Approximate empirical formula for X-ray intensity in radioactive nuclides

Known intensities of X-rays emitted from radioactive nuclides have been plotted against atomic number, and a distinct correlation has been found only for EC-decay type nuclides, as follows: 2.75 Z^1.06>X>0.507 Z^1.06, and X_{most probable}=1.18 Z^1.06, where X is the absolute percentage and Z is the atomic number of the decay product.     

Determination of radioactive nuclides of uranium and thorium series and estimation of α-flux in LSI constituent materials

Gamma-rays of nuclides of uranium and thorium series in silicone resin and ceramics were measured with a Ge(Li) detector. The state of radioactive equilibrium was determined by comparing the concentrations of uranium and thorium with the radioactive concentrations of²¹⁴Pb and²¹²Pb. The radioactive equilibrium was attained in silicone resin but not in ceramics. The -flux was calculated from the concentrations of uranium and thorium and their daughter nuclides. The calculated values of -flux agreed with that of -flux measured.     

Leaching of glass components and surrogate nuclides from glassy waste forms for radioactive incineration ash

Three kinds of soil, collected in various places (in northwestern and southeastern Poland and near Chernobyl) were used as a subject of sequential extraction and plutonium distribution study. The modified method of Tessier was applied to separate readily available, carbonate, organic, Fe/Mn oxide and residual fractions. Plutonium isotope activity in soil as well as in particular separated fractions was determined by means of alpha spectrometry. The method of plutonium separation and purification for alpha-spectrometric measurements was modified according to the chemical properties of the extracted fraction. It was found that the major part (about 90%) of ^239,240Pu is bound to organic and Fe/Mn oxide fractions (in uncultivated soil samples of northwestern Poland and Chernobyl). In soil samples coming from river valley (southeastern Poland) almost equal amounts of plutonium are distributed between the available, organic and residual fractions.     

Radon survey in office room and effective dose estimation for staff

This study aims to: (1) Acquire the radon level in closed office rooms, providing radon exposure data for preliminary health risk assessment of office-working population. (2) Pre-analyze the relationship between radon concentration and indoor temperature, relative humidity. (3) Estimate seasonal, annual and total radon effective dose for ordinary office-working population. The results show that the 24-h or 8-h average radon concentrations in closed office rooms were about 32.0 Bq/m³ and 29.5 Bq/m³ during detection period, and the estimated effective doses in office rooms calculated by using 24-h and 8-h average radon concentrations were all far below that in residential environment.

     

Sample pretreatment for the determination of gamma emitting nuclides in dry radioactive waste using a dry ashing and high-performance microwave digestion system

A sample pretreatment procedure for the dry radioactive waste such as paper, cotton, vinyl, and plastic generated from nuclear power plants (NPPs) was established to determine the activity concentrations of ⁶⁰Co and ¹³⁷Cs. Because the volatility of cesium is temperature-dependent, the heating temperature was examined from 300 to 650 °C. Although the cesium was not volatile until 500, 450 °C was selected to save time. Cesium with a paper towel and a planchet of stainless steel were quantitatively recovered at 450 °C. The produced ash was completely dissolved with 10 mL of HNO₃, 4 mL of HCl, and 0.25 mL of HF in a high-performance microwave digestion system using a nova high temperature rotor at 250 °C for 90 min until 0.2 g was reached. This procedure was applied to low and intermediate level radioactive wastes generated from NPPs.     

Principle of single and multiple time interval analysis applicable to radioactive nuclides with half-lives of millisecond order

A delayed coincidence method has been developed for the selective extraction of radionuclides with half-lives of millisecond order using a personal computer. The time interval analysis is fundamentally based on the distinction of the time interval distribution between the correlated and random events, which arise from radioactive disintegration and/or background events within a certain fixed time. Theoretical functions of a time spectrum or a time distribution curve were dealt with from aspects of statistical treatments consisting of a single time interval analysis and a multiple one (STA and MTA). The theoretical equations obtained were used to simulate time spectra on the assumption of some ideal data and compared with the experimental results. Conclusively, the MTA method has been verified to be more suitable for the selective extraction of the objective correlated events from random or background events for the search of radioactive nuclides with millisecond life-times.     

Calculation of dose conversion coefficients for radioactive cesium in contaminated soil by depth and density

Journal of Radioanalytical and Nuclear Chemistry - Radiation dose to personnel on the ground contaminated with radioactive cesium after nuclear power plant accident depends on cesium activity,...     

A radioactive method for the localization and estimation of sitosterol on paper chromatograms

Summary A new method is described for the localization and estimation of sitosterols on a radiochromatogram. The method depends upon the addition of rado-iodine at the double bond of sitosterol on the developed paper chromatogram. It denotes the presence of - and -sitosterol in the two materials investigated with new R_f values in a new developing system.

