This work aims at gaining information on the effects of different thermal treatments on radiocarbon measurements of organic (OC) and elemental (EC) carbon fractions in the atmospheric aerosol. ...Improvements to the traditional approaches for the determination of the fraction of modern carbon of OC and EC−fm(OC) and fm(EC)- are proposed.
As for fm(EC) determination, we propose to add a He step at high temperature to the standard oxygen treatment. Our tests demonstrate that the addition of a high temperature He step (final choice: 750°C) to the oxygen treatment is effective in removing the refractory OC.
As for fm(OC) determination, we propose to quantify it by measuring either the fraction of modern carbon of TC and EC or the fraction of modern carbon of water soluble (fm(WSOC)) and water insoluble (fm(WINSOC)) organic carbon to limit the influence of possible pyrolysis on the direct determination of fm(OC). Tests on the equivalence of the approaches have shown good agreement between them.
Our tests were carried out on samples collected in a heavily polluted area (Milan, Italy) during wintertime. fm(OC), fm(EC), and fm(TC) values obtained in our tests were also used to attempt a preliminary source apportionment in the area using 14C measurements. Wintertime EC resulted to be mainly fossil (84%), whereas OC was dominated by modern contribution (63%).
Two approaches were tested for the evaluation of the wood burning contribution to OC and a good agreement was found. Wood burning primary contribution accounted for about 18% of OC in Milan during wintertime.
Secondary OC from biomass burning and the contribution from other urban sources were tentatively identified following literature approaches, with the aim of evaluating the biogenic contribution to OC in the area, which was estimated to be about 18%.
► Improvements to thermal protocols for 14C analysis of OC and EC were carried out. ► A suitable filter washing procedure was set up. ► A high temperature He step was added to the oxygen step to improve EC isolation. ► Two alternative approaches for fm(OC) determination were tested. ► Carbonaceous particles source apportionment was attempted.
Single-photon sources are a fundamental element for developing quantum technologies, and sources based on colour centres in diamonds are among the most promising candidates. The well-known nitrogen ...vacancy centres are characterized by several limitations, and thus few other defects have recently been considered. In the present work, we characterize, in detail, native efficient single colour centres emitting in the near infra-red ( = 740-780 nm) in both standard IIa single-crystal and electronic-grade polycrystalline commercial chemical vapour deposited (CVD) diamond samples. In the former case, a high-temperature (T > 1000 °C) annealing process in vacuum is necessary to induce the formation activation of luminescent centres with good emission properties, while in the latter case the annealing process has marginally beneficial effects on the number and performance of native centres in commercially available samples. Although displaying significant variability in several photo-physical properties (emission wavelength, emission rate instabilities, saturation behaviours), these centres generally display appealing photophysical properties for applications as single photon sources: short lifetimes (0.7-3 ns), high emission rates (∼50-500 × 103 photons s−1) and strongly (>95%) polarized light. The native centres are tentatively attributed to impurities incorporated in the diamond crystal during the CVD growth of high-quality type-IIa samples, and offer promising perspectives in diamond-based photonics.
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
14
C 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.
Ion irradiation is a widely employed tool to fabricate diamond micro- and nano-structures for applications in integrated photonics and quantum optics. In this context, it is essential to accurately ...assess the effect of ion-induced damage on the variation of the refractive index of the material, both to control the side effects in the fabrication process and possibly finely tune such variations. Several partially contradictory accounts have been provided on the effect of the ion irradiation on the refractive index of single crystal diamond. These discrepancies may be attributable to the fact that in all cases the ions are implanted in the bulk of the material, thus inducing a series of concurrent effects (volume expansion, stress, doping, etc.). Here we report the systematic characterization of the refractive index variations occurring in a 38 µm thin artificial diamond sample upon irradiation with high-energy (3 MeV and 5 MeV) protons. In this configuration the ions are fully transmitted through the sample, while inducing an almost uniform damage profile with depth. Therefore, our findings conclusively identify and accurately quantify the change in the material polarizability as a function of ion beam damage as the primary cause for the modification of its refractive index.
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
14
C 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.
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.
