Proton-induced Gamma-ray Emission Research Articles

A borate fusion method for the determination of fluorine in coal

A new analytical method has been developed for determining fluorine in coal. It incorporates a two stage sinter-fusion procedure using lithium carbonate, lithium tetraborate and zinc oxide. In the sinter stage, coal is ashed at 600 °C and the lithium carbonate and zinc oxide act as collectors to capture volatile species of fluorine. In the second stage, the ash residue is decomposed by fusion with the lithium carbonate and lithium tetraborate at 1050 °C. The fused material is dissolved in nitric acid and the fluoride in solution is determined using an ion selective electrode. The results for a number of coal samples including Certified Reference Materials are reported. These are in good agreement with the certified values and with the results obtained by proton induced gamma ray emission spectrometry. The good agreement confirms that no fluorine is lost during ashing/sintering of the coal and that complete dissolution of the residual ash is obtained by fusion with the lithium carbonate and lithium tetraborate The method is simpler and less labour intensive than pyrohydrolysis and is suitable for use in most commercial coal laboratories.

Proton induced X-ray emission and proton induced gamma ray emission analysis in geochemical exploration for gold and base metal deposits

Proton induced X-ray emission (PIXE) and proton induced gamma ray emission (PIGME) analysis has been used in geochemical exploration to determine various elements in rocks and regolith in relation to gold and base metal mineralisation. Elements analysed by PIXE include K, Fe, Ca, Ti, Mn, Cl, Ga, Rb, Sr, Zr, Y, Nb, Cu, Zn, Pb, Ni, As, V and Mo, and those by PIGME are Al, Na, Mg, F and Li. One of our research areas is Cobar, northwest of New South Wales, Australia. The study areas include the McKinnons and Peak gold deposits, the Wagga Tank base metal deposit and Lower Tank prospect, northeast of the CSA mine. Au, Cu, Zn, Pb, As and Ni are elevated as ore indicators near and around the ore deposits while K, Al, Ca, Na, Ti, Rb, Sr, Ga and V are depleted due to feldspar and mica destruction during alteration.

Elemental analysis of limestone samples from Ewekoro limestone deposit in southwest Nigeria

Limestone samples of different colours from Ewekoro limestone deposit in Ogun State, Nigeria were subjected to elemental analysis by proton-induced X-ray emission (PIXE) and proton-induced gamma-ray emission (PIGME) techniques. The irradiation was by 2.5 MeV proton beams from the ion beam analysis (IBA) facility of the 3 MV Van de Graaff accelerator at the Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights. Elemental composition and concentrations of 22 major, minor and trace elements were determined. The NIST geological standard, NBS278, was analysed for quality assurance. The concentrations of the major elements (Ca, Fe, K and Al) are similar in the samples while the other major elements differed. Calcium accounts for about 38%, giving 86.8% CaCO 3 content in the limestones. The major elements (Al, Ca, Fe, Si, S and K), present in the limestones, were also found to be enriched in airborne particulate matter studied by earlier workers, thus confirming cement dust as the major contributor to the particulate matter within and around cement factories.

Geochemical analysis of radiolarite samples from the Carpathian basin

A very important raw material of the prehistoric age, radiolarite was investigated in this work. Samples from geological and archaeological sites of the Carpathian basin, Greece and Austria were analyzed by ion beam methods, namely proton-induced gamma-ray emission (PIGE) and proton-induced X-ray emission (PIXE) techniques. Our aim was to study to what extent we are able to classify the specimens with various macroscopical features and different source areas. In order to answer this question, a cluster analysis was carried out on the concentration data set deduced from the analysis. Correlations between the elemental compositions and the source regions are established.

19F(p,p ′γ) 19F and 18O(p,γ) 19F gamma-ray interferences studied on liquids

The interference effects for the 110 and 197 keV γ-ray lines of the nuclear reactions 19F(p,p ′γ ) 19F and 18O(p,γ) 19F were studied quantitatively. For this, thick liquid targets were examined by proton induced gamma-ray emission (PIGE) using an external proton beam of 3.4 MeV energy. Several grades of dilutions were prepared from 76.3% 18O enriched H 2O and from 1000 ppm F standard NaF solution. From this, a data base was obtained in order to extrapolate the 110 and 197 keV γ-ray yields of the 18O(p,γ) 19F reaction for a target of water containing 0.2% 18O. As a result it was obtained that, for fluorine in oxygen-rich materials, the reaction 19F(p,p ′γ) 19F allows minimum detection limits of (1.06±0.12) and (1.85±0.2) at.ppm for the 110 and 197 keV γ-rays, respectively.

