Determination of the 54Fe(n, 2n)53gFe and 54Fe(n, 2n)53mFe cross sections averaged over a 235U fission neutron spectrum

The reaction cross sections averaged over a ²³⁵U fission neutron spectrum have been measured for the ⁵⁴Fe(n, 2n)^53gFe and ⁵⁴Fe(n, 2n)^53mFe threshold reactions. The values found are, respectively: (1.14±0.13) mb, and (0.52±0.16) mb. The measured cross sections are referred to the (111±3) mb standard cross section of the ⁵⁸Ni(n, p)^58m+gCo reaction. The (81.7±2.2) mb standard cross section value for the ⁵⁴Fe(n, p)⁵⁴Mn reaction, was also used as a monitor to check the results obtained with the Ni standard, leading to an excellent agreement.     

Determination of trace elements in petroleum by neutron activation analysis

Instrumental neutron activation analysis (INAA) and Ge(Li) spectrometry have been used to determine Sc, Cr, Fe, Co, Ni, Zn, As, Se, Sb, Eu, Au, Hg, and U in crude petroleum. The technique involves no chemical separations and no pre-concentration of the samples by ashing is necessary, thus avoiding contamination or loss of volatile elements. The estimated detection limits in ppb for the elements are Sc (0.1), Cr (0.16), Fe (400.0), Co (0.6), Ni (1.1), Zn (200.0), As (6.0), Se (23.0), Sb (1.0), Eu (0.58), Au (0.11), Hg (4.3), U (1.5). Precision values ranged from 0.1% to 15% (relative standard deviation). Interferences in the Co and Fe determinations due to fast neutron reactions (n, p) and (n, α) on Ni isotopes are small and are easily corrected. Losses of As, Se, and Hg due to escape of volatile gases during irradiation are negligible     

The measurement of neutron-induced radionuclides from Chinese nuclear weapons tests

The concentrations of neutron-induced radionuclides have been measured in ground level air during the period between 1976 and 1981 at Nagoya (35° N, 137° E), Japan. Six Chinese atmospheric nuclear weapons tests were conducted by the government of China at Lop Nor (40° N, 90° E) during the period 1976–1981. The Chinese nuclear tests of November 17, 1976 (the 21st test) and October 16, 1980 (the 26th test), high-yield devices, produced⁵⁴Mn,⁵⁵Fe and⁸⁸Y whose production reactions are⁵⁴Fe(n, p),⁵⁶Fe(n, 2n) and⁸⁹Y(n, 2n), respectively. The tests of September 26, 1976 (the 19th test), September 17, 1977 (the 22nd test) and March 15, 1978 (the 23rd test), low-yield devices, produced⁵⁴Mn,⁵⁷Co and⁵⁸Co whose production reactions are⁵⁴Fe(n, p),⁵⁸Ni(n, pn) and⁵⁸Ni(n, p) respectively. No neutron activation product from the 24th test (December 14, 1978) was observed.     

Neutron activation analysis of high purity nickel by solvent extraction using 2-benzylpyridin/benzene

A radiochemical neutron activation analysis using solvent extraction has been applied for the determination of trace impurities in high purity nickel. Because of the high activity of⁵⁸Co produced by the nuclear reaction,⁵⁸Ni(n,p)⁵⁸Co, cobalt should be separated from the impurities. Removal of cobalt from the other trace elements in the aqueous acidic solution containing 1M thiocyanate ion (KSCN) was achieved by extraction with 1M2-benzylpyridin (BPy) in benzene. From the result of tracer experiments, cobalt was completely separated from most other elements except Fe, Mo and Zn. To determine the experimental accuracy, NIST SRM 673 nickel oxide was analyzed and the results agreed well within 10% deviation. This established radiochemical method was applied to the analysis of high purity nickel samples.     

