• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1609-1612
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• 2006

The determination of the boron isotopic ratio in solutions was achieved by means of a solid state track detector by using an alpha track. The neutron flux was optimized by using a Cd-foil to find the optimum conditions for counting the number of alpha tracks on the selected solid detector caused by the (n, $\alpha$) nuclear reaction of boron. The home-made multi-dot detector plate was utilized in this study to increase the reproducibility of the measurement by uniformly drying the boron solution within the marked circle area on the detector plate. The experimental results of this study verified that the $^{11}B/^{10}B $ isotopic ratio can be measured by observing the number of alpha tracks for different concentrated standard solutions with various isotopic compositions. This technique was applied to the determination of $^{10}B$ enrichment factor in a biological sample for a boron neutron capture therapy.

• Analytical Science and Technology
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• v.17 no.5
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• pp.434-437
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• 2004

Alpha track technology can provide useful isotopic information of boron in the primary coolant water. In the quantitative analysis using the alpha track analysis, the shape or area of sample on the solid track detector becomes very important, especially for the analysis of liquid samples. In this research, a multi-dot plate has been developed for this purpose. The multi-dot plate provides fixed standard shape of the sample solution that stays inside of the printed circle, and consequently increases the reproducibility of the boron analysis.

• Journal of Radiation Protection and Research
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• v.21 no.3
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• pp.167-173
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• 1996

The calibration method for the detection efficiency of solid state track detector to alpha is presented, and the detection efficiency of CN-85 and LEXAN to alpha is measured by this method. The results are 97% and 57% in CN-85 and LEXAN, respectively. The reason for a better result in CN-85 in not only the high sensitivity but also the low energy dependency with comparing for LEXAN. The peak detection efficiency is 3MeV and 1.8MeV in CN-85 and LEXAN, respectively.

• Journal of Radiation Protection and Research
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• v.2 no.1
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• pp.1-8
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• 1977

A base of photographic posi-film which is commecially available has been found to be a possible alpha-particle track detector. Its neutron dosimetric characteristics, i. e., alpha-particle track registrating efficiency and optimum condition of track formation by chemical etching, have been determined experimentally. The range of neutron fluence and dose capable of being measured by a neutron dosimeter consisting of alpha-particle radiator foils $(^{10}B\;and\;^{27}Al)$ and posi-flim solid state track detector, has been estimated on the basis of experimental results and theoryetical background. This detector seems to be useful for neutron dosimetry because of many favorable properties, i. e., simplicity, cheapness and a wide range of sensitivitiy.

• Analytical Science and Technology
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• v.17 no.1
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• pp.8-15
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• 2004

The detection efficiencies of the several solid track detectors were investigated for the determination of boron content in aqueous solution by using the alpha muti-Radioisotope(RI) source. Polycarbonate (Lexan and CR-39) and cellulose nitrate (CN-85 and LR-115) were selected as materials for alpha track detection of boron. Alpha muti-RI source, uranium metal particles and boron standard solution were used for alpha emission. In this study, four solid track detectors(CN-85, LR-115, Lexan and CR-39) were characterized under various etching conditions as well as neutron irradiation conditions. As a result, the CN-85 was turned out to be best to provide good efficiency among the four detectors. The selected solid track detector was utilized for the determination of trace amount of boron in aqueous sample and its results were discussed in the text.

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.353-358
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• 2006

Alpha track analysis for the determination of the trace amount of alpha emitting nuclides in a very small particle was performed as an efficient and powerful technique during safeguard inspection. Metal particles with well-defined spherical shape, size and isotopic compositions as a reference material were used to correlate the number of tracks or track diameter with an isotopic composition eventually to identify the uranium enrichment in the environmental swipe samples. Slopes in the number of tracks versus the exposure time curve provide a simple insight into the uranium enrichment of an unknown particle. Low enriched uranium metal particles result in slopes still steeper than the depleted or natural uranium metal particles. In addition, a linear relationship between track diameter and particle size Is thought to be a useful first stage analytical tool as an efficient and convenient inspection guide. The significance of the simple linear model was also judged using the usual statistical tests.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.71-76
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• 2002

