• Journal of the Korean Society of Radiology
• /
• v.7 no.1
• /
• pp.31-36
• /
• 2013

The radioactive gas radon ($^{222}Rn$), which is generated from the decay process of uranium ($^{238}U$) originating from the soil of more than 85 percent higher the porosity of the soil, the soil can radiate out the possibility that many isotopes. In order to protect the human body from radon, above all, the development of accurate measurement techniques to formulate appropriate measures should be followed. This study Gamma-ray spectrometry using a high purity germanium (HPGe) detector, if you want to measure radon unstable the nature radiation of the background problems can be reduced, radium and radon daughter nuclides after radioactive equilibrium leads to Radon concentration was measured, the soil samples from the Gamma-ray emitting nuclides, and the energy spectrum is analyzed.

• Journal of the Korean Society of Radiology
• /
• v.13 no.5
• /
• pp.819-824
• /
• 2019

In this study, we proposed a method for identifying isotopes generated from high-energy proton $^{nat}Pb$(p,xn) nuclear reactions through the difference of gamma rays generated through nuclear reactions using different proton energies. The experiment was performed by using a high energy proton generated from a 100 MeV proton linear accelerator of the Korea Atomic Energy Research Institute. Gamma rays generated by various nuclides generated through proton nuclear reactions were measured using a gamma-ray spectroscopy system composed of HPGe detectors. Gamma-ray standard sources were used for accurate energy calibration and efficiency measurements of HPGe gamma-ray detectors. For the proposed method, 100 and 60 MeV proton energy beams were used for the same natural lead samples. This method was found to be very effective in identifying nuclides produced by comparing gamma rays generated from the same sample with each other. The results of this study are expected to be very effective in obtaining other proton nuclear reaction results in the future.

• Journal of Radiation Protection and Research
• /
• v.15 no.2
• /
• pp.87-100
• /
• 1990

For the quantitative evaluation and assessment of radiation exposure from terrestrial component of natural environmental radiation, successive thermoluminescence dosimetry and periodical in-situ gamma ray spectrometry were carried out for a period of 24 months. LiF PTFE dise TLDs and $3&{\phi}{\times}3'$cylindrical NaI(Tl)scintill ation detector in association of portable multichannel analyzer (4096 ch) were used in this study. The doses measured were evaluated and assessed in terms of effective dose equivalent. As a concomitant output, the dose equivalent due to ionizing component of cosmic ray was able to be evaluated. According to the results obtained in terms of variance weighted mean, the annual effective dose equivalents of terrestrial gamma ray and cosmic ray ionizing component in Taejeon area came out to be $564{\pm}4\;{\mu}Sv(64.8{\pm}0.5nSv{\cdot}h^{-1}$ and $300{\pm}2\;{\mu}Sv(34.3{\pm}0.2nSv{\cdot}h^{-1}$, respectively, which are reasonable comparably with that appeared in UNSCEAR Report[28]as per caput annual effective dose equivalent in 'areas of normal background radiation'.

• Analytical Science and Technology
• /
• v.20 no.6
• /
• pp.460-467
• /
• 2007

Dose rate conversion factor was calculated to estimate the absorbed effective annual doses for soils for the beta-rays and gamma-rays, which were emitted from $^{238,235}U$, $^{232}Th$, and $^{40}K$ isotopes. The most recent data of the emitted energies per decay, half-lifes, and branching ratios, which were obtained from National Nuclear Data Center, were used. When this factor and the effective annual doses for the beta-rays and the gamma-rays of natural radioisotopes were compared with those of Aitken, these of $^{238}U$, $^{232}Th$ and $^{40}K$ are estimated to have good agreements but a large difference is shown in this for $^{235}U$. Through the calculations of effective annual doses by using these factor and the measurements of gamma-ray spectra for soils, which were extracted from prehistoric remains (Mansuri) on Osong, Chungchengbuk-do, The annual effective doses were obtained to be 3.8~5.9 mGy/yr. Also, when these doses including decay elements upper Rn were compared with those on all isotopes, the differences within 9~30 % were obtained. The analysis method of the annual effective doses for the beta-rays and the gamma-rays of the natural isotopes of soils was established by this dose rate conversion factor.

