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Authors: Leuangtakoun, Somsavath; Bui, Thi Hong; Bui, Van Loat; Phan, Viet Cuong (2018) - This paper presented the method of determining the radioactivity of 40K, 226Ra and 232Th in soil samples by gamma-ray spectrometer using NaI (Tl) scintillation detector. The radioactivity of each isotope is calculated based on the net count rate in the energy window characteristic for the 40K, 226Ra and 232Th radioisotopes respectively. We have determined activity concentrations of the natural radionuclides 226Ra,232Th and 40K in 15 soil samples collected around gold mines of Khamkeut district, Bolikhamxay Province, Laos. The average activity concentrations of the natural radionuclides 226Ra, 232Th and 40K are 46.58 ± 7.36 , 71.19 ± 5.42 and 574.62 ± 25.02 Bq.kg-1, respectively...
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Authors: Nguyen, Quang Mien; Bui, Van Loat (2008) - This paper presents a method for measuring the gross alpha/beta radioactivity of ancient pottery by using the liquid seintillation technique, Tri - carb2770TR/SL in the alpha/beta discrimination counting mode.
The beta radioactivity is converted to the annual dose, which can be applied in dating of pottery by theimoluminescence technique. In coniparision with the radiocarbon technique, the preliminary results shown that the liquid scintillation technique may be applied effectively for ancient ceramic dating in Vietnam.
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Authors: Bui, Van Loat; Le, Tuan Anh; Nguyen, Cong Tam; Pham, Duc Khue; Bui, Minh Hue (2013) - During the last years, as the international illicit traffic of radioactive/ fissionable materials have increased, it became important to be able to apply fast reliable methods for the uranium enrichment determination. In order to determine the uranium enrichment the activity ratios of 234U/235U and 238U/235Uwas measured. Uranium isotopic abundance can be determined by alpha spectrometry and mass- spectrometry methods, which are destructive methods. In this work the non-destructive gamma – spectroscopic method for uranium enrichment is presented. The method is applicable to material of any physical form and geometrical shape, and does not require the use of reference materials nor the ...
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Authors: Nguyen, Van Quan; Bui, Van Loat; Nguyen, Cong Tam (2016) - Passive non-destructive methodswere developed for determining total U, 235U and total Pu content of damaged spent fuel. The methods based on correlations between 137Cs and U, Pu content and using referent spent fuel assemblies. It means that the nuclear material content can be derived from measurable137Cs content, which depends on gamma ray transmission factor. In this work, this factor was determinedby aninfinite energy method and the same for both damaged and referentspent fuel with error less than 12%.
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Authors: Dang, Huy Uyen; Bui, Van Loat; Dang, Phuong Nam; Dang, Dinh Hung; Ly, Van Quynh (2004) - The gamma - radiation field in Hue city was detected by gamma-ray semtillation spectrometer GAD - 12 and CPri-68-01. The concentration of Uranium was detected through the 1,76 MeV photopeak of Bi“14. The concentration of Thorium was detected through the 2,62 MeV photopeak of T J 208. The concentration of Potassium was detected directly by the 1,46 MeV photopeak of K40. The gamma-ray activity has been calculated from the concentrations of Uranium, Thorium and Potassium. The deteced radiation exposure rate I (/iR/h) agrees with the measured mean values by CPII-68-01 ranges from 3,5 (/i R/h) to 14,5(/i R/h). Average value of the external radiation level is 8,25(/i R/h)
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Authors: Nguyen, Van Hung; Bui, Van Loat (2009) - The paper resented the results of assessing internal dose for 131I by the direct method for Vietnamese objects that was issued in the Intercomparison Program of IAEA. The results on experimental measurements, caculating intake (I) or 131I to thyroid by the specializing system for measuring thyroid activity, and committed effective dose E(50) using the specializing code of LUDEP 2.0 were shown that the results carrying out at the Nuclear Research Institute were goof and were in accordance with the those of the authors in other laboratories in the world.
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Authors: Bui, Van Loat; Somsavath, Leuangtakoun; Cao, Dang Luu; Bui, Thi Hong; Khong, Nam Khang (2017) - In this work, we present the results of using the non-destructive gamma spectroscopic method for uranium isotopic analysis and checking the status of radioactive equilibrium between 238U and 226Ra in soil samples. In order to analyze uranium isotopes and check the status of equilibrium between 238U and 226Ra the activity ratios 235U/238U and 238U/226Ra were measured. The these activity ratios were determined based on the characteristic gamma rays and using intrinsic (relative) detection efficiency calibration method. The results obtained shows that this suggested analytical method can be used to determine the uranium concentration in the case of the samples having arbitrary shapes and...
