Hydrogen behavior in monocrystalline diamonds with different concentrations and types of nitrogen defects was studied using Nuclear Reaction and micro-Elastic Recoil Detection Analyses and Thermal Desorption Spectroscopy. Diamonds were studied in as-received state, after HPHT treatment and after hydrogenation in molecular hydrogen. A considerable amount of hydrogen was found to be bonded to diamond surfaces. Kinetics of surface hydrogen desorption is similar to what was reported for plasma-hydrogenated diamonds. The solubility of hydrogen in type IIa diamonds is very low. The efficiency of hydrogen traps in diamond bulk varies with the dominant type of nitrogen-related defects. The cross-section of traps decreases in row Ib>IaA>IaB diamonds, though binding energy in type IaB crystals may be higher, than in type IaA. Dislocations may promote hydrogen diffusion. A marked dependency of the hydrogen content and diffusivity between diamond growth sectors were observed for some samples. The total hydrogen content is higher in octahedral sectors.

Channeling implantation of Ga into Ge is performed at two very different ion fluxes (1012 and 1019cm−2s−1), at two temperatures (room temperature and 250°C), and at five different fluences. The fluence dependence of the range profiles and of the implantation damage is strongly influenced by defect accumulation and dynamic annealing. At 250°C, the maximum lifetime of the defects is less than 10s. On the other hand, at room temperature no significant annealing is found within the first 10s after ion impact. The measured Ga depth profiles are reproduced very well by atomistic computer simulations.

Ion implantation-induced damage depth profiles of 450keV Al+ ion-implanted 6H-SiC were studied using RBS/C technique for implantations along channeling direction and non-channeling direction with fluence of 3.4×1015cm−2. Bevelling method of sample preparation was used to get access to the deeper situated layers over the whole damaged region and below. To determine damage degree at the specific depth of the bevelled sample, RBS/C technique combined with a 3MeV Li2+ ion beam of size of about 30μm×30μm was utilized (micro-RBS/C). The micro-RBS/C method combined with the bevelling technique gave us a possibility to probe deeper reaching damage regions than in the case of conventional RBS/C investigations. It also utilizes a near-surface part of backscattered spectra, which is slightly influenced by damage created by probing ions and a random fraction of probing beam. Additionally, there is no need to perform energy calibration of detector for backscattered particles. Due to much smaller sample area hit by probing ions of micro-beam, the required fluence, comparable to that at conventional RBS/C measurements is obtained at much lower charge. Negligibly small effect of bevelling-induced mechanical damage has been observed in this study. The obtained results by micro-RBS/C method validate the results of computer simulations (Crystal-TRIM software).

On using of nuclear reaction analysis, X-ray analysis, electron microscopy, the mechanisms of structure and phase composition change of thin vanadium films at treatment in a flow consisting of molecular and atomic hydrogen (AH) have been studied. A comparative analysis on regularities of the film saturation with hydrogen and its resistance changing was carried out. It has been settled that the resistance dependence on hydrogen concentration in the case of thin film hydrogenised in AH flow differs from the analogous dependence for the bulk material hydrogenised in an atmosphere of molecular hydrogen in the conditions of thermodynamic equilibrium. Nevertheless, the found peculiarities of thin film resistance dependence on hydrogenation time, the same as in the case of bulk material, are determined by formation of vanadium hydride β-phase in the film. It is shown that with transient metal films it is possible to measure AH flow densities under reduced pressure of gas (10−1 to 10−3Pa). The principle of measurement is based on dependence analysis of the film resistance increment determined by hydrogen solubilization in the film versus exposure time in AH flow. The suggested measurement method is characterized by high selectivity to AH allowing measurement of partial density of atomic flow over the range from 5×1013 up to 1016atcm−2s−1 in a mixed atomic–molecular flow. The sensor made on the basis of this method can find applications in microelectronic techniques where semiconductor treatment by atomic hydrogen flows is employed.

L'existence d'hydrogene dans des aggregats contenant une phase a Pd-O, qui constitue, avec des oxydes de fer la patine sombre caracteristique d'une pepite de ouro preto prelevee a Gongo Soco, Minas Gerais,Brazil, est confirmee par une analyse par detection du recul elastique avec un micro-faisceau d'ions lourds (technique micro-ERDA). L'hydrogene est libere des regions contenant la phase Pd-O au cours des analyses, mais non de la goethite. Les donnees montrent ainsi que la phase a Pd-O-H est instable par rapport a la goethite, et etayent l'hypothese fondee sur les observations anterieures qu'il s'agit d'une phase transitoire dans une transformation en palladium natif.

