• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.605-608
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• 2004

A $Pt/Al_xGa_{l-x}N$ Schottky type Ultra-violet photodetector was modeled and simulated using the commercial SILVACO software program. In the carrier transport, we applied field model and other analytic model to determine the electron saturation velocity and low field mobility for GaN and $Al_xGa_{l-x}N$. A C-Interpreter function was defined to described the mole-fraction for the ternary compound semiconductor such as $Al_xGa_{l-x}N$. As comparing the simulated and experimental results, we found that the simulated result for type-1 has $15.9 nA/cm^2$ of leakage current at 5V. We confirmed a good agreement of photo-current in the UV Photo-detector, while applying the absorption coefficient and reflective index of active $Al_xGa_{l-x}N$ and other layers. There had been an intensive search for the proper refractive indices of the layers.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.437-440
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• 1992

We design a multi-element photo-detector to measure the size of particles using the diffracted light energy distribution. The light energy that is scattered by particles in the collimated laser beam is collected by the Fourier transform lens and directed to the multi-semicircular concentric annular detecters. The scattered profile measured by the photodetector is sampled by a 32 channel analog-to-digital converter. A nonnegative least squares analysis translates the light energy distribution into the corresponding unique particle size distribution.

• Journal of Ocean Engineering and Technology
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• v.13 no.3B
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• pp.38-46
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• 1999

Increasing stringent emissions legislation and requirement of more effective energy used for diesel engine demand the fine control of the fuel injection system. Recently, the electromagnetic fuel injection control system for diesel engine is tried to realize the optimum diesel combustion by the feel back sensing as optical signal of combustion flame. The photo detectors were made for the feed back signal of electromagnetic fuel injection control for small DI diesel engine. Their abilities to detect defining combustion events were examined. By evaluating test results, it was shown that the wider acceptable optical range design of optical probe window face, and selection of installation position and installation method of detector were important point for improving sensing ability. The detector was shown to detect start and end of diffused combustion and maximum point of flame intensity impossible for pressure sensor, and also shown that the maximum point of flame intensity was 75% of accumulated heat release point within the experimental conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1051-1052
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• 2013

• Journal of radiological science and technology
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• v.23 no.2
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• pp.27-32
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• 2000

It was produced radiation dosimeter used photo-diodes for which ionization by x-ray was applied and evaluated the value of utility in clinics as compared with ion-chamber. The result obtained were as follows : 1. Comparison of ion-chamber with photo-diode dosimeter's x-ray output by the change of x-ray tube voltage, and the ratio of ion-chamber to diode was $0.96{\sim}1.02$ which was not affected by x-ray beam quality. 2. The ratio of ion-chamber to diode was 0.96 by change of tube current and 0.97 by change of exposure time that is not affected by x-ray quantity. 3. The ratio of ion-chamber to diode was $0.97{\sim}1.04$ by thickness and $0.93{\sim}1.10$ by radiation field that is little affected by second ray quantity. 4. Reproducibility of photo-diode dosimeter was 0.011(CV) and it is a good result. 5. Photo-diode dosimeter was affected by the surface angle of detector over 30 degrees. Produced dosimeter was small, light, and meets good result compared with ionization chamber. It was expected come into wide use in clinic.

• Fire Protection Technology
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• s.29
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• pp.39-45
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• 2000

All objects emit thermal radiation and this radiation is the basis of the techniques used to detect flames. The usual phenomena occurring in the initial stage of a fire are generally invisible products of a combustion and visible smoke. Liquid or gaseous materials do not undergo a smoldering stage such fires develop very rapidly. Also, the heat generated by the initial flames is usually not sufficient to active a heat detector. In this case the most effective criterion for automatic fire detection is the flame. In fire regulation of korea, the compulsory standard provided that a flame detector shall be installed a place of the attachment hight of detector is higher than 20 m, chemical plants, hangar, refinery, etc.. The result of the research and development are discriminated between a flame and other radiant emitters, developed PZT pyroelectric element is based on the use of photo-voltanic cell, developed IR band-pass filter that only allow a 4.3 radiation wavelength to reach the sensors and developed IR flame detector.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1426-1432
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• 2018

This paper presents a neutron detector configuration using EJ-301 scintillation liquid, a R9420 photo-multiplier and a homemade preamplifier. The detector qualities which include the energy linearity, efficiency response and neutron/gamma discrimination are guaranteed for neutron detection in the energy range from 0 to 3000 keVee. Regarding the neutron/gamma discrimination capability, four pulse shape discrimination (PSD) methods which are the threshold crossing time (TCT), pulse gradient analysis (PGA), charge comparison (CC) and correlation pattern recognition (CPR), were evaluated and discussed; among of these, the CPR method provides the best neutron/gamma discrimination.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1983.10a
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• pp.32-34
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• 1983

In this paper, an analog optical filter link is evaluated for the transmission of baseband video signals over a single fiber. LED and PIN photo diode are used as the optical source and the detector. Frequency response of the system, DP, DG and SNR are measured.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.4
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• pp.53-58
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• 2010

In this paper, the output characteristics of PSD(Position Sensetive Detector) used in measurement system are described. Most of the precision measurment systems are accomplished by a laser diode(LD), a photo diode(PD) and PSD(Position Sensetive Detector), which are used in reflection of mirror or projection of infrared spectrometer. But it is especially restricted by resolution of PD and PSD in nano-measurement. A new inclined light methods into the PSD are employed in the surface measurement system for increasing the resolution. As the results, we can know that the output characteristics of detective senser (PSD) become more than 2 or 3 times by changing inclined angle(range: 5 degree) compared with common angle. In addition, the experiment results are confirmed that the change of inclined angle is not affecting to the linearity and repeating.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.35-37
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• 2002

Conceptual design of the next generation PET with both high sensitivity and high spatial resolution has been performed. A detector unit using a depth encoding scheme was designed and constructed for trial. The unit consists of four Gd$_2$SiO$\sub$5/:Ce crystal blocks in a 2x2x4 array coupled to a position-sensitive photomultiplier tube having metal channel dynodes and 4x4 multi-anodes. Our proposed detector is a very reliable and simple solution suitable for volume PET devices since the proposed depth encoding scheme does not need additional photo-detectors.