共查询到20条相似文献,搜索用时 15 毫秒
1.
F. Bou-Rabee Y. Y. Bakir H. Bem 《Journal of Radioanalytical and Nuclear Chemistry》1995,194(2):403-409
A chemical procedure for transferring deposited solid matter from a cellulose filter into the liquid scintillation cocktail has been described. The influence of chemical and color quenching on alpha and beta detection efficiency, as well as on misclassification of beta and alpha pulses was corrected by an external standard method. Under the chosen pulse shape discrimination level (PSD), the alpha and beta detection efficiencies were above 85% and spillovers of alpha and beta pulses were below 10% and 2% respectively. Determination limits for samples containing up to 200 mg of mineral matter were 0.015 mBq m–3 for alpha, 0.055 mBq.m–3 for210Pb and 0.055 mBq.m–3 for beta activity (counting time 12000 s and volume of filtered air 1000 m3). The method has been applied for routine monitoring of210Pb as well as for gross alpha and beta activities of longer-living radionuclides (T1/2.>11 hrs) in suspended air matter. 相似文献
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B. F. Scott 《Journal of Radioanalytical and Nuclear Chemistry》1968,1(1):61-71
A desk-top computer is used to calculate the absolute specific activities of batches of chemicals routinely in a central assay laboratory of a manufacturer of labeled chemicals. Errors and operator fatigue were reduced and reporting was speeded out due mainly to the elimination of hand-transcribing of results. Other advantages were that tedious calculations of the absolute activities of double-labeled compounds were as easy to perform as for single-labeled compounds, and that samples having identical dilution parameters can be calculated without any manual manipulation at all. Programming methods are explained. 相似文献
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S. K. Perera 《Journal of Radioanalytical and Nuclear Chemistry》2005,264(2):357-363
Summary The standard procedure for analyzing gross alpha and gross beta in water is evaporation of the sample and radioactivity determination of the resultant solids by proportional counting. This technique lacks precision, and lacks sensitivity for samples with high total dissolved solids. Additionally, the analytical results are dependent on the choice of radionuclide calibration standard and the sample matrix. Direct analysis by liquid scintillation counting has the advantages of high counting efficiencies and minimal sample preparation time. However, due to the small sample aliquants used for analysis, long count times are necessary to reach required detection limits. The procedure proposed consists of evaporating a sample aliquant to dryness, dissolving the resultant solids in a small volume of dilute acid, followed by liquid scintillation counting to determine radioactivity. This procedure can handle sample aliquants containing up to 500 mg of dissolved solids. Various acids, scintillation cocktail mixtures, instrument discriminator settings, and regions of interest (ROI) were evaluated to determine optimum counting conditions. Precision is improved and matrix effects are reduced as compared to proportional counting. Tests indicate that this is a viable alternative to proportional counting for gross alpha and gross beta analyses of water samples. 相似文献
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J. M. Pates G. T. Cook A. B. Mackenzie J. Thomson 《Journal of Radioanalytical and Nuclear Chemistry》1993,172(2):341-348
Scintillation cocktail components were studied with regard to their impact on pulse decay discimination (PDD) and hence the separation of alpha from beta activity, using a Packard 2250 CA /. Di-isopropyl naphthalene (DIN) was found to be the most suitable solvent, both from safety considerations and also the fact that it acts in a very similar manner to naphthalene in stretching the pulses produced at the photomultiplier tube anode and hence enhancing the separation. Increasing the surfactant concentration and the use of dimethylanthracene (DMA) as secondary fluor degraded the cocktail's performance. PMT anode pulse shapes were found to be a useful indicator of PDD efficiency but could not give a quantitative guide. 相似文献
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Yoon Yeol Yoon Soo Young Cho Kil Yong Lee Kyung Seok Ko Kyoochul Ha 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):397-402
234U, 238U, 226Ra, and 228Ra were analyzed in 14 Korean hot spring waters. Uranium was extracted with mixture of extractive scintillation cocktail containing HDEHP and 234U, 238U were analyzed with LSC. Radium isotopes were separated using Ba coprecipitation method and counted with LSC and 228Ra was also analyzed its daughter 228Ac with HPGe γ-detector. Among them 226Ra was ranged <0.01–0.155 Bq/L and 228Ra is below detection limit <0.1 Bq/L. And also, uranium content was ranged <0.01–49.7 μg/L and 234U/238U ratio was ranged 0.69–1.17. 相似文献
