• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.100-103
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• 2003

Signal detection technologies such as fluorescence, charge and electrochemical detection used in the monolithic capillary electrophoresis system to convert the biochemical reaction into the electrical signal. The fluorescence detection using photodiodes that measure fluorescence emitted from eluting molecules is widely used for the monolithic capillary electrophoresis system. In this paper, in order to fabricate a photosensor has the increased sensitivity, we investigated on the sensitivity of general type and p-i-n type diode. The p-i-n diode has higher sensitivity than photodiode. Considering these results, we fabricated p-i-n diodes on the high resistive$(4k{\Omega}{\cdot}cm)$ wafer into rectangle and finger pattern and compared internal resistance of each pattern. The internal resistance of p-i-n diode can be decreased by the application of finger pattern has parallel resistance structure from $571{\Omega}$ to $393{\Omega}$.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.11-20
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• 1996

In this paper, the characteristics of therapy radiation diode sensors have been studied by using therapy radiation from the MM22 microtron accelerator. The linearity, reproducibility and error ratio were measured for feasibility as a radiation detector. Energy dependence, sensitivity change after a amount of irradiation and output value according to a number of diodes were also measured for same purpose. We have formed pulse shaping of diode signal with nuclear instruments for portal image reconstruction. The percent depth dose ratio according to field size and depth was compared with that of the detector of a ion chamber. Using thirteen silicon diodes, we can directly read diode outputs on a computer monitor after A/D conversion with 16 channels analog to digital conversion board with 12 bit resolution. The possibility for portal image with diodes has been suggested from output comparison between output value with a human phantom and that without a human phantom.

• Progress in Medical Physics
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• v.17 no.1
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• pp.47-53
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• 2006

The accuracy of the dosimetry in the Cyberknife system is accomplishing important role from all processes of the stereotactic radiosurgery. In this study, we estimated relative output factors for Cyberknife. All measurements were peformed by six different detectors: diode detector, X-Omat V film, Gafchromic EBT film, 0.015 cc, 0.125 cc and 0.6 cc ionization chamber The diode detector and three ionization chambers peformed using water phantom at 80 cm SSD and 1.5 cm depth. When the film measurements were peformed, the water phantom was replaced with a solidwater phantom. Each collimator normalized with respect to the output factor of the largest collimator (60 mm). For the collimators over than 30 mm, the output factors from the different detectors showed a good agreement within 0.5% except 0.6 cc ion chamber For the collimators less than 15 mm, there were substantial differences In the output factors among different detectors. That is, the value of output factor for the 5 mm collimator of a diode and Gafchromic film was each $0.656{\pm}0.009$ and $0.777{\pm}0.013$. In the ion chamber and diode detector, those difference were due to the presence of large dose gradients and lack of electronic equilibrium in narrow megavoltage x-ray beams Therefore, the Gafchromic EBT film were considered more accurate than the others detectors.

• Progress in Medical Physics
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• v.20 no.4
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• pp.290-297
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• 2009

In case of radiation treatment using small field high-energy photon beams, an accurate dosimetry is a challenging task because of dosimetrically unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, and non-uniformity between the detector and the phantom materials. In this study, the absorbed dose in the phantom was measured by using an ion chamber and a diode detector widely used in clinics. $GAFCHROMIC^{(R)}$ EBT films composed of water equivalent materials was also evaluated as a small field detector and compared with ionchamber and diode detectors. The output factors at 10 cm depth of a solid phantom located 100 cm from the 6 MV linear accelerator (Varian, 6 EX) source were measured for 6 field sizes ($5{\times}5\;cm^2$, $2{\times}2\;cm^2$, $1.5{\times}1.5\;cm^2$, $1{\times}1\;cm^2$, $0.7{\times}0.7\;cm^2$ and $0.5{\times}0.5\;cm^2$). As a result, from $5{\times}5\;cm^2$ to $1.5{\times}1.5\;cm^2$ field sizes, absorbed doses from three detectors were accurately identified within 1%. Wheres, the ion chamber underestimated dose compared to other detectors in the field sizes less than $1{\times}1\;cm^2$. In order to correct the observed underestimation, a convolution method was employed to eliminate the volume averaging effect of an ion chamber. Finally, in $1{\times}1\;cm^2$ field the absorbed dose with a diode detector was about 3% higher than that with the EBT film while the dose with the ion chamber after volume correction was 1% lower. For $0.5{\times}0.5\;cm^2$ field, the dose with the diode detector was 1% larger than that with the EBT film while dose with volume corrected ionization chamber was 7% lower. In conclusion, the possibility of $GAFCHROMIC^{(R)}$ EBT film as an small field dosimeter was tested and further investigation will be proceed using Monte Calro simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1423-1426
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• 2005

