Atmospheric depositional fluxes of cosmogenic <Superscript>32</Superscript>P, <Superscript>33</Superscript>P and <Superscript>7</Superscript>Be in the Sevastopol region

⁹⁰Y was separated from ⁹⁰Sr using an extraction chromatographic resin consisting of 4, 4′(5′)-bis-t-butylcyclohexano-18-crown-6 (DtBuCH₁₈C₆), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (C₂mimNTf₂), and a polymer (Amberlite XAD-7). Ionic liquid was introduced into the column to improve the separation efficiency. The column showed an excellent performance for the separation of Y from Sr. After the separation, the ratio of ⁹⁰Sr/⁹⁰Y was <2.0 × 10^?5; the column was recycled for >18 times. This study provides preliminary results on columns to produce ⁹⁰Y with a high purity in radiopharmaceuticals.     

Mixing of atmospheric <Superscript>210</Superscript>Pb and <Superscript>7</Superscript>Be and <Superscript>137</Superscript>Cs and <Superscript>90</Superscript>Sr fission products in four characteristic soil types

Depth distribution of atmospheric ²¹⁰Pb and ⁷Be and ⁹⁰Sr and ¹³⁷Cs fission products was measured in two types of aeolian soils (desert dust and volcanic ash), irrigated paddy soil and strongly acidic soil. The depth dependence of ²¹⁰Pb, ⁷Be and ¹³⁷Cs show that these radionuclides have been diffused as solid soil particles in surface soil layers. In aeolian soil layers, about 50% of ⁹⁰Sr were diffused in surface soil layer and the remaining 50% had penetrated to deeper layers. The half of the fission particles containing ⁹⁰Sr were shown to have decomposed over the past 35 years.     

Atmospheric deposition fluxes of <Superscript>7</Superscript>Be, <Superscript>210</Superscript>Pb and <Superscript>210</Superscript>Po at Xiamen,China

The atmospheric deposition fluxes of ⁷Be, ²¹⁰Pb and ²¹⁰Po at Xiamen were measured. The samples were collected from March 2004 to April 2005 and the sampling period was one month. The ⁷Be and ²¹⁰Pb activity were measured using HPGe γ-spectrometer after concentration using Fe(OH)₃ co-precipitation method. The ²¹⁰Po was counted with an α-spectrometer after the sample was digested and spontaneous plated onto a silver planchet. At Xiamen, the atmospheric deposition fluxes of ⁷Be varied between 0.11 and 2.93 Bq·m⁻²·d⁻¹ and the average was 1.64 Bq·m⁻²·d⁻¹; ²¹⁰Pb fluxes varied between 0.04 and 0.85 Bq·m⁻²·d⁻¹, and the average was 0.51 Bq·m⁻²·d⁻¹; ²¹⁰Po fluxes varied between 0.002 and 0.133 Bq·m⁻²·d⁻¹, and the average was 0.061 Bq·m⁻²·d⁻¹. There were positive correlations between the deposition fluxes of ⁷Be, ²¹⁰Pb or ²¹⁰Po and the amount of precipitation. The residence time of aerosols varied between 6.0 and 54.0 days with a mean of 27.1 days, which were calculated by ²¹⁰Po/²¹⁰Pb fluxes ratios.     

Simultaneous measurements of cosmogenic radionuclides <Superscript>32</Superscript>P, <Superscript>33</Superscript>P and <Superscript>7</Superscript>Be in dissolved and particulate forms in the upper ocean

A technique to determine concentrations of ³²P, ³³P and ⁷Be in dissolved and particulate forms, in the upper ocean was developed. By using a large volume in situ filtration and concentration system (LV-FiCS), several tons of seawater at different depths were filtered concurrently through two kinds of filters. The dissolved radionuclides were concentrated onto adsorbents in the LV-FiCS. The radionuclides obtained were further purified by precipitation and ion-exchange chromatography, and quantified by gamma-spectrometry and ultra-low level liquid scintillation counter measurements. The technique was used with good results in a coastal area of Ibaraki, Japan.     

