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Folding fans are complex artifacts that include a variety of materials that have been processed and assembled to produce very small supports and decorations. Unfortunately, due to their fragility, as well as the lack of suitable non-invasive and non-destructive analytical techniques, the constituent materials and stratigraphies of historic folding fans have been rarely studied so far. This work aimed to develop and demonstrate a suitable analytical methodology for characterizing a French fan and to establish manufacturing techniques employed in its production. To this goal, advanced non-destructive and micro-destructive photonic techniques were employed to gather compositional and processing information with a non-invasive approach. This artifact provided the opportunity to evaluate the potential of different techniques: Portable Raman spectroscopy (with excitation at 785 nm) was used for identifying the pigments of the painted leaves and the gemstones; particle-induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) were employed to quantify metal alloy compositions and stratigraphy of the decorations; portable laser-induced breakdown spectroscopy (LIBS) allowed the measurement of elemental depth profiles of metal decorations which were congruent with those provided by PIXE. Finally, additional stratigraphic information on metal decorations, in terms of gold distribution and state of conservation, was achieved through selective laser ablation.

CERN has been building a transportable RFQ for use in the examination of art masterpieces based mainly on the PIXE (Proton Induced X-ray Emission) technique with an extracted beam. This new PIXE-RFQ accelerator is very compact, only one meter in length with a power consumption of less than 6 kVA for a beam energy of 2 MeV and an average current of 5 nA. The PIXE-RFQ will be used for the MACHINA (Movable Accelerator for Cultural Heritage In-situ Non-destructive Analysis) project developed jointly by CERN and INFN. This paper will present the detailed design and performances of the PIXE-RFQ as well as the fabrication technologies used and the current status of the project. The beam size and the peak current/duty cycle of the RFQ have been optimised for the Ion Beam Analysis (IBA) of artwork objects.

At present, macro X-ray fluorescence (MA-XRF) is one of the most essential analytical methods exploited by heritage science. By providing spatial distribution elemental maps, not only does it allow for material characterisation but also to understand, or at least to have a likely idea of, the production techniques of an analysed object. INFN-CHNet, the Cultural Heritage Network of the Italian National Institute of Nuclear Physics, designed and developed a MA-XRF scanner aiming to be a lightweight, easy to transport piece of equipment for use in in situ measurements. In this study, the INFN-CHNet MA-XRF scanner was employed for the analysis of a painting by the Flemish artist Rogier van der Weyden. The painting belongs to the collection of the Uffizi gallery in Florence and was analysed during conservation treatments at the Opificio delle Pietre Dure, one of the main conservation centres in Italy. The research aims were to characterise the materials employed by the artist and to possibly understand his painting technique. Although MA-XRF alone cannot provide a comprehensive characterisation, it nonetheless proved to be an invaluable tool for providing an initial overview or hypothesis of the painting materials and techniques used.

The LABEC laboratory, the INFN ion beam laboratory of nuclear techniques for environment and cultural heritage, located in the Scientific and Technological Campus of the University of Florence in Sesto Fiorentino, started its operational activities in 2004, after INFN decided in 2001 to provide our applied nuclear physics group with a large laboratory dedicated to applications of accelerator-related analytical techniques, based on a new 3 MV Tandetron accelerator. The new accelerator greatly improved the performance of existing Ion Beam Analysis (IBA) applications (for which we were using since the 1980s an old single-ended Van de Graaff accelerator) and in addition allowed to start a novel activity of Accelerator Mass Spectrometry (AMS), in particular for 14C dating. Switching between IBA and AMS operation became very easy and fast, which allowed us high flexibility in programming the activities, mainly focused on studies of cultural heritage and atmospheric aerosol composition, but including also applications to biology, geology, material science and forensics, ion implantation, tests of radiation damage to components, detector performance tests and low-energy nuclear physics. This paper describes the facilities presently available in the LABEC laboratory, their technical features and some success stories of recent applications.

At INFN-LABEC (Florence, Italy), a new pretreatment for radiocarbon dating based on chloroform has been recently set up. This method aims to remove the synthetic resins used for artwork restoration, which otherwise could alter the original 14C content. The present study characterizes the efficiency of the process when applied to wood. We have verified whether the effectiveness of the pretreatment depends on the number of extractions in chloroform. We prepared samples by applying different volumes of Paraloid B-72®, one of the most widespread products used in restoration, on poplar wood of known age. Contaminated samples were artificially aged in a climatic chamber. A fraction from each sample was collected before any treatment and after respectively 1, 2, 3, and 4 extractions in chloroform, and 14C dating by AMS, the resin appears to be already removed after the first two extractions. Furthermore, the extracted mixtures of chloroform and possible removed Paraloid were measured by FTIR spectroscopy, the results of which confirmed the 14C results. The efficiency of the pretreatment was also verified on historical wooden materials that had been previously restored. In these cases, a higher number of extractions is required, suggesting a careful approach when dealing with “real” artworks.