Multielement neutron activation analysis of biological materials using chemical group separation and Ge(Li) gamma spectrometry

Neutron activation analysis (NAA) for the determination of some trace elements in biological materials is described. The method presented permits the simple and rapid determination of Se, Ag, Au, Sb, Pt (via¹⁹⁹Au), Hg, Co, Ni (via⁵⁸Co), Fe, Zn, Mo, Sn, Cr, Cd, Cu and As after radiochemical separation from Na, K, Cs, Rb and partially Br. For this purpose, postirradiation separation by extraction with mercury or zinc amalgam was used. Separation of gold by extraction with ethyl acetate or by precipitation with dimethylglyoxime was applied for the determination of gold and platinum in biological materials.     

Neutron energy spectrum determination and flux measurement using MAXED, GRAVEL, and MCNP for RACE experiments

Stainless steel flux wires were used to determine the neutron energy spectra and total flux during the Reactor Accelerator Coupling Experiments (RACE) at The University of Texas at Austin. A LINAC electron accelerator produced 20 MeV electrons at a power of 1.6 kW, which struck a tungsten-copper target to produce bremsstrahlung radiation and photoneutrons. The neutrons produced in the target were multiplied by the subcritical core of a Triga reactor. The purpose of the RACE experiments is to develop a sub-critical accelerator driven system that would be capable of transmuting actinides from spent fuel. Flux measurements were made with 1.58 mm diameter stainless steel wires placed throughout the core between the fuel rods and cadmium covered and uncovered gold and indium foils above the target. The MAXED and GRAVEL computer codes were used to perform the spectrum unfolding. The composition of the stainless steel wires was determined using neutron activation analysis with comparators prior to the flux measurement. The reactions measured in the stainless steel to determine the flux were ⁵⁰Cr(n,γ)⁵¹Cr, ⁵⁸Ni(n,p)⁵⁸Co, ⁵⁴Fe(n,p)⁵⁴Mn, and ⁵⁸Fe(n,γ)⁵⁹Fe. Flux measurements agreed well with an MCNP simulation of the experiment.     

Determination of trace elements in water by non-destructive neutron activation

A systematic study was undertaken in order to find out which of the most relevant elements can be determined in water under normal conditions by non-destructive neutron activation simultaneously using a suitable monostandard method. Standardized water samples as well as natural water of different kind were used, brought to dryness by freeze-drying and irradiated in quartz at a neutron flux of 10¹⁴ cm⁻² s⁻¹ for 1 day. The trace element content in quartz ampoules of different origin was determined separately. The following elements are discussed in detail including possible interferences: As, Au, Br, Ca, Cd, Co, Cr, Cu, Eu, Fe, Hg, K, La, Mo, Na, Ni, Sb, Sc, Se, U, Zn. Presented at the Euroanalysis II Conference, Budapest, 25–30. Aug. 1975.     

Use of INAA and ICP-MS for the assessment of trace element mass fractions in adult and geriatric prostate

The variation with age of the mass fraction of 54 trace elements (Ag, Al, As, Au, B, Be, Bi, Br, Cd, Ce, Co, Cr, Cs, Dy, Er, Eu, Fe, Ga, Gd, Hf, Hg, Ho, Ir, La, Li, Lu, Mn, Mo, Nb, Nd, Ni, Pb, Pd, Pr, Pt, Rb, Re, Sb, Sc, Se, Sm, Sn, Ta, Tb, Te, Th, Ti, Tl, Tm, U, Y, Yb, Zn, and Zr) in intact nonhyperplastic prostate of 65 healthy 21–87 year old males was investigated by instrumental neutron activation analysis with high resolution spectrometry of long-lived radionuclides and inductively coupled plasma mass spectrometry. This work revealed that there is a significant tendency for an increase in Bi, Cd, Co, Fe, Hg, Sc, Sn, Th, U, and Zn (p < 0.0014) mass fraction in normal prostate from age 21 years to the sixth decade. In the sixth to ninth decades the mass fractions of almost all chemical elements investigated in nonhyperplastic prostates were maintained at approximately stable levels. Our finding of correlation between pairs of prostatic chemical element mass fractions indicates that there is a great disturbance of prostatic chemical element relationships with increasing age.     

