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A high-speed wavelength-dispersive ion beam induced luminescence (IBIL) detector was demonstrated using a newly developed photon-counting mode spectrometer based on a 32-channel photomultiplier tube (PMT) array combined with a high-efficiency optical grating. An integrated electrical circuit based on a field-programmable gate array was prepared to process 32 individual IBIL signals from different PMT channels. These signal were further processed conventionally by a micro-PIXE analysis system. Individual pulses corresponding to each IBIL photon incident from the PMT array were multiplexed into a single analog chain with different amplitudes corresponding to the channel number of the array. The signal had a pulse width of 2 μs in the amplitude range 0–10 V. The results suggest that the demonstrated IBIL detector can be used to detect differences in IBIL images at multiple wavelengths. [ABSTRACT FROM AUTHOR]

Continuous measurement of ion beam induced luminescence (IBIL) spectra was demonstrated with organic targets of nicotinamide adenine dinucleotide (NADH), tryptophan, riboflavin, and a polycyclic aromatic hydrocarbon (PAH), which are typically used as markers of biological contaminants in airborne particles. A 3 MeV external proton microbeam from a single-ended accelerator at QST/Takasaki was used to probe for changes in the IBIL spectrum using micro-optics sharing a focal point with the microprobe. We find that the decay of IBIL spectra from NADH and riboflavin varied by target organic species. Moreover, new peaks in the IBIL spectrum were recorded by continuous IBIL spectroscopy from the PAH target after destruction of a peak originally obtained in the initial measurement. These results suggest that IBIL monitoring can detect changes in the chemical composition of organics under focused beam irradiation. [ABSTRACT FROM AUTHOR]

A new external microbeam set-up has recently been installed as the extension of the existing microprobe system at the Laboratory of Ion Beam Applications of Atomki, Debrecen, Hungary. The external beam set-up, based on the system of Oxford Microbeams (OM), is equipped with two X-ray detectors for PIXE analysis, a digital microscope, two alignment lasers and a precision XYZ stage for easy and reproducible positioning of the sample. Exit windows with different thicknesses and of different materials can be used according to the actual demands, currently silicon-nitride (Si 3 N 4 ) film with 200 nm thickness is employed in our laboratory. The first application was demonstrated in the field of archaeometry, on Bronze Age hoards from Hungary. [ABSTRACT FROM AUTHOR]

Resorting to an external proton microbeam, PIXE analyses of three oil paintings on copper support dated from the XVII century and attributed to the Flemish artist Frans Francken II, were undertaken. The present work aims to contribute to the compositional study of the painting materials employed by XVII century artists that exploited copper as a support for oil painting, and specifically the materials used by Francken’s workshop, particularly copper plates. Because of the low thickness of the pictorial layers of this type of paintings and its non-destructive character, PIXE is the ideal technique to study the elemental composition of the paintings. Several spots in each painting were chosen for analysis in order to cover almost all the pigments used in the colour palette. Lead and calcium were detected in practically every analysed regions, probably related to the presence of lead white and chalk, usually used as ground layer on copper paintings. Small quantities of gold were also detected, which is present in many of this artist’s works to embellish some details of the representations. Also this work reports the first application of the external proton microbeam set-up available at CTN/IST in Portugal for the characterization of oil paintings. [ABSTRACT FROM AUTHOR]

Ion beam induced luminescence (IBIL) analysis was performed on organic targets are typical organic contaminants in aerosols. An external proton microbeam with an energy of 3 MeV was selected as the probe for the continuous IBIL measurement. Commercially available organic standards, including common amino acids (nicotinamide adenine dinucleotide, riboflavin and tryptophan) and a polycyclic aromatic hydrocarbon (benzo[ a]pyrene), were used to test the analysis. Differences in chemical composition were distinguished by the shape of the IBIL spectrum in the UV/visible/near-IR region (200-900 nm). The IBIL spectrum changed as the proton irradiation damage increased. These results suggest that qualitative characterization of organic materials might be possible through the continuous measurement of IBIL spectra. [ABSTRACT FROM AUTHOR]

Abstract: Simultaneous microscopic imaging and spectroscopy of individual aerosol particles were performed with an external microbeam. Visible luminescence induced by the external microbeam was successfully used as a probe to detect organic contaminants in the targets. Combined ion luminescence (IL)/particle-induced X-ray emission (PIXE) analysis of the aerosol targets revealed microscopic chemical and elemental composition distributions under ambient atmospheric conditions. The simple confocal micro-optics for the IL spectroscopy and microscopic imaging were sufficiently sensitive for detecting these molecules at sub-parts per million concentrations and at a wavelength resolution of less than 5nm. The IL spectra were monitored to prevent severe damage to the samples. Furthermore, our IL system has the advantage that it is simple to add to a conventional micro-PIXE system. [Copyright &y& Elsevier]

