• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3824-3836
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• 2021

Workers' safety from radiological exposure in a 1 ton/day capacity spent resin treatment facility was evaluated according to the operating times and outflow rate due to process related leakages. The conservative annual dose based on the operating times of the workers exceeded the dose limit by at least 7.38E+01 mSv for close work. The realistic dose range was derived as 1.62E+01 mSv-6.60E+01 mSv. The conservative and realistic annual doses for remote workers were 1.33E+01 mSv and 3.00E+00 mSv respectively, which were less than the dose limit. The MWR was identified as the major contributor to worker exposure within the 1 h period required for removal of radioactive materials. The dose considering both internal and external exposures without APF was derived to be 1.92E+01 mSv for conservative evaluation and 4.00E+00 mSv for realistic evaluation. Furthermore, the dose with APF was derived as 7.27E-01 mSv for conservative evaluation and 1.51E-01 mSv for realistic evaluation. Considering the APF for leakage from all parts, the dose range was derived as 1.25E+00 mSv-2.03E+00 mSv for conservative evaluation and 2.61E-01 mSv-4.23E-01 mSv for realistic evaluation. Hence, it was confirmed that radiological safety was secured in the event of a leakage accident.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.540-544
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• 2017

In this study, we analyzed the effects of TID(Total Ionizing Dese) and TREE(Transient Radiation Effects on Electronics) on nMOSFET and pMOSFET fabricated by 0.18um CMOS process. The size of nMOSFET and pMOSFET is 100um/1um(W/L). The TID test was conducted up to 1 Mrad(Si) with a gamma-ray(Co-60). During the TID test, the nMOSFET generated leakage current proportional to the applied dose, but that of the pMOSFET was remained in a steady state. The TREE test was conducted at TEST LINAC in Pohang Accelerator Laboratory with a maximum dose-rate of $3.16{\times}10^8rad(si)/s$. In that test nMOESFET generated a large amount of photocurrent at a maximum of $3.16{\times}10^8rad(si)/s$. Whereas, pMOSFETs showed high TREE immunity with a little amount of photocurrent at the same dose rate. Based on the results of this experiment, we will progress the research of the radiation hardening for CMOS unit devices.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.2
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• pp.170-177
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• 1992

Contact resistance and contact leakage current of the Al/TiSiS12T/Si system are investigated for NS0+T and PS0+T junctions. SALICIDE (Self Aligned Silicide) process was used to make the Al/TiSiS12T/Si system. Titanium disilicide is one of the most common silicides because of its thermal stability, ability to form selective formation and low resistivity. In this paper, RTA temperature effect and Junction implant dose effect were evaluated to characterize contact resistance and contact leakage current. The TiSiS12T contact resistance to NS0+T silicon is lower than that to PS0+T silicon, and TiSiS12T of contact leakage current to NS0+T silicon is lower than that to PS0+T silicon. Contact resistance and contact leakage current of the Al/TiSiS12T/Si system by this method were possible for VLSI application.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.9
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• pp.43-49
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• 1997

The dependence of the electrical properties in planar MQW - APD & pn, and p - i - n photodiode implanted with oxygen on the annealing emperatures and ion dose has been investigated. The oxygen implantation was performed for inter-device isolation. The leakage current of as-impanted p-i-n photodiode obtained was less than 50 nA. An annelaing temperature dependence study shows an abrupt increase of leakge current at 600.deg.C for all devices under study. This indicates that donor complex centers introduced by the chemical activity of oxygen increase with increasing annelaing temperatures. Furthermore, leakage current was highly correlated with oxygen dose due to th eimplanted related defects.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.768-777
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• 2013

The purpose of this study is to minimize radiation exposure to the workers and public members during CT examination. The objects are seven of the CT rooms in university hospitals and four of the CT rooms in clinics located in Busan and Gyung-nam area. The places of measurement for radiation leakage are 1) 3 m above the ground of shielding wall in the control room 2) particular space in the control room 3) worker's gate in the control room 4) the patient gate. Its values were calculated maximum leakage radiation per week(MLRW). As a result, the worker's gate of M clinic displayed the highest dose. When it was calculated by MLRW in classic method, it showed 1) $5.97{\pm}0.23$, 2) $0.50{\pm}0.02$, 3) $10.00{\pm}0.11$, 4) $2.37{\pm}0.47$ mR/week. All of them did not exceed limit for maximum permissible dose per week(MPDW). However, When MLRW of M clinic was calculated by empirical method, its value displayed $118.31{\pm}17.72$ mR/week.(MPDW>100 mR/week). Radiation leakage influenced in the control room(p<0.05). Therefore, The way of calculating MLRW must be developed and shielding wall in control room is designed 3 m above the ground for reducing dangerous of leakage radiation.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1619-1626
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• 2017

Electronic components that are used in high-level radiation environment require a semiconductor device having a radiation-hardened characteristic. In this paper, we proposed a radiation-hardened I-gate n-MOSFET (n-type Metal Oxide Semiconductors Field Effect Transistors) using a layout modification technique only. The proposed I-gate n-MOSFET structure is modified as an I-shaped gate poly in order to mitigate a radiation-induced leakage current in the standard n-MOSFET structure. For verification of its radiation-hardened characteristic, the M&S (Modeling and Simulation) of the 3D (3-Dimension) structure is performed by TCAD (Technology Computer Aided Design) tool. In addition, we carried out an evaluation test using a $Co^{60}$ gamma-ray source of 10kGy(Si)/h. As a result, we have confirmed the radiation-hardened level up to a total ionizing dose of 20kGy(Si).

