화생방 보호의 성능평가를 위한 무선 실시간 가스 검출기 개발

가동하 한국군사과학기술학회 2020 한국군사과학기술학회지 Vol.23 No.3

Man-In-Simulant Test(MIST) provides a test method to evaluate chemical protective equipments such as protective garments, gloves, footwear and gas mask. The MIST chamber is built to control concentration of chemical vapor that has a activity space for two persons. Non-toxic methyl-salicylate(MeS) is used to simulate chemical agent vapor. We carried out to measure inward leakage MeS vapors by using passive adsorbent dosimeter(PAD) which are placed on the skin at specific locations of the body while man is activity according to the standard procedure in MIST chamber. But more time is required for PADs and there is concern of contamination in PADs by recovering after experiment. Therefore detector for measuring in real time is necessary. In order to analyze in real time the contamination of the personal protective equipment inside the chemical environment, we have developed a wireless real-time gas detector. The detector consists of 8 gas-sensors and 1 control-board. The control-board includes a CPU for processing a signal, a power supply unit for biasing the sensor and Bluetooth-chipset for transmission of signals to external PC. All signals from gas-sensors are converted into digital signals simultaneously in the control-board. These digital signals are stored in external PC via Bluetooth wireless communication. The experiment is performed by using protective equipment worn on manikin. The detector is mounted inside protective equipment which is capable of providing a real-time monitoring inward leakage MeS vapor. Developed detector is demonstrated the feasibility as real-time detector for MIST.

Comparison Between the Capacitance and the Signal-to-noise Ratio of a PIN Diode

가동하,김현옥,배재범,현효정,박환배 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.1

PIN diodes with areas of 1 × 1 cm^2 were fabricated on 5-in., high-resistivity, <100>-orientation, and 380-μm-thick n-type silicon wafers. When a charged particle passes through the PIN diode and a reverse voltage is applied, electron-hole pairs are created and collected into the electrodes by the electric field. The capacitance and the signal-to-noise ratio of the PIN diode were measured as functions of the reverse bias voltage. The reciprocal of the capacitance has the same electrical behavior as the signal-to-noise ratio.

준실시간 소형 풍동 시스템을 이용한 화학작용제(HD) 증발특성 연구

가동하,정현숙,서지윤,이준오,이해완 한국군사과학기술학회 2019 한국군사과학기술학회지 Vol.22 No.1

Upon chemical agent release, it is of importance to study the characteristic persistence and evaporation of chemical agents from surfaces for the prediction of dispersion hazard. We have recently developed a fast and near real-time wind tunnel system proving the controlled environment(air flow, temperature, and humidity), continuously collects agent vapor and analyzes it. A thermal sorber/desorber is unnecessary to collect the vapor in the system we have developed. Instead, a tandem thermal sorber collects the vapor, which is then directly transferred to a fast gas chromatography(GC) for analysis. As a proof of concept, the evaporation of sulfur mustard agent(HD) was studied from glass, sand and concrete. The results were in an excellent agreement with those obtained from the conventional wind tunnel system.

고고도핵폭발 전자기펄스 피해 분석을 위한 전산모사 연구

가동하,심우섭,Kah, Dong-Ha,Shim, Woosup 한국군사과학기술학회 2015 한국군사과학기술학회지 Vol.18 No.6

This paper describes computer simulation program of high-altitude electromagnetic pulse (HEMP). The HEMP is produced by the gamma rays form high-altitude nuclear explosion. The gamma rays generate a current of compton electron that leads to the production of electromagnetic fields. In case of high altitude nuclear burst, the electrical fields at the earth's surface are strong enough to be damaged for electrical and electronic device over a very much larger area. Therefore, national infrastructure will be serious damage such as power grid and communication network. In this paper introduce simulation program for calculation of HEMP and present to simulation study results of high altitude nuclear explosion experiment from U.S. and U.S.S.R.

Radiation Hardness Study for Silicon Strip Sensors Using the 35-MeV Proton Beam from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences

이직,가동하,김홍주,박환배,소중호 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.4

We present the result of a radiation hardness study for silicon strip sensors that was done by using 35-MeV proton beam from the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences. In this study, we compare the leakage current of the sensors before and after the silicon sensors were irradiated by the proton beam.

Signal-to-Noise Ratio Measurement for Silicon Strip Sensors with a Proton Beam

유상수,가동하,박환배,현효정,H.D Kang,김홍주,J.B Bae,Kyeryung Kim,Y.I Kim 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I

The signal-to-noise performance of DC-coupled single-sided silicon strip detectors (SSSD) of our own design and front-end readout electronics is presented. Good separation of the signal from the noise is essential for the successful accomplishment of their intended functions. For the tracking of charged particles, a good signal-to-noise ratio ($>$$10$) is required. For X-ray applications, much better signal-to-noise performance is desirable because of less energy being deposited by an incident photon. We report a signal-to-noise ratio of the fabricated DC-coupled SSSD with electronics for the 45-MeV proton beam from the MC-50 cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS) in Seoul, Korea

