• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.251-256
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• 2004

CsI(Tl), $CdWO_4(CWO),\;Bi_4Ge_3O_{12}(BGO)\;and\;Gd_2SiO_5:Ce(GSO)$ scintillators were studied to manufacture a phoswich detector. The maximum wavelengths of the CsI(Tl), CWO, BGO and GSO scintillators are 550 nm, 475 nm, 490 nm and 440 nm for the radioluminescence, and the absolute light outputs of the CsI(Tl), CWO, BGO and GSO scintillators are 54890 phonon/MeV, 17762 phonon/MeV, 8322 phonon/MeV and 8932 phonon/MeV with a neutral filter, and the decay time of the CsI(Tl), CWO, BGO and GSO scintillators is $1.3{\mu}s,\;8.17{\mu}s$, 213 ns and 37 ns by a single photon method. The phoswich detector which was manufactured with plastic and CsI(Tl) scintillators could separate the ${\beta}$ particle and ${\gamma}$ ray. The phoswich detector could also measure the pulse height spectra of the ${\beta}$ particle and ${\gamma}$ ray by a PSD method.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.159-165
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• 2005

The characterization of radiological contamination inside pipes generated during the decommission of a nuclear facility is necessary before pipes can be recycled or disposed. But, existing direct measurements of radioactive contamination level using the survey-meter can not estimate the characteristic of contamination on a local area such as the pipe inside. Moreover, the measurement of surface contamination level using the indirect methods has many problems of an application because of the difficulty of collecting sample and contamination possibility of a worker when collecting sample. In this work, plastic scintillator was simulated by using Monte Carlo simulation method for detection of beta radiation emitted from internal surfaces of small diameter pipe. Simulation results predicted the optimum thickness and geometry of plastic scintillator at which energy absorption for beta radiation was maximized. In addition, the problem of scintillator processing and transferring the detector into the pipe inside was considered when fabricating the plastic detector on the basis of simulation results. The characteristic of detector fabricated was also estimated. As a result, it was confirmed that detector capability was suitable for the measurement of contamination level. Also, the development of a detector for estimating the radiological characteristic of contamination on a local area such as the pipe inside was proven to be feasible.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.99-106
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• 2016

When radon is staying at alveoli and bronchial tubes, the collapse of radon creates progeny nuclides (alpha ray, beta ray, gamma ray, etc.). They emit radiation causing a mutation in the chromosome of the cell, resulting in lung cancer. In other words, the main cause of lung cancer is radiation emitting as the result of radon collapse rather than radon gas. The 82% of radiation exposed to people is the natural radiation. Most of the natural radiation is radon. If we properly control the concentration of radon indoors, the probability of occurrence of lung cancer could be decreases to be 70%. Until now, to measure the indoor radon concentration, imported radon sensors are needed. So, DB construction of indoor radon emission and popular radon measuring apparatus should be developed. In this paper, we propose the radon detecting method using PIN photodiode. Also, we confirmed the PIN photodiode could be used as radon sensor module through some experimental studies.

• Journal of Radiation Protection and Research
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• v.39 no.3
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• pp.150-158
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• 2014

Radiation-related practitioners and radiation-treated patients at medical institutions are inevitably exposed to radiation for diagnosis and treatment. Although standards for maximum doses are recommended by the International Commission on Radiological Protection (ICPR) and the International Atomic Energy Agency (IAEA), more direct and available measurement and analytical methods are necessary for optimal exposure management for potential exposure subjects such as practitioners and patients. Thus, in this study we developed a system for real-time radiation monitoring at a distance that works with existing portable device. The monitoring system comprises three parts for detection, imaging, and transmission. For miniaturization of the detection part, a scintillation detector was designed based on a silicon photomultiplier (SiPM). The imaging part uses a wireless charge-coupled device (CCD) camera module along with the detection part to transmit a radiation image and measured data through the transmission part using a Bluetooth-enabled portable device. To evaluate the performance of the developed system, diagnostic X-ray generators and sources of $^{137}Cs$, $^{22}Na$, $^{60}Co$, $^{204}Tl$, and $^{90}Sr$ were used. We checked the results for reactivity to gamma, beta, and X-ray radiation and determined that the error range in the response linearity is less than 3% with regard to radiation strength and in the detection accuracy evaluation with regard to measured distance using MCNPX Code. We hope that the results of this study will contribute to cost savings for radiation detection system configuration and to individual exposure management.