In the combustion and graphitization line for 14C-AMS samples used at INFN-LABEC for archaeological and geological applications, samples are burnt using an elemental analyser (EA). Advantages and drawbacks of EAs are known, a drawback being the possibility to introduce some contaminations or memory effects. Different parts inside an EA, e.g. the autosampler and the gas-chromatography column, might in principle be responsible of such problems. During a measurement run some time ago, we measured, indeed, radiocarbon concentration values somewhat higher than usual in nominally blank samples. These “bad” data could be explained by memory effects. By assuming a constant contribution from the sample of the prior combustion, this effect might be corrected: indeed, by repeating cycles of sequential combustions of standards and blanks, we observed a good reproducibility of the amount of contamination from the previous sample needed to explain the results. However, we were obviously unhappy with the fact itself of such corrections being needed, and several tests were performed to identify the source of contamination and eliminate it. Eventually, we succeeded in finding the cause of this failure and in recovering the full performance of the system.

Recently, developments have been made to the external scanning microbeam of INFN-LABEC laboratory in Florence. A new system for mechanical sample scanning was implemented. This system allows us to acquire large maps (up to 20 × 20 cm 2 ), of great interest in the Cultural Heritage field. In parallel, the possibility of using carbon microbeams for experiments, such as, for example, ion beam modification of materials and MeV Secondary Ion Mass Spectrometry, has been investigated. As a test application, Particle Induced X-ray Emission with carbon microbeams has been performed on a lapis lazuli stone. First results for both wide area imaging and external carbon microbeams are briefly reported.

In the last few years some new implementations and upgrades have been made to the external scanning microbeam of INFN-LABEC laboratory in Florence, enriching the existing PIXE, PIGE, BS, IBIL set-up with complementary techniques, when possible allowing for simultaneous multi-technique analyses. We developed a system, compatible with the existing set-up, for the out-of-vacuum detection of the forward scattered particles. This system makes feasible the external-STIM (Scanning Transmission Ion Microscopy) and external-FS (Forward Scattering), now both available at our beamline. Test measurements are shortly presented.

Since its first invention and demonstration [1], saturated-absorption cavity ring-down spectroscopy (SCAR) of CO2 gas samples at 4.5 μm wavelength has been approaching accelerator mass spectrometry (ams) precision in radiocarbon measurements. The first intercomparison between SCAR and ams measurements was performed with modern (fermentation of brown cane sugar) and fossil (high-purity industrial gas cylinder) carbon dioxide samples [2]. These successful results have triggered further optimization of the data fitting procedure [3] and significant upgrades of the SCAR experimental apparatus, leading to an improved performance of the spectrometer in terms of precision and repeatability [4]. Recently, an independent research group has reproduced SCAR spectroscopy, assessing the working limits of this techniques in terms of saturation parameter with measurements on a different molecular species [5].

The issue of contamination in radiocarbon dating is well known and can affect not only archaeological findings but also artworks. In the latter case, a possible source of contamination is represented by the products used during the restoration, e.g. resins of synthetic origin like the well-known Paraloid, applied to wood artifacts as a strengthening and preserving agent. In the case of incomplete removal prior to dating, the resins produce an apparent aging of the samples. Mechanical cleaning using traditional tools and the standard pretreatment acid-base-acid (ABA) protocol are not sufficient to remove such contaminants, while the use of organic solvents, in particular petroleum solvents and chlorine-based products, can be effective. However, the most widely used protocol, based on the Soxhlet extraction system, is very time consuming. Here, in the presence of chloroform-soluble applied products, like the widespread Paraloid B-72, this study proposes the use of a new easily operated pretreatment procedure, developed at INFN-LABEC in Florence, based on the use of chloroform (CHCl3) as solvent and on a simple extraction. First, the effectiveness of this procedure was checked by applying it to remove the resin from wood samples of known age, which had been previously intentionally contaminated by applying large quantities of Paraloid. 14C AMS measurements performed on the test samples before and after contamination and application of the proposed procedure proved its effectiveness for removal, while this was not the case when applying standard ABA protocols. Fourier transform infrared (FTIR) spectroscopy analyses also were used to check the removal of contaminants. The new procedure was applied in two case studies: the wood frame of an altar piece from the Renaissance and a painting on canvas from the early 20th century. For both artworks, the use of synthetic resins was documented in restorations performed a relatively long time ago: the wood frame was restored using just Paraloid, the canvas using a thermoplastic polymer soluble in chloroform. Enough time elapsed for the resins to create cross-linking bonds with the original material. Despite this, the results obtained by 14C AMS dating confirm the reliability of the new chloroform-based pretreatment in removing the contaminations. Also in these cases, spectroscopic techniques were used to compare the effectiveness of the ABA and the new treatments in removing the contaminants.

