Non-destructive Ion Research Articles

Development of a non-destructive micro-analytical method for stable carbon isotope analysis of transmission electron microscope (TEM) samples

The biogenicity of ancient morphological microfossil-like objects can be established by linking morphological (e.g. cell remnants and extracellular polymeric matrix) and chemical (e.g. isotopes, biomarkers and biominerals) evidence indicative of microorganisms or microbial activity. We have developed a non-destructive micro-analytical ion beam system capable of measuring with high spatial resolution the stable carbon isotope ratios of thin samples used for transmission electron microscopy. The technique is based on elastic scattering of alpha particles with an energy of 2.751 MeV. At this energy the 13C cross section is enhanced relative to the pure Rutherford cross section for 13C, whereas the 12C cross section is reduced relative to its pure Rutherford cross section. Here we report the initial results of this experimental approach used to characterize ultramicrotomed sections of sulfur-embedded graphite and microbial cells.

Observation of non-exponential orbital electron capture decays of hydrogen-like 140Pr and 142Pm ions

We report on time-modulated two-body weak decays observed in the orbital electron capture of hydrogen-like 140Pr59+ and 142Pm60+ ions coasting in an ion storage ring. Using non-destructive single ion, time-resolved Schottky mass spectrometry we found that the expected exponential decay is modulated in time with a modulation period of about 7 seconds for both systems. Tentatively this observation is attributed to the coherent superposition of finite mass eigenstates of the electron neutrinos from the weak decay into a two-body final state.

Physico-chemical analyses of Hispano-Moresque lustred ceramic: a precursor for Italian majolica?

The paper presents a comprehensive physico-chemical investigation on a series of Hispano-Moresque objects produced in the eastern Spain workshops between the XIV and XVIII centuries and fragments from XII century, in order to compare them with the Italian Renaissance majolica production. The techniques used are mainly non-destructive (ion beam analyses and X-ray diffraction), sometimes complemented by SEM observation and microanalysis, and electrothermal atomic emission spectrometry. Such methods allow a full description of the terra cotta, of the glaze and of the different surface layers which constitute the lustre decoration indicating individual elemental composition and thickness of each layer containing or not metallic nanoparticles. Principal results show the following: i) a constant source of supply for the eastern Spain terra cotta; ii) a significant change in the composition of the Spanish glazes around the XVII century, with the disappearance of the opacifying tin oxide addition; iii) significant evolutions in the structure and composition of the lustre layers, in particular related to the presence or not of a metal-free surface glaze film and its thickness; iv) interesting analogies and differences with the Italian majolica; v) confirmation of the change in the quality of blue pigment during XVI century, already evidenced by the authors in previous publications. A discussion about the transmission of the lustre technique between eastern Spain and Italy at the Renaissance period is proposed.

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.

Oxygen uptake of InN thin films as determined by ion beam analysis

All as-grown InN is n-type, with carrier concentrations typically in the range of 10 18–10 20 cm − 3 . Whether the native carrier concentration is attributable to defects, oxygen impurities, or other causes has yet to be determined. We have employed nondestructive ion beam analysis techniques to study both layer stoichiometry and oxygen content in a series of InN films grown by plasma-assisted molecular beam epitaxy on a variety of substrates. We show that not only does the InN surface readily oxidise, but a significant amount of oxygen can be drawn from the substrate as well.

NON-DESTRUCTIVE DETERMINATION OF NITRATE ION IN LEAF STALK OF QING GIN CAI USING VISIBLE (VIS)-NEAR INFRARED (NIR) SPECTROSCOPY

Nitrate ion content of vegetables is of concern for food safety. Fifty to ninety percent of the nitrate ions that man intakes are derived from vegetables. As previously reported, VIS-NIR spectroscopy gave the possibility to estimate nitrate ion of Japanese radishes non-destructively and rapidly (Ito et al., 2003a). We selected the leaf stalk of Qing gin cai as the first target in leafy vegetables. A multiple linear regression (MLR) equation was developed to enable the non-destructive nitrate ion determination. The wavelengths (514, 902, 884, 906 nm) that relate to nitrate ion or carbohydrate content were included in the MLR equation as the independent variables for Japanese radishes. Then we found that a wavelength of 514 nm was proportional to nitrate ion content. Although chlorophyll and carotenoids are contained in leafy vegetables, their bands were not observed in the vicinity of the 514 nm wavelength. Nitrate ion content is related physiologically to carbohydrate content. This VIS-NIR determination had a higher correlation coefficient (R) than the determination using a colorimeter. R between actual and VIS-NIR calculated nitrate ion content of the third leaf stalk from the outside and whole nitrate ion content was high.

