMT by irradiating a gamma ray uniformly from a point source. Flat panel PS-PMT is a new promising device for PET. We need to evaluate it if its performance is sufficiency. The performance was compared to the one with a 16ch PS-PMT.

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Construction of a Distribution Photometer System for Automobile Light Sources (자동차용 광원의 광도분포 측정장치(배광측정기)제작)

  • 김용완;김홍기;이인원;이완순;이상원
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.10 no.4
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    • pp.53-61
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    • 1996
  • A distribution photometer was constructed to measure the angular distribution of luminous intensity of light sources and the reflected luminance of retroreflectors. This system incorporates a goniometer to rotate test light source(360 degree in yaw rotation and $\pm$30 degree in pictch rotation), a photomultiplier tube as light detector, light projector for retroreflection measurements, and the control and display unit. The ranges of luminous Intensity measurements and observation angles are 0.01~199900 cd and 0.2~1.5 degree respectively. The uncertainty of luminous intensity measurements is $\pm$3%. This paper describes the construction of the distribution photometer and the performance characteristics.

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