• Analytical Science and Technology
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• v.18 no.6
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• pp.495-499
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• 2005

Notwithstanding antipathies against radiation, radiations are extensively used in various fields with development of the radiation technology. In order to safely manage such radiation it is necessary for development of the radiation measurement materials. In this paper a thin film type of plastic scintillator using in the contamination measurement devices was prepared. The plastic organic scintillator was prepared by simple solvent methods. It was possible to prepare in easy way and in various forms. The polysulfone which has high transparency and solubility was chosen. As the radiation measurement scintillator, the optical properties and radiation detection abilities were estimated.

• Journal of Radiation Protection and Research
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• v.24 no.1
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• pp.39-43
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• 1999

Thermoluminescent (TL) response characteristics of a thin LiF:Mg,Cu,Na,Si Teflon detectors have been studied for use in beta radiation detection. The detectors were fabricated from a mixture of LiF:Mg,Cu,Na,Si phosphor and Teflon powder which was molded into a thin disk form of $50mg/cm^2$ thickness. These detectors were irradiated to beta fields of $^{147}Pm,\;^{204}Tl\;and\;^{90}Sr/^{90}Y$ sources with a covering of Kapton foil ($2mg/cm^2$) and photon irradiation was carried out with a $^{137}Cs$ source at the Korea Atomic Energy Research Institute (KAERI). Batch uniformity was estimated to be 4.7% and the beta dose response presented linear relationship from 0.1 mGy to 100 Gy. The beta energy responses of thin detectors normalized to $^{137}Cs$ were presented as 0.46, 1.09 and 1.06 for $^{147}Pm,\;^{204}Tl\;and\;^{90}Sr/^{90}Y$ beta rays, respectively. The evaluated values for angular responses were $0.93{\pm}0.03\;(^{147}Pm),\;0.94{\pm}0.04\;(^{204}Tl),\;and\;0.92{\pm}0.05\;(^{90}Sr/^{90}Y)$. The results satisfied well a proposed ISO Standard for beta ray dosimeters.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.198-206
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• 2001

The structure of Yb complex with 3-nitro-1,2,4-triazol-5-one(NTO), $[Yb(NTO)3(H2O)4].5H2O$ has been investigated by X-ray diffraction method. Crystallographic data for the title compound : monoclinic, C2/c, $a=36.925(2){\AA},$ b=6.6770(4)${\AA},$ c=25.6376(15)${\AA},$ {\beta}=130.978(1)^{\circ},$ V=4772.0(5)${\AA}^3,$ Z=8, $D_c,=1.952\; Mg/m^3.$ The intensity data were collected on a Broker SMART diffractometer equipped with a CCD area detector using Mo $K\alpha$ radiation. The structure was solved by direct method and refined by full-matrix least-squares calculations to a final R value of 0.0424 for 4727 independent reflections and 335 parameters. The three carbonyls of three NTO anions and four ligand water molecules which are formed the pentagonal bipyramid are coordinated with $Yb^{3+}$ and also five water molecules are included in the form of the crystal water in the molecular structure.

• Journal of Radiation Protection and Research
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• v.23 no.1
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• pp.33-47
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• 1998

Using a combination of an X-ray generator Installed in radiation calibration laboratory of Korea Atomic Energy Research Institute (KAERI) and a series of 8 radiators and filters described in ISO-4037, monoenergetic fluorescent X-rays from 8.6 keV to 75 keV were produced. This fluorescent X-rays generated by primary X-rays from radiator were discriminated $K_{\beta}$ lines with the aid of filter material and the only $K_{\alpha}$ X-rays were analyzed with the high purity Ge detector and portable MCA. The air kerma rates were measured with the 35 co ionization chamber and compared with the calculational results, and the beam uniformity and the scattered effects of radiation fields were also measured. The beam purities were more than 90 % for the energy range of 8.6 keV to 75 keV and the air kerma rates were from 1.91 mGy/h (radiator : Au, filter : W) to 54.2 mGy (radiator : Mo, filter : Zr) at 43 cm from center of the radiator. The effective area of beam at the measurement point of air kerma rates was 12 cm ${\times}$ 12 cm and the influence of scattered radiation was less than 3 %. The fluorescent X-rays established in this study could be used for the determination of energy response of the radiation measurement devices and the personal dosemeters in low photon energy regions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.4
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• pp.314-320
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• 2001

