Proton Activation Analysis Research Articles

Analysis of Roman and other archaeological glasses by 12 MeV proton activation analysis

14 elements were determined, at trace level, in Roman and other archaeological glasses by 12 MeV proton activation analysis. The results show that the natural glass from Mongolia and Brazilian quartz are the purest of all the samples analysed with detection limits at 1 ppm level for Ti, V, Cr, As, Sr, Y and Zr. In several cut pieces of one variety of Roman glass, using the concentration of Ca, Ti, Fe, Sr and Sb as markers, the homogeneity of glass production and their potential use in provenance studies were discussed.

Excitation functions and yield measurements for Proton Induced Reactions in Stainless Steel: Special relevance to Proton Activation Analysis

In this work, the excitation functions for protons induced nuclear reactions with stainless steel's constituent elements were measured and the results were used in Proton Activation Analysis (PAA) of 18/10 steel samples which was carried out at Egyptian MGC-20 cyclotron. The elemental concentrations were also checked using the EDX technique. The reactions natFe(p,x)56Co, natNi(p,α)55Co and natCr(p,x)52gMn were studied from threshold up to 14.3 MeV proton energy. TALYS-1.6 and EMPIRE-3.2.2 codes were used to model the excitation functions of the investigated reactions. For quantitative analysis using PAA, the apparent reaction yields (i.e. not corrected for the γ-ray attenuation), were measured for each reaction along the proton energy range as well as the target thickness, and normalization factors were given.

Application of 12 MeV proton activation to the analysis of archaeological specimens

12 MeV proton activation analysis is applied to a variety of archaeological specimens (glass, pottery, mortar and ivory) and its usefulness studied. The method is non-destructive and Ca, Ti, V, Cr, Fe, Cu, Zn, As, Sr, Y, Zr and Sb, ranging from percentage to parts per million (ppm) level were determined. The detection limits in archaeological glass for Ti, V, Cr, Fe, As, Sr, Y and Zr are at 1–10 ppm level; Cu, Zn and Sb at 20–35 ppm level, and Ca at 150 ppm level.

Activation cross-section measurements of some proton induced reactions on Ni, Co and Mo for proton activation analysis (PAA) purposes

Abstract The experimental proton induced reaction cross sections on some elements of the Havar alloy were measured using the activation method and the well established stacked-foil technique combined with high resolution gamma-ray spectroscopy. They included the reactions natNi(p,x)57Ni, natCo(p,x)58(m+g)Co and natMo(p,x)94g,95g,96(m+g)Tc, the aim being to obtain reliable data in the proton energy range up to 26 MeV for some important reactions to be used in the proton activation analysis of steel or other alloys. Irradiations were performed using the CS-30 Cyclotron at KFSH and RC, Riyadh, Saudi Arabia. The activity measurements were carried out in PNU laboratories, Riyadh, Saudi Arabia. The experimental excitation functions for the investigated reactions were constructed and compared with the performed computed theoretical nuclear model calculations using two different codes: ALICE-IPPE and TALYS. A comparison between our measured cross-section values and the available published data is also presented, with a view to checking the consistency of the reported experimental work from various laboratories.

Determination of iodine concentration in aqueous solutions by proton activation analysis: preliminary results for digested human thyroids

The aim of our studies is to check the possibilities of using proton activation analysis as a competitive method over other analytical techniques applied for iodine determination. It is well known that long-term irradiation of biological samples leads to their decomposition and formation of gaseous radiolysis products, which increase the pressure inside the sample container. In case of using proton beam another problem with liquid samples appears. It is the production of 7Be via spallation reactions 16O(p, spall)7Be. The Compton effect from 7Be γ-line increases the detection limits for isotopes with low-energy γ-lines. AIC-144 cyclotron at The Niewodniczanski Institute of Nuclear Physics Polish Academy of Science can accelerate protons up to energy of 60 MeV which is sufficient for (p,5n) reaction needed to obtain 123I (T1/2 = 13.27 h, Eγ = 159 keV, I = 83%) from stable 127I, thus the Compton effect from 7Be was the main factor perturbing the analysis. Separation and removal of 7Be is required to improve the detection limit. The paper presents a method and an example of its application to the determination of iodine concentration in digested fragments of human thyroids obtained during surgical treatment of patients with different types of thyroid tumor.