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Zusammenfassung Eine radiochemische Methode wird beschrieben zur Lokalisierung und Bestimmung von Sitosterinen auf Papierchromatogrammen. Das Verfahren beruht auf der Addition von radioaktivem Jod an die Doppelbindung des Sitosterols auf dem entwickelten Chromatogramm. In zwei untersuchten Substanzen konnten mit einem neuen Lösungsmittelsystem - und -Sitosterin nachgewiesen werden.

     

Evaluation of additional absorbed radiation dose from radioactive impurities in radiopharmaceuticals

The additional absorbed radiation doses to total body from radioactive impurities in radiopharmaceuticals were estimated for a total of 10 samples (i.e., 99mTc generator eluates, 99mTc solutions, 67Ga, 81mKr generator eluates, 111In, 123I, 201Tl, 75Se, 197Hg, 198Au) selected from commonly used radiopharmaceuticals. The radioactive impurities in radiopharmaceuticals used in this estimation were previously identified. The radiation doses were calculated according to the MIRD procedures, assuming each radionuclide to be uniformly distributed throughout the body. In the case of the cyclotron-produced radioisotopes and 198Au, the additional total body absorbed doses from impurities were found to be rather high: 280% for 123I, 55% for 81mKr, 5% for 198Au, 4% for 111In and 2% for 201Tl. The absorbed doses due to impurities in the other radioisotopes were less than 1%.     

Uranium, thorium and potassium contents and radioactive equilibrium states of the uranium and thorium series nuclides in phosphate rocks and phosphate fertilizers

Uranium, thorium and potassium contents and radioactive equilibrium states of the uranium and thorium series nuclides have been studied for 2 phosphate rocks and 7 phosphate fertilizers. Uranium contents were found to be rather high (39-117 ppm) except for phosphate rock from Kola. The uranium series nuclides were found to be in various equilibration states, which can be grouped into following three categories. Almost in the equilibrium state, 238U approximately 230Th greater than 210Pb greater than 226Ra and 238U greater than 230Th greater than 210Pb greater than 226Ra. Thorium contents were found to be, in general, low and appreciable disequilibrium of the thorium series nuclides was not observed except one sample. Potassium contents were also very low (less than 0.3% K2O) except for complex fertilizers. Based on the present data, discussions were made for the radiation exposure due to phosphate fertilizers.     

A new microanalytical radioactive method for the estimation of the iodine number in linseed oil

Summary A microanalytical radioactive method for the estimation of the iodine number in linseed oil has been fully described. The application of the method was carried out on three varieties of linseed oil, namely: Guiza IV, Indian and Baladi. The relationship between the radioactivity measured on the oil spot and the iodine consumed for saturation is described.A simple equation has been put forward for the direct estimation of the iodine value from the specific activity and the number of counts on the oil spot. The method could be used on different varieties of oils and fats.     

Radiological dose assessment of naturally occurring radioactive materials in concrete building materials

Previous studies have shown that the natural radioactivity contained in building materials have significantly influenced the dose rates in dwelling. Exposure to natural radiation in building has been of concerned since almost 80 % of our daily live are spend indoor. Thus, the aim of the study is to assess the radiological risk associated by natural radioactivity in soil based building materials to dwellers. A total of 13 Portland cement, 46 sand and 43 gravel samples obtained from manufacturers or bought directly from local hardware stores in Peninsular of Malaysia were analysed for their radioactivity concentrations. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the studied building materials samples were found to be in the range of 3.7–359.3, 2.0–370.8 and 10.3–1,949.5 Bq kg^?1 respectively. The annual radiation dose rates (μSv year^?1) received by dwellers were evaluated for 1 to 50 years of exposure using Resrad-Build Computer Code based on the activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K found in the studied building material samples. The rooms modelling were based on the changing parameters of concrete wall thickness and the room dimensions. The annual radiation dose rates to dwellers were found to increase annually over a period of 50 years. The concrete thicknesses were found to have significantly influenced the dose rates in building. The self-absorption occurred when the concrete thickness was thicker than 0.4 m. Results of this study shows that the dose rates received by the dwellers of the building are proportional to the size of the room. In general the study concludes that concrete building materials; Portland cements, sands, and gravels in Peninsular of Malaysia does not pose radiological hazard to the building dwellers.     