For the first time, a quick method to discriminate between undamaged, well-maintained katanas and worn artificially restored blades is presented. The peculiar hardening process that a Japanese katana undergoes results in creation of a tempered martensitic phase near the blade edge. After the temper, traditional polishing with stones is performed, which gives the sword its final look: the hardened zone exhibits matte finish, and it is separated from the shinier zone by the hamon line, which is the most characteristic feature of a katana. If the sword is worn, the martensitic phase disappears and so does the hamon line, the sword losing most of its commercial value. However, an acid bath can simulate the matte texture of an undamaged martensitic structure, making it really difficult to recognize valuable blades from worn ones. So far, no analytical approach helping in this task was available. The method we present is based on the hypothesis that traditional polishing leaves a very tiny amount of stone dust on the blade, whereas the acid bath rinses it away. The presence on the blade surface of Si (the major component of the stones used for polishing) when the hamon line is clearly visible could thus be a reasonable marker indicating that the blade is maintaining its original martensitic structure and thus is in a good conservation state. For the Si detection, X-ray fluorescence technique was chosen, which ensures non-destructivity, high sensitivity, and short measurement time with a portable instrument. Copyright © 2013 John Wiley & Sons, Ltd.

Lapis lazuli has been used for glyptics and carving since the fifth millennium BC to produce jewels, amulets, seals, inlays, etc; the identification of the origin of the stone used for carving artworks may be valuable for reconstructing old trade routes. Since ancient lapis lazuli art objects are precious, only non-destructive techniques can be used to identify their provenance, and ion beam analysis (IBA) techniques allow us to characterise this stone in a fully non-invasive way. In addition, by using an ion microprobe, we have been able to focus the analysis on single crystals, as their typical dimensions may range from a few microns to hundreds of microns. Provenance markers, identified in previous IBA studies and already presented elsewhere, were based on the presence/absence of mineral phases, on the presence/quantity of trace elements inside a phase and on characteristic features of the luminescence spectra. In this work, a systematic study on pyrite crystals, a common accessory mineral in lapis lazuli, was carried out, following a multi-technique approach: optical microscopy and SEM-EDX to select crystals for successive trace element micro-PIXE measurements at two Italian facilities, the INFN Laboratori Nazionali di Legnaro and the INFN LABEC laboratory in Firenze. The results of this work allowed us to obtain new markers for lapis lazuli provenance identification.

Radiocarbon dating of bones can be very useful in archaeological contexts, especially when dealing with funerary deposits lacking material culture, e.g. pottery vessels. 14C measurements of bone samples are usually performed on the extracted collagen residue. The content and the quality of collagen can vary significantly, mainly depending on bone preservation and diagenesis. Generally speaking, environmental conditions such as low pH level of soils, high temperatures, and percolating groundwaters, typical of arid and tropical zones, can affect the preservation of collagen; at the same time, bones recovered in such environments are more likely to be contaminated with carbon from the surrounding environment. Possible contamination of samples can also occur in temperate zones. While low collagen content is a condition we cannot overcome, we can use several chemical and elemental indicators in order to assess collagen quality. Among these, the C/N atomic ratio is considered a good parameter for detecting low-quality collagen and possibly contaminated samples. In a combustion and graphitization setup like that installed at INFN-LABEC, Florence, measurement can be easily performed using an elemental analyzer when combusting the sample prior to graphitization, thus requiring no extra effort (or extra amount of sample) during the preparation procedure. Bone samples recently 14C dated at INFN-LABEC have confirmed that the measurement of C/N atomic ratios can give some indications of the collagen quality. The bone material was collected from 3 necropoles of the Bronze Age period in Cyprus (Erimi-Laonin tou Porakou, Lophou-Kolaouzou, and Erimi-Kafkalla&Pitharka, along the Kouris Valley), an area characterized by environmental conditions that do not favor bone preservation. Samples were treated to extract collagen and measured by accelerator mass spectrometry (AMS). 14C results have been compared with the archaeological evidence, showing some relationship between measured C/N atomic ratios and collagen quality. In particular, when grouping the measured samples according to their C/N ratio, the agreement between 14C dates and archaeological evidence is good or inconsistent when the C/N ratio clearly falls inside or outside the “recommended” range, respectively, with a still reasonable agreement also when it is slightly above the upper limit of that range.