INFN-CHNet is the cultural heritage network of the Italian National Institute of Nuclear Physics (INFN) and is constituted by units from Italy and from outside Europe, one of them at Universidad ...Nacional de San Martín (UNSAM) in Buenos Aires, Argentina. As a result of the initiative carried out during 2015 by the
Accademia dei Lincei
for the year of the Italian culture in Latin America, an INFN-CHNet laboratory was set at CEPyA-UNSAM with the collaboration of INFN and the Restoration Workshop Centro Tarea. Noteworthy, this laboratory is conceived as a multidisciplinary research facility with complementary skills, both scientific and humanistic. In this context, the first instrument jointly set up, optimised, and applied to Cultural Heritage was an X-ray fluorescence scanner. In this manuscript, we describe the instrument and its main features together with a set of representative yet novel applications in the field of cultural heritage, namely, the experimental study of hidden rock art through laboratory replicas that imitates the problems found in the archaeological sites (hematite drawings hidden below carbon deposition); the study and chemical characterisation of archaeological decorated pottery; and finally, the application of the XRF scanner to ancient photography, for quick and accurate identification of materials and techniques employed. Beyond these specific results, the primary output of this initiative has been the conception of a future network of scientific laboratories in South America, coordinated by CEPyA at UNSAM.
Over the time, instrument transportability has become more and more important, especially in Cultural Heritage, as often artworks cannot be moved from their site, either because of the size or due to ...problems with permission issues, or simply because moving them to a laboratory is physically impossible, as e.g. in the case of mural paintings. For this reason, the INFN-CHNet, the network for Cultural Heritage studies of the Italian National Institute of Nuclear Physics (INFN), has developed an XRF scanner for in situ analyses. The instrument is the result of a wide collaboration, where different units of the network have been developing the diverse parts, then merged in a single system. The XRF scanner has been designed to be a
four-season
and
green
instrument. The control/acquisition/analysis software has been fully developed by our group, using only open-source software. Other strong points of the system are easiness of use, high portability, good performances and ultra-low radiation dispersion, which allows us to use even when the public can be present. It can run both with mains or on batteries, in the latter case with a maximum runtime longer than 10 h. It has a very low cost, when compared to commercial systems with equivalent performances, and easily replaceable components, which makes it accessible for a much wider portion of the interested community. The system has been thought and designed as an open system, suitable for further development/improvements, that can result interesting for non-conventional XRF analysis. The CHNet XRF scanner has proved to be really very well suited for applications in the Cultural Heritage field, as testified by the many recent applications. This paper describes the present version of our instrument and reports on the tests performed to characterise its main features.
Graphical abstract
The application of cleaning treatments for the restoration of nineteenth–twentieth-century photographs represents an innovative and still little explored aspect. In this work, in order to remove the ...degradation products, two cleaning methods were used for two different photographic techniques: poly(vinyl alcohol)-based hydrogels were applied to clean an albumen-based print, while calcium chlorine was used to remove the silver mirroring effect on a gelatin silver print. The constituent materials and conservation state of the analyzed photographs were characterized using a multi-analytical approach: imaging analyses (UV–VIS-NIR), attenuated total reflection (ATR) Fourier transform infrared spectroscopy (FT-IR) spectroscopy, macro-X-ray fluorescence scanning (MA-XRF) spectroscopy, pH analyses and particle-induced X-ray emission (PIXE) were applied before and after the cleaning treatments. The two treatments have permitted of the recovery the degraded parts of the two photos, especially in the first study case. For the silver mirroring effect, further treatments will be required to obtain a complete removal of the effect.
Graphical abstract
Monoenergetic pulsed proton beams at energies of 1 and 3 MeV per proton have been employed to characterize a segmented double-sided silicon strip detector. The detector is manufactured from a neutron ...transmutation doped silicon wafer and features a bulk resistivity of 2300 Ω · cm. Signals from both P-side and N-side strips have been digitized at 14 b, 100 MS/s. The beam was focused either in the middle of one strip or on the gap in between two strips. Energy resolution, charge collection time, and interstrip effects (charge sharing, charge losses, and inverted polarity pulses) have been investigated at different bias voltages and for particles entering either from the junction side or from the ohmic side.
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