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1.
A simple method is described for estimation of sulfur in coal using fast neutron activation of sulfur, i.e.32S(n,p)32P and subsequent measurement of32P -activity (1.72 MeV) by a Geiger-Müller counter. Since the sulfur content of Indian coal ranges from 0.25 to 3%, simulated samples of coal containing sulfur in the range from 0.25 to 3% and common impurities like oxides of aluminium, calcium, iron and silicon have been used to establish the method. 相似文献
2.
A simple and accurate technique has been developed to analyse the commercial fertilizers for phosphorous, potassium, chlorine,
magnesium and silicon. The method is based on the fast neutron activation. 相似文献
3.
S. Szegedi D. S. Mosbah M. Váradi I. Szalóki 《Journal of Radioanalytical and Nuclear Chemistry》1988,127(2):121-132
For a non-destructive determination of the protein content in soya bean samples, 14-MeV neutron activation analysis /NAA/ was applied. To check the method, results obtained by X-ray fluorescence /XRF/ analysis and the Kjeldahl procedure were compared. For pressed pellet samples of about 1 g and choosing 15 min irradiation and 10 min measuring times the accuracy of the protein determination was found to be 15%.This work was supported by the Hungarian Research Foundation /Contract No. 259/. 相似文献
4.
For the non-destructive deermination of the nitrogen content in plant samples 14-MeV neutron activation analysis was applied. Using powder samples of 0.7 g, irradiation time of 1 h and measuring time of 10 min, the accuracy of the determination is about +15%. The potassium content of the plant samples was determined by X-ray fluorescence analysis and correction was made for their contribution to the nitrogen activities.This work was supported in part by the Hungarian Academy of Sciences. 相似文献
5.
N. I. Ward S. A. Kerr T. Otsuka 《Journal of Radioanalytical and Nuclear Chemistry》1987,115(1):113-123
Due to the interaction with components present in natural waters, radionuclides may be present in different physico-chemical forms, varying in size, charge and density. The distribution pattern will influence the transport, mobility and biological uptake of the radionuclides. Size fractionation based on hollow fiber is useful for the determination of the size distribution pattern of radionuclides in natural waters. Furthermore, a continuous mixing and separation system has been developed for the investigation of the association of radionuclides with naturally occurring colloids. Results based on radionuclides in waste water from the Forsmark nuclear power plant, Sweden, will illustrate the potential usefulness of the technique. 相似文献
6.
Cadmium is determined by activation analysis with fast neutrons, obtained by irradiation of a thick beryllium target with 14.5-MeV deutrons. Cadmium-111m, formed via the 112Cd(n, 2n)111mCd and 111Cd(n, n′)111mCd reactions, is separated by liquid—liquid extraction with zinc dithyldithiocarbamate in chloroform and measured with a Ge(Li) γ-spectrometer. For low concentrations, cadmium is precipitated as cadmium ammonium phosphate after the extraction. NBS and BCR reference materials were analyzed: for concentrations between 3 and 500 μg g?1, the relative standard deviation ranges from 5 to 3% The results obtained for sewage sludge are compared with those obtained by reactor neutron activation analysis. 相似文献
7.
A routine method is presented for the determination of fluorine in small bone samples by activation analysis with fast conversion
neutrons. Both the purely instrumental determination and the analysis by chemical separation are discussed. The activations
are performed with the AVF cyclotron of Philips-Duphar at Petten. Use was made of a rabbit system equipped with a Be-target,
which can be inserted in the internally deflected beam of the cyclotron. The sensitivity of the instrumental method is ≈1
μg. Application of chemical isolation results in a sensitivity of ≈0.1 μg. 相似文献
8.