Methods of nuclear reactions, x-ray diffraction analysis, transmission electron and nuclear microscopy were used to investigate the mechanism of hydrogenation of thin vanadium films in their treatment in a flow consisting of a mixture of molecular and atomic hydrogen. It has been shown that the main component penetrating into the metal from the gas phase is atomic hydrogen. At a gas pressure of 10 –2 Pa and room temperature, the dissolution of particles which, in the gas phase, are in molecular form, occurs at a much lower rate. It has been established that the (initially high) rate of variation of the hydrogen concentration in the film decreases during hydrogenation and gradually approaches zero. As this takes place, the hydrogen concentration in vanadium reaches its limiting value equal to about 42.5 at. %. A mathematical model of the hydrogenation of a vanadium film is proposed which describes experimental results based on the relaxation dependence of the hydrogen concentration on hydrogenation time. Comparative analysis of the variations in hydrogen concentration in a film and in film resistance is performed. It has been established that the dependence of the resistance on hydrogen concentration for a thin film hydrogenated in a flow of atomic hydrogen differs from the similar dependence for a bulk material hydrogenated in the atmosphere of molecular hydrogen under the conditions of thermodynamic equilibrium. The features of the behavior of the resistance of a thin film on hydrogenation time revealed experimentally are caused, as in the case of a bulk material, by the formation of the β phase of vanadium hydride in the film. The possibility of using vanadium thin films for measuring absolute values of the atomic hydrogen flow density is discussed.

The influence of bending stress on the hydrogen behaviour in titanium was investigated by elastic recoil detection analysis with a heavy ion microbeam (micro ERDA) and X-ray diffraction (XRD). The samples were made by hydrogen ion implantation into polished pure titanium sheets. Three-dimensional hydrogen distributions were obtained by scanning the microbeam over the sample using the depth information of ERDA. Inhomogeneous hydrogen distributions in the titanium were observed which vary with the depth. With mechanical bending of the samples the inhomogeneities increased in varied grade. The surface hydrogen loaded by surface polishing is stable, whereas the implanted hydrogen located inside of the sample is mobile under bending. These different hydrogen behaviours are relevant to the chemical states of hydrogen. Different titanium hydrides are formed by the different loading methods. An relatively unknown titanium-dihydride phase (TiH2(x)) with a tetragonal texture was identified by XRD in the depth region of implanted hydrogen. It is less stable than the normal titanium-dihydride phase (TiH2(δ)) observed in the surface region. The change of hydrogen distribution is related to the dehydrogenation of the TiH2(x) and TiH(γ) under bending.

The titanium hydrogenation process in the H-2(+) implanted Ti225 titanium alloy has been studied in this work. The Ti/H phase transformation from hydrogen solid solution (hcp) to gamma phase titanium hydride (TiH(gamma)) with a primitive tetragonal structure and then to a titanium dihydride (TiH2(x)) with a body centred tetragonal structure has been characterized by x-ray diffraction, nuclear reaction analysis and elastic recoil detection analysis. This process is very different from the usual hydrogenation mechanism, in which the delta phase titanium dihydride (TiH2(delta)) with a face centred cubic structure is always involved. Both of the TiH(gamma) and TiH2(x) are rare phases, which are formed under extreme conditions. The TiH(gamma) was considered to be a metastable phase in low hydrogen concentration titanium, and the TiH2(x) phase has not yet been notated in the present Ti/H phase list. The characteristics of the TiH2(x) are unclear, but it is very stable at room temperature and exists as a mixture state with the titanium. A saturated fraction of the hydride to titanium phase has been obtained, as about 15% (H/Ti similar to 0.3) in a H-2(+) implanted sample.