Application of ion beam analysis for the control of the improvement of the oxidation resistance of TiAl at 900 °C in air by fluorine ion implantation and HF-treatment

The oxidation resistance of TiAl at elevated temperatures >750°C can be improved by the addition of small amounts of fluorine. The fluorine is applied in two ways: ion implantation and wetting with diluted HF. Using non-destructive Ion Beam Analysis the fluorine depth concentration profiles in the near surface region are determined before and after oxidation. The fluorine maximum is found to be at the metal/oxide interface, which supports the theoretical explanation of the fluorine microalloying effect. The time dependent behaviour of the fluorine content is characterized by a fast decrease of the fluorine concentration during the first hours of oxidation followed by a moderate decrease. The results offer the possibility for a technical application of the fluorine microalloying effect to improve the oxidation resistance of TiAl-alloys at temperatures >750°C.

Preparative Soft and Reactive Landing of Multiply Charged Protein Ions on a Plasma-Treated Metal Surface

Soft landing on a plasma-treated metal surface of multiply protonated protein ions from the gas phase results in a substantial retention of protein function, as demonstrated for trypsin and streptavidin. The majority of trypsin ions soft-landed at hyperthermal kinetic energies are undamaged and retain 72-98% of enzymatic activity after being washed into solution. A small fraction of trypsin ions that were landed at nominal kinetic energies of 130-200 eV remain tethered to the surface and show approximately 50% enzymatic activity. The streptavidin tetramer is found to dissociate to monomer units upon multiple charging in electrospray. The majority of soft-landed monomers can be washed into solution where they show affinity to biotin. The layer of streptavidin monomer that is immobilized on the surface can be detected if fluorescence-tagged and retains the ability to reversibly bind biotin. A mechanism is proposed to explain nondestructive protein ion discharge on the surface that considers proton migration from the soft-landed cations to the metal oxide layer and metal ion reduction by electron transfer from the bulk metal.

The statue of Karomama, a testimony of the skill of Egyptian metallurgists in polychrome bronze statuary

The statue of Karomama, Divine Adoratress of Amon during the XXII° Dynasty, is one of the masterpieces of the Department of Egyptian Antiquities, Louvre Museum. It has been recently restored, for the first time since the restoration by Alfred André done in 1896. That operation led to a description of the circumstances of the former restoration. It allowed to better understanding, through the detailed examination of the decoration, the techniques of polychromy on bronze pieces of art, as they were practiced by Egyptian metallurgist craftsmen. A comprehensive laboratory characterization of the different parts of the statue has been performed: X-ray radiography to evidence the mode of casting of the statue itself, of the assembled parts as the arms and the wig and of the base; analyses by non-destructive ion beam techniques on the particle accelerator AGLAE of the various inlays present on the statue and on the base. The results show an impressive juxtaposition of various metal alloys (gold, gold–silver and gold–copper) used to obtain a polychrome effect. The detailed examination and the analyses have evidenced for the first time the presence of an intentional patina on the inlays present in the wing quills of the statue and on the inlaid hieroglyphs of the base. This black patina, referred in the Egyptian texts as Hmty-km, was in general observed as a background on the Egyptian objects but is here reported for the first time on inlays. It is moreover demonstrated that several copper–gold alloys and perhaps several recipes are used to obtain a blackish coloration on various copper–gold alloys. Those observations are discussed in view of the existing literature about “black bronzes” or “black copper”.