• Journal of IKEEE
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• v.27 no.3
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• pp.303-307
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• 2023

In this paper, the creation of an Electron-Hole Pair due to Total Ionizing Dose (TID) effects inside the oxide of a Buried Channel Array Transistor (BCAT) device is induced, resulting in an increase in leakage current and threshold due to an increase in hole trap charge at the oxide interface. By comparing and simulating changes in voltage with the previously proposed Partial Isolation Buried Channel Array Transistor (Pi-BCAT) structure, the characteristics in leakage current and threshold voltage changed regardless of the increased oxide area of the Pi-BCAT device, compared to the asymmetrically doped BCAT structure. It shows superiority.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.643-654
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• 1987

The effect of prostacyclin[PGI, ] on myocardial preservation during global ischemia was studied in the isolating working rabbit heart model. Forty hearts underwent a 15 minute period of retrograde nonworking perfusion with Krebs-Henseleit buffer solution [37*C] and were switched over to the working mode for 15 minutes. After baseline measurement of heart rate, peak aortic pressure, aortic flow, and coronary flow, all hearts were subjected to 60 minutes of ischemic arrest at 10*C induced with St. Thomas Hospital cardioplegic solution: Group I had single dose cardioplegia, Croup II double dose, Croup III oxygenated double dose, and Group IV single dose with PCI, infusion [10ng/min./gm heart weight]. Hearts were then revived with 15 minute period of nonworking reperfusion at normothermia, followed by 30 minutes of working perfusion. Repeat measurements of cardiac function were obtained and expressed as a percent of the preischemic baseline values. Oxygen content of arterial perfusate and coronary effluent was measured by designed time interval. Leakage of creatine kinase was determined during post-ischemic reperfusion period. Finally wet hearts were weighed and placed in 120*C oven for 36 hours for measurement of dry weight. In the PGI, treated group [IV], heart rate increased consistently throughout the period of reperfusion from 100*5.0% [p<0.001] to 107*6.2% [p<0.001]. The percent recovery of aortic flow showed 95*5.7% [p<0.001] at the first 3 minute and full recovery through the subsequent time. Coronary flow was augmented significantly in the 3 minute [96*6.2%, p<0.001] and then sustained above baseline values. Among the Croup I, II, and III, all hemodynamic values were significantly below preischemic levels. PGI2 relatively increased oxygen delivery [1.22*0.19ml/min, p<0.001] and myocardial oxygen consumption [0.90*0.13ml/min, p<0.001] during reperfusion period. Leakage of creatine kinase in the PGI2 group was 9.3*1.58IU/15min [p<0.001]. This was significantly lower than Group I [33.0*2.68 IU/15min]. The water content of PCI2 treated hearts [81*0.9%, p<0.001] was also lower than the other groups.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.131-136
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• 2018

Background: We investigated the current characteristics of a thin-film Ag electrode on a chemical vapor deposition (CVD) diamond. The CVD diamond is widely recognized as a radiation detection material because of its high tolerance against high radiation, stable response to various dose rates, and good sensitivity. Additionally, thin-film Ag has been widely used as an electrode with high electrical conductivity. Materials and Methods: Considering these properties, the thin-film Ag electrode was deposited onto CVD diamonds with varied deposition thicknesses (${\fallingdotseq}50/98/152/257nm$); subsequently, the surface thickness, surface roughness, leakage current, and photo-current were characterized. Results and Discussion: The leakage current was found to be very low, and the photo-current output signal was observed as stable for a deposited film thickness of 98 nm; at this thickness, a uniform and constant surface roughness of the deposited thin-film Ag electrode were obtained. Conclusion: We found that a CVD diamond radiation detector with a thin-film Ag electrode deposition thickness close to 100 nm exhibited minimal leakage current and yielded a highly stable output signal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.713-716
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• 2013

The device performances of N-channel Tunneling FET have been characterized with different intrinsic length between drain and gate($L_{in}$), drain and source doping, permittivity and oxide thickness when the total effective channel length is constant. N-channel Tunneling FET of SOI structure have been used in characterization. $L_{in}$ was from 30nm to 70nm, dose concentration of drain and source were from $2{\times}10^{12}cm^{-2}$ to $2{\times}10^{15}cm^{-2}$ and from $1{\times}10^{14}cm^{-2}$ to $3{\times}10^{15}cm^{-2}$, permittivity was from 3.9 to 29, and oxide thickness was from 3nm to 9nm. The device performances were characterized by Subthreshold slope(S-slope), On/off ratio, and leakage current. From the simulation results, the leakage current have been reduced for long $L_{in}$ and low drain doping. S-slope have been reduced for high source doping, high permittivity and thin oxide thickness. With considering the leakage current and S-slope, it is desirable that are long $L_{in}$, low drain doping, high source doping, high permittivity and thin oxide thickness to optimize device performance in n-channel Tunneling FET.