Activity of the <Superscript>7</Superscript>Be isotope in plants from south-west Finland

We report the measurements of ⁷Be activity in nine vegetable species through the detection of its 477.6 keV γ-ray of ⁷Li. The plants were grown 10 km south of the city of Turku in south-west Finland, located at approximately about 23E, 62N. The results show that nettle, salad and cucumber have activities that exceed the detection limit.     

Distribution of <Superscript>137</Superscript>Cs, <Superscript>40</Superscript>K and <Superscript>7</Superscript>Be in silver fir-tree (<Emphasis Type="Italic">Abies alba</Emphasis> L.) from Gorski Kotar,Croatia

Distribution of ¹³⁷Cs, ⁴⁰K and ⁷Be in tissues of the silver fir-tree was studied. Samples of the shoots were taken at six locations in Croatia during five years. Shoots were cut according to the year of growth and analyzed. Distribution between needles and twigs was also studied. Samples of the tree rings and the bark were taken at three locations. ¹³⁷Cs and ⁴⁰K showed very similar distributions. ¹³⁷Cs and ⁴⁰K activities were age-dependent and increased in decreasing age of twigs and needles. The highest activities were measured in the youngest twigs. The highest ⁷Be activities were found in the twigs.     

Behavior of <Superscript>7</Superscript>Be and <Superscript>210</Superscript>Pb deposited via rainwater on a coniferous forest,a broad-leaved forest,and grassland

Fall water, stem flow water and falling litter in a coniferous forest (C. japonica) and a broad-leaved forest (L. edulis), and rainwater on a grassland near the forests were collected, and their ⁷Be and ²¹⁰Pb contents were measured. The average residence times of ⁷Be and ²¹⁰Pb in the forest crowns were calculated from the balances of their radionuclides, those in the forest crown of C. japonica were 88 days for ⁷Be and 9.2 years for ²¹⁰Pb, and those in the forest crown of L. edulis were 52 days and <1 year, respectively.     

Determination of activity ratios of <Superscript>238,239+240,241</Superscript>Pu, <Superscript>241</Superscript>Am, <Superscript>134,137</Superscript>Cs,and <Superscript>90</Superscript>Sr in Bulgarian soils

The origins of different artificial radionuclides found in soils from Northern and Southern Bulgaria was determined by measurements of their actual concentrations and respective ratios. On the basis of the measured mobility and concentrations of the investigated radionuclides in soils, it was estimated that after the Chernobyl accident the mean depositions of fresh ¹³⁷Cs were 3.0 ± 2.5 kBq/m² for Northern Bulgaria and 15 ± 7 kBq/m² for Southern Bulgaria. As a result of global fallout following atmospheric nuclear weapon tests in the 1950s, mean depositions (corrected to 1965) were calculated for Northern and Southern Bulgaria as follows: for ⁹⁰Sr—1.0 ± 0.5 and 2.3 ± 1.3 kBq/m², ²³⁸Pu—1.3 ± 0.8 and 2.8 ± 1.6 Bq/m², ^239+240Pu—15 ± 14 and 47 ± 38 Bq/m², and ²⁴¹Pu—520 ± 200 and 760 ± 260 Bq/m².     

Global fallout levels of <Superscript>99</Superscript>Tc and activity ratio of <Superscript>99</Superscript>Tc/<Superscript>137</Superscript>Cs in the Pacific Ocean

Summary Global fallout levels of ⁹⁹Tc and ¹³⁷Cs of surface seawater in the Pacific Ocean were measured. The ⁹⁹Tc concentrations ranged from 0.62 to 3.33 mBq^. m^-3and 5 of 6 samples showed less than 1 mBq^. m^-3except one sample taken in the Great Barrier Reef, Australia. The ¹³⁷Cs concentrations ranged from 2.13 to 3.14 Bq^. m^-3, showing a gradual decrease in the North Pacific toward the equator and a constant level in the South Pacific. The ⁹⁹Tc/¹³⁷Cs activity ratios ranged from 2.5^. 10^-4to 2.9^. 10^-4, which is very close to that calculated theoretically from the fission yield.     