Raman spectroscopy, spreading resistance probe (SRP) analysis, scanning electron microscopy (SEM) and elastic recoil detection analysis (ERDA) studies were carried out on H-plasma treated and annealed p-type Czochralski (Cz) Si. The formation of voids filled with hydrogen molecules was observed by Raman spectroscopy after plasma hydrogenation. The Raman and ERDA measurements show that molecular hydrogen can be released from nanovoids at 600 degreesC which leads to the formation of empty voids. ERDA and SEM investigations show that after the hydrogen plasma treatment the formation of voids filled by hydrogen occurs at a depth of about 400nm. SRP measurements show, that at 400 degreesC post-hydrogenation annealing for 10-60 min a fast diffusion of hydrogen into the bulk occurs. This leads to the hydrogen enhanced thermal donor formation and therefore to a carrier profiles modification up to a depth of a few hundred microns. The Raman measurements show that the molecular hydrogen can not be released from nanovoids at 400 degreesC which is in good agreement with ERDA data. Our investigations give a method for the low-temperature, low-cost modification of the Cz Si substrates which leads to the formation of a carrier gradient in the bulk, to surface structuring and to voids formation in the subsurface region.

A uniformly distributed multipolar microwave plasma reactor using electron cyclotron resonance at 2.45 GHz (600 W) was used to deposit a-C:H thin films at RT. C2H2 was used as the precursor gas. Single crystal [100] Si and CR39 allelic resin substrates were RF biased to a negative voltage within the range between - 10 and - 200 V. The influence of the process parameters (gas flow and substrate bias) on the growth rate and hydrogen content have been investigated in detail. Optical parameters (optical gap E-T, index of refraction n and extinction coefficient k) were measured using spectroscopic ellipsometry. The resonant (6.385 MeV) nuclear reaction: H-1(N-15, alpha gamma )12C was used to determine the hydrogen content. For the C2H2 pressure range of 0.6 < P(C2H2) < 1.1 mtorr the optical parameters remain constant within the limits of experimental uncertainty. The sp(3) content is seen to vary monotonically as a function of pressure and to be reaching a maximum of approximately 40% for 0.6 < P(C2H2) < 0.7 mtorr. The variation of the substrate bias within the range from -10 to - 190 V [at P(C2H2) = 0.6 mtorr] has no measurable impact neither on the deposition rate nor on the hydrogen content. The corresponding average values of E-T and n remain stable (E-T= 1.83 +/- 0.11 eV, n = 2.12 +/- 0.04). However, an increase in the bias is followed by a significant decrease of the extinction coefficient k and of the absorption tail width E-o. The observed evolution of k and Eo suggests that the sp(2) clustering mode may be related to the substrate bias. (C) 2001 Elsevier Science B.V. All rights reserved.

The interference effects for the 110 and 197 keV gamma-ray lines of the nuclear reactions F-19(p,p'gamma)F-19 and O-18(p,gamma)F-19 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% O-18 enriched H2O and from 1000 ppm F standard NaF solution. From this, a data base was obtained in order to extrapolate the 110 and 197 keV gamma-ray yields of the O-18(p,gamma)F-19 reaction for a target of water containing 0.2% O-18. As a result it was obtained that, for fluorine in oxygen-rich materials, the reaction F-19(p,p'gamma)F-19 allows minimum detection limits of (1.06 +/- 0.12) and (1.85 +/- 0.2) at.ppm for the 110 and 197 keV gamma-rays, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.

The fish otolith is a calcium carbonate (usually aragonite) crystal that grows continuously by accretion over the life of the fish and unlike bone is not continuously re-metabolised. Consequently, the otolith has long been regarded as a potential store of information about the life history of an individual fish, and this information is encoded in the deposition pattern of trace elements in the otolith. The code has been difficult to crack. However, recent developments have show that: (1) Sr is one of the few non-mobile trace elements in the otolith; and (2) the pattern of Sr deposition summarises the effects of environment changes that affect the growth rate of the otolith crystal. The remaining difficulties in cracking the chemical code in the otolith have hinged about making reliable micro-measurements of the stable Sr content at spatial resolutions of 10 mu m or less; this interval represents about 4-6 days of otolith growth in most species of fish. This paper describes high beam resolution 2 mu m linear measurements, and 6 mu m square measurements over narrow windows of about 300 mu m square, and links these micro-measures to macro-measures of 2D maps of the entire surface of sections of otoliths up to 5 mm square at beam resolutions of 25 mu m square. The otoliths used in this study are from the Jurel, or Peruvian Jack mackerel, Trachurus murphyi (Carangidae: Teleostei). (C) 2000 Elsevier Science B.V. All rights reserved.