Matrix metalloproteinases have long been viewed as ideal candidates for proteinases that enables tumor cells to permeated basement membrane defenses and invade surrounding tissue. There is growing evidence that the MMPs have an expanded role, as they are important for the creation and maintenance of a microenvironment that facilitates growth and angiogenesis of tumors at primary and metastatic sites. MT-MMPs are not secreted but instead remaining attached to cell surfaces. Although not all of the MT-MMPs are fully characterized, MT-MMPs have important role in localizing and activating secreted MMPs. The MMP genes are transcriptionally responsive to a wide variety of oncogene, growth factors, cytokine, and hormones. Currently, a number of MMP inhibitors are being developed and some have reached clinical trials as anti-metastatic or anti-cancer therapies. MT1-MMP is involved in the activation of proMMP-2. MT1-MMP is significant not only as a tumor marker but as a new target for chemotherapy against cancer. The purpose of this study was to evaluate the effects of protein kinase C inhibitor(genistein) on the proliferation of HT1080 and expression of MT1-MMP mRNA. Human fibrosarcoma cell line HT1080 was cultured and divided 2 groups. The experimental group was treated with $100{\mu}M$ genistein and incubated 12h, 24h for $[3^H]-thymidine$ uptake assay and northern hybridization individually. And the control group was treated with same amount of PBS for the above procedures. $[3^H]-thymidine$ incorporation was measured with ${\beta}$ ray detector. And RT-PCR and northern blotting for MT1-MMP mRNA was performed. The results were as follows 1. $[3^H]-thymidine$ uptake was reduced in experimental group with statistical significance. 2. MT1-MMP mRNA expression was significantly reduced in experimental group. These results showed that protein kinase C inhibitor (genistein) inhibited proliferation of HT1080 and almost completely blocked transcription of MT1-MMP mRNA. So, it is possible to use the protein kinase inhibitor (genistein) as anti-metastatic and anti-proliferative agent.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.49-55
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• 2016

Background: For the purpose of baseline data collection and enhancement of environmental monitoring the distribution studies of $^{137}Cs$ and $^{90}Sr$ in the soil of Uljin province was performed and the relation between surface soil activities and soil properties (pH, TOC and median of the surface soil) was analyzed. Materials and Methods: For 14 spots within 10 km from the NPP surface soil samples were collected and soils for depth profile were sampled for 3 spots in April 2011. Using ${\gamma}$-ray spectrometry with HPGe detector, the concentrations of $^{137}Cs$ were determined and the concentrations of $^{90}Sr$ were measured by counting ${\beta}$-activity of $^{90}Y$ (in equilibrium with $^{90}Sr$) in a gas flow proportional counter. Results and Discussion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ were $<0.479-39.6Bq{\cdot}(kg-dry)^{-1}$ (avg. $7.51Bq{\cdot}(kg-dry)^{-1}$) and $0.209-1.85Bq{\cdot}(kg-dry)^{-1}$ (avg. $0.74Bq{\cdot}(kg-dry)^{-1}$) which were similar to the reported values from other regions in Korea. The activity ratio of $^{137}Cs$ to $^{90}Sr$ in surface soils was around 9.67, which is much bigger than the initial value of 1.75 for worldwide fallouts because of faster downward movement of $^{90}Sr$ after fallout than that of $^{137}Cs$. For depth profile studies soils were collected down to 40 cm depth for the locations of Deokgu, Hujeong and Maehwa. The $^{137}Cs$ concentration distribution of the first two showed maximum values at top soils and decreased rapidly in exponential manner, while $^{90}Sr$ showed two local maximum values for soils near top and about 30 cm depth. Through linear fittings between the $^{137}Cs$ and $^{90}Sr$ concentrations of surface soil and pH, TOC and median of the surface soil, the only probable relationship obtained was between $^{137}Cs$ and TOC (determination coefficient $R^2=0.6$). Conclusion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ in Uljin were similar to the reported values from other regions in Korea. The only probable relationship obtained between activities and soil properties was between $^{137}Cs$ and TOC.