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1.
J. B. Luten H. A. Das C. L. De Ligny 《Journal of Radioanalytical and Nuclear Chemistry》1977,35(1):147-155
A routine-method for the determination of bromine and iodine in environmental water by neutron activation is presented. The
elements are isolated by isotope exchange between the irradiated sample and a solution of Br2 or I2 CCl4. The method is not sensitive to the chemical species in which the halogen is present. The lower limit of the determination
is 1.0 μg Br·1−1 and 0.1 μgI·1−1. 相似文献
2.
Detection of small quantities of uranium in silicon wafers has been carried out by neutron activation followed by observation
of fission product140La. Irradiations of about one week were made at a flux of 6·1014n cm−2 s−1 and the activity of the 1596 keV line was determined. Counting rates of as low as 1 count per minute have been observed.
This indicates uranium concentrations of about 5·1010 atoms per cubic centimeter of silicon or about 0.01 mg/g, assuming activity from other fissionable nuclides to be negligible. 相似文献
3.
A procedure has been developed for the detection of gunpowder residues deposited on the hand of a person firing a gun. The
method is based on neutron activation analysis of the antimony level on the surface of the hand. The surface materials are
removed by a film made by spraying a 4% solution of cellulose acetate in acetone, which sets to form a thin film that can
readily be stripped off. This technique was found to be preferable to the paraffin-lift technique which is in common use.
Following neutron activation of the film in a nuclear reactor, antimony is assayed by high-resolution Ge(Li) spectrometry
without prior chemical processing. The sensitivity of the method is about 5·10−9 g Sb, with a precision of about ±10% at a neutron flux of 5·1013 n·cm−2·sec−1. Analysis of twenty samples taken from the hands of persons who had fired a pistol gave Sb levels of 0.4±0.2 μg, compared
with 0.024±0.013 μg found on the hands of persons who had not fired a revolver. The possible extension of the present technique
to include the determination of additional elements is discussed.
Project carried out with the support of the Office of the Chief Scientist to the Ministry of Defense and with the collaboration
of the Israel Police. 相似文献
4.
T. Nozaki M. Ichikawa T. Sasuga M. Inarida 《Journal of Radioanalytical and Nuclear Chemistry》1970,6(1):33-40
Uranium in human bone, drinking water and daily diet has been determined by neutron activation analysis using the238U(n, γ)239U reaction. An improved scheme for the separation of the239U is proposed; with this scheme, after neutron irradiation in a 100 kW TRIGA reactor, a uranium content as low as 5·10−11 g can be determined reliably, rapidly and easily. A wide range of uranium concentrations, from about 0.1 ppb up to about
10 ppb has been found in the bones of normal Japanese. Water from several Japanese city water services, and the daily diet
taken in two Japanese cities, have been found to contain an average 9·10−9 g/l and 1.5 μg per person-day uranium, respectively. 相似文献
5.
J. H. Augustson J. W. Haynes T. W. Sanders 《Journal of Radioanalytical and Nuclear Chemistry》1980,60(2):373-383
A method for the determination of uranium based on235U thermal neutron fission, has been developed and employed on samples of ashed fish tissue and seaweed. The method involves
a post-irradiation ion exchange separation of iodine isotopes. The 884 keV photopeak of134I is used for measurement. Uranium detection limits in the samples concerned have been estimated to be 1·10−8g in terms of natural uranium. The precision achieved in analysing several series of 3–5 samples was 4–10 per cent. The accuracy
of the method was tested by employing an independent neutron activation procedure based on239U measurement. The accuracy of both methods was checked by analysing NBS SRM 1571 ‘Orchard Leaves’. 相似文献
6.
A. Gaudry B. Maziere D. Comar D. Nau 《Journal of Radioanalytical and Nuclear Chemistry》1976,29(1):77-87
For the simultaneous determination of many elements in small biological samples, a multi-element analysis has been developed
using neutron activation. After a 24-hr irradiation in a neutron flux of 2.5·1014 n·cm−2·sec−1 and after immediate chemical separation without cooling, it was possible to analyse 24 elements in bovine liver (NBS-SRM
1577). The separation apparatus, set up in a shielded cell can work four samples simultaneously, and its operation is fast
enough to allow the detection of radioisotopes with a half-life of about 2 hrs (165Dy,57mSr,56Mn). Amounts lower than 10−3 μg of Dy, Eu, Pr, Sm and Yb were determined. 相似文献
7.
H. -U. Fanger R. Pepelnik W. Michaelis 《Journal of Radioanalytical and Nuclear Chemistry》1981,61(1-2):147-163
At the GKSS Research Center Geesthacht, a new 14 MeV activation facility—a 5·1012 n/s neutron generator combined with a fast rabbit system (KORONA)—is being installed. Homogeneous neutron flux at a level
of 5·1010 n·cm−2·s−1 and sample transfer times of 140 ms to a 16m distant detector station are characteristic features of the facility described
in the paper. With special consideration of short-lived nuclides and including cyclic activation, the analytical prospects
with the intense neutron source are discussed, and sensitivities for 78 elements are presented. 相似文献
8.