Particle-induced X-ray emission (PIXE) is the most popular among the ion beam analysis (IBA) techniques, which are based on the use of the specimen to be analyzed as a target for a beam of accelerated particles. The detection of the radiation induced by the beam bombardment is then used to discriminate and quantify the presence of the different elements in the specimen. In PIXE, what is exploited is, in particular, the X-rays emitted from the target, whose energies are characteristic of the emitting atomic species. After a general, simple description of the main features of PIXE, with a short historical overview and a brief comparison to other X-ray fluorescence (XRF) techniques, the article covers in greater depth all the specific aspects of this technique. The basic aspects of X-ray emission from the atoms are first recalled; then, the extraction of quantitative compositional data from thin and thick specimens is explained, and a discussion is given of the excellent performance of PIXE in terms of minimum detection limits, and of the factors affecting them. A technical description then follows of how proper beams for PIXE are produced and of the experimental setups commonly used. The X-ray detector characteristics, the electronics for constructing the energy spectra, and the software processes for their deconvolution, leading to the extraction of quantitative data, are then briefly described. The last section surveys the main analytical applications of PIXE in various fields (environmental monitoring, biomedicine, earth sciences, cultural heritage, and materials analysis), with no intent of exhaustiveness but rather with the purpose of focusing on when and why PIXE may be particularly suitable in each of them. Keywords: characteristic X-rays; nuclear microprobe; proton microprobe; external beam; trace elements; elemental mapping; micro-PIXE; 3D PIXE; differential PIXE; dynamic analysis; IBA

The atmospheric tests of nuclear weapons caused a sudden increase in the radiocarbon concentration in the atmosphere from 1955, reaching its maximum value in 1963–1965. Once the nuclear tests in the atmosphere were halted, the 14C concentration started to decrease. This behavior of the radiocarbon concentration is called the “Bomb Peak”, and it has successfully been used as a tool for high-precision radiocarbon measurements, in forensic sciences and biology. In the art field, the possibility of dating canvas, wood and paper, widely used as supports for paintings, may be an invaluable tool in modern art studies.

X-ray fluorescence (XRF) analysis is one of the most widely used techniques for material analysis in the field of cultural heritage, thanks to its non-destructive and multi-elemental character and also to the possibility of using portable instrumentations. The need of compact systems for in situ analyses results generally in a worse, more limited performance: the detection of low-Z elements is the most affected aspect. In this article, we present a custom-realised portable XRF spectrometer developed in Florence at the LABEC laboratory of Istituto Nazionale di Fisica Nucleare (INFN), in collaboration with ICVBC of Consiglio Nazionale delle Ricerche (CNR). The system features a high efficiency for a wide range of elements, even at low Z (down to sodium), thanks to the use of two tubes with different anodes and to the presence of a continuous helium flow in front of the tubes and the detector, in order to enhance transmission of both primary and characteristic X-rays. After a detailed description of the spectrometer, the experimental characterisation of its performance is presented: efficiency curves obtained from the analysis of thin standards are reported, together with minimum detection limits for some elements in a thick target of medium-low density matrix. Examples of measurements, which demonstrate the capability and effectiveness of this spectrometer, are also reported.

Among ion beam analysis (IBA) techniques, particle induced x-ray emission (PIXE) is the most widely used in the field of cultural heritage, providing the elemental composition of materials in a non-invasive and non-destructive way. This paper reports on the analysis by PIXE performed at one of the external beamlines of the 3 MV Tandetron accelerator of the LABEC laboratory (Istituto Nazionale di Fisica Nucleare (INFN)—Florence) on a wood painting by Giorgio Vasari, belonging to the altar-piece ‘Pala Albergotti’ (church of Sts Flora and Lucilla, Arezzo). The measurements were taken in the framework of a campaign of scientific investigations, promoted by the Soprintendenza of Arezzo, preliminary to the restoration of the whole altar-piece. PIXE was used to identify the elemental composition of the original materials and to characterise the alteration layer visible on the surface of the painting. Measurements on the same spot with proton beams of different energies (differential PIXE) also allowed us to get information on the depth distribution of elements and on the structure of layers without the need of picking up samples. Copyright © 2009 John Wiley & Sons, Ltd.

Since natural textiles usually originate from short-lived organisms, they can represent a useful material to date samples from historical periods with a good accuracy. In this work, we present a set of radiocarbon measurements on medieval textile relics: two woollen habits and a pillow traditionally associated with St. Francis of Assisi, the saint patron of Italy. The strategy in choosing samples for radiocarbon dating is first discussed and the procedures for measurements – performed at the 3 MV Tandetron accelerator of Laboratorio di Tecniche Nucleari per i Beni Culturali (LABEC), Florence – are described; AMS results for the two frocks showed that only one of them, presently kept in the church of St. Francis in Cortona, is compatible with the Saint’s period of life, as is the pillow also kept in Cortona. Another frock attributed to St. Francis appears to date from at least 80 years after his death. However, the goal of these measurements was not a bare authentication/disconfirmation of the relics; they just represent an example of how scientific analysis can integrate with humanistic studies. Indeed, AMS results, combined with a thorough analysis of the textiles typologies, confirmed the historical hypotheses based on documentary studies and on tradition. The overall conclusions contributed to the decisions taken for conservation, and have as a whole enhanced the religious importance of the relics.