Map building is the most important thing for the mobile robots navigation. It requires specific vision system such as CCD camera, range finding system, and many other things. Laser range finder has highly collimated beams can be obtained easily, thus achieving lateral resolution. Laser Diode is used for a continuous laser source. The Automatic Current Control Circuit and the Bias-T is used for mix AC signal with DC bias. This signal is used for driving Laser Diode. The main idea of the calculating distance is detecting phase shift between reference signal and detected signal by photo detector. For the signal processing, the Lock-in amplifier system is addressed in this paper. We used a diffused reflected beam to detect phase shift in this system. But this beam is minuteness signal so it can be easily buried in nose. Lock-in amplifier is used to measure the amplitude and phase of signals which are buried in noise.

• Journal of Sensor Science and Technology
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• v.20 no.1
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• pp.53-57
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• 2011

We developed a small methane detection system because methane gas is used in many areas and is dangerous. The developed system consisted of LD(Laser Diode) tuned a wavelength of $1.65\;{\mu}m$, two mirrors to collect a laser beam, photo detector. It could detect methane gas at a long range and its sensitivity was 1.98 V/$CH_4%$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.3
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• pp.26-29
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• 1975

In this paper, the input equivalent resistances of the n phase-diode average and envelope detection. circuits for the sinusoidal signal waveforms are analytically derived from the power loss in their load resistances, and the input equivalent resistance of the n phase-diode envelope detection circuits for the arbitrary signal waveforms is also obtained from the same physical conception.

• 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.

• The Magazine of the IEIE
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• v.8 no.1
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• pp.16-32
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• 1981

물리학적인 측면과 공학적인 측면에서의 CT(computerized tomography)의 최근 동향과 발전 과정을 되돌아 보고 의료 현장에서 실제 사용되고 있거나 아직 연구되고 있는 CTsystem의 성능과 그 특성에 대해 기술해 보았다. 또한 CT의 역사적인 발전과정, tomophysics 및 chemistry, system의 구성, detector 및 sensing diode, 신호의 수집과 처리를 위한 전자회로, computer system 및 주변 연산장치등에 대해서 고찰하였다.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.77-80
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• 2010

The spectroscopy toolkit has been developed and tested. The toolkit consists of a CsI(Tl)/PIN diode detector, integrated electronics, and a multi.channel.analyzer and its size was 40 cm(width) by 20 cm(length) by 6 cm(high). It is compact, very portable and simpler and cheaper compared to the conventional spectroscopy system. The gamma energy resolutions of the toolkit were 7.9% for the 660 keV of $^{137}Cs$ and 4.9% for 1,332 keV of $^{60}Co$ respectively. The linearity for gamma energies was good. When the energy spectrum of a ceramic sample containing $^{232}Th$ was measured with the spectroscopy toolkit for 20 minutes, there were significant peaks of the heavy metal. These results show that the resolution of the spectroscopy toolkit is sufficient to accumulate a quality spectrum in a few minutes by using weak, encapsulated commercial sources. Furthermore a toolkit experiment that how to measure energy spectra using the toolkit, and how to identify specific isotopes in a pottery piece, could be widely adopted for education and even for more sophisticated and higher level experiments.