Variation in the Electrical Properties of 100 V/100 A Rated Mesh and Stripe TDMOSFETs (Trench Double-Diffused MOSFETs) for Motor Drive Applications

나경일,가동하,김상기,Jin-Gun Koo,김종대,양일석,이진호 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.10

The vertical power MOSFETs with deep trench structure is one of the most promising candidates to overcome the trade-off relationship between ON-resistance (RON) and blocking voltage (BVDS). Especially, 100V/100A rated trench power MOSFETs are used in component of many power systems, such as motor and LED lighting drive IC, DC-DC converter in electric vehicle, and so on. In this work, we studied the variation of electrical characteristics, such as threshold voltage (VTH), BVDS, and current drivability, with p-well doping concentration via SILVACO simulator. From simulation results, we found the dependence of BVDS and drain current (ID) as a function of p-well doping concentration with ion implantation energy of 80 KeV. As increase of p-well doping concentration at guard-ring region, both VTH and BVDS slowly increased but ID decreased because the boron lateral diffusion during fabrication process below gate trench region have an effected on doping concentration of p-body at active region. Additionally, 100V/100A rated TDMOSFETs (Trench Double-Diffused MOSFETs) with mesh and stripe types were successfully developed by using silicon deep etching process, respectively. The variations of electrical properties of the fabricated two different kinds of devices, such as VTH, BVDS, and current drivability, with cell design and density in TDMOSFETs were also studied. BVDS and VTH in stripe type TDMOSFET were 110 and 3 V, respectively. In the case of mesh type device, VTH was smaller 0.5 V than that of stripe type because of corner effect, BVDS improved about 20V compared to stripe type TDMOSFET due to the edge termination, and the maximum drain current (ID.MAX) was improved about 10% due to increase of gate length at same chip size. These effects reflected in different cell density devices. When the cell density increases, however, the increasing amount of current density has changed due to mobility degradation by increase of device temperature during high power operation.

A Novel Trench Gate MOSFET with a Multiple-layered Gate Oxide for High-reliability Operation

김상기,가동하,나경일,양일석,Jin Gun Koo,김종대,이진호,박훈수 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.10

Gate dielectrics in trench structures for trench gate metal oxide semiconductor field-effect transistor (MOSFET) power devices are very important to realize excellent characteristics. In this paper we describe multiple-layer gate dielectrics for trench gate MOSFETs with both thermal and chemical vapor deposition (CVD) gate oxides that exhibit excellent gate oxide properties and surface roughness. Through various trench etching experiments for better surface conditions in the trench, the optimum etching gas chemistry and etch conditions were found. The destruction of gate dielectric in trench gate MOSFET occurs at the top and the bottom trench corner edges. The structure of the gate electrode is pulled out with the polysilicon layer which is buried in the trench. Thus, high electric field operation is inevitable at the gate between source diffusion and the gate polysilicon. Moreover, the trench corner oxide suffers from the high electric field. We propose a multiple-gate dielectric structure of a thermal oxide and CVD oxide for highly reliable operation of the device. This enables trench surface smoothing and low thermal stress at the trench corners and provides the oxide thickness uniformity, giving superior device characteristics of high breakdown voltage and low leakage current. These improvements are caused by the excellent quality of the gate oxide and the good thickness uniformity that is formed at the inner trench with a specific geometrical factor.

Electrical Characteristics and Radiation Detection Performance of Large-area Photodiodes

배재범,현효정,가동하,강국현,박환배 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.7

Photodiodes with the size of 2.3 × 2.3 cm2 are fabricated on n-type silicon wafers with highresistivity (>5 k·cm) for physics applications. The photodiodes are fully depleted to collect signalsproduced by incoming particles. We measure the leakage currents and the capacitances of thephotodiodes as functions of the reverse bias voltage. The photodiodes with leakage currents < 70nA/cm2 are used to measure the signal-to-noise ratio (SNR) by using a 45 MeV proton beam fromthe MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS) and a90Sr radioactive source. The SNRs are measured for the photodiode only and for photodiode coupledwith a 5 mm thick plastic scintillator. The proton beam energy is controlled by using a degrader,and the pulse heights are measured for different energies of the proton beam. The radiation damageeffect is also measured in an environment of 1.18 × 1010 protons/cm2. In this paper, we present notonly the SNR measurements using the proton beam and the radioactive source but also the resultof the radiation damage test.

Measurement of Radiation Damage on a Back-illuminated Silicon PIN Photodiode Caused by a 35 MeV Proton Beam

배재범,현효정,가동하,김현옥,박환배,정명환,라세진 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.22

We develop a backside illuminated photo-sensor that is fabricated on a <100>-oriented, high resistivity n-type 400 μm thick silicon wafer. The PIN photodiode is designed and manufactured as a radiation detector for alpha particles and low energy gamma-rays. The silicon photo-sensor is susceptible to radiation damage. Therefore, it is important to investigate the effects of radiation damage to the fabricated PIN photodiode. We measure the radiation damage to a PIN photodiode by a 35 MeV proton beam at the Korea Institute of Radiological and Medical Sciences (KIRAMS). We present the effects of proton radiation on the electrical properties of the PIN photodiode.