An instrumental neutron activation analysis (INAA) method has been developed for multi-element determination in geological
samples. The INAA method consists of irradiation of samples for 90 sec at a flux of 1.0·1012 n·cm−2·sec−1 and determination of 12 elements by using their short-lived nuclides. Samples have been re-irradiated for 3 hrs for measuring
concentrations of another 10 elements. Precision and accuracy of the INAA method have been evaluated by analysing samples
and USGS standard reference materials. Precision and accuracy are within±15% and ±10%, respectively. 相似文献
9.
A. M. Yusof S. K. Gill A. K. H. Wood 《Journal of Radioanalytical and Nuclear Chemistry》1998,235(1-2):279-283
The concentrations of iodine in fresh waters are known to be within the range of 0.5 to 35 ng·ml−1, much lower than in oceanic waters. The iodine concentrations, particularly that of129I which is significant from the radiation safety aspect, in public drinking waters have to be specified in order to verify
the required level before distribution for domestic use. A modified version of an established method was used in the adsorption
of iodine, iodate, total inorganic iodine and charcoal-adsorbable iodine using activated carbon prepared from oil palm kernel
wastes. A thorough investigation of the physical properties of the activated carbon was carried out to determine its viability
as an adsorbent for volatile species such as iodine. The iodine species were preconcentrated from water samples collected
from wells in villages and from water intake points along rivers. The quantitative analysis of the species adsorbed was done
by irradiating the activated charcoal loaded with the respective species in a neutron flux of 5.1·1012 n·cm−2·s−1 from a TRIGA MkII, nuclear reactor. Recovery experiments using spiked samples was done to provide quality assurance controls. 相似文献
10.
A sensitive, simple and time-saving method has been developed for the neutron activation analysis of gallium at concentrations
around 10−4 ppm in biological tissues. After a 24-hour irradiation in a thermal neutron flux of 2.8·1013 n·cm−2·s−1 and a purification by ion-exchange chromatography to eliminate troublesome elements such as sodium, iron and copper, the72Ga activity is measured with enough accuracy for the method to be applicable in animal physiology and clinical toxicology. 相似文献
11.
P. K. Nayak B. Wierczinski S. Lahiri 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):179-184
Representative banded iron-formations (BIFs) from various locations of the eastern Indian geological belt were investigated
by instrumental neutron activation analysis (INAA). After pre-concentration, irradiation was carried out using a neutron flux
of 5.1·1016 m−2·s−1, 1.0·1015 m−2·s−1 and 3.7·1015 m−2s−1, with thermal, epi-thermal and fast neutrons, respectively. The activities in these samples were measured by a HPGe detector.
Ten rare-earth elements, such as La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu, have been qualitatively identified and quantitatively
estimated in these samples. The present investigation is an example of employing a pre-concentration method for high iron-containing
ores prior to neutron activation analysis. 相似文献
12.
A. M. Golubenkov A. F. Malenchenko 《Journal of Radioanalytical and Nuclear Chemistry》1977,36(2):547-556
For the solution of most of the problems which are connected to the biological and physiological role of natural uranium in
plants and animal organisms about 10−14 g uranium should be determined. However most of the physico-chemical methods for the determination of natural uranium in
biomaterials are time-consuming and possess considerable error. On the basis of addition and inner standard methods a version
of Solid State Nuclear Track Detectors (SSNTD) method has been developed in order to determine the natural uranium in biospecimens.
According to the experimental data simple relations have been obtained for the calculation of uranium concentration in biomaterial
and minium uranium concentration in biosolution which can be measured by the detector used. Under irradiation of SSNTD at
a thermal neutron flux of (3–5)·1015n·cm−2 the detector sensitivity is 2.30·10−9 g U/ml for glass detectors; 9.60·10−10g U/ml for the detectors made from artificial mica. 相似文献
13.
A procedure for the determination of chromium in blood has been developed with a sensitivity of 5×10−3 μg Cr. Dried blood was irradiated with a neutron flux of 1012 n·cm−2·sec−1 in the VVRS reactor for 4 weeks, then the sample was mineralized and the chromium isolated by extraction as perchromic acid.
The determination of the chromium content was accomplished by measuring the 0.32 MeV gamma energy of51Cr. In order to make correction for the interfering reaction54Fe(n,α)51Cr, the formation of chromium from high-purity iron was investigated. The chromium content of the blood samples was between
1.03×10−2 and 5.2×10−2 ppm Cr. 相似文献
14.
