• Journal of Radiation Protection and Research
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• v.33 no.4
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• pp.173-181
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• 2008

To ensure the performance of radon detectors, three passive radon detectors ($RadTrak^{(R)}$, $Radopot^{(R)}$, and $E-PERM^{(R)}$)have been reviewed. The difference ratios of RadTrak and Radopot tested in the radon standard chamber were -13.2% and -6.0%, respectively, which were in good accordance within 20% of the value measured by $AlphaGUARD^{(R)}$. To ensure the performance of the long term measurement, the 3 detectors were installed at the same position of approximately one hundred of dwellings for one year. The correlation curve between RadTrak and Radopot shows good agreement with a correlation coefficient ($R^2$) of 0.91. However, The correlation curve between E-PERM and Radopot shows bad agreement ($R^2$ = 0.021). In addition, the distribution map of annual mean indoor gamma dose rate measured with E-PERM was not in accordance with the distribution map of outdoor gamma dose rate measured by Portable Ion Chamber. According to the results, some requisites for the selection of the radon passive detectors in the large-scale indoor radon survey were discussed.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.11a
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• pp.249-249
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• 2004

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.311-318
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• 2006

Ionizing radiation is a both a natural and man-made phenomena that plays a major role in contemporary applications. The detection of this radiation has evolved over the past several decades from simple observations to precise measurements in space, time, and energy, even in harsh environmental conditions. Tn this paper, we present a snapshot of the current state-of-the-art in radiation measurement technology, highlighting the major applications and detector developments.

• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.34-40
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• 2009

The phase delay of output signal of APD(avalanche photo diode) caused by intensity of reflected light which comes from target. These difference of phase delay is an one of the main reason of measurement error, but there is no reasonable measurement meter and method to detect it. In this paper, to solve the problem, we propose and implement a method to measure the intensity of radiation. The method measures DC voltage which is proportional to the reflected intensity of radiation and come out from APD in receiver by realtime.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.7-13
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• 2017

An experimental study was conducted to identify the quantitative measurement bias for the bare-bead thermocouple (TC), which was widely used for measuring temperature in fire experiments. To this end, an apparatus could be controlled individually gas flow rate, preheating temperature and incident radiative heat flux was developed to simulate the thermal environments of fire. A relative measurement bias of bare-bead TC was evaluated with the comparison of double-shield aspirated TC. As a result, the relative measurement bias of bare-bead TC was gradually increased with the increase in radiative heat flux with constant gas temperature. The relative bias was also significantly increased with the decrease in gas temperature. Quantitatively, at the gas temperature of $20^{\circ}C$, the bare-bead TC had the relative bias of approximately 400% with the radiative heat flux of $20kW/m^2$ corresponding to thermal radiation level of the flashover. The present study was intend to provide fire researchers with methodologies for the reanalyses of temperature measured using bare-bead TC, radiation corrections, and validation of fire modeling.

• Journal of Radiation Protection and Research
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• v.48 no.3
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• pp.144-152
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• 2023

Background: Color texture analysis was applied as a tool for quantitative evaluation of radiation-induced skin injuries. Materials and Methods: We prospectively selected 20 breast cancer patients who underwent whole-breast radiotherapy after breast-conserving surgery. Color images of skin surfaces for irradiated breasts were obtained by using a mobile skin analyzer. The first skin measurement was performed before the first fraction of radiotherapy, and the subsequent measurement was conducted approximately 10 days after the completion of the entire series of radiotherapy sessions. For comparison, color images of the skin surface for the unirradiated breasts were measured similarly. For each color image, six co-occurrence matrices (red-green [RG], red-blue [RB], and green-blue [GB] from color channels, red [R], green [G], blue [B] from gray channels) can be generated. Four textural features (contrast, correlation, energy, and homogeneity) were calculated for each co-occurrence matrix. Finally, several statistical analyses were used to investigate the performance of the color textural parameters to objectively evaluate the radiation-induced skin damage. Results and Discussion: For the R channel from the gray channel, the differences in the values between the irradiated and unirradiated skin were larger than those of the G and B channels. In addition, for the RG and RB channels, where R was considered in the color channel, the differences were larger than those in the GB channel. When comparing the relative values between gray and color channels, the 'contrast' values for the RG and RB channels were approximately two times greater than those for the R channel for irradiated skin. In contrast, there were no noticeable differences for unirradiated skin. Conclusion: The utilization of color texture analysis has shown promising results in evaluating the severity of skin damage caused by radiation. All textural parameters of the RG and RB co-occurrence matrices could be potential indicators of the extent of skin damage caused by radiation.