Effects of the behaviour of the proton-induced isotopes production on the analysis of ancient alloys

The present work concerns non-destructive ion beam analysis carried out by means of proton-beam-induced nuclear reactions in the 10–30MeV energy range. We focused our attention on the yield distribution of the isotopes produced in the internal region of a metal alloy. This distribution, which defines the analytical region, displays, at incident energy of about 20MeV in a bronze based alloy, a bell-shaped curve centred at about 600μm with an average width of about 400μm. By changing the incident proton energy it is possible to displace the above region in the interior of the metal body. It should be pointed out that if we neglect to take into account the correct behaviour of the isotope yield distribution in samples with surface inhomogeneities we can obtain erroneous analytical results. We describe some experiments based on proton activation analysis (PAA) carried out at the INFN-Laboratori Nazionali del Sud (LNS) in Catania where we verified the bell-shape of the radioactive isotope distribution. The resulting formulas are given for quantitative analysis.It is straightforward that, by choosing the appropriate incident proton energy, it is possible to confine the whole analytical region to the interior of the body, thus eliminating any influence of surface effects. We have called this particular approach deep proton activation analysis (DPAA). Examples of its use on archaeological artefacts are given.

Activation techniques for the determination of stable isotopes of cerium in blood plasma

Information on the biokinetics of cerium can be obtained directly from humans by using stable isotopes as tracers. Neutron, photon and proton activation analysis have all been tested as analytical techniques able to quantify different isotopes of the same element in biological fluids. The experimental conditions were optimized for Ce analysis in blood plasma samples. The performances of the different techniques have been explored. The simultaneous determination of two Ce isotopes with the required sensitivity in the order of few ppb is difficult to obtain using a single technique, and, therefore, a combination of techniques can be envisaged.

A technique for the determination of ruthenium stable isotopes in urine samples

Proton activation analysis has been recently applied for the determination of stable isotopes of trace metals in blood plasma samples taken from volunteers during tracer kinetic studies. The very low values of intestinal uptake for some elements, like ruthenium, make the kinetics of the excretion crucial for interpreting the bioassay data. Therefore, a procedure has been developed to process urine samples in order to have proper targets for the activation with protons. Preliminary tests with Ru-doped samples, conducted using the MC-40 Cyclotron at JRC Ispra, has confirmed the feasibility of the method. The minimum detectable concentrations, in the current operating conditions, are 16 ng 99Ru·ml−1 and 0.5 ng 101Ru·ml−1.

The circulation of South American precious metals in Brazil at the end of the 17th century

Abstract The lack of important silver and gold sources in Brazil before the finds in the region of Minas Gerais at the end of the 17th century is known. Information concerning the first gold finds reached the Portuguese capital in 1695 but it was only in 1697 that the first ship arrived at Lisbon harbour with a gold load identified in the documents as ‘Peruvian’ but supposed to be Brazilian. The first Brazilian mint was itinerant, and the first silver and gold coins were struck in Bahia from 1694 to 1698. In order to try to find out which metals were struck before 1698 in Brazil, we analyzed gold and silver coins issued by the first Brazilian mint, Bahia, and coins issued in Mexico and in South America—Peru, Bolivia, Colombia, Chile—as well as Brazilian gold ingots from different mining regions. Fingerprinting was done using several analytical techniques: 12 MeV proton activation analysis, moderated neutrons activation analysis and inductively coupled plasma mass spectrometry with laser ablation. We could show that in general the platinum group elements discriminate gold and that elements such as gold, indium and tin discriminate silver. The comparison of the Brazilian coins and ingots with the coins issued elsewhere in South America and Mexico showed that the gold and silver coins circulating in Brazil between 1694 and 1698 were mostly made from a mixture of metals from the main Latin American sources.

Gold traces to trace gold

Tracing gold back to its source by means of the elemental composition of objects contributes to the knowledge of the trade routes used in the past. The analysis of a large number of ancient gold objects showed that in most cases only a few elements are useful to characterize the metal. Quantitative analysis of these elements was performed on a set of gold samples with different techniques: inductively coupled plasma mass spectrometry in liquid mode and with laser ablation, 12 MeV proton activation analysis, fast neutron activation analysis, particle induced X-ray emission (PIXE) and PIXE induced X-ray fluorescence. The aim of this paper is to present a discussion on the possibilities and limitations of these techniques to characterize gold.