In this work, we describe the compositional analysis performed by scanning-mode PIXE on the metal threads of a XIII century embroidery. The precious work analysed is the pillow-case used to cover the pillow, on which – according to tradition – St. Francis of Assisi was resting his head when he died. Measurements were performed in order to characterise the embroideries of the two sides and the passementerie in the lateral hems. Several areas, each of the order of two square millimetres, were scanned with a 3 MeV proton external beam of 20 μm size on target, using the external micro-beam facility of our laboratory, with list-mode acquisition. Analysis of elemental maps and spectra from selected homogeneous sub-areas allowed us to extract the quantitative composition of the gilded tape and estimates of its thickness.

A new ionoluminescence (IL) apparatus has been successfully installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC in Firenze; the apparatus for photon detection has been fully integrated in the existing ion beam analysis (IBA) set-up, for the simultaneous acquisition of IL and PIXE/PIGE/BS spectra and maps. The potential of the new set-up is illustrated in this paper by some results extracted by the analysis of art objects and advanced semiconductor materials. In particular, the adequacy of the new IBA set-up in the field of cultural heritage is pointed out by the coupled PIXE/IL micro-analysis of a lapis lazuli stone; concerning applications in material science, IL spectra from a N doped diamond sample were acquired and compared with CL analyses to evaluate the relevant sensitivities and the effect of ion damage.

This work will present preliminary results concerning the use of time-resolved ion beam induced luminescence applied to provenance studies of lapis lazuli. Measurements were performed at the pulsed beam facility at LABEC laboratory in Florence. Lapis lazuli is a semi-precious gemstone, used as ornament since the early civilizations that can be found in few places on Earth. The importance of this work lies in understanding the origin of various samples of lapis lazuli, from which it may be possible to gain insight into trade routes from ancient times. The samples studied in this work originated from Chile, Afghanistan, Tajikistan, Myanmar, and Siberia. The stones were irradiated with 3 MeV protons and the resulting luminescence was detected by a photomultiplier tube, whose output was acquired using a sampling digitizer VME module (CAEN/V1720). Wavelength discrimination was performed at 430 nm utilizing a range of beam currents. The results showed that, by changing the beam current intensity, one can study different features of lapis lazuli, and this may aid in distinguishing lapis lazuli from different provenances.

The main facility of the new INFN laboratory in Florence (LABEC, LAboratorio di tecniche nucleari per i BEni Culturali) is a 3 MV Tandetron accelerator, manufactured by High Voltage Engineering Europe, used for both Accelerator Mass Spectrometry and Ion Beam Analysis (IBA) measurements. The AMS beam line is equipped with a 59-sample sputter ion source and a sequential injector – on the low energy side – and a spectrometer composed of a 115° analysing magnet and a 65° electrostatic analyser – on the high energy side. A sample preparation laboratory has been installed for radiocarbon measurements. Combustion of pre-treated organic samples is performed using an elemental analyser; four parallel graphitisation reactors are available for CO2 reduction. In this paper, the performance of the whole system is presented: 14C values of chemistry blanks correspond to radiocarbon ages in the order of 50,000 years BP; measurements of 14C concentration in different standard reference materials demonstrate good accuracy.

In this paper, we discuss the convenience of performing external PIXE and PIGE measurements by scanning relatively large areas (some mm2) with a beam size of the order of hundred microns, rather than performing “spot” compositional analysis. Examples of test runs on samples of archaeometric interest are presented: scanning-mode measurements of ancient inks, Roman glass and metal point drawings clearly demonstrate that using this procedure to perform IBA may become fundamental to avoid deceptive information and to obtain more reliable quantitative results.

The external microbeam facility at the 3 MV Tandetron accelerator of the LABEC Laboratory of INFN in Florence has been used to determine, by PIXE, major, minor and trace element abundances of minerals and groundmass in the lavas from the active Nyiragongo Volcano (Democratic Republic of Congo), which is well known for its lava lake intra-crateric activity [e.g. 1, 2]. During the last eruption of this volcano (January, 2002), two main flows entered the Goma town producing major devastation, forcing the rapid exodus of about 300,000 people and causing the death of 150 persons [3]. After this eruption, the interest of the scientific community on this volcanic area suddenly increased. In this respect, determination of major and trace element abundances in mineral phases and groundmass of lavas may allow to constrain the evolution of magma within the volcanic system from a quantitative view point, thus helping to better understand the way this volcano works.

This paper reports an example of how the differential PIXE technique can be successfully applied to the investigation of wood or canvas paintings. The work analysed is a famous wood painting by Leonardo da Vinci, the “Madonna dei fusi” (ex-Reford version, 1501), chosen for a pilot study in a wide international project aimed at analysing Leonardo’s works of art by means of non-destructive techniques. While illustrating the results obtained concerning the identification of pigments and the discrimination of the stratigraphy of layers, the merits and limits of differential PIXE in general are pointed out.

Traditional PIXE does not provide information about the layered structure that is characteristic of wood and canvas paintings. In such cases, a solution to discriminate the depth sequence of elements within the analysed sample is to use differential PIXE, i.e. by measuring on the same spot with different beam energies. At the Florence accelerator, laboratory differential PIXE measurements were performed on the wood painting Madonna deifusi (ex-Redford version, 1501) by Leonardo da Vinci, in the framework of an extensive project aimed at discovering the 'secrets' of the painting and drawing techniques of the artist. The analysis allowed us to characterize the pigments and the substrate composition.