A study of trace element distribution in the solvent refined coal (SRC) process using neutron activation analysis

Twenty-two trace elements have been measured by INAA in materials produced in the Solvent Refined Coal (SRC) pilot plant. The elements As, Sb, Se, Hg, Ni, Br, Na, K, Cr, Sc, Fe, Co, Cs, Ce, Rb, Th, Sr, Ba, Tb, Eu, Sm and Lu were measured in coal, SRC, insoluble residues, solvents, and process waters. The liquefaction process produces a fuel lower in toxic trace elements than the parent coal. Elemental balances indicate that except for As, and Hg the SRC and insoluble residues contain more than 80% of the trace elements found in the coal. Evidence is presented indicating significant organic binding of As, Se, Hg, Br, Ni, and Co in the SRC.     

Mechanism of the hydrolysis of 1-chloro-2-ethylthioethane extraction

To evaluate the potentiality of the blue-green algae Spirulina platensis as a matrix for the production of Se-containing pharmaceuticals, the background levels of 31 major, minor and trace elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni using (n,p) reaction), As, Br, Zn, Rb, Mo, Ag, Sb, I, Ba, Sm, Tb, Tm, Hf, Ta, W, Au, Hg, Th were determined in Spirulina platensis biomass by means of epithermal neutron activation analysis. The possibility of the purpose-oriented incorporation of Se into Spirulina platensis biomass was demonstrated. The polynomial dependence of the Se accumulation on nutritional medium loading was revealed. The analytical technique used allows to control the amount of toxic elements in algae Spirulina platensis. Based on this study, a conclusion of the possibility to use Spirulina platensisas a matrix for the production of Se-containing pharmaceutical was drawn.     

Epithermal neutron activation analysis of blue-green algae Spirulina platensis as a matrix for selenium-containing pharmaceuticals

To evaluate the potentiality of the blue-green algae Spirulina platensis as a matrix for the production of Se-containing pharmaceuticals, the background levels of 31 major, minor and trace elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni using (n,p) reaction), As, Br, Zn, Rb, Mo, Ag, Sb, I, Ba, Sm, Tb, Tm, Hf, Ta, W, Au, Hg, Th were determined in Spirulina platensis biomass by means of epithermal neutron activation analysis. The possibility of the purpose-oriented incorporation of Se into Spirulina platensis biomass was demonstrated. The polynomial dependence of the Se accumulation on nutritional medium loading was revealed. The analytical technique used allows to control the amount of toxic elements in algae Spirulina platensis. Based on this study, a conclusion of the possibility to use Spirulina platensisas a matrix for the production of Se-containing pharmaceutical was drawn.     

Determination of minor, trace and toxic elements in chewing tobacco products by instrumental neutron activation analysis and identification of glutamic acid

Tobacco smoking/chewing has been a cause of concern because of it being related with oral cancer. It causes stimulation and ill physiological effects. Ten different brands of spit tobacco, eight gutkaas and five paan masalas have been analyzed for seven minor (Al, Na, K, Ca, Cl, Mg, and P) and 17 trace (As, Ba, Br, Co, Cr, Cs, Cu, Eu, Fe, Hg, La, Mn, Rb, Sb, Sc, Th, and Zn) elements by instrumental neutron activation analysis. Also Ni and Pb were determined by atomic absorption spectrophotometry. Concentration of Cd was below detection limit (<10?mg?kg^?1) in the tobacco samples. Mg, generally added as MgCO₃ to prevent caking, is present as minor constituent in spit tobacco and gutkaas but is below detection limit (<1?g?kg^?1) in paan masalas. Most elemental concentrations vary in a wide range depending on the nature of chewing tobacco. Spit tobacco has been found to be more enriched in essential elements (Ca, K, Na, P, Mn, and Rb), whereas gutkaas contain higher concentrations of Fe, Cr, Cu, and Zn. Paan masalas contain lower contents of other elements but higher content of Hg. Gutkaas also contain higher amounts of As and Pb. Further glutamic acid has been separated from tobacco leaves and characterized as it might bind with some elements.     