• Journal of Radiation Protection and Research
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• v.20 no.3
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• pp.155-162
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• 1995

The state-of-the art of detection and measurements of non-ionizing radiations are reviewed in relation to protection requirements, especially for electromagnetic and ultraviolet radiations. Dosimetric quantities, instruments and considerations needed for measurement are briefly explained. For electromagnetic radiation, the power density levels from various practical sources are summarized for reference uses. Large errors remain in the measurements of non-ionizinf radiations in general. Technical needs of development in measurement and dosimetry of non-ionizing radiations, therefore, are promissing when the increasing public concerns about the adverse health effects of non-ionizing radiations and proliferation of their uses are taken into account.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.264-269
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• 2011

To increase therapeutic efficiency and biological safety, it is important to precision control of acoustic output for therapeutic ultrasound equipment. In this paper, the electro-acoustic radiation conductance, one of electroacoustic characteristics of therapeutic ultrasound equipment, was measured by the radiation force balance method according to IEC 61161 standards and the acoustic output was estimated using the electro-acoustic radiation conductance. The estimation of acoustic output was conducted to continuous wave mode and pulse wave mode of duty cycle between 20% and 80%. The differences between prediction values and measurement results are within 5% of measurement uncertainty, which is a reasonably good agreement. The results show that acoustic output controlled by electro-acoustic radiation conductance was found to be an effective method.

• Journal of Korean Society for Quality Management
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• v.51 no.3
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• pp.435-444
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• 2023

Purpose: To attain advanced performance certification, safety aspects along with functionality and performance are essential. Hence, this study suggests radiation leakage assessment methods for aviation security equipment during its performance certification. Methods: Detection technology guided the choice of radiation leakage assessment targets. We then detailed measurement and evaluation methods based on equipment type and operation mode. Equipment was categorized as container or box types for establishing measurement procedures. Results: We've developed specific radiation leakage assessment procedures for different types of aviation security equipment, crucial for ensuring airport safety. Using these procedures allows efficient evaluation of compliance with radiation leakage standards. Conclusion: The suggested radiation leakage assessment method aims to enhance aviation security and reliability. Future research will focus on identifying risks in novel aviation security equipment detection technologies and establishing safety standards.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.471-479
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• 2023

In In-situ radioactivity measurement techniques, efficiency calibration models use predefined models to simulate a sample's geometry and radioactivity distribution. However, simplified efficiency calibration models lead to uncertainties in the efficiency curves, which in turn affect the radioactivity concentration results. This study aims to develop an efficiency calibration optimization methodology to improve the accuracy of in-situ gamma radiation measurements for byproducts from industrial facilities. To accomplish the objective, a drive mechanism for rotational measurement of an byproduct simulator and a sample was constructed. Using ISOCS, an efficiency calibration model of the designed object was generated. Then, the sensitivity analysis of the efficiency calibration model was performed, and the efficiency curve of the efficiency calibration model was optimized using the sensitivity analysis results. Finally, the radiation concentration of the simulated subject was estimated, compared, and evaluated with the designed certification value. For the sensitivity assessment of the influencing factors of the efficiency calibration model, the ISOCS Uncertainty Estimator was used for the horizontal and vertical size and density of the measured object. The standard deviation of the measurement efficiency as a function of the longitudinal size and density of the efficiency calibration model decreased with increasing energy region. When using the optimized efficiency calibration model, the measurement efficiency using IUE was improved compared to the measurement efficiency using ISOCS at the energy of ²²⁸Ac (911 keV) for the nuclide under analysis. Using the ISOCS efficiency calibration method, the difference between the measured radiation concentration and the design value for each simulated subject measurement direction was 4.1% (1% to 10%) on average. The difference between the estimated radioactivity concentration and the design value was 3.6% (1~8%) on average when using the ISOCS IUE efficiency calibration method, which was closer to the design value than the efficiency calibration method using ISOCS. In other words, the estimated radioactivity concentration using the optimized efficiency curve was similar to the designed radioactivity concentration. The results of this study can be utilized as the main basis for the development of regulatory technologies for the treatment and disposal of waste generated during the operation, maintenance, and facility replacement of domestic byproduct generation facilities.