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Zhai Xiufang Fan Jinlong Dong Jiangpeng Wang Yufeng Bai Tao Wang Jiangfan Zhang Xiangbo Chen Guowei 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(7):2911-2917
Journal of Radioanalytical and Nuclear Chemistry - A novel method for direct measurement of 90Sr in liquid samples was developed by using liquid scintillation counter. Based on the shielding... 相似文献
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María Cabello Concepción Dueñas Esperanza Liger Elisa Gordo Sergio Cañete 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(2):299-307
Variations of gross alpha and beta atmospheric radioactivity have been analyzed in Málaga (Spain) focusing on the influence of local meteorology and air mass origin during 2012–2015. Air mass origin and their features, as well as the airborne particulate levels play a critical role in atmospheric radioactive aerosol concentrations. African air masses at 3000 m and Mediterranean flows at 500 m are associated to high gross alpha and beta activities. A potential decay with increasing distance travelled by back-trajectories is found. Air temperature and wind speed present significant correlation with alpha and beta activities, while relative humidity has negligible impact. 相似文献
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Y. Yamada K. Yasuike M. Itoh N. Kiriyama K. Komura K. Ueno 《Journal of Radioanalytical and Nuclear Chemistry》1995,201(5):381-390
A neutron activation method based on the measurement of tritium radioactivity produced by6Li (n,)3H reaction was applied to determine the isotopic abundance of6Li in aqueous solution with known lithium concentration. Tritium radioactivity was measured with a low background liquid scintillation counter over a period of 2000 min. The present method demonstrated a good linearity between the isotopic abundance of6Li and tritium radioactivity produced per unit amount of lithium in a wide range of lithium concentration. A comparison of the present data with those from mass spectrometry showed agreement, though our method was 10 times less sensitive, than mass spectrometry. The present new approach should thus prove quite useful for determining the isotopic abundance of6Li. 相似文献
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Pannee Pakkong Sarinya Wongsanit Yutthana Tumnoi Suchin Udomsomporn 《Journal of Radioanalytical and Nuclear Chemistry》2013,297(2):297-302
Gross alpha and beta activities were determined in seawater and plankton samples collected during the wet and dry seasons from 10 different sampling stations in Chonburi, the Upper Gulf of Thailand. Seawater samples were sampling, 1 km from the coastal and 2 m below the water surface, during July 2008 to July 2009. Seawater samples were prepared by coprecipitation technique. Plankton samples were prepared by filtration and dryness on filter paper. Both types of samples were counted using a low background alpha/beta proportional counter with multiple detector type (Berthold LB770). The results showed that gross alpha activities in seawater and plankton sample are in the range of 0.0591 ± 0.0209–0.3914 ± 0.0606 Bq/l and 0.0029 ± 0.0020–0.0294 ± 0.0043 Bq/l, respectively and also showed the lowest and highest activity level in the same sampling time. The activities of gross beta in seawater and plankton sample are in the range of 0.2803 ± 0.0177–1.3064 ± 0.0319 Bq/l and 0.0208 ± 0.0123–0.9151 ± 0.0262 Bq/l, respectively. Minimum detectable activity (MDA) had been observed in the measurements. The MDA of seawater sample were estimated to be 0.0832 Bq/l for alpha and 0.0577 Bq/l for beta at counting time of 100 and 200 min, respectively. In plankton samples, the MDA were estimated to be 0.0053 Bq/l for alpha and 0.0409 Bq/l for beta at the same counting time of 250 min. 相似文献
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Kwon Eunhwa Chae Jung-Seok Kim Yong-Jae 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1431-1436
Journal of Radioanalytical and Nuclear Chemistry - Lead-210 is a useful tracer in environmental studies for a wide range of applications, particularly in atmospheric research and geochronology.... 相似文献
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Kil Yong Lee Yoon Yeol Yoon Soo Young Cho Kyung Seok Ko Byung-Woo Yum 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(1):27-30