• Analytical Science and Technology
• /
• v.22 no.4
• /
• pp.302-306
• /
• 2009

A trace amount of boron in steel significantly influences its mechanical and physical properties. A prompt gamma ray activation analysis (PGAA) method is used to measure boron in low alloy steel samples of KRISS 101-01-C21~C26. NIST SRMs of 362, 364, 1761 and 1767 serve as the control standards to validate the measurement method. The measured values of the NIST SRMs are consistent with their certified values within the expected uncertainties, except for that of NIST SRM 362. Experimental uncertainties are evaluated according to the guidelines given by the International Organization for Standardization (ISO). The expanded uncertainties are calculated with a coverage factor of 2, at approximately 95% confidence level. The calculated relative expanded uncertainties of boron mass fractions are between 3% and 7% at the mg/kg level. The results are compared with the results measured by the solvent extraction-inductively coupled optical emission spectrometry (ICP/OES) method.

• Journal of Radiation Protection and Research
• /
• v.41 no.1
• /
• pp.71-79
• /
• 2016

Background: It is necessary to analyze radioactivity of naturally occurring radioactive materials (NORM) in products to ensure radiological safety required by Natural Radiation Safety Management Act. The pretreatments for the existing analysis methods require high technology and time. Such destructive pretreatments including grinding and dissolution of samples make impossible to reuse products. We developed a rapid and simple procedure of radioactivity analysis for thorium series in the products containing NORM. Materials and Methods: The developed method requires non-destructive or minimized pretreatment. Radioactivity of the product without pretreatment is initially measured using gamma spectroscopy and then the measured radioactivity is adjusted by considering material composition, mass density, and geometrical shape of the product. The radioactivity adjustment can be made using scaling factors, which is derived by radiation transport Monte Carlo simulation. Necklace, bracelet, male health care product, and tile for health mat were selected as representative products for this study. The products are commonly used by the public and directly contacted with human body and thus resulting in high radiation exposure to the user. Results and Discussion: The scaling factors were derived using MCNPX code and the values ranged from 0.31 to 0.47. If radioactivity of the products is measured without pretreatment, the thorium series may be overestimated by up to 2.8 times. If scaling factors are applied, the difference in radioactivity estimates are reduced to 3-24%. Conclusion : The developed procedure in this study can be used for other products with various materials and shapes and thus ensuring radiological safety.

• Clean Technology
• /
• v.22 no.2
• /
• pp.122-131
• /
• 2016

Caesium radioisotopes, ¹³⁴Cs and ¹³⁷Cs which come from the atmospheric nuclear tests and discharges from nuclear power plants, are very important to study artificial radioactivity. In this work, in order to lower the minimum detection activity (MDA) we investigated environmental radioactivity according to the Environment Measurement Laboratory procedure by ¹³⁷Cs and ¹³⁴Cs which is similar to chemical and environmental behaviors of ¹³⁷Cs. The environmental soils in high mountain areas near nuclear power plant were collected, and an Ammonium Molybdophosphate (AMP) precipitation method, which showed high selectivity toward Cs⁺ ions, was applied to chemically extract and concentrate Caesium radioisotopes. Radioactivity was estimated by a gamma-ray spectrometry. In gamma energy spectrum, with an increasing of ⁴⁰K radioactivity, it increased the MDA of ¹³⁴Cs and ¹³⁷Cs. Therefore, if the natural radionuclides were removed from the soil samples, the MDA of Caesium may be reduced, and the contents of ¹³⁷Cs of in the environmental soils can effectively be estimated. In the standard soil sample of Korea Institute of Nuclear Safety, radioactivity of ⁴⁰K was removed more than 84% on average, and the MDA of ¹³⁴Cs was reduced 2 times. The content of ¹³⁷Cs was recovered over 84%. On the other hand, in environmental soils, AMP precipitation method showed removal ratio of ⁴⁰K up to 180 times, which reduced the MDA about 5 times smaller than those of Direct method. ¹³⁷Cs recovery ratio showed from 54.54% to 70.06%. When considering the MDA and recovery ratio, AMP precipitation method is effective for detection of Caesium radioisotopes in low concentration.