A survey of radon concentrations in both indoor and outdoor atmospheres was carried out using EIRM and Cup Monitor for the period of February 1996 to March 1997. EIRM were used to measure the indoor and outdoor radon concentration at five major cities university. Cup Monitor were also used to measure the indoor radon concentrations at shopping store, office building, apartment, hospital and house in Seoul. The mean indoor and outdoor radon concentrations at the five major cities(Seoul, Daegu, Daejon, Cwangiu and Busan) were 24.1 Bq/m$^3$and 8.62 Bq/m$^3$, respectively. The ratio of indoor to outdoor radon concentrations ranged front 1.7 to 3.9. Inspection of its seasonal distribute pattern indicates the enhancement during winter relative to summer, consistently for both indoor and outdoor air. The results of the survey showed that the concentrations in basements were clearly higher than those in usual living/working places.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.881-885
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• 2017

This work presents a new technique for discriminating between alpha particles of different energy levels. In a first study, two groups of alpha particles emitted from radium-226 and americium-241 sources were successfully separated using a CR-39 microfilm of appropriate thickness. This thickness was adjusted by chemical etching before and after irradiation so that lower-energy particles were stopped within the detector, while higher-energy particles were revealed on the back side of the detector. The number of tracks on the front side of the microfilm represented all alpha particles incident on that side from the two sources. However, the number of tracks on the back side of the microfilm represented only the long-range alpha particles of higher energy that arrived at that side. Therefore, by subtracting the number of tracks on the back side from the number of tracks on the front side, one could easily determine the number of tracks for the short-range alpha particles of lower energy that remained embedded in the microfilm. Discrimination of the two energy levels is thus achieved in a simple, fast, and reliable process.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.432-438
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• 2018

The occurrence of saturation in the CR-39 detector reduces and limits its detection dynamic range; nevertheless, this range could be extended using spectroscopic techniques and by measuring the net bulk rate of the saturated CR-39 detector surface. CR-39 detectors were irradiated by 1.5 MeV high alpha-particle fluence varying from $0.06{\times}10^8$ to $7.36{\times}10^8\;alphas/cm^2$ from Am-241 source; thereafter, they were etched in a 6.25N NaOH solution at a temperature of $70^{\circ}C$ for different durations. Net bulk etch rate measurement of the 1.5 MeV alpha-irradiated CR-39 detector surface revealed that rate increases with increasing etching time and reaches its maximum value at the end of the alpha-particle range. It is also correlated with the alpha-particle fluence. The measurements of UV-Visible (UV-Vis) absorbance at 500 and 600 nm reveal that the absorbance is linearly correlated with the fluence of alpha particles at the etching times of 2 and 4 hour. For extended etching times of 6, 10, and 14.5 hour, the absorbance is saturated for fluence values of $4.05{\times}10^8$, $5.30{\times}10^8$, and $7.36{\times}10^8\;alphas/cm^2$. These new methods pave the way to extend the dynamic range of polymer-based solid state nuclear track detectors (SSNTDs) in measurement of high fluence of heavy ions as well as in radiation dosimetry.

• Analytical Science and Technology
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• v.18 no.4
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• pp.263-270
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• 2005

Nuclear track is an useful tool for elemental analysis of radionuclides, such as uranium, plutonium and thorium, etc., and for elements undergoing nuclear reactions with thermal neutrons such as lithium and boron. This method has various application fields such as detecting fissionable radionuelides, measuring the fission rate in nuclear technology, analyzing cosmic radiation from meteorite, calculating the age of minerals as well as their history, etc. Track registration method has been applied to the microscopic analysis of boron and fissionable element such as uranium in KAERI. This report reviews the theoretical background of the nuclear track formation, practical procedures to obtain etched tracks and a perspective of the future.