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Authors: Bui, Van Loat; Le, Tuan Anh; Dong, Van Thanh; Nguyen, The Nghia; Pham, Duc Khue (2012) - Nowadays, semiconductor detectors, in general, and high purity gemanium detectors (HPGe) in particular are widely used in various fields of experimental nuclear physics. In gamma ray experiments, energy resolution and the efficiency are very important characteristics of detectors. In this paper, the gamma standard sources such as 137Cs, 57Co, 60Co, 54Mn, 133Ba, and 109Cd were used to study the characteristics of the BEGe 3050 detector. The methods of determining the absolute photo- peak efficiency and the dependence of the energy resolution on γ-ray energy are presented.
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Authors: Bui, Van Loat; Le, Tuan Anh; Nguyen, Van Quan; Dinh, Van Thin; Nguyen, Cong Tam (2012) - In this work the non-destructive gamma - spectroscopic method for determination of uranium enrichment is presented. The method is applicable to material of any physical form and geometrical shape, and does not require the use of reference materials or the use of efficiency calibrated geometry. The X Rays and gamma rays below 100 keVfrom 235U were used to determine their relative detection efficiency internally. The activity ratios of 234U/235U and U238/U235in studied sample were calculated based on the measurents of the count rate of 53.2keV (0.123%) gamma ray of 234U and 92.6 keV (5.16%) of 234Th, a daughter of 238U. As a test of this method, a highly enriched uraniumsample was meas...
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Authors: Bui, Van Loat; Nguyen, Van Hung; Hoang, Sy Minh Phuong (2010) - At present, thickness measurement of materials based on effect of backscattering gamma-ray has been widely used in industry in our country. The report presented research in measuring thickness of some materials such as paper, plastic, aluminum and steel with using the dedicated system of MYO-101, having scintillation detector of YAP(Ce) and gamma-ray of 60 keV of Am-241 source, by Monte-Carlo simulation using the code of MCNP. The simulation was checked by experimental measurements. The results were shown that they were in accordance with the range of error. This research has been useful for training activities with a view of human resowces development in the field of application of n...
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Authors: Somsavath, Leuangtakoun; Bui, Van Loat; Vu, Thi Kim Duyen; Khong, Nam Khang (2017) - We have determined activity concentrations in 33 soil samples collected from Bolikhamxay Province, Laos. The activity concentrations of the natural radionuclides 226Ra,232Th and 40K in soil samples were measured by a gamma spectrometer with a HPGe detector. The average activity concentrations of the natural radionuclides 226Ra, 232Th and 40K are 43.8 ± 5.6, 57.0 ± 7.3 and 426.4 ± 23.1 Bq.kg-1, respectively. The average activity concentrations of 226Ra and 232Th in this work are higher than those of the world average values. Meanwhile, the activity concentration of 40 K is almost the same of the world average value. The estimated average outdoor annual effective dose (E) and radium eq...
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Authors: Bui, Thi Hong; Vu, Anh Hung; Nguyen, Quang Mien; Bui, Van Loat (2018) - The samples of LiF: Mg,Cu,P powder (xeri: GR-200) were irradiated by the gamma radiation resource with varied exposed dose. The glow curves of thermoluminescence (TL) material were observed with the defferent heating rates. The influence of heating rate on the thermoluminescence property of LiF: Mg,Cu,P was analyzed. The results showed that as the heating rate increases, the peak intensity at the maximum decreases and shifts to higher temperature. The thermoluminesecnce sensitivity of the material also changes and has the optimal value at 6oC/s. This value is also adaptable for measurement of natural environmental and archaeologicaldose.
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Authors: Bui, Van Loat; Nguyen, Van Quan; Le, Tuan Anh; Tran, The Anh; Nguyen, The Nghia; Nguyen, Van Hung (2009) - Radioactive sources which used to study were the standardized radioactive of common monoenergetic radionuclide Cs137 and standardized multigamma Co60, Ba133, Eu152. Determination of the absolute efficiency curve and energy resolution as a function of energy of GEM40P4 HPGe spectrometer are presented in this paper.
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Authors: Hoang, Huu Duc; Nguyen, Duc Minh; Phan, Viet Cuong; Le, Toan Anh; Leuangtakoun, Somsavath; Bui, Van Loat (2019) - The soil-to-plant transfer factors of natural uranium isotopes (238U and 232Th) were studied in Luong My tea farm, Tan Thanh district, Luong Son commune, HoaBinh province. The activity concentrations in leaves, trunk and root were determined for the tea tree at no harvest period (winter break). The measurements were carried out using gamma spectroscopy with high puritygermanium detector HPGe. Research results show that the activity of 238U and 232Th is higher in leaves than in trunk and roots.Soil-leaves transfer factor (TF) for238U and 232Th were as follows:TFU238 = 0,52 – 0,87; TFTh-232 = 0,25 – 0,43.
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