• Analytical Science and Technology
• /
• v.30 no.5
• /
• pp.252-261
• /
• 2017

Naturally occurring radioactive materials (NORMs) increase radiation exposure to the public as these materials are concentrated through artificial manufacturing processes by human activities. This study focuses on the development of a method for the quantitative analysis of $^{232}Th$, $^{235}U$, and $^{238}U$ in building materials. The accuracy and precision of inductively coupled plasma mass spectrometry (ICP-MS) for determination of digestion processes was evaluated for certified reference materials (CRMs) digested using various mixed acid (e.g., aqua regia, hydrofluoric acid, and perchloric acid) digestions and a $LiBO_2$ fusion method. The method validation results reveal that a $LiBO_2$ fusion and $Fe(OH)_3$ co-precipitation should be applied as the optimal sample digestion process for the quantitative analysis of radionuclides in building materials. The radioactivity of $^{232}Th$, $^{235}U$, and $^{238}U$ in a total of 51 building material (e.g., board, brick, cement, paint, tile, and wall paper) samples was quantitatively analyzed using an established process. Finally, the values of $^{238}U$ and $^{232}Th$ radioactivity were comprehensively compared with those from the indirect method using ${\gamma}$-spectrometry.

• Korean Journal of Food Science and Technology
• /
• v.46 no.2
• /
• pp.256-261
• /
• 2014

This study was conducted to determine the effect of gamma-ray and electron-beam irradiation on dried spices (black pepper, red pepper, parsley, and basil) using the photostimulated luminescence (PSL), thermoluminescence (TL) and electron spin resonance (ESR) methods. The spices were irradiated at 0, 1, 5, and 10 kGy. All non-irradiated spices had photon counts (PCs) less than 700 PCs. The PCs of three irradiated spices (red pepper, parsley, and basil) were clearly distinguishable from those of non-irradiated ones, exhibiting PSL signals higher than 5000 PCs. However, negative PSL counts (<700 PCs) were obtained for most irradiated black pepper, except those irradiated with 5 kGy gamma rays and 10 kGy electron-beams. TL glow curves of the irradiated spices showed a higher peak at $150-250^{\circ}C$. TL ratios were found to be less than 0.1 for non-irradiated spices and higher than 0.1 for irradiated ones. No ESR signal was observed for any irradiated spice except red pepper, which displayed cellulose-based ESR spectra. Therefore, the results suggest that the PSL, TL, and ESR methods are effective detection techniques for dried spices irradiated with electron beams as well as gamma rays.

• Nuclear Engineering and Technology
• /
• v.21 no.4
• /
• pp.277-286
• /
• 1989

Destructive methods are used for the turnup determination of an irradiated PWR fuel. One of the methods includes U, Pu, Nd-148 and Nd-(145+146) determination by an isotope dilution mass spectrometry using triple spikes (U-233, Pu-242 and Nd-150). The method involves two sequential ion exchange resin separation procedures. Pu is eluted from the first anion exchange resin column (Dowex AG 1$\times$8) with 12 M HCl-0.1 M HI mixed solution, followed by U elution with 0.1 M HCl. Nd is isolated from other fission products on the second anion exchange resin column (Dowex AG 1$\times$4) with a nitric acid-methanol eluent. Each fraction is analysed by thermal ionization mass spectrometry. The difference between Nd-148 and Nd-(145+146) method is found with an average 2.07%. The results are compared with those by the heavy element method using U and Pu isotopes and by the destructive y-spectrometric measurement of Cs-137. The dependences of isotope composition of U and Pu on burn-up, and correlation between those isotopes are illustrated graphically.