W. D. James W. D. Ehmann C. E. Hamrin L. L. Chyi 《Journal of Radioanalytical and Nuclear Chemistry》1976,32(1):195-205
The feasibility of using fast neutron (14 MeV) activation analysis techniques for the determination of oxygen and nitrogen
in coal has been investigated. Conditions that favor instrumental neutron activation analysis (INAA) include the absence of
problems associated with sample dissolution and the capability of extremely rapid analyses as compared to older techniques
such as the Kjeldahl method for nitrogen. Most previous oxygen determinations have been by difference after major component
analyses. In the present study, oxygen was determined in sized coal and its low temperature ash (LTA) with the difference
representing the organic oxygen content. Both the oxygen and nitrogen analyses employ a multiscaling technique with the former
based on the16O(n, p)16N reaction, while the latter utilizes the annihilation radiation produced by the product of the14N(n, 2n)13N reaction. The high-energy gamma-radiation associated with the decay of16N was essentially free of spectral interferences for coal analysis, although fluorine could cause a primary interference if
the F/O ratio exceeds 0.02. In the nitrogen work, experiments were performed to determine correction factors to account for
the effects of the12C(p, γ)13N and13C(p, n)13N “knock-on” reactions and the39K(n, 2n)38K reaction which produce interfering β+ emitting radionuclides. Data are presented for oxygen in Western Kentucky No. 9 and No. 11 coal and coal ash and for nitrogen
in eleven different coals. 相似文献
9.
A procedure involving the irradiation of coal samples with 14 MeV neutrons and subsequent gamma-ray spectrometry of the irradiated
sample for the estimation of solfur in coal, has been outlined. The samples were irradiated with 14MeV neutrons from a Cockroft-Walton
type generator for one minute and then subjected to gamma-ray spectrometry for another minute using an automated transfer
cyclic system. Ten such cycles were repeated for accumulating events under the 2130 keV gamma ray photopeak belonging to34P (T=12.4 s) produced by the34S(n, p)34P reaction for assessing the lower level of detection, LLD, of Sulfur. Interferences due to the presence of other elements
in coal were also determined. Sulfur can be determined at LLD of 0.25% in coal provided a 5 g sample of the coal is irradiated
with a neutron flux of 5·109 n·cm−2·sec−1 assayed with a gamma ray spectrometer having a large hollow core Ge(Li) detector and an anti-Compton shield. 相似文献
10.
A method for the determination of oxygen based on the reaction16O(n, p)16N is suggested. The samples are irradiated in stainless steel capsules with fast neutrons. The total neutron flux passing
through the sample is proportional to the flux passing through the wall of the capsule. Therefore, the activity induced in
the capsule according to the reaction56Fe(n, p)56Mn can be used to monitor the neutron flux through the sample. Thus, the necessity of maintaining the sample in an exact position
during the irradiation is eliminated. 相似文献
11.
S. A. Lis Ph. K. Hopke J. L. Fasching 《Journal of Radioanalytical and Nuclear Chemistry》1975,24(1):125-251
In the past several years, a number of gamma-ray tables have been published. All of the tables limit themselves to those nuclides formed in (n, γ) reactions or at most to a few of the more prominent (n, 2n) products. A number of investigators are developing activation analysis methods using fast neutrons or photons. These investigations have been hampered by the lack of tables of gamma-rays of those nuclides that can be formed by (n, 2n), (n, p), (n, α), (n, n′) and (n, d) reactions. Since (γ, n) yields the same product as (n, 2n) the table would also be useful to photon activation studies. The authors have compiled such a table. Section II: list of the gamma-rays for all isotopes in order of increasing energy will be published in the J. Radioanal. Chem., 25 (1975) No. 2. 相似文献
12.
The determination of Al2O3, in bulk coal samples to an accuracy of about 0.2% Al2O3 has been achieved by means of a thermal-neutron activation technique based on the reaction 27Al(n,γ)28Al. In the analysed samples, which had widely different compositions, the Al2O3 concentrations ranged from 1 to 11% and the ash contents from 7 to 40%. Al2O3 concentrations measured by x-ray fluorescence showed a linear relationship with both the 1.78-MeV γ-ray count following the decay of 28Al and the thermal-neutron count near the samples during irradiation. The linear relationship, which was obtained by regression analysis of the experimental data, determined the Al2O3concentrations with a standard deviation of 0.24% Al2O3. The particle sizes in the samples ranged from —0.5 to —40 mm, the moisture contents ranged from 1 to 6%, and the sample weights ranged from 8 to 11 kg. However, inclusion of these parameters in the regression analysis did not significantly improve the results for Al2O3. 相似文献
13.
A simple and rapid method is described for the estimation of the rubidium in coconut palm leaves by neutron activation analysis.