Depth profiling of light elements in the surface layer of solids by means of ERDA is limited to depths smaller than about 1 mu m. In order to measure the distributions of hydrogen isotopes in larger depth regions such as needed for the divertor tiles from the tokamak fusion experiment ASDEX-Upgrade in the Max-Planck-Institut fur Plasmaphysik, samples cut from the divertor tiles (about 0.6 mm tungsten on carbon) were bevelled at different angles by mechanical cutting and polishing or by ion beam slope cutting. The mechanically cut slopes were additionally cleaned and polished by oblique incidence ion beam sputtering with target rotation to avoid anisotropic etching.The surface composition along the slope was measured by ERDA with the Rossendorf Nuclear Microprobe, A 10 MeV Si ion beam was focused to about 3 mu m and scanned linearly across the slope. The hydrogen and deuterium recoils were detected by a surface barrier detector at a recoil angle of 30 degrees after passing through a 10 mu m thick Al foil for stopping scattered primary ions. Deuterium was found at depths up to about 25 mu m and hydrogen up to 750 mu m on the samples analysed. (C) 1999 Elsevier Science B.V. All rights reserved.

Thin films of Ba3Ca1.18Nb1.82O8.73, prepared in a sol-gel process by multiple dip-coating on silicon wafers, and powder samples, prepared by the conventional carbonate route, were charged with hydrogen by dissociative water absorption at definite values of water vapour pressure and temperature. The hydrogen content was determined ex situ at room temperature using nuclear resonance reaction analysis. From the resulting water vapour pressure–composition isotherms the absorption enthalpies Δ∅HO, Δ∅Ht and the absorption entropy Δ∅S were calculated, using a two-site model, based on Fermi-Dirac statistics. On Ba3Ca1.18Nb1.82O8.73 bulk material also impedance spectroscopy, concentration and fuel-cell measurements as well as neutron diffraction were performed. From these data, taken together, the proton diffusion coefficient DH could be evaluated and compared to quasielastic neutron scattering results.

Thin films of Ba3Ca1.18Nb1.82O8.73, prepared in a sol–gel process by multiple dip-coating on silicon wafers, were charged with hydrogen by dissociative water absorption at definite values of water vapour pressures and temperatures. The hydrogen content was determined using nuclear resonance reaction analysis. From the resulting water vapour pressure/hydrogen composition isotherms the absorption enthalpies and the absorption entropy were calculated in the framework of a two site model, based on Fermi–Dirac statistics. On Ba3Ca1.18Nb1.82O8.73 also impedance spectroscopy was performed yielding the bulk conductivity. From these data in combination with proton transport numbers and the thermodynamic results as noted above the proton diffusion coefficient could be evaluated.

This paper describes investigations using the Particle Induced X-ray Emission method (PIXE) to evaluate the concentration of Ca together with that of other elements (S, Cl, and K) across the articular cartilage of domestic pigs in order to verify a putative influence of calcium on the structural changes in early arthrotic stage, derived from NMR microscopic imaging. The measurements were carried out with focused ion beams of a lateral resolution down to 20 μm. The main matrix components (C, N, O) were evaluated from proton backscattering spectra.

At the Rossendorf nuclear microprobe facility, a beam of protons with MeV energy was used to analyse ancient human bones of the Merowingian period (6-8th century AD), Emitted X-rays were detected to determine the elemental composition of the bones and to estimate the influence of the burial environment on the elemental content of the skeletons, In cross sections of human femora, a different behaviour of the radial distributions of the main and trace elements like P, Ca, Mn, Fe, Zn, Br, and Sr was observed using lateral-resolved mu PIXE. This result indicates post mortem mineral exchange processes and diagenetic alteration during burial of bone tissue in soil. (C) 1998 Elsevier Science B.V.

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.

Bone structures, represented in the form of so-called lines of arrested growth, were observed in medieval human femur. Because process and causes of line formation are not yet understood multielement analysis on a cross section of a femoral bone was carried out by micro PIXE using the Rossendorf nuclear microprobe. A series of line profiles across the bone lines, elemental maps and point analyses on a line and beside it show reproducibly increased concentrations of the trace elements Mn, Fe, Zn, Pb and Sr on the bone lines.