An extensive investigation was carried out for the characterisation of the air particulate composition in Florence. The aim was to determine the aerosol elemental concentrations, as well as to identify pollution sources. For our investigation, the external Particle-Induced X-Ray Emission-Particle-Induced gamma-Ray Emission beam facility of the Istituto Nazionale di Fisica Nucleare, Van de Graaff accelerator at the Physics Department of the Florence University was used. We report the results of the analysis of a long temporal series (approximately 1 yr) of PM10 particulate samples, collected on Millipore filters on a daily basis in three different sites (characterised by different urban settings). Daily concentrations of more than 20 elements were detected. The long sampling period (approximately 1 yr) allowed a comparison with the air quality recommended values and the identification of seasonal variations. Four main sources (traffic, oil-combustion, soil-dust, and wind transported sea-salt) were extracted with the help of Principal Component Analysis (PCA). An absolute PCA showed traffic to be the major source both in the high traffic site and in the urban background site.

Lapis-lazuli is a semi-precious stone used in the past to produce a blue pigment. Its main component is lazurite, 3Na2O·3Al2O3·6SiO2·2Na2S. The possibility of using PIXE to identify this pigment in canvas and wood painting is severely limited by the strong absorption of low-energy X-rays in the protective varnish and – when, as typical, the pigment is mixed with lead white – by the overlapping of Pb M lines with S Kα. In this work we discuss the possibility of identifying lapis-lazuli by detecting sodium with PIGE. PIXE and PIGE measurements have been performed on samples containing lapis-lazuli mixed to lead white in different percentage, covered with polymeric foils to simulate the presence of varnish. At a percentage of lapis-lazuli below 50%, Na X-rays are hardly detectable even with the thinner foil; on the contrary the characteristic γ-rays are clearly detected down to about 1%. A first application has been successfully performed on the “Madonna dei fusi” by Leonardo da Vinci, in the framework of an extensive scientific investigation on the painting techniques used by the Renaissance genius.

In the silicon tracker for the Compact Muon Solenoid experiment at the forthcoming Large Hadron Collider of CERN, each silicon sensor is connected to the front-end electronics by a pitch adapter, the structure of which consists of a fan of very thin chromium strips coated with a few microns aluminium deposition, on a glass support. The absence of contaminants in the depositions is of crucial importance for the electrical and mechanical reliability of the micro-bonding connections. The PIXE set-up of the Florence external micro-beam facility appeared to be suitable to analyse the metal deposition of an adapter, on which the micro-bonds had shown mechanical and electrical problems. Our measurements pointed out a significant copper contamination of the metal deposition on the faulty adapter, while no copper was detected in another one, which showed a correct behaviour at bonding. This suggests a possible role of Cu impurities in the encountered problems during micro-bonding.

A high resolution time of flight (TOF) system has been developed at LABEC, the 3 MV Tandem accelerator laboratory in Florence, in order to improve the sensitivity of AMS measurements on carbon samples with ultra-low concentration and also to measure other isotopes, such as 129I. The system can be employed to detect and identify residual interfering particles originated from the break-up of molecular isobars. The set-up has been specifically designed for low energy heavy ions: it consists of two identical time pick-off stations, each made up of a thin conductive foil and a Micro-Channel Plate (MCP) multiplier. The beamline is also equipped with a silicon detector, installed downstream the stop TOF station. In this paper the design of the new system and the implemented readout electronics are presented. The tests performed on the single time pick-off station are reported: they show that the maximum contribution to the timing resolution given by both the intrinsic MCP resolution and the electronics is ⩽500 ps (FWHM). For these tests, single particle pulsed beams of 2–5 MeV protons and 10 MeV 12C3+ ions, to simulate typical AMS conditions, were used. The preliminary TOF and TOF-E (TOF-energy) measurements performed with carbon beams after the installation of the new system on the AMS beam line are also discussed. These measurements were performed using the foil–MCP as the start stage and a silicon detector as the stop stage. The spectra acquired with carbon ions suggest the presence of a small residual background from neighboring masses reaching the end of the beamline with the same energy as the rare isotope.

Micro-fabrication in diamond is involved in a wide set of emerging technologies, exploiting the exceptional characteristics of diamond for application in bio-physics, photonics, radiation detection. Micro ion-beam irradiation and pulsed laser irradiation are complementary techniques, which permit the implementation of complex geometries, by modification and functionalization of surface and/or bulk material, modifying the optical, electrical and mechanical characteristics of the material. In this article we summarize the work done in Florence (Italy) concerning ion beam and pulsed laser beam micro-fabrication in diamond., 14 pages, 5 figures

An external beam microprobe facility, based on a quadrupole doublet supplied by Oxford Microbeam Ltd, has been installed on a new beamline at the 3 MV single-ended Van de Graaff accelerator in Florence. The goal was to obtain a beam with a spot size on target of 10–20 μm and a current in the order of at least 1 nA, in order to allow PIXE, PIGE and RBS elemental analysis in air or in a helium atmosphere. The beam was extracted from the vacuum lines through a 0.1 μm thick Si 3 N 4 window to minimise lateral straggling. The design goals have been successfully achieved; the measurements of the beam spot characteristics in vacuum as well as in air and in helium atmosphere, are here reported.