Application of nondestructive ion beam analysis to measure variations in the elemental composition of armor materials

Lightweight, state-of-the-art armors rely on ceramics for their enhanced performance. One goal of the United States Army is to expand the industrial base of companies that provide the armors. A systematic study of armor performance as a function of ceramic stoichiometry will result in a better understanding of the fundamental relations between composition and mechanical performance. One ceramic of interest is aluminum oxynitride (AlON). The stoichiometries of representative samples of AlON were investigated with the nondestructive techniques of Rutherford backscattering spectrometry and resonant nuclear reaction analysis. Future tests of the performance of the AlON samples are to be correlated with the stoichiometries, and hence will lead to optimum, standardized processes for the manufacture of the AlON.

Polymer Track Membranes for Extraction of Ions from Aqueous Solutions at Atmospheric Pressure

The possibility of the application of the electromembrane technique for production of ions of biological molecules at atmospheric pressure is demonstrated. This technique has previously only been used for extraction of ions from liquids directly into vacuum. The membrane technique for ion extraction at atmospheric pressure was tested with both time-of-flight and Fourier transform ion cyclotron resonance mass spectrometers. The mass spectra of intact molecular ions obtained from aqueous solutions of peptides and proteins are presented. The possible mechanisms of non-destructive ion extraction are discussed. The new technique is promising for achieving absolute sensitivity (charging every analyte molecule) and for performing spatially-resolved analysis of liquid biological samples.

Influence of the Native Oxide Layer on the Silicon Surface During Initial Stages of Nitridation

Thin SiO2 layers were produced by thermal oxidation of Si wafer material. To study the effect of nitridation on the oxide layers, the specimens were nitrided in a furnace at high temperature. Non-destructive ion beam analysis was performed to determine changes in the elemental concentrations and depth profiles of the major components. In particular, N and O concentrations were measured using the non-resonant nuclear reactions 14N(d, α)12C and 16O(d, p)17O, respectively. To obtain depth profiles of the as-prepared and nitrided specimens, the samples were measured with RBS and heavy ion elastic recoil detection analysis. The ion beam analyses revealed an increase in thickness of the SiO2 layers with temperature. The specimens nitrided at 1200 °C were almost free of N. Surface topology investigations with scanning electron microscopy revealed concentric annular artificial patterns at the surfaces. In the centre of the pattern, only silicon was measured. Additionally, a band consisting of Si, O, and N surrounding the pattern was discovered. The findings are in agreement with specimens prepared at higher temperatures.

Diffraction radiation from relativistic heavy ions

In recent years, the relativistic heavy ion beams at new accelerator facilities are allowed to obtain some new interesting results (see, for instance, Datz et al., Phys. Rev. Lett. 79 (18) (1997) 3355; Ladyrin et al., Nucl. Instr. and Meth. A 404 (1998) 129). The problem of non-destructive heavy ion beam diagnostics at these accelerators is highly pressing. The authors of the papers (Rule et al., Proceedings of the Seventh Beam Instrumentation Workshop, Argonne IL, AIP Conference Proceedings, Vol. 390, NY, 1997; Castellano, Nucl. Instr. and Meth. A 394 (1997) 275) suggested to use diffraction radiation (DR) appearing when a charge moves close to a conducting surface (Bolotovskii and Voskresenskii, Sov. Phys. Usp. 9 (1966) 73) for non-destructive electron beam diagnostics. The DR characteristics are defined by both Lorentz-factor and the particle charge, and do not depend on its mass. The estimation of feasibility of using DR for relativistic ion beam diagnostics is undoubtedly interesting.

Characteristics of a broad-band Fourier transform ion trap mass spectrometer

The characteristics of a novel Fourier transform ion trap mass spectrometer capable of broadband nondestructive ion detection are described. Details of the instrumentation, including the custom-built detection circuitry, are provided. An approximate mathematical model for the image current signal-to-noise ratio is derived from the work of Comisarow [J. Chem. Phys. 69 (1978) 4097] and used to estimate the sensitivity of the technique. Data obtained using impulsive dc excitation and ac excitation are presented and frequency shifts, mass calibration, mass resolution and sensitivity are discussed. The detrimental effects of space charging and nonlinear fields on performance are examined using experimental data and computer simulations. The effect of dc biasing on ion frequency and signal intensity is investigated and mass calibration data are presented.

Fourier Transform Detection in a Cylindrical Quadrupole Ion Trap

Broad-band nondestructive ion detection based on induced image current measurement is performed in a quadrupole ion trap having cylindrical geometry. Spectra of krypton and acetophenone are shown to demonstrate the first use of nondestructive detection with a cylindrical ion trap.