Gold traces to trace gold

Tracing gold back to its source by means of the elemental composition of objects contributes to the knowledge of the trade routes used in the past. The analysis of a large number of ancient gold objects showed that in most cases only a few elements are useful to characterize the metal. Quantitative analysis of these elements was performed on a set of gold samples with different techniques: inductively coupled plasma mass spectrometry in liquid mode and with laser ablation, 12 MeV proton activation analysis, fast neutron activation analysis, particle induced X-ray emission (PIXE) and PIXE induced X-ray fluorescence. The aim of this paper is to present a discussion on the possibilities and limitations of these techniques to characterize gold.

Fingerprinting ancient gold with proton beams of different energies

The analytical techniques used in the field of cultural heritage are as far as possible non or almost non-invasive. Among them those based on proton beams show for gold fingerprinting, a good compromise between detection limits and destructiveness. The main characteristics of PIXE, PIGE, PIXE-XRF and proton activation analysis (PAA) are given for the study of gold alloys. Their main advantages and disadvantages are cited and their use in the field of archaeological sciences is illustrated by two historical examples. One example concerns the identification of the origin of the gold used in the decoration of the coffins from a Xiongnu necropolis (3rd c. BC to 2nd c. AD) found in present Mongolia. The other example establishes whether the coins attributed to the first king of Portugal, Alfonso I, were struck in the 12th century or in modern time.

Influence of the chemical form on the plasma clearance of ruthenium in humans

The radioisotopes of ruthenium ( 103Ru and 106Ru) are abundant fission products and represent a radiological risk for the population in case of nuclear accidents. Few biokinetic studies have been performed on humans up to now and consequently the current model recommended by ICRP for ruthenium is derived mainly by extrapolation from animal data. The stable isotope 101Ru and proton activation analysis have been used to study the biokinetics of Ru in blood plasma samples taken during 8 studies in three healthy volunteers. The results obtained demonstrated that complexed Ru (in the form of citrate Ru(IV) complexes) is cleared from blood plasma very rapidly (characteristic half time of 17±2 min), while inorganic Ru remains longer in the systemic circulation, and is transferred to other organs and/or excreted with a biological half time of 23±2 h. Good reproducibility of the clearance curves indicated no evidence of inter- or intra-individual variability when the same Ru solution was injected in repeated experiments to different subjects.

Charged particle activation analysis of oxygen in fluoride and chalcogenide glasses used for fiber amplifiers

The proton activation analysis of oxygen was studied in fluoride and chalcogenide glasses used for fiber amplifiers. First, we studied the interfering nuclear reactions from glass matrices to determine the oxygen concentration in these glasses. By using substoichiometric separation for 18F after irradiation, we found that the oxygen concentration was 12 to 204 ppm in InF3-based fluoride glass and 0.04% to 0.7% in chalcogenide glass containing sodium. We also discuss the relation between oxygen concentration and optical properties such as the infrared absorption spectrum and fluorescence lifetime.

Determination of biokinetic parameters for ingestion of radionuclides of zirconium in animals using stable tracers.

Exposure to the radioactive isotope 95Zr, as in nuclear accidents, and to stable zirconium, due to its use in industry, has increased the interest in the biokinetics of this element. Information has been derived mainly from tests performed on animals by means of radioactive tracers. Due to the fact that extrapolation from animals to humans is always open to question, there is an increasing need of a methodology which allows data to be obtained directly from humans. The use of stable tracers, being ethically justifiable, is a powerful tool for providing this information. As two tracers of the same element must be utilized in order to evaluate gut absorption, an analytical technique which is capable of distinguishing and measuring simultaneously different isotopes of zirconium in biological samples is required. Preliminary tests on laboratory animals were performed in order to assess the feasibility of the double tracer technique combined with proton activation analysis.

Proton, Photon and Neutron Activation Analysis for the Determination of Stable Isotopes of Gadolinium in Human Blood Plasma

The biokinetics of radioactive substances can be studied using stable tracers. For the highly radiotoxic actinides, for which no stable isotopes are available as tracers, the use of stable isotopes of lanthanides as chemically related surrogates has been suggested. In this work, the possibility of using activation analysis with protons, photons, or thermal neutrons for the determination of single stable isotopes of gadolinium in biological samples has been tested. All the techniques show very good linearity response, and may be considered as complementary. Whereas activation analysis with protons is recommendable for the simultaneous determination of two different isotopes, neutron and photon (gamma) activation analysis should be chosen whenever a better sensitivity or simplicity of the analysis is required.

