• 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.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2399-2401
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• 1999

This paper indicate that phase resolved partial discharge pattern are investigated on PET films with semiconductor particle. In this study, we measured phase-resolved PD pattern and statistical parameter from PET specimens according to containing semiconductor particle. Measurement system is the conventional PD detector using digital signal processing technique. The relationship of semiconductor particle in PET film was discussed through the difference of $\psi$-q-n distribution and statistical analysis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.spc
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• pp.23-29
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• 2022

To detect harmful chemical substances in seawater, we fabricated a prototype sensor and evaluated its performance. The prototype sensor consisted of a detector, housing, and driving circuit. We built the detector by printing an Indium-Tin-Oxide (ITO) nanoparticle film on a flexible substrate, and it had two detection parts for simultaneous detection of temperature and HNS concentration. The housing connected the detector and the driving circuit and was made of Teflon material to prevent chemical reactions that may affect sensor performance. The driving circuit supplied electric power, and display measured data using a bridge circuit and an Arduino board. We evaluated the sensor performances such as response (ΔR), the limit of detection (LOD), response time, and errors to confirm the specification.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.1
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• pp.22-28
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• 2009

This paper presents a fast received signal strength indicator (RSSI) circuit for wireless communication application. The proposed circuit is developed using power detectors and an analog-to-digital converter to achieve a fast settling time. The power detector is consisted of a novel logarithmic variable gain amplifier (VGA), a peak detector, and a comparator in a closed loop. The VGA achieved a wide logarithmic gain range in a closed loop form for stable operation. For the peak detector, a fast settling time and small ripple are obtained using the orthogonal characteristics of quadrature signals. In $0.18-{\mu}m$ CMOS process, the RSSI value settles down in $20{\mu}s$ with power consumption of 20 mW, and the maximum ripple of the RSSI is 30 mV. The proposed RSSI circuit is fabricated with a personal handy-phone system transceiver. The active area is $0.8{\times}0.2\;mm^2$.

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.63-69
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• 2023

Although Korea is the world's No. 1 semiconductor producing country, most studies are conducted with risk assessment for simple material risks due to the closedness of the site for industrial protection. In terms of industrial safety, a monitoring system such as a gas detector to determine the leakage of hazardous substances has been established, but research on effectively discharging harmful gastritis substances in case of leakage has only recently begun. Semiconductor manufacturing facilities (gas boxes) where a large amount of flammable materials are handled are currently being safety managed by using a gas detector and blocking the air inlet. It is difficult to dilute in a short time in case of leakage of flammable substances. Therefore, in this study, based on various criteria, the size of the duct according to the size of the gas box is determined and the appropriate size of the air inlet is studied to minimize the exhaust performance requirement without exposing hazardous chemicals to the outside in the event of a flammable leak. We want to do an optimal exhaust design.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.2
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• pp.198-201
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• 2014

The phase frequency detector (PFD) is one of the most important building blocks of a phase locked Loop (PLL). Due to blind-zone problem, the detection range of the PFD is low. The blind zone of a PFD directly depends upon the reset time of the PFD and the pre-charge time of the internal nodes of the PFD. Taking these two parameters into consideration, a PFD is designed to achieve a small blind zone closer to the limit imposed by process-voltage-temperature variations. In this paper an enhanced architecture is proposed for dynamic logic PFD to minimize the blind-zone problem. The techniques used are inverter sizing, transistor reordering and use of pre-charge transistors. The PFD is implemented in 180 nm technology with supply voltage of 1.8 V.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.576-580
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• 2013

We investigate the enhanced effects of asymmetry ratio variations of the source and drain area in silicon (Si) field-effect transistor (FET). Photoresponse according to the variation of asymmetry difference between the width of source and drain are obtained by using the plasmonic terahertz (THz) wave detector simulation based on technology computer-aided design (TCAD) with the quasi-plasma 2DEG model. The simulation results demonstrate the potential of Si FETs with asymmetric source and drain structures as the promising plasmonic THz detectors.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.3
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• pp.287-292
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• 2016

A multiphase clock and data recovery (CDR) circuit having a novel rotational bang-bang phase detector (RBBPD) is demonstrated. The proposed 1/4-rate RBBPD decides the locking point using a single clock phase among sequentially rotating 4 clock phases. With this, our RBBPD has significantly reduced power consumption and chip area. A prototype 10-Gb/s 1/4-rate CDR with RBBPD is successfully realized in 65-nm CMOS technology. The CDR consumes 5.5 mW from 1-V supply and the clock signal recovered from $2^{31}-1$ PRBS input data has 0.011-UI rms jitter.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.87-91
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• 2016

Background: A hand-held detector for an emergency response was developed for nuclide identification and to estimate the information of the ambient dose rate in the scene of an accident as well as the radioactivity of the contaminants. Materials and Methods: To achieve this, the most suitable sensor was first selected as a cadmium zinc telluride (CZT) semiconductor and the signal processing unit from a sensor and the signal discrimination and storage unit were successfully manufactured on a printed circuit board. Results and Discussion: The performance of the developed signal processing unit was then evaluated to have an energy resolution of about 14 keV at 662 keV. The system control unit was also designed to operate the CZT detector, monitor the detector, battery, and interface status, and check and transmit the measured results of the ambient dose rate and radioactivity. In addition, a collimator, which can control the inner radius, and the airborne dust sampler, which consists of an air filter and charcoal filter, were developed and mounted to the developed CZT detector for the quick and efficient response of a nuclear accident. Conclusion: The hand-held CZT detector was developed to make the in-situ gamma-ray spectrometry and its performance was checked to have a good energy resolution. In addition, the collimator and the airborne dust sampler were developed and mounted to the developed CZT detector for a quick and efficient response to a nuclear accident.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3286-3292
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• 1996

An experimental results of optical requency locked loop with DFB semiconductor laser as VCO are presented. Using quadricorrelator as frequency difference detector and frequency off-set locking technique with 1GHz reference frequency, frequency locking range of 140MHz was achieved. This paper reports the design and realization details of the loop.