Simultaneous PIXE and PIGME Analysis of a Nigerian Tar Sand Sample from a Deep Borehole

Tar sands from a deep borehole in southwestern Nigeria were subjected to elemental analysis by simultaneous proton induced X-ray emission (PIXE) and proton induced gamma-ray emission (PIGME) techniques. The concentration of 22 major, minor and trace elements, namely Al, Ca, Cr, Cu, F, Fe, Ga, Ge, K, Li, Mg, Mn, Na, P, Pb, Rb, S, Si, Sr, Ti, Zn and Zr were determined. The accuracy and precision of the techniques for chemical analysis were assured by analysing the NBS 278 geological standard.

Amorphous lithium cobalt and nickel oxides thin films: preparation and characterization by RBS and PIGE

Thin films have been deposited by radio-frequency magnetron sputtering, using LiCoO 2, LiNiO 2 and LiNi 0.7Co 0.3O 2 targets, in argon or Ar/O 2 gas mixture. The composition of the thin films has been determined by proton induced gamma-ray emission (PIGE) analysis and by Rutherford backscattering spectroscopy (RBS). The oxygen partial pressure in the plasma influences the composition of the thin films; these results are discussed with regard to the film morphology.

Non-destructive evaluation of glass corrosion states

Ion beam based composition analysis of silicate materials can be strongly affected by natural surface corrosion. The simultaneous application of Proton Induced X-ray Emission (PIXE) and Proton Induced Gamma-ray Emission (PIGE) proves useful to distinguish between thin or extended leached surface areas on glasses. Among others, those preliminary studies form the basis to decide on the applicability of PIXE to analyse the composition of bulk glass. The novel method of non-destructive glass surface evaluation may assist in the field of conservation and restoration of art objects made from glass.

External-beam PIGE for fluorine determination in atmospheric aerosol

Air pollution measurements have been performed at Montelupo, a town about 20 km west of Florence, characterised by the presence of a large number of ceramic and glass factories just inside the inhabited area. Both filters collecting aerosols during 24 h and streaker filters with 1-h resolution capability have been analysed, using external Particle Induced X-ray Emission (PIXE) and Proton-Induced Gamma-Ray Emission (PIGE) simultaneously. The best operating conditions for getting quantitative information from the PIGE analysis of fluorine in the external beam set-up have been investigated. The minimum detection limit for the concentration of fluorine in air is in the order of 10 ng/m 3. Some specific results concerning fluorine determination in both the 24 and 1-h resolution measurements are finally presented. While the average detected concentrations in air come out to be well below the air quality limits, time episodes of relatively higher concentration have been detected and thanks to the time correlation with the other elements the origin of these pollution episodes can be hypothesised with a good degree of confidence.

Tracing fossil and present day fluids in rocks: application of the nuclear microprobe

Geological fluids contain water, chlorides and Na as major components, and metals, CO 2 gas and CH 4 gas as minor or major components. Quantitative analysis of geological fluids in fluid inclusions and hydrothermal minerals is vital to the characterization of fluid-rock interactions. The presence and quantity of trace and minor elements can be determined in fluid inclusions and minerals by Proton-induced-X-ray-emission (PIXE) and Proton-induced-gamma-ray-emission (PIGE) with EDS analysis, based on computer-aided interpretation of X-ray spectra. A feature of the PIXE-PIGE method is the long range (deep penetration) of protons in light matrices, which allows near-surface inclusions to be analysed. The applications presented here concern samples from submarine hydrothermal deposits (Red Sea, Lau Basin), and from skarns in Central Morocco. In submarine hydrothermal processes, PIXE data show trace-element-bearing-mineral(s) in assemblages with bulk geochemical anomalies, e.g. Co- and Pb-contents in the 1000 ppm range in chalcopyrite from the Hine-Hina field, Lau basin. PIXE data for high T chimneys of the Atlantis II deep record trace element perturbations due to boiling. Hypersaline magmatic fluids in the Sn-skarns of El Hammam contain more than 1000 ppm Cu and Pb but no Zn. A Sn-borate, nordenskiöldine, has been identified in the high T-skarns, trapping a Li-bearing concentrated brine.