Multi-element analysis of blood for trace metals by neutron activation analysis

Fourteen elements can be rapidly determined in whole blood by the neutron activation analysis procedure described. Three of these (Ag, Cl, Se) are measured after a 10-s irradiation and eleven others (Al, Ba, Br, Ca, Cu, I, Mg, Mn, Mo, Rb, V) are determined by a 180-s irradiation of a 1-cm³ sample of whole blood after destruction of organic matter and removal of sodium by hydrated antimony pentoxide. A further 13 elements (As, Au, Co, Cr, Cs, Fe, Hg, K, Na, Ni, Sb, Sc, Zn) are determined after overnight irradiation in the SLOWPOKE reactor.     

A compilation of cross-sections for charged particle production by 14 MeV neutrons for Fe,Co and Ni isotopes

A compilation of the (n, p), (n, n′p), (n, α, (n, n′α) and (n,³He) cross-sections for⁵⁴Fe,⁵⁶Fe,⁵⁷Fe−⁵⁸Fe,⁵⁹Co,⁵⁸Ni,⁶⁰Ni,⁶¹Ni,⁶²Ni and-⁶⁴Ni by 14 MeV neutrons is presented in the from of a table containing the results of some 180 different measurements, mainly obtained by activation analysis. Brief assessments of the experimental methods and the data status are given.     

Neutron activation analysis of major and trace elements in crude petroleum

We have determined the concentration of 25 trace elements in crude petroleum from seven Libyan oil fields by instrumental neutron activation analysis. Crude oil samples were irradiated with a thermal neutron dose rate of 10¹² and 10¹³ n·cm^–2·s^–1 in the Tajoura research reactor. The concentration of U, Br, Mg, Cu, Na, V, Cl, Al, Mn and Ca is in a range of 0.015 to 84 ppm and that of sulphur of 0.12 to 1.8%. The elements Sc, Cr, Ni, Fe, Co, Zn, Ag, Se, Sb, Ba, Cs, Yb, Hf and Hg have a concentration range of 0.009 to 8747 ppb. The coefficients of variation are within 10%. The elements V and Ni occur as both porphyrin and non-porphyrin and the ratio of these two forms varies over a wide range. The V/Ni ratios are located between 0.17 and 6.67, which are comparable to the reported values for the crude oils from other countries.     

Multivariate analysis applied to some elements in human fluids and whole bloods of hemodialysis patients determined by INAA

This research is a framework of a big project aimed to the knowledge of human metabolism in hemodialysis patients. For reaching high sensitivity and obtaining accurate values for elements at very low concentrations Instrumental neutron activation analysis (INAA) was used for its characteristics to be a primary analytical method and because it does not require any chemical–physical pretreatment. The samples analyzed (160) are representative of groups of homogeneous population and specific matrices (hemodialysis fluids and whole human blood). The irradiation was performed in the rotating rack (Lazy Susan) of the Triga Mark II reactor of the R.C. Casaccia-ENEA at a neutron flux of 2.6 × 10¹² n cm^?2 s^?1 with an irradiation time of 12 h. The results on the hemodialysis fluids report the values and the behavior of selected trace elements: the levels of Br and Na show a decrease between the pre- and post-dialysis whereas Fe, K and Zn an increase. The other elements such as Cs, Rb and Se seem to keep constant between the two phases. Similar data are found for the whole human blood for the same selected elements. Finally, exploiting the INAA peculiarity it has been investigated the levels of trace and ultra-trace elements interesting from a toxicological (Hg, Ni, Sb) and nutritional (Co, Cr) point of view and seldom determined due to their analytical implications. Finally, a chemiometric investigation performed through dendrogram trees, Canonical discriminant analysis and principal component analysis, has evidenced the similar effects of the HF, HDF and BIC-treatments on the investigated fluids respect to the CAPD dialysis.     