M. Kubota 《Journal of Radioanalytical and Nuclear Chemistry》1977,36(2):565-576
In determining the trace impurities existing in high-purity rare earth samples by the neutron activation analysis, there are
much interference due to nuclides induced from neutron induced second order nuclear reaction. This paper presents the degree
of interference calculated over the ranges of irradiation time from 105 to 107 sec and of thermal-neutron flux from 1·1012 to 1·1015 n·cm−2·sec−1. According to the results of these calculations, degree of interference under the neutron irradiation condition for 288 hrs
in the thermal-neutron flux of 3·1013n·cm−2·sec−1 is concluded to be 6.4·106 ppm Gd in Eu, 2.2·104 ppm Sm in Eu, 1.9·104 ppm Ho in Dy, 1.1·103 ppm Eu in Sm, 1.1·102 ppm Ce in La and 1.1·10 ppm Tb in Gd, respectively. Especially, the Gd determination in the Eu target is extremely affected
by153Gd formed from the151Eu (n, γ)
reaction. On the contrary, this reaction is effective in producing153Gd activity. 相似文献
15.
The purpose of this study was to define experimentally the sensitivity of determination for 63 different elements by 14 MeV
neutron activation, with a 150 kV Cockroft-Walton accelerator at a neutron flux of 2·108 n·cm−2·sec−1 on the sample. The obtained gamma ray spectra are given, and the origin of the photopeaks observed are explained. A maximum
irradiation time of five minutes was used as a convenient experimental limit to obtain the maximum sensitivity, considering,
however, that the tritium target life is limited, and that the time to perform an analysis has to be reasonable. The practical
use of 14 MeV neutron activation analysis is demonstrated by the detection limits obtained. 相似文献
16.
A method was developed for the determination of 15 trace elements in tin. High-purity tin samples (99.9999% and 99.999%) as
well as tin of technical quality were analysed. Reactor neutron activation of the tin samples was followed by distillation
of the matrix activities from a HBr−H2SO4 medium and Ge(Li) gamma-ray spectrometry of the distillation residue. The sensitivity of the method is generally high. For
the high-purity samples the detection limits vary from 0.02 ppb (scandium) to 200 ppb (iron) for irradiation of 1 g of tin
for 1 week at a thermal flux of 5·1012n·cm−2. ·sec−1. To decontaminate the surface of the tin samples, pre- and post-irradiation etching procedures were applied. The efficiency
of these etching techniques was studied. 相似文献
17.
A non-destructive method for the determination of hafnium in zirconium and various alloys, based on the formation of178mHf and179mHf, is proposed. For a neutron flux of 109
n
th
·cm−2·sec−1, the limit of determination is about 0.5 μg. This limit can fall to 50 ng with the multiple irradiation runs system (ten
runs at 92-second cycles). The simple determination is complete within 15 minutes, whereas the multiple irradiation runs method
requires about 15 minutes longer time.
相似文献
18.
R. v. Hentig T. Goldbrunner F. v. Feilitzsch G. Angloher 《Fresenius' Journal of Analytical Chemistry》1998,360(6):664-668
For the determination of trace elements in organic liquids radiochemical neutron activation analysis has been combined with
counting methods geared to various decay modes of indicator radionuclides leading to a high sensitivity required for ultrapure
samples. The activation parameters such as irradiation time, sample mass and neutron flux have been enlarged to the maximum
possible in the available irradiation facility. Separation yields and adsorption losses have been studied in detail for a
set of elements in order to rule out losses during the separation process. The attainable limits of detection are 2 · 10–16g/g for U and Lu, in the 5 · 10–15g/g range for Th and Sm, in the 1 · 10–14g/g region for La, 5 · 10–13g/g for Rb, Cd and 2 · 10–12g/g for K and In. Although the analysis focused on traces of naturally occurring radioisotopes, results for Cr, Fe, W and
Zn are presented as well.
Received: 14 May 1997 / Revised: 28 August 1997 / Accepted: 9 September 1997 相似文献
19.
F. Bunus 《Journal of Radioanalytical and Nuclear Chemistry》1973,13(2):443-449
Experimental work was carried out in order to determine inorganic impurities in PVC latex by activation analysis. Arsenic
and bromine were detected and quantitatively determined by means of two alternative methods: (a) comparison of the samples
and As2O3 and KBr standard simultaneously irradiated with slow neutrons; (b) the same as (a), but considering only bromine and using
standards made by adding and homogenizing known amounts of KBr in the PVC latex. All measurements were based on γ-spectrometry.
The mean values given by method (a) are: arsenic (2.5±0.4)·10−4%, bromine (1.9±0.1)·10−3%. In method (b) the bromine found was (2.47±0.03)·10−3%. 相似文献
20.
I. F. Yazikov N. N. Rodin M. A. Dembrovsky V. G. Lambrev 《Journal of Radioanalytical and Nuclear Chemistry》1969,3(1-2):11-16
A method is described for the radioanalytical determination of traces of chlorine in aqueous solutions without radiochemical
separation or purification. Using a gamma-spectrometer with monocrystal scintillator, the sensitivity of the analysis is about
1·10−8 g of chlorine/ml, the time of analysis being 15 minutes. For the selective determination of chlorine in aqueous solutions
containing a large amount of impurities, a bicrystal scintillation sum-coincidence spectrometer was employed with 120×100
mm NaI(Tl) crystals and thus the38Cl cascade radiation could be used. Application of the sum-coincidence spectrometer allowed a reliable determination of 1·10−7 g of Cl/ml against a background of 1·10−5 g of Na/ml. 相似文献