The method is found suitable for the estimation of stable Rb used as a tracer in root distribution studies. The average of
five determinations is 5.15 μg, which varies between 5.07 μg and 5.26 μg at 95% confidence limit. 相似文献
14.
J. B. Cross D. H. Cleveland L. V. Harris 《Journal of Radioanalytical and Nuclear Chemistry》1982,72(1-2):353-364
Two improvements in the analytical techniques used for fast neutron activation analysis have been developed and put into routine
use. The first is neutron shielding of a NaI (TL) counting system, which reduces the counting noise encountered during neutron
generation. The second is a modification of batch type irradiation for long lived nuclides so they can be done simultaneously
with other test. 相似文献
15.
Ch. L. Ndiokwere V. P. Guinn D. Burtner 《Journal of Radioanalytical and Nuclear Chemistry》1983,79(1):123-128
The instrumental neutron activation analysis (INAA) technique has been used to determine 17 major, minor, and trace elements
in samples of the three major sources of Nigerian coal. The NBS Standard Reference Material, Coal SRM 1632, was also analyzed,
for the purpose of verifying the accuracy of the method. The results obtained with it were in good agreement with the NBS
certified values. The concentrations of the major elements determined for the Nigerian coal were found to be much lower than
the mean values of those reported for coal samples from other parts of the world. 相似文献
16.
Cyclic neutron activation analysis (CNAA), has, in recent years been developed as a useful analytical tool for the assay of short-lived isotopes in single element situations. The work described in this paper investigates the potential of the technique for composite samples having a wide range of elements that produce short-lived and long-lived isotopes on neutron irradiation. Accelerator-derived neutrons with average energies of 3 MeV, 6MeV and 14MeV were employed in what has been dubbed Fast Neutron Cyclic Neutron Activation Analysis (FNCAA). The approach to multi-element analysis entailed: (a) determination of cycle parameters in single element samples via the reactions27Al(n, p)27Mg (9.6 min,E
=840keV), and137Ba(n, n)137mBa(2.3min,E
=662keV), (b) a test of the method on a composite rock sample, (c) determination of analytical sensitivities using both powdered kale and rock standards and (d) a comparison of analytical results with other techniques. The results obtained in all these measurements are presented and discussed. 相似文献
17.
R. L. Paul 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(1):243-249
A method has been developed for the determination of low-level sulfur in steels by radiochemical neutron activation analysis.
During sample irradiation, 35S is produced by the 34S(n,γ)35S reaction. Irradiated steels are mixed with sulfur carrier and dissolved in HCl/HNO3. Sulfur is reduced to H2S by reaction with HI/H3PO2/HCl. The evolved H2S is absorbed in dilute NaOH, which is mixed with scintillation cocktail for the measurement of 35S by liquid scintillation counting. Sulfur carrier yield is determined by iodometric titration. Chlorine is also determined
by RNAA in order to correct for 35S produced via the 35Cl(n,p)35S reaction. Sulfur has been determined at mass fractions as low as ≈5 mg/kg in ultra-high-purity iron using this method. 相似文献
18.
A. Faanhof H. A. Das J. Zonderhuis 《Journal of Radioanalytical and Nuclear Chemistry》1980,56(1-2):173-184
The applicability of a 400 kV neutron generator in the elemental analysis of dry biological material is considered. Data for
the specific count-rates of 66 elements are given. A procedure for the determination of N, Mg, Si, P, K and Ca is described.
The results for three Standard Reference Materials and some samples are given. 相似文献
19.
Silicon, phosphorus, and sulfur in alloy steel were determined by neutron activation analysis involving rapid radiochemical separation procedures. The standard deviations for silicon, phosphorus, and sulfur were 1.6%, 2.3%, and 2.4% respectively; the sensitivity limits were 3.2, 0.20, and 2.50 p.p.m., respectively. The three constituents could be determined in alloy steel within 2 h of the irradiation. 相似文献
20.
Sources of error in the fast neutron activation analysis determination of oxygen have been investigated and minimised. The oxygen contents of eighteen international rock standards and a sulphide ore standard have been determined, and compared with the values calculated by difference using the reported full analyses. Accuracies of 0.3% average deviation and reproducibilities of ±0.2% standard deviation have been obtained, where oxygen contents exceeded 1.0 g. 相似文献