The composition of particulate matter in the atmosphere of four major Italian towns (Florence, Genoa, Milan and Naples) has been studied with the extensive application of IBA techniques. The aerosol has been collected simultaneously in the four towns during the first weeks of year 2001, by two-stage continuous streaker samplers, which provide the separation of the particulate matter in two fractions. The concentrations in air of about 20 elements, and the total particulate mass, have been extracted in the PM2.5 and PM10 fractions with hourly resolution by PIXE, PIGE and optical analyses of about 2700 samples. IBA analyses have been performed at the 3 MeV external proton beam of the INFN accelerator facility at the University of Florence.

An electrostatic chopper has been installed at the KN 3000 accelerator in Florence to obtain short beam pulses with a number of particles per pulse whose average value can be chosen by varying the current intensity at the deflector plates input. Beam pulses can be obtained containing an average number of particles per pulse from less than one to thousands. The transmitted beam pulses can be as short as 200 ps FWHM, at a repetition rate up to about 100 kHz. Among the many applications of the facility, the direct measurement of energy loss and straggling of protons in Kapton and aluminium is reported. In this measurement, the facility has been tuned for transmission of mainly single-proton pulses; the beam energy is directly measured downstream with a good energy-resolution detector, without and with absorbers in front. In general, measurements of this kind can be directed both to study the basic processes of charged particles interactions in materials, or more practically to obtain the effective values of energy parameters useful in many IBA applications, avoiding the need to rely on simulations or theoretical estimates. Also briefly described is an application to Si-detector testing. In this case, the facility has been tuned for transmission of pulses containing many hundreds of protons of energy E p =2.5 MeV and the detector is directly exposed to the pulses. Spectra containing equally spaced peaks at energies multiple of E p are obtained and the response linearity of the detector plus electronics system can thus be checked.

A series of PIXE analyses has been performed on glazes from terracotta sculptures of the Italian Renaissance and on reference standards. The problems related to the investigation of such heterogeneous materials are discussed and the experimental uncertainties are evaluated, for each element, from the PIXE analysis of standard glasses. Some examples from artefacts coming from Italian collections are given. This research has been conducted in the framework of the COST-G1 European action.

PIXE analysis performed with protons of different energies makes it possible to obtain information about the depth sequence of different elements within the analysed sample. In this paper we report on the differential PIXE set-up installed at the external-beam facility of the KN3000 accelerator in Florence. In order to change beam energy on the sample, our choice was to insert energy degraders between beam exit window and sample. 25 μm Upilex foils are used to degrade the beam: with 3 MeV protons, the energy loss is about 500 keV; higher energy losses are obtained by sandwiching more foils. Measurements of lateral beam profiles and of energy loss and straggling after the Upilex foils are reported, compared to those obtained with other materials such as aluminium and copper. We also investigated the possible damage to the foil due to beam irradiation. Preliminary applications of this set-up to the stratigraphic analysis of samples of archaeometrical interest are described.

It is well known that an accurate measurement of beam currents in an external set-up is not a straightforward task. Charge collection in a Faraday cup can be altered by ionisation along the beam path in atmosphere. These problems are more and more relevant when weaker currents are used, as in the ion beam analysis of precious objects where beam-induced damage should be strictly avoided. We performed a calibration of the integrated charge values obtained with a Faraday cup in an external set-up, at different beam current intensities, versus the “true” values. Effects of wrong charge integration have been detected, with increasing relevance at currents below 3 nA. The measurement of ultra-weak currents in atmosphere adds further problems for their integration. By measuring the X-ray yield obtained from a rotating chopper made of thick nickel in front of the target we obtain a sufficiently accurate beam current monitoring and charge-equivalent normalisation down to below 1 pA.

We describe the results of an aerosol sampling campaign performedin 1999 in the medium-size industrial town of La Spezia, in theNorthwest of Italy. We used two-stage continuous streakersamplers in three different sites and periods of the year. This kind of samplers allows the separation of the PM10 andPM2.2 fractions of the particulate matter. Moreover, the hourly resolution in the aerosol collection is particularly useful inan urban environment where, typically, many pollution sourceswith fast variations are present. Up to 1700 samples have beenanalysed by Particle Induced X-ray Emission (PIXE) at the INFNaccelerator facility in Florence, obtaining hourly concentrationfor about 20 elements from Na to Pb, with a sensitivity rangingfrom below 1 to about 10 ng m-3. The total hourly aerosolmass has been estimated with an optical analysis of the samesamples performed (before the PIXE analysis) by an equipment designed and mounted in Genoa. An extensive statistical analysisof the data included standard and Absolute Principal ComponentFactor Analysis (PCFA and APCFA) to deduce the compositionand the weight of the major aerosol sources in both fractions.Thorough different statistical approaches, we generally resolvedcontributions from vehicle emission, fossil fuel combustion,soil-road dust and sea salt aerosol.

