C. Yang

PIXE and ionoluminescence — A synergetic analytical combination

The purpose of this paper is to demonstrate that ionoluminescence and PIXE are genuinely complementary techniques and that the combination represents a powerful analytical tool, particularly in geochemistry. Ionoluminescence can be used for imaging and qualitative analysis of elements and chemical compounds. The quantification of ionoluminescence data, however, requires an improved understanding of luminescence physics. The trace element properties of PIXE may be of major importance in this development.

A NEW DETECTOR FOR HYDROGEN ANALYSIS WITH A NUCLEAR MICROPROBE

Abstract A new detector for hydrogen analysis of thin samples has been designed for utilization at a nuclear microprobe. An annular surface barrier detector is divided into two halves that are read out individually, and the two protons resulting from p-p scattering are detected in each half. Coincidence technique is applied in order to suppress the background. The minimum detection limit is 20 pg/cm2 for an integrated beam charge of 1 μC. The depth profiling properties are discussed, and three-dimensional images with a resolution of 1 μm or less are considered to be attainable. The detector can be employed in conjunction with other detectors to simultaneously analyze light elements with optimal nuclear reactions and large solid angles.

IONOLUMINESCENCE AND PIXE STUDY OF INORGANIC MATERIALS

Abstract The combined use of IL and PIXE is promising in characterizing the inorganic materials. IL is sensitive to the condition of chemical binding and ion valence state, crystallinity and defects. IL can also provide a unique way to monitor and study the ion-beam induced effects in samples. PIXE can provide quantitative information on the elemental distribution of major and trace elements in samples, which in turn helps to understand IL results. The combination of the two techniques provides a new tool for studying the intrinsic and extrinsic luminescence phenomena and is capable of micro-characterizing various inorganic materials, including the ones of geological and synthetic origins.

New CAMAC based data acquisition and beam control system for Lund nuclear microprobe

Abstract A new CAMAC based data acquisition system has been installed at the Lund Nuclear Microprobe facility. This paper reports on the development and present status of the data acquisition system. The system is a true multiparameter CAMAC based system with fast Fera bus readout and in crate memory buffer. The user interface is based on Sparrow Kmax software for a Power Macintosh platform. The system read out and tag the event data with position on-line, which make fast on-line monitoring of spectra or element maps possible.Simultaneously, all data can be saved event by event for off-line analysis. The beam scanning part is software controlled through a timed D/A converter, this allows fast scanning of the beam. With a CCD-camera and video card the area to be analysed could be defined directly from the image, and the sample position can be moved. Any kind of irregular scan patterns could be defined.

Corrosion phenomena in electron, proton and synchrotron X-ray microprobe analysis of Roman glass from Qumran, Jordan

Abstract A series of 89 glass fragments of Roman glass are studied using electron, proton and synchrotron radiation induced X-ray emission from microscopic areas on the sample surface. The glass originates from Qumran, Jordan and was buried for 1900 years. The weathering layers that result from the extended contact with ground water have been studied, next to the trace composition of the original glass of these pieces. The latter information indicates that at Qumran, large quantities of glass objects were being used in Ancient times. Cross-sectional profiles of the glass show a complex migration behaviour of various groups of major and trace elements.

IONOLUMINESCENCE TECHNIQUE FOR NUCLEAR MICROPROBES

Abstract Ionoluminescence (IL) produced by MeV/amu particles in the Nuclear Microprobe carries rich information on the nature of the chemistry and physics in the various types of materials, such as the molecular structure and ions valence, etc. IL/PIXE methods offer unique ways to study the general luminescence phenomenon by directly relating the trace element information provided by PIXE to IL spectroscopic results. The IL can also be used to identify the organic molecular structure, hence, the combination of the IL data with the PIXE elemental data provide a new tool for biology and medicine studies. One example is the epidermis from the human skin, which exhibits a clear IL. IL is very sensitive to the local chemical environment conditions of the excitation point, therefore, it can be very effective to study the beam modification and beam damage effects. The beam damage problem in the Nuclear Microprobe applications is discussed.

THE IDENTIFICATION OF GROWTH LINES IN ABALONE SHELL USING A NUCLEAR MICROPROBE

Abstract Ionoluminescence (IL) combined with particle induced X-ray emission (PIXE) imaging has been employed to identify intrinsic growth bands in the spire region, and extrinsic bands at the growth edge of Australian Black-lip abalone shell ( Haliotis rubra ). Previous studies using optical flood cathodoluminescence, scanning electron microscope cathodoluminescence (SEM-CL) and Raman spectroscopy on samples from the same population suggest that the visible luminescence is due to Mn 2+ activated calcium carbonate. In this study we confirm Mn 2+ as the activator in both the spire and growth edge regions of the shell. The sensitivity of ionoluminescence to the co-ordination environment of the Mn 2+ activators in the shell allows for the spatial identification of the calcium carbonate polymorph responsible for the growth lines observed optically. Furthermore the detection and mapping of trace elements such as Mn and Sr with the PIXE technique enables comparisons to be made between calcite and aragonite biomineralized in the wild and under laboratory conditions.

Subcellular analysis of boron with a nuclear microprobe

Abstract The boron distribution in cells from a rat brain, into which a boron compound (BOPP) had been injected in the context of Boron Neutron Capture Therapy (BNCT), was analyzed with a nuclear microprobe by Nuclear Reaction Analysis. The 11B(p,α)Be∗ reaction was utilized at the resonance at 0.63 MeV. Boron images and Scanning Transmission Ion Microscopy (STIM) images were recorded and evaluated by various methods. The sample preparation was straightforward and introduced only a minimum of steps which could potentially interfere with the result. Methods to to compare different boron compounds for BNCT are suggested. The boron was distributed fairly evenly in the cells. The average boron concentration was about 7 ppm dry weight, and the variation over individual cells small.

Nuclear microprobe analysis of Evate (Mozambique) apatites

Abstract A characterization of mineral apatite samples using Nuclear Microprobe techniques was made. Thin polished sections of apatite in calcite matrix were analyzed by PIXE (particle-induced X-ray emission) and IL (ion luminescence) for major and trace elements quantification. Some Rare Earth Elements (REE), which are IL activators mainly in the UV and visible region, present in the sample in concentrations far below the minimum detectable limit by PIXE method, could still display characteristic luminescence spectra. Hence, IL is a very useful complementary method to traditional ion beam analytical techniques such as PIXE, and NRA (nuclear reaction analysis) for application in geology. The results are in perfect agreement with some available information about previous tectonic studies performed in the Nampula geological province and show some possibility of beginning a semi-artesian exploitation of the apatite for use in local subsistence farming as a cheap fertilizer.

Macro- and microbeam analysis of lithium by the 7Li(p,α)α reaction, and STIM imaging of white blood cells

Abstract Two different experimental arrangements for lithium analysis through the 7Li(p,α)α reaction are described. The minimum detection limit (MDL) was 300 pg/cm2 for an integrated charge of 60 μC for a macrobeam set-up optimized for high-current applications. For a Nuclear Microprobe (NMP) arrangement the MDL was 6 ng/cm2 for an integrated charge of 1 μC in a set-up with large solid angles. One type of blood cells, lymphocytes, was analyzed at the NMP in the context of the treatment of patients with affective disorders (“manic-depressive illness”) with lithium. The amount of lithium in the lymphocytes was found to be below the detection limit, i.e. less than 150 fg/cell. Separated lymphocytes were found to be well suited for both STIM and off-axis STIM imaging.