Variations in the <Superscript>7</Superscript>Be content in the ground layer of the atmosphere at middle latitudes

Data from measurements of the volume activity ⁷Be in the ground layer of the atmosphere, taken at the middle latitudes over a period of five and a half years, are discussed. The studies allowed us to determine that the course of changes in the volumetric activity (VA) of ⁷Be over time is a superposition and interaction of three kinds of fluctuations: short-period irregular, caused by meteorological factors; seasonal, associated with ⁷Be entering the troposphere from the stratosphere; and long-term, determined by changes in the Galaxy’s cosmic ray flux.     

<Superscript>234</Superscript>U/<Superscript>235</Superscript>U activity ratios as a probe for the <Superscript>238</Superscript>U/<Superscript>235</Superscript>U half-life ratio

High-resolution alpha-particle spectrometry was performed on three uranium materials enriched in ²³⁵U. Besides the ²³⁵U peaks, separate peaks belonging to impurity traces of ²³⁴U could be quantified. Relying on the isotopic composition of the uranium, as determined by mass spectrometry, the ratio of the half-lives of ²³⁸U and ²³⁵U was determined via the activity ratio of ²³⁴U and ²³⁵U in the materials. As an intermediate link, the ²³⁴U/²³⁸U half-life ratio was taken from published mass spectrometric analyses of ‘secular equilibrium’ uranium material. The resulting half-life ratio T _1/2(²³⁸U)/T _1/2(²³⁵U) = 6.351±0.031 is in agreement with the commonly adopted half-life values determined by Jaffey et al.     

Vertical distribution of <Superscript>210</Superscript>Pb and <Superscript>226</Superscript>Ra and their activity ratio in marine sediment core of the East Malaysia coastal waters

Marine sediment cores were collected from two stations at East Malaysia coastal waters on June 2004. Activity concentrations of ²¹⁰Pb in sediment core were ranged from 11 Bqkg⁻¹ to 84 Bqkg⁻¹ dry wt. for SR 01 and 4 Bqkg⁻¹ to 66 Bqkg⁻¹ dry wt. for SB 03. Meanwhile, activity concentrations of ²²⁶Ra in sediment core were varied significantly depending on the sampling location of SR 01 and SB 03 with ranged 17–26 Bqkg⁻¹ dry wt. and 8–11 Bqkg⁻¹ dry wt., respectively. The activity ratios of ²¹⁰Pb/²²⁶Ra were no significantly different at all sampling stations with an average of 1.78. Refer to the entire results; the activities of ²¹⁰Pb and ²²⁶Ra were higher at station SR 01 than station SB 03, but contrast with ratio of ²¹⁰Pb/²²⁶Ra. The reasons of different ²¹⁰Pb and ²²⁶Ra activity concentration and distribution of their ratios were strictly related to their half lives, environment origin, potential sources and behavior.     

<Superscript>1</Superscript>H and <Superscript>7</Superscript>Li NMR in defect cobaltite Li<Subscript>0.6</Subscript>CoO<Subscript>2</Subscript>

Within a temperature range of 120–330 K, ⁷Li NMR spectra in Li_0.6CoO₂ are obtained. It is shown that as the temperature increases, both smooth and stepwise variation of ⁷Li NMR contact shifts occurs. The observed effects are explained by the occupation of the excited levels of cobalt ions. The stepwise change of the resonance line width depending on the temperature is revealed. It is driven by the features of the diffusive motion of lithium ions. The calculation of the ¹H NMR line shape provides the determination of the ratio of one-, two-, and three-spin proton clusters in Li_0.6CoO₂·xH₂O.     