Using a set-up for simultaneous many-angle detection of backscattered particles, the proton elastic scattering cross-section on 10B and 11B has been measured for beam energies from 0.5 to 3.3 MeV and in the angular range from 100° to 170° in steps of 5°. The overall accuracy in the measured cross-section is estimated to be better than ±5% at all the beam energies and angles.

A combined PIXE and XPS analysis has been performed on a few Roman coins of the republican and imperial age. The purpose was to investigate via XPS the nature and extent of patina in order to be capable of extracting PIXE data relative to the coins bulk. The inclusion of elements from the surface layer, altered by oxidation and inclusion, is a known source of uncertainty in PIXE analyses of coins, performed to assess the composition and the provenance.

An extensive investigation is in progress aiming at the characterisation of the air particulate composition in Florence. For our investigation, we use the external PIXE-PIGE beam facility of the I.N.F.N. Van de Graaff accelerator at the Physics Department of the Florence University. In order to gather information on both the longer- and shorter-time trends of the aerosol elemental composition, we are analysing both long temporal series (about 1 year) of 24-h Millipore filters collected by the health authorities in 3 different sites, and filters collected simultaneously in two of the above sites for about one month, by two streakers with one-hour resolution, providing size fractionation between particle size smaller than 2.5 μm and from 2.5 μm to 10 μm. The streakers sampling period includes two days during which the Municipality of Florence has banned the circulation of non-catalytic cars, due to the increase of NO2 above the “recommended safety values”. We present here the first obtained results for the sampling site located near a heavy traffic road.

An aerosol sampling campaign has been carried out in the town of La Spezia, Italy, from 10th to 31th March 1999, using two-stage continuous streaker samplers that provide, in conjunction with proper IBA techniques, a hourly resolution of aerosol concentration and the separation of the particulate matter in two fractions. Particulate analysis was performed by PIXE at the INFN Van de Graaff accelerator of the University of Florence extracting hourly concentrations for elements from Na to Pb. The total particulate concentration in the two fractions has been determined as well by an optical analysis of the deposition. The statistical analysis of the concentration time series obtained by PIXE and by optical scanning of the streaker frames is presented. The contribution of some pollution source to the local aerosol composition is also discussed.

The particulate emissions near a large steel plant, located inside the town of Genoa (Italy) have been studied from May to December 1997. We have used two-stage continuous streaker samples and subsequent PIXE (particle-induced X-ray emission) analysis with hourly resolution, to follow both seasonal and daily trends. A first streaker sampler remained installed very close to the plant cokery and furnaces, while another sampler was moved to different locations in town. Samples were analysed by PIXE, deducing concentrations for elements from Na to Pb. We have always collected the PM10 fraction of the aerosol: during part of the campaign, the fine (PM2.5) and coarse (PM2.5–10) aerosol fractions have been also resolved. We have measured and analysed about 8500 PIXE spectra. The steel plant emissions have been identified and resolved from other aerosol sources using principal component analysis (PCA) and other statistical techniques. Finally, the impact of the steel smelter on its surrounding has been evaluated.

An extensive investigation is in progress aiming at the characterisation of the air particulate composition in Florence. For our investigation, we use the external PIXE-PIGE beam facility of the I.N.F.N. Van de Graaff accelerator at the Physics Department of the Florence University. In order to gather information on both the longer- and shorter-time trends of the aerosol elemental composition, we are analysing both long temporal series (about 1 year) of 24-h Millipore filters collected by the health authorities in 3 different sites, and filters collected simultaneously in two of the above sites for about one month, by two streakers with one-hour resolution, providing size fractionation between particle size smaller than 2.5 µm and from 2.5 µm to 10 µm. The streakers sampling period includes two days during which the Municipality of Florence has banned the circulation of non-catalytic cars, due to the increase of NO2 above the "recommended safety values". We present here the first obtained results for the sampling site located near a heavy traffic road.

The particulate emissions near a large steel plant located in a densely inhabited suburb of the town of Genova (Italy) have been studied for a period of six months. We have used two-stage continuous streaker samplers and subsequent PIXE analysis with hourly resolution, to follow both seasonal and daily trends. The first streaker sampler remained installed very close to the plant cokery and furnaces, while another sampler was moved to different locations. Samples have been analysed by PIXE, deducing concentrations for elements from Na to Pb. During part of the campaign, the aerosol fractions with aerodynamic diameter (Dae)