Fission neutron spectrum averaged cross sections for threshold reactions on arsenic

Summary We have measured the cross sections, averaged over a ²³⁵U fission neutron spectrum, for the two high threshold reactions: ⁷⁵As(n,p)^75mGe and ⁷⁵As(n,2n)⁷⁴As. The measured averaged cross sections are 0.292±0.022 mb, referred to the 3.95±0.20 mb standard for the ²⁷Al(n,p)²⁷Mg averaged cross section, and 0.371±0.032 mb referred to the 111±3 mb standard for the ⁵⁸Ni(n,p)^58m+gCo averaged cross section, respectively. The measured averaged cross sections were also evaluated semi-empirically by numerically integrating experimental differential cross section data extracted for both reactions from the current literature. The calculations were performed for four different representations of the thermal-neutron-induced ²³⁵U fission neutron spectrum. The calculated cross sections, though depending on analytical representation of the flux, agree with the measured values within the estimated uncertainties.     

Elemental composition studies of fugitive and ambient air dust particulates from a thermal power station by instrumental neutron activation analysis

In order to assess the source of pollutants and the atmosphere quality in and around a thermal power plant, fugitive dust particulates from seven different locations and ambient air dust from six locations have been analyzed for 32 elements (As, Au, Ba, Br, Ce, Cl, Co, Cr, Cs, Cu, Eu, Fe, Ga, Hg, Hf, K, La, Lu, Mg, Mn, Na, P, Rb, Sb, Sc, Se, Ta, Tb, Te, Th, W and Yb) by employing instrumental neutron activation analysis (INAA). The method involves the irradiation of samples and comparator standards in a thermal neutron flux range of 10¹²–10¹³ n·cm^–2·s^–1 in a nuclear reactor for 10 min and 1 day followed by high resolution -spectrometry. Wide differences have been observed in the mean elemental concentrations of Fe, Co, Br, Mn, As, P. Ba and Cu in fugitive and ambient dust particulates coliected from these different locations. Further, a comparison of the elemental contents of the dust particulates from the plant with environmental standards (Urban Particulate Matter, Coal Fly Ash, Vehicle Exhaust and Coal) show significantly lower or comparable amounts of toxic and pollutant elements in the environmental samples.     

Determination and geochemical significance of trace elements in Iraqi crude oils using instrumental neutron activation analysis

The trace-element composition of crude oil was studied using instrumental neutron activation techniques and a large-volume high-resolution Ge(Li) detector. A total of 29 elements were determined in oils representing the various producing formations of the Iraqi oil fields. These were: Al, Ar, As, Au, Br, Ca, Cl, Co, Cr, Cu, Eu, Fe, Ga, Hg, K, La, Mn, Mo, Na, Ni, Re, S, Sb, Sc, Se, Sm, V, W and Zn. The significance of these trace elements in the geochemical investigation of crude oil is discussed.     

Determination of Trace Elements in Liquid Fuels by Instrumental Neutron Activation Analysis

Abstract

An instrumental neutron activation analysis with Ge(Li) γ -spectrometry and computer-assisted data reduction, has been developed for the determination of more than 20 elements in different liquid fuels. Organo-metallic standard solutions were mixed to obtain suitable standards. Two neutron irradiations and 4 γ-spectrometric measurements are required for each sample. Corrections were taken into account for a few spectrometric and nuclear interferences. The overall standard deviation for nearly all elements is mainly determined by counting statistics. The following elements can be determined : Na, Al, S, Cl, K, Sc, V, Cr, Fe, Co, Ni, Cu, Zn, As, Se, Br and La whereas the concentration of the following elements are mostly near the limit of detection: Mg, Mo, Sb, Ba, Th and Hg.