Determination of plutonium and <Superscript>90</Superscript>Sr in air particulate samples

Within the surveillance program of the gaseous effluents coming from the nuclear reprocessing plant EUREX of ENEA (Italian National Agency for New Technologies Energy and Environment, CR Saluggia) in the North of Italy, the content of some radionuclides is continuously monitored. The so-called 1AW high-activity liquid waste (HLLW) is the aqueous raffinate of the first cycle of PUREX extraction process which was the starting point of the reprocessing activity of some MTR and CANDU spent fuel elements. Nowadays, 1AW-HLLW is stored in five tanks placed inside the EUREX plant site. This paper describes the sampling and radioanalytical methods employed to determine the activities of ²⁴¹Am, plutonium isotopes and ⁹⁰Sr in the total suspended particulate material (TSP) of the 1AW tank primary ventilation air circuit.     

Chemometrics of the distribution and origin of <Superscript>226</Superscript>Ra, <Superscript>228</Superscript>Ra, <Superscript>40</Superscript>K and <Superscript>137</Superscript>Cs in plants near the West Macedonia Lignite Center (Greece)

Summary The distribution and origin of ⁴⁰K, ²²⁶Ra, ²²⁸Ra and ¹³⁷Cs has been investigated in trees, mosses and lichens in the basin of the West Macedonia Lignite Centre. In tree leaves ¹³⁷Cs is negligible, while the ²²⁶Ra and ²²⁸Ra concentrations are affected by the fly ash particles. Concerning ²²⁶Ra and ²²⁸Ra values of mosses and lichens, which are systematically larger than those of unpolluted areas, the application of chemometrics proved that they originate mainly from the lignite fly ash.     

Disequilibrium of dissolved <Superscript>234</Superscript>U/<Superscript>238</Superscript>U and <Superscript>210</Superscript>Po/<Superscript>210</Superscript>Pb in Greek rivers

For the first time, a radiological study for the dissolved ²³⁸U, ²³⁴U, ²¹⁰Pb and ²¹⁰Po was held in major Greek rivers across the country. ²³⁴U/²³⁸U activity ratios are above one in all samples and ²¹⁰Po/²¹⁰Pb activity ratios are respectively below the unit indicating the disequilibrium in the samples. Quite satisfactory correlations were observed among ²³⁴U and ²³⁸U as well as among ²¹⁰Po and ²¹⁰Pb values. Uranium isotopes were separated by ion exchange and electroplated on stainless steel plates. ²¹⁰Po was spontaneously deposited on nickel plates, while ²¹⁰Pb was indirectly determined through the ingrowth of ²¹⁰Po. The sources were measured by a-spectrometry.     

Diffusion mobility of alkali metals in perfluorinated sulfocationic and carboxylic membranes as probed by <Superscript>1</Superscript>H, <Superscript>7</Superscript>Li, <Superscript>23</Superscript>Na,and <Superscript>133</Superscript>Cs NMR spectroscopy

Water self-diffusion and ion mobilities in various ionic forms (H⁺, Li⁺, Na⁺, Rb⁺, Cs⁺, and Ba²⁺) of perfluorinated sulfocationic membranes MF-4SK were studied by NMR and impedance spectroscopy. When degrees of hydration are low, the self-diffusion coefficients of water and ionic conductivities are considerably affected by the water content of the membrane. The self-diffusion coefficients decrease in the order H⁺ > Ba²⁺ > Cs⁺ > Rb⁺ > Na⁺ > Li⁺, whereas the ion mobility decreases in the order H⁺ > Li⁺ > Na⁺ > Cs⁺ > Ba²⁺.     

Primary activity standardization of <Superscript>134</Superscript>Cs

Cesium-134 has been measured by means of a new coincidence counting system which is equipped with a liquid scintillation detector to count β particles and a NaI crystal to detect γ-rays which are emitted simultaneously. In order to validate this new technique, additional measurements were carried out with an established 4πβ–γ-coincidence counting system with a proportional counter in the β channel. The coincidence counting experiments were complemented with measurements in further liquid scintillation counters with two and three photomultiplier tubes. The counting efficiencies for these systems were determined using CIEMAT/NIST efficiency tracing and the triple-to-double coincidence ratio (TDCR) method, respectively.