Abstract: Confocal optics for ion luminescence (IL) was developed for the precise analysis of the chemical composition of microscopic targets with an external proton microbeam probe. Anti-reflection-coated confocal micro-lens optics with an effective focus area of approximately 800×800μm was installed on the microbeam line of a single-ended accelerator. Chromatic aberrations of the confocal optics were examined at wavelengths of 300–900nm. An electrically-cooled back-thinned charge coupled device spectrometer with a wavelength resolution of 0.5nm was used for the microscopic spectroscopy and IL imaging of microscopic mineral targets. Simultaneous microscopic IL and micro-PIXE analysis were performed using an external 3MeV H+ microbeam with a current of less than 100pA. A spectral resolution of 3nm was achieved for a single IL peak which corresponded to Cr3+ impurities in a single-crystal of aluminum oxide. The use of IL spectroscopy and imaging for aerosol targets revealed microscopic distributions of the chemical and elemental composition in the atmosphere. [Copyright &y& Elsevier]

Abstract: A new external ion microbeam ion luminescence (micro-IL) imaging system was developed on a microbeam line of a 3MV single-ended accelerator at the TIARA facility of the Japan Atomic Energy Agency. Micro-IL was combined with an in-air micro-PIXE (particle-induced X-ray emission) system to determine the chemical composition and structures of microscopic airborne particles of several micrometers in size. The hardware and software for the combined in-air micro-IL analysis system, called ion luminescence microscopic imaging and spectroscopy (ILUMIS), were studied. Wavelength-dispersive optics, including a collimator lens, a monochromator, and a photon-counting photomultiplier, were installed on the beam line. The signal processing of the IL photon signals, which were collected as spectra and two-dimensional microscopic images, was examined. Several aerosol particles were characterized to demonstrate the ILUMIS/PIXE combined analysis. The external microbeam ILUMIS analysis method provided a variety of information on the chemical and elemental composition of the micrometer-sized aerosol targets under ambient atmospheric conditions. [Copyright &y& Elsevier]

Multiwavelength optics was improved to create a high-resolution ion luminescence (IL) spectroscopy system. An electrically cooled back-thinned CCD array with an effective wavelength range from 200 nm to 980 nm was used for the IL detector. The spectra of IL were acquired during microbeam irradiation of targets with 3 MeV H+ ions. The IL spectroscopy system provides IL spectra with a wavelength resolution of approximately 2 nm. IL spectroscopy was combined with in-air micro-particle-induced X-ray emission (micro-PIXE) at a beam current of approximately 100 pA, and a specific analysis allows us to determine the chemical composition of the target. Compared with the conventional wavelength-dispersive IL systems, the proposed IL spectroscopy system is more sensitive to IL, making it possible to observe the changes in spectra that correspond to changes in the chemical state of the elements inside the target. [ABSTRACT FROM AUTHOR]

Ion microbeam facilities are analytical tools with high spatial resolution exploiting MeV ion beams. The interactions of beam particles with atoms and nuclei of the target induce the emission of characteristic radiation, the energy of which provides signatures of the compositional and/or structural properties of the target; Ion-Beam Analysis (IBA) techniques, based on the detection of such radiation, enable characterisation of samples of interest, e.g. in material and earth sciences, cultural heritage, biology, medicine, and environmental studies. External beams, obtained by extracting the particles into the atmosphere through a thin window, have many attractive features, e.g. non-destructive/non-invasive analysis and ease of working, so many laboratories have dedicated beam-lines to ex-vacuo IBA analyses. External microprobes have made it possible to obtain probes in the micron range by adopting strong focusing lenses, ultra-thin windows for beam extraction, and short/ultra-short external path of beam particles in light gases; they have also made possible the use of new external IBA techniques, e.g. BS, ERDA, STIM, and IBIC. By adopting systems to raster scan the beam over the sample, imaging capabilities have also become available for ex-vacuo analysis. External scanning microprobes + IBA techniques have enabled the characterisation of samples with high spatial resolution, comparable with that achievable in-vacuum for thick samples, avoiding sample damage. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: In this paper we report about the micro-PIXE characterisation of lapis lazuli, for a provenance study of this semi-precious stone, used for glyptic as early as 7000years ago. The final aim is to find markers permitting to identify the origin of the raw material coming from three quarries in regions of historical importance: Afghanistan, Pamir Mountains and Siberia. This may help to reconstruct trade routes, especially for ancient objects for which written testimonies are scanty or absent at all. Due to the heterogeneity of lapis lazuli we concentrate our attention on single phases instead of the whole stone; in particular we focused on two of the main phases: lazurite, responsible for the blue colour, and diopside, the most frequent accessory mineral. This study was preceded and completed by means of microanalysis with Scanning Electron Microscopy (SEM-EDX) and Cold-Cathodoluminescence (cold-CL) analysis. Despite the limited number of analysed samples, results are sufficient to exclude/suggest a few features as provenance markers, partly confirming what has been previously published in literature. [Copyright &y& Elsevier]

