P. Massiot

PIGME fluorine determination using a nuclear microprobe with application to glass inclusions

Abstract Fluorine quantitative microanalysis was performed on geological samples, using the 19 F (p, p ′ γ) 19 F reaction, with a 30 (μm proton microbeam at an energy of 3.4 MeV. We have detailed the analytical procedure and the calibration method in relation to a large range of fluorine concentrations in natural glasses and some minerals. This procedure was applied to study the fluorine distribution in melt inclusions trapped in minerals of different origins. The potential of this nuclear microanalysis method is discussed.

Study of hydrogen in melt inclusions trapped in quartz with a nuclear microprobe

Abstract Elastic recoil spectrometry induced by a 3 MeV 4He microbeam has been used to determine the hydrogen distribution within melt inclusions trapped in quartz. These minerals were selected from different geological environments: Guadeloupe (West Indies), Pantelleria Island (South Sicily, Italy) and San Pietro (South Sardinia, Italy). Bulk hydrogen contents are calculated (H assumed to be in H2O form). The knowledge of hydrogen distribution assists both in a better understanding and in the establishment of volcanic dynamism hypotheses. Finally, hydrogen-rich fluid inclusions are evidenced, the H concentration profile was obtained from simulation of the data and reported for the first time in a glass inclusion.

3D hydrogen profiling by elastic recoil detection analysis in transmission geometry

Abstract An analytical procedure and a simulation-optimization algorithm are described for hydrogen determination based on elastic recoil detection induced by low-energy 4He ions (⩽ 3 MeV) using transmission geometry. Hydrogen concentration depth profiles can be derived from the experimental recoil spectra for a depth range of up to 6 μm with a resolution better than 40 nm at the surface. The method is applied to thin polyimide films irradiated by high-energy heavy ions. The 3D hydrogen distribution is determined with a 4He+ mubeam. A high-hydrogen-concentration zone below the surface is shown. The hydrogen distribution is seen to evolve during the 4He+ irradiation.

Simultaneous determination of 14N and 15N by elastic backscattering and nuclear reaction: application to biology

Abstract The aim of this study is to use a nuclear microprobe for simultaneous localization and quantification of 14 N and 15 N in plant cells. A summary of the main nuclear reactions usually used for this purpose is presented. For 15 N, we tested the nuclear reaction 15 N(p,αγ) 12 C. The yeild curve was measured between 2.90 and 3.35 MeV; following the gamma ray at 4.439 MeV, it exhibited two resonances at 2.970 and 3.270 MeV. The choice of this energy range also made it possible to measure 14 N by photon elastic backscattering. The yeild curve of the reaction 14 N(p,p) 14 N was measured in the same energy range. The choice of a 3 MeV proton beam energy enabled us to optimize the 15 N detection limit and to have enough sensitivity for 14 N determination. The stability of nitrogen under the proton beam with these analytical conditions was tested.

Nuclear reaction microanalysis and electron microanalysis of light elements in minerals and glasses

Abstract Electron microprobe analysis (EMA) and nuclear microanalysis (NMA) have been used to determine light elements (Z ⩽ 30) in minerals and glasses. Optimum NMA reaction conditions for the detection of various elements are presented and detection limits are estimated for both micro- and macrobeams. A comparison is made between results of EMA and NMA analyses for several elements. Peculiarities of both methods are emphasized. While EMA is convenient in fast routine measurement for most elements in the periodic table above Na, with analytical sensitivities ranging from 100 to 1000 wt. ppm, NMA in charged-particle or prompt gamma-ray nuclear reaction analysis (NRA) mode allows the analysis of all the isotopes between 1H and 19F (except 4He and 20Ne), with a sensitivity often better than 50 ppm. In addition, proton-induced gamma-ray emission (PIGE) enables the determination of heavier elements (from Na to Zn) with relatively good performances. Furthermore, depth profiling and local isotopic ratio measurements constitute some new interesting applications for NMA.

Nuclear microprobe study of the composition degradation induced in polyimides by irradiation with high-energy heavy ions

Abstract The hydrogen profile is determined in polyimide films (kapton-H from Dupont) previously irradiated by 50 MeV 32 S ions. Results from elastic recoil detection analysis show the existence of high hydrogen concentration zones located more than 3 μm beneath the surface of the irradiated kapton. Deuteron-induced nuclear reaction analysis is also performed to determine C, N and O distributions. The N and O losses and C content variations are discussed in terms of the irradiation dose. These experimental data do not support suggestions that molecular damage invariably results in loss of volatile species and consequent reorganization of the organic skeleton leading to the formation of carbon-enriched material. Rather they indicate that the molecular rearrangement is influenced by H trapped within the degraded organic matrix.

Seven years of research using the Bruyeres le Chatel microprobe facility: A review

Abstract After a brief description of different research topics which have been explored between 1983 and 1988, we show several original results obtained using the Bruyeres le Châtel nuclear microprobe facility. Then we discuss the instrumental improvements carried on in the middle of 1988, by presenting recent works conducted in the new analysis chamber. Finally, looking forward to the starting of the second-generation French nuclear microprobe (beginning of 1991) at Laboratoire Pierre Sue in Saclay, we mention the 1989–1990 research projects of our Nuclear Microanalysis Group.

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

Abstract 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 Bruyeres-le-Châtel. An experimental approach for quantitative 14N and 15N analysis by these nuclear methods in cryofixed and resin embedded soybean leaves is proposed.

Deuterium, nitrogen and carbon mapping in oilfield rocks

Abstract Natural samples from oilfield deposits have been characterized using a nuclear microprobe in nuclear reaction analysis mode. Carbon, deuterium and nitrogen mapping have been carried out on an oolitic carbonate and on a sandstone. Both rocks exhibit a heterogeneous impregnation. Carbon, deuterium and nitrogen seem to be preferentially adsorbed at grain boundaries, rims and on structural defects on some grains for the sandstone. In the carbonate, these elements penetrate more deeply into the porous structures of some oolites.

Hydrogen microdetermination in geological materials using elastic recoil detection analysis (ERDA)

Abstract For the first time, hydrogen has been determined (by means of nuclear microanalysis) within glassy inclusions trapped in volcanic minerals. Elastic recoil detection of protons has been used by means of the transmission and reflection geometry. The two major originalities of this work consist in the quantitative absolute method and the application of this technique to natural materials. Some of our results are close to those obtained with other methods. We reached a detection limit smg g within the San Carlos olivine.