A simple method for the determination of the air?Cwater partition coefficient (Kair/water) of radon (Rn-222) was studied using a liquid scintillation counter. In the present work, the radon activity of groundwater phase in a closed container was measured and used to calculate the partition coefficient instead of the radon activity of gaseous phase in other works. The partition coefficient was determined for four groundwater samples by using a modified equilibrium partition coefficient in closed system method. The effect of temperature on the partition coefficient was investigated at 0, 10, 20 and 30?°C. Within the temperature range, the partition coefficients were 1.72?C2.03, 2.11?C2.28, 2.78?C3.92 and 4.93?C5.61 at 0, 10, 20, and 30?°C, respectively. It was found that the effect of temperature on the air?Cwater partition coefficient of groundwater radon was agreed well with literature values. 相似文献
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K. H. Abel A. J. Schilk D. P. Brown M. A. Knopf R. C. Thompson R. W. Perkins 《Journal of Radioanalytical and Nuclear Chemistry》1995,193(1):99-106
A large area beta scintillation detector has been developed which is currently capable of determining Sr-90/Y-90 contamination in surficial soils. The detector system employs scintillating fiber optic arrays, with active dimensions approximately 15 cm wide by 100 cm long, both ends of which are coupled to multiple photomultiplier tubes (PMTs). Electronic processing includes coincidence requirements to optimize sensitivity and selectivity for the 2.28 MeV (maximum) beta particle from Y-90. Low energy beta particles and gamma rays are discriminated against using double ended and multi-layer coincidence requirements. The detector system is personal-computer-software controlled and data restored in a format compatible with standard database software for ease of final data reduction. Experimental calibration studies have shown a linear response for Sr-90/Y-90 soil concentrations from 12 to over 500 pCi/g and a discrimination factor of 50 to 1 versus Cs-137.Pacific Northwest Laboratory is operated for the U.S. Department of Energy by Battelle Memorial Institute under Contract DE-AC06-76RLO 1830. 相似文献
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A novel extraction chromatographic resin based on diisobutyl ketone has been developed for the isolation of 55Fe. This material has been used in conjunction with a dimethylglyoxime-based resin for the sequential separation of 55Fe and 63Ni and isolation of these radionuclides from associated contaminants. The preparation and characterisation of these resins is described along with an assessment of their performance for the isolation of 55Fe and 63Ni from a mixture of nuclear activation products. In addition, a refined approach for the measurement of these nuclides by liquid scintillation counting is discussed. The findings of these studies have been combined to develop a robust procedure for the analysis of 55Fe and 63Ni in reactor effluents which is now the preferred method for a number of UK analytical laboratories. 相似文献
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D. N. Abrams S. A. Mcquarrie C. Ediss 《Journal of Radioanalytical and Nuclear Chemistry》1981,65(1-2):331-339
The viability of a dual label liquid scintillation technique has been investigated. To avoid the need for two procedures,
gamma counting for125Iodine (125I) and liquid scintillation counting for14C. Since the125I spectrum covers almost as wide a range of pulse heights as14C, conventional dual label methods would result in very low14C counting efficiencies. The conventional dual label technique has ben modified to increase the14C counting efficiency and to accomodate the consequent additional spillover of125I counts into the upper window. This dual label technique has been applied to the determination of125I and14C activities in blood samples. The accuracy of the method has been tested, and its advantages and limitations are discussed. 相似文献
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Yang Dazhu Zhu Yongjum S. Möbius C. Keller 《Journal of Radioanalytical and Nuclear Chemistry》1990,144(1):63-71
The determination of - and -emitting nuclides has been studied with a commercial liquid scintillation counter /Tri-Carb 2200CA/ equipped with Pulse Shape Analysis /PSA/. The results indicated that the efficiency for -emitters is virtually 100% and discrimination for -emitters is more than 99.9%. Liquid scintillation counting with PSA can be used for the determination of - and -emitting nuclides simultaneously. 相似文献
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V. Gómez Escobar F. Vera Tomé J. C. Lozano 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):913-915
Two important effects in quenching evaluation when using some commercial extractive scintillators in alpha liquid scintillation
counting are described. One affects the system quenching value but not the efficiency, while the other modifies the efficiency
with no important change in the quenching. For these cocktails, alternative procedures for efficiency evaluation must be chosen.
We propose an inner standard procedure which gave adequate results in the application to different kinds of samples. 相似文献