Urinary volatomic profile of traditional tobacco smokers and electronic cigarettes users as a strategy to unveil potential health issues

Many harmful and potentially harmful constituents are present in tobacco products. Cigarette smoke is known to cause different forms of cancer and trigger the development of chronic diseases. In the last decade, electronic cigarettes have emerged as a healthier alternative associated to less harmful effects in comparison to traditional tobacco. However, the lack of standardization of electronic cigarettes products makes it difficult to establish and compare the real effects on health of products from different manufacturers. To better understand the impact of smoking and vaping, the volatomic composition of urine samples from traditional tobacco smokers and electronic cigarette users was established and compared with nonsmokers (control group), using headspace solid-phase microextraction combined with gas chromatography–mass spectrometry. A total of 45 urinary volatile organic metabolites belonging to different chemical families were identified in the urine of the studied groups. Benzene derivatives, terpenes, and aromatics were the chemical families that contributed the most to the urinary profile of smokers. The vapers urinary volatomic pattern was also dominated by terpenes and aromatics, in addition to alcohols. The orthogonal partial least squares-discriminant analysis of the data obtained indicated that the urinary profile of vapers is more closely related to the control group, reinforcing the hypothesis of the lowest harmfulness of electronic cigarettes. Further studies recruiting a higher number of subjects are therefore necessary to consolidate the data obtained.     

Trends in instrumentation for activation analysis of short-lived nuclides

This paper reports on the last year's two major activities of our nuclear instrumentation group it the field of high rate and high resolution gamma spectrometry which were mainly devoted to the needs of activation analysis of short-lived nuclides. The first of the projects was the completion of a state-of-the-art spectrometry system for very high counting rates which has been installed at the fast inrradiation and transport facility of the TRIGA reactor and now is the main instrument for the short-lived work of our radiochemistry group. Based on a laboratory-designed gated integrator pulse processing system and equipped with an Ortec Gamma-X detector of 20% relative efficiency with cooled FET and transistor reset preamplifier, it exhibits a basic resolution of 2.3 keV at 1332 keV which at a counting rate of 1.1 million cps of⁶⁰Co degrades to 3.4 keV. An essential feature of the system is a novel quantitative pileup rejector of the pulse counting type which has been specially designed for high rejection efficiency and at the same time, for the reliable exemption of valid events, and thus is a necessary prerequisite for quantitative real-time correction of counting losses by means of the Virtual Pulse Generator method. The second project included the successful implementation of the novel Preloaded Filter Technique (applied for patent), a new method for high resolution and high throughput processing of nuclear detector signals which, in contrast to conventional techniques, does not rely on a fixed pulse processing time per event which up to now was the main reason for pulse pileup and limited throughput, but, at the latest, terminates the filtering process of an individual event at the instant of arrival of the next event which results in optimized throughput and, at the same time, in a self-adapting, counting rate dependent shaping time. To that aim, the delta-noise filter of the system must be preloaded with the best estimate of the final result of the filtering process which is simply the unfiltered signal amplitude, to make sure that at the instant of termination of the filtering process the output of the filter deviates from the final value not more than by the decaying noise amplitude. Complemented by counting rate dependent step-noise filtering, this technique made possible the creation of a spectrometry system for all purposes which at low to medium counting rates is comparable to the best of the semi-Gaussian amplifiers and at high counting rates to the gated integrator. An experimental implementation of the Preloaded Filter combined with an Ortec Gamma-X detector of 15% relative efficiency resulted in a basic resolution of 1.9 keV at 1332 keV at a counting rate of 5000 cps slowly degrading to 3.2 keV at a counting rate of 650 000 cps of⁶⁰Co.     

Preliminary results of a small X-ray irradiator for equivalent dose estimation

In most established method for luminescence dating, the ratio of ⁹⁰Sr/⁹⁰Y radionuclides has been employed to provide reference laboratory doses to sample. Recently a small X-ray irradiator (Varian VF-50J) was introduced as an alternative to the traditionally used radioactive sources. Test results are presented whether the use of the small X-ray irradiator is possible in the dating technique. Aspects of the assessment of the X-ray irradiator include consideration of the measured optically stimulated luminescence signal and the relationship between X-ray tube currents and dose rates, as well as the dependence of equivalent dose for various dose rates. The test performances are assessed in relation to use with heated quartz.     

Natural radioactivity and its gamma dose rate in Mission (Texas) soils

The activity concentration of radionuclides in ²³⁸U, ²³²Th, and ⁴⁰K were determined in Mission (Texas) surface soils through gamma-ray spectrometry measurements using hyper pure germanium detector. Activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were 13–32 Bq kg^?1 (mean value: 23 Bq kg^?1), 17–47 Bq kg^?1 (mean value: 31 Bq kg^?1), and 100–460 Bq kg^?1 (mean value: 300 Bq kg^?1) respectively. The absorbed gamma dose rate in air from these soils were found in the range of 23 to 56 nGy h^?1 with an average value of 42 nGy h^?1. The contribution to the absorbed gamma dose rate in air was observed as 26 % from ²³⁸U, 45 % from ²³²Th, and 29 % from ⁴⁰K. The outdoor annual effective dose equivalent varied between 28 and 69 μSv y^?1 with the mean value of 52 μSv y^?1.The evaluated data were compared with the data from different countries and also with the world mean value.