Abstract: Fluid inclusions are small portions, usually smaller than 100μm, of fluid trapped within minerals during or after growth. Their characteristics provide therefore fundamental information on nature and evolution of fluids present in the past in different geological environments. At the LABEC laboratory in Firenze, high-salinity fluid inclusions in quartz crystals, coming from the Apuan Alps metamorphic complex, were analysed at the external scanning microbeam. Results, although still preliminary, have already provided us with hints on fluid-rock interaction processes during the metamorphism of the Apuan Alps. [Copyright &y& Elsevier]

Abstract: In this paper, we describe the main features of the ionoluminescence (IL) apparatus recently installed at the external scanning microbeam facility of the 3MV Tandetron accelerator of the INFN LABEC Laboratory in Firenze. The peculiarity of this IL set-up resides in the fact that the light produced by the ion irradiation of the specimen is collected by a bifurcated optical fiber, so that photons are shunted both to a CCD spectrometer, working in the 200–900nm wavelength range, and to a photomultiplier (PMT). The accurate focusing of the optical system allows high photon collection efficiency and this results in rapid acquisition of luminescence spectra with low ion currents on luminescent materials; simultaneously, luminescence maps with a spatial resolution of 10μm can be acquired through the synchronization of PMT photon detection with the position of the scanning focused ion beam. An optical filter with a narrow passband facing the photomultiplier allows chromatic selectivity of the luminescence centres. The IL apparatus is synergistically integrated into the existing set-up for ion beam analyses (IBA). The upgraded system permits simultaneous IL and PIXE/PIGE/BS measurements. With our integrated system, we have been studying raw lapis lazuli samples of different known origins and precious lapis lazuli artworks of the Collezione Medicea of Museum of Natural History, University of Firenze, aiming at characterising their composition and provenance. [Copyright &y& Elsevier]

Ion beam analysis (IBA) techniques are often used to study works of art, mainly for their non-destructive character. In these techniques, products of interactions between beams and targets are exploited to determine the elemental composition of the sample surface down to depths from few micrometres to hundreds of micrometres, depending on incident particles, their energy and target material. For samples with surface inhomogeneities, information about elemental distribution can be essential to discriminate contributions from different areas. At the authors' laboratory in Florence (LABEC), the external scanning proton microprobe facility — installed on a beam line of the 3 MV Tandem Accelerator — allows samples to be analysed in atmosphere, with spatial resolution down to around micrometres, and to extract elemental maps from the investigated areas. Recently, there has been the opportunity of analysing a 'gold lace embroidery' (using silk threads, spiral wrapped by a sort of miniature golden tape) after a cartoon by Raffaellino del Garbo (the fifteenth–sixteenth centuries). [ABSTRACT FROM AUTHOR]

Abstract: A set of ancient gold jewellery was found in Cádiz (formerly Gadir, south Spain) in tombs dated in Phoenician-Archaic period (VII-VI century BC), and nowadays is exhibited in the local Museum. The production of this strategic area is of great interest for the knowledge of the commercial routes along the Mediterranean Sea at that time. Part of this production has already been analyzed by the authors, finding compositional differences and identifying soldering procedures, thanks to the use of the external microbeam. Absolutely non destructive analysis was performed. For this work we have again employed PIXE spectrometry with 2.2MeV protons from the 3MV Pelletron accelerator at the CNA to characterize the metallic alloys and the manufacturing techniques. We have found an unusual composition characterized by around 50wt.% gold, 50wt.% silver and some copper, which can be identified as ELECTRUM. Few analytical data of this particular kind of alloy are reported in the bibliography. The study of these objects can help to follow the trade of metals in the Phoenician-colonial period. [Copyright &y& Elsevier]

Damage of polyimide windows for external ion microbeams was monitored by analyzing backscattering protons from the window. A 1.5 MeV proton microbeam focused to approximately 50 × 50 μm2 was transmitted through the polyimide window from vacuum to oxygen atmosphere. The changes in backscattering spectra of the window were monitored as a function of irradiation dose up to 2 × 1018 H+/cm2. For comparison, the polyimide window was irradiated in vacuum in the same way as the oxygen case. The backscattering spectra drastically changed in the case of oxygen. We observed that the carbon spectrum width, corresponding to the thickness of the window, substantially decreased with increasing the irradiation dose. The in situ monitoring of backscattering protons demonstrated the ability to detect the damage of the window and to predict the rupture of the window. [Copyright &y& Elsevier]