A research cruise was organized on board the Italian National Research Council (CNR) R/V Urania to test the oil spill monitoring system developed during the PRogetto pilota Inquinamento Marino da ...Idrocarburi project (PRIMI, pilot project for marine oil pollution). For the first time, this system integrated in a modular way satellite oil spill detection (Observation Module) and oil spill displacement forecasting (Forecast Module) after detection. The Observation Module was based on both Synthetic Aperture RADAR (SAR) and optical satellite detection, namely SAR and Optical Modules, while the Forecast Module on Lagrangian numerical circulation models. The cruise (Aug. 6–Sep. 7, 2009) took place in the Mediterranean Sea, around Sicily, an area affected by heavy oil tanker traffic with frequent occurrence of oil spills resulting from illegal tank washing. The cruise plan was organized in order to have the ship within the SAR image frames selected for the cruise, at acquisition time. In this way, the ship could rapidly reach oil slicks detected in the images by the SAR Module, and/or eventually by the Optical Module, in order to carry out visual and instrumental inspection of the slicks. During the cruise, several oil spills were detected by the two Observation Modules and verified in situ, with the essential aid of the Forecasting Module which provided the slick position by the time the ship reached the area after the alert given by the SAR and/or optical imagery. Results confirm the good capability of oil spill SAR detection and indicate that also optical sensors are able to detect oil spills, ranging from thin films to slicks containing heavily polluted water. Also, results confirm the useful potential of oil spill forecasting models, but, on the other hand, that further work combining satellite, model and in situ data is necessary to refine the PRIMI system.
Accurate measurements of physical processes in high energy frontier experiments demand exceptional spatial, temporal, and energy precision to discern the physics behind high-energy particle jets. ...Calorimeters, like other detection systems, must be able to meet these increasingly challenging performance requirements. In the prospective TeV-scale Muon Collider, the primary hurdle in designing detectors and devising event reconstruction algorithms is the challenge posed by Beam-Induced Background (BIB). Nevertheless, it is conceivable to mitigate the impact of BIB on the Muon Collider's calorimeter by capitalizing on certain characteristics and ensuring key features such as high granularity, precise timing, longitudinal segmentation, and superior energy resolution. This is what the here described Research and Development is trying to achieve with an innovative semi-homogeneous electromagnetic calorimeter constructed from stackable and interchangeable modules composed of lead fluoride crystals (PbF2). These modules are equipped with surface-mount UV-extended Silicon Photomultipliers (SiPMs) and are collectively referred to as the Crilin calorimeter (CRystal calorImeter with Longitudinal INformation). The challenge lies in making sure this calorimeter can operate effectively within an extremely harsh radiation environment, enduring an annual neutron flux of <inline-formula> <tex-math notation="LaTeX">10^{14}~n_{1\text {MeV}}/\text {cm}^{2} </tex-math></inline-formula> and a total ionizing dose (TID) of 10 kGy. In this article, the radiation tolerance