The application of secondary ion mass spectrometry (SIMS) to the study of high temperature proton conductors (HTPC)

The oxygen tracer diffusivity of CaZr 0.9In 0.1O 2.95, SrCe 0.95Yb 0.05O 2.975, and BaCe 0.9La 0.1O 2.95 at a nominal oxygen partial pressure of 1 atm ( P H 2O ∼10 −6 atm) has been measured in the temperature range 500–1000°C by means of 18O/ 16O Isotope Exchange Depth Profiling (IEDP) with SIMS. The results are interpreted in terms of the ordering of oxygen vacancies in the orthorhombic structured perovskites. Negative secondary ion mass spectra ( m/z=16 to 19) obtained from SrCe 0.95Yb 0.05O 2.975 samples are also discussed, with particular reference to the presence of fluorine. Confirmation of fluorine contamination was provided by 19F Proton Induced Gamma-ray Emission (PIGE) analysis.

Determination of total fluorine in five coal reference materials by proton-induced gamma-ray emission spectrometry

The direct non-destructive proton-induced gamma-ray emission (PIGE) technique with a germanium detector was applied to the determination of total fluorine concentration in five coal reference materials (BCR 40, NIST 1632b, NIST 1635, SARM 20 and USGS CLB-1). Duplicate analyses were made from five randomly selected bottles of each coal. Individual data are presented and some problems (calibration, proton stopping power, effects of sample heating by the proton beam, background estimation) which were encountered during this study are discussed. Sensitivity and reproducibility of the determinations, and homogeneity of the coal samples with respect to fluorine contents by analysis of variance were investigated. The present data are also compared with the few published values for these reference samples, including other PIGE data. The use of synthetic standards and spiked samples in the present study suggested that the PIGE method was more accurate than other techniques.

EPR spectra and lithogeochemistry of jasperoids at Carlin, Nevada: distinction between auriferous and barren rocks

The acid insoluble residue of twenty-nine gold-bearing and ten barren jasperoids from Carlin, Nevada, were analysed by electron paramagnetic resonance powder spectroscopy (EPR), and by simultaneous proton-induced X-ray emission (PIXE) and proton-induced gamma ray emission (PIGME) spectroscopy. The mineralised samples are characterised by high Li, F, AI, K, Ti, Rb, V, Y, and Zr values in general and by significantly higher Rb/Al and V/Al ratios in particular. The chemical differences are largely caused by the abundance and type of sericite present. Significant differences in EPR intensity exist between the mineralised and barren jasperoids.

Assessment of the usefulness of the PIGE method to determine nitrogen in human blood serum

Proton-induced gamma-ray emission (PIGE) analysis has been applied to the determination of total nitrogen concentration of blood sera from hospital patients. Both the reaction14N(p,p′γ)14N,Eγ= =2313 keV, and the reaction15N(p,αγ)12C,Eγ=4439 keV, have been used. From 37 patients, the range of the nitrogen concentrations obtained was 9.54–16.3 g/l with a mean of 12.0 g/l. The corresponding total protein concentrations varied between 59 and 96 g/l, measured in a clinical laboratory autoanalyser using the biuret method. The range of the albumin concentrations was 29–46 g/l. The nitrogen concentrations correlated well with the total protein concentrations (r=0.802). The multiple correlation of nitrogen versus (albumin+(total protein-albumin)) gives a coefficient of 0.175 for albumin and 0.161 for total protein-albumin. The results agree with expectations and support the potential usefulness of the rapid PIGE method for medical studies.