Ion beam analysis of MgAl 2O 4 spinel irradiated with fast neutrons to 50–250 dpa

Non-destructive ion beam analysis techniques have been employed to examine the radiation damage in MgAl 20 4 spinel single crystals irradiated with fast neutrons at 400 and 750°C to high fluences (≥ 5 × 10 22 n/cm 2, E n > 0.1 MeV). Rutherford backscattering and ion channeling measurements using 1–4 MeV He-ion beams revealed that the radiation damage saturated after irradiation at 400°C to 50 displacements per atom. The energy dependence of dechanneling indicated the dominant extended defects present in the highly irradiated spinel are in the form of dislocations. Channeling angular scans of particle induced X-ray emission further suggested that neutron irradiation tends to randomize cation distribution for Mg 2+ and Al 3+ cations on the lattice sites. These results are compared to the microstructure observations of Kinoshita et al. and the neutron scattering results of Sickafus et al.

Broad-Band Fourier Transform Quadrupole Ion Trap Mass Spectrometry

Broad-band nondestructive ion detection is achieved in a quadrupole ion trap mass spectrometer by impulsive excitation of a collection of trapped ions of different masses and recording of ion image currents induced on a small detector electrode embedded in but isolated from the adjacent end cap electrode. The image currents are directly measured using a simple differential preamplifier, filter, and amplifier combination and then Fourier analyzed to obtain broad-band frequency domain spectra characteristic of the sample ions. The use of the detector electrode provides a significant reduction in capacitive coupling with the ring electrode. This minimizes coupling of the rf drive signal, which can saturate the front-end stage of the detection circuit and prevent measurement of the relatively weaker ion image currents. Although impulsive excitation is preferred due to its broad-band characteristics and simplicity of use, results are also given for narrow-band ac and broad-band SWIFT (stored wave-form inverse Fourier transform) excitation. Data using argon, acetophenone, and n-butylbenzene show that a resolution of better than 1000 is obtained with a detection bandwidth of 400 kHz. An advantage of nondestructive ion detection is the ability to measure a single-ion population multiple times. This is demonstrated using argon as the sample gas with an average remeasurement efficiency of >90%. Tandem mass spectrometry experiments using a population of acetophenone ions are also shown.

Non-destructive ion beam analysis of surfaces

Non-destructive ion beam analysis of surfaces

Applications of ion beam analysis to calcified tissue research

Various nondestructive ion beam analysis techniques have been developed and applied to study the concentrations of fluorine and other trace elements in calcified tissues.Fluorine has been determined by prompt gamma activation analysis through the F(ϱ,αγ)O reaction. This method is quick, convenient, and sensitive, and can also be applied to measure fluorine depth distribution nondestructively in teeth and bone samples. By the application of this technique, fluorine concentrations have been determined in a number of teeth with known histories and bones of experimental animals. Moreover, F-depth-distributions to 10-μm depths have also been obtained in a number of selected human and animal teeth.Carbon was measured by activation analysis with He-3 ions, and the technique of Proton-Induced X-ray Emission (PIXE) has been developed to simultaneously determine Ca, P, and trace elements in well-documented teeth. Dental hard tissues, i.e., enamel, dentine, cementum, and their junctions, as well as different parts of the same tissue, have been examined separately. A number of elements, Na, Mg, Al, P, Cl, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Br, Rb and Pb, have been determined in these dental tissues. The concentrations of some of these elements vary considerably in different teeth and in various parts of the same tooth.The special advantages of these nuclear techniques for studying metabolic bone diseases, renal diseases, and the effect of Pb on childrens' intelligence are discussed.

Studies in heavy ion activation analysis

Nondestructive heavy ion activation analysis has been used to determine the carbon content in various NBS SRM steel samples with a 7.0MeV 6 Li* beam. The reaction J2C(6Li, an)~3N allows for carbon analysis with the only possible interference being beryllium, 9Be(~Li, 2n)~3N. Under interference-free conditions, and employing a post-irradiation etch, the detection limit for carbon analysis in steel was 5 ppm.