Photon and proton activation analysis of iron and steel standards using the internal standard method coupled with the standard addition method

The internal standard method coupled with the standard addition method has been applied to photon activation analysis and proton activation analysis of minor elements and trace impurities in various types of iron and steel samples issued by the Iron and Steel Institute of Japan (ISIJ). Samples and standard addition samples were once dissolved to mix homogeneously, an internal standard and elements to be determined and solidified as a silica-gel to make a similar matrix composition and geometry. Cerium and yttrium were used as an internal standard in photon and proton activation, respectively. In photon activation, 20 MeV electron beam was used for bremsstrahlung irradiation to reduce matrix activity and nuclear interference reactions, and the results were compared with those of 30 MeV irradiation. In proton activation, iron was removed by the MIBK extraction method after dissolving samples to reduce the radioactivity of56Co from iron via56Fe(p,n)56Co reaction. The results of proton and photon activation analysis were in good agreement with the standard values of ISIJ.

CPAA for studying biokinetics with stable isotopes: A preliminary investigation on zirconium metabolism in animals

In order to estimate gut absorption by determining tracer concentration in plasma, a technique based on the administration of two stable isotopes of the same element was combined with proton activation analysis. The optimization for the determination of Zr isotopes in biological samples is presented together with the results of a preliminary study on Zr biokinetics in animals. (p,n) reactions on90Zr and96Zr resulted the most convenient. The obtained minimum detectable quantities are 3 and 2 ng/ml plasma, respectively, for90Zr and96Zr. Zr plasma clearance and Zr response to a simple oral test were studied separately in different subjects by using the natural Zr solution. The data analysis was performed measuring the concentration of90Zr to obtain indication on the time behavior and fractional level of Zr appearance in plasma depending on the administration routes. Two rabbits were intravenously injected 50 μg90Zr and a third rabbit was orally given 2.5 mg of90Zr. Concentration in plasma samples of intravenously and orally given Zr isotopes are reported, as a function of time after administration. The injected tracer concentration relative to the first two rabbits were fitted simultaneously to obtain clearance parameters. Zr intestinal absorption is evaluated to be less than 0.2%. The work confirms that proton activation is a powerful tool for biokinetic studies with stable isotopes.

Enhanced diffusion in sapphire during microwave heating

The diffusion of oxygen in sapphire was accelerated by heating in a 28 GHz microwave furnace as compared with heating in a conventional furnace. Tracer diffusion experiments were conducted using 18O. Single crystal sapphire wafers with a (1 0 1 2) rhombohedral planar orientation were used as the substrate. Concentration depth profiling was done by proton activation analysis using a 5 MeV Van de Graaff accelerator. The diffusion of 18O was greatly enhanced by microwave heating as compared with conventional heating in the 1500–1800°C range. The apparent activation energy for 18O bulk diffusion was determined to be 390 kJ mol-1 with microwave heating and 650 kJ mol-1 with conventional heating.

Determination of oxygen in fluoride glass by proton activation analysis

Oxygen was determined in three kinds of ZrF4-based fluoride glass [ZrF4−BaF2−GdF3−AlF3 (ZBGA), ZrF4−BaF2−LaF3−YF3−AlF3−LiF−NaF (ZBLYALN) and ZrF4−BaF2−LaF3−YF3−AlF3−LiF (ZBLYAL)] used for fabricating optical fiberby18O(p, n)18F reaction without significant nuclear interference. The main long life96Nb nuclide was produced by the96Zr(p,n) reaction in a non-destructive analysis of ZBGA-fluoride glass and reduced by using a coincidence system with Ge(Li) and NaI(T1) detectors. Substoichiometric separation of18F was also used to determine oxygen in fluoride glass, especially in glass containing yttrium as a component element because the89Zr produced by the89Y(p,n) reaction is a positron emitter, the same as18F. It was confirmed that the oxygen concentration in fluoride glass was 13–2460 ppm related to the loss by scattering.