Lithium, boron and beryllium in volcanic glasses and minerals studied by nuclear microprobe

The detection of lithium, boron and beryllium was performed using a nuclear microprobe. The γ-emission yields have been measured for the most favourable nuclear reactions: 7Li(α, α′γ) 7Li, 7Li(p, p′γ) 7Li, 10B(p, αγ) 7Be and 7Li(p, nγ) 7Be. The possible interferences and the minimum detection limits (MDL) are presented, at different energies and for a total integrated charge of 1 μC. Lithium and boron, studied by the reactions (p, p′γ) and (p, α), respectively, have been determined in silicated glasses, as trace elements and on the scale of few micrometers. In the case of beryllium, using the 9Be(p, αγ) 6Li reaction, the MDL is calculated to be 1100 ppm for beryllium. This element has not been further studied in our glass samples. PIGE (Proton Induced Gamma-ray Emission) allows the simultaneous measurement of lithium, fluorine and sodium. Standardization curves were made for lithium and boron on the basis of natural and synthetic glasses and minerals. Our results point out high boron contents in rhyolitic obsidians from Eolian Islands (Italy), compared with other rhyolites. Concentrations in lithium, fluorine and boron were determined, for the first time, in glass inclusions trapped within primitive minerals of the 1906 eruption of Vesuvius (Italy).

高エネルギーイオン線の鉱物科学への応用

In recent years, many studies has been reported in physic journals concerning the ion-beam analysis of the trace elements and light elements using accelerator induced MeV-range high energy ion-beam. A high-energy ion beam bombardment on a target materialinduces many types of emission of particles and radiations. The detection of these emissions make possible a wide variety of analytical methods. These ion-beam analyses, e.g. PIXE (Proton induced X-ray emission), RBS(Ruatherford backscattering spectrometry), NRA (Neutron reaction analysis), PIGE (Proton induced gamma-ray, emission), PAA (Proton activation analysis), have many advantages in comparison with electron beam probe analytical methods. These ion-beam analyses (IBA) also has unique capabilities for trace element analysis, light element analysis, depth profile analysis, external beam analysis, channeling analysis, ion beam induced luminescence, subsurface fluid inclusion analysis and accelerator mass spectroscopy. These analytical methods are suitable for the mineral science related materials although the application on the mineral science is not yet made in Japan. In view of this situation, the basis of each analytical technique and recent progress on mineralogical applications are reviewed.

The distribution of fluorine and other elements in teeth using proton induced reaction analysis techniques

Proton induced gamma-ray emission (PIGE) and proton induced X-ray emission (PIXE) analysis was employed to investigate the distribution of the concentration of fluorine and ten other elements along sections of teeth samples, extracted from eight individuals. These sections which included the bulk of dentine and enamel were scanned using a proton beam of 250 μm diameter. Rutberford backscattering spectra were also collected in order to obtain information about the concentration of major elements and to correct for matrix inhomogeneities.

Nuclear microprobe analysis of 14N and 15N in soybean leaves

A combination of two nuclear microprobe exploitation modes of spectroscopy has been developed to detect 14N and 15N in plant tissues. 14N was determined by proton elastic scattering analysis (PESA) and 15N by proton induced gamma ray emission (PIGE). The advantages of each mode are outlined. The preparation method of the soybean samples which allows the preservation of the tissue structure is described. After checking the linearity of the quantitative evaluations using calibration curves, we have studied the irradiation damages, evaluating the nitrogen mass loss with the nuclear microprobe facilities of Bruyères-le-Châtel. An experimental approach for quantitative 14N and 15N analysis by these nuclear methods in cryofixed and resin embedded soybean leaves is proposed.

Applications of simultaneous IBA techniques to aerosol analysis

The simultaneous use of proton induced X-ray emission (PIXE), proton induced gamma ray emission (PIGME) and proton elastic scattering analysis (PESA) for the determination of up to 35 different elemental concentrations, from hydrogen to uranium, in aerosol samples will be discussed. These techniques are fast, nondestructive, require no sample preparation and can analyse the microgram size samples found on typical fine aerosol filter papers. Minimum detectable limits corresponding to around 1 ng m 3 of air are readily obtainable after just a few minutes of machine running time.

Calibration method in isotopic carbon analysis

Unlike neutrons or gamma-rays, charged particles readily lose energy when they penetrate matter; thus, the main difficulty in its calculation is, perhaps, the complication introduced in its mathematical treatment. In our experiments, determination of 13C in breath test samples by proton-induced gamma-ray emission, interesting regularities were found that allowed drastic simplification in the theoretical treatment of the problem, and led to the derivation from first principles of a simple, sufficiently accurate basic equation which proved reliable for the determination of the isotopic abundance ratio 13C 12C by low-energy proton bombardment of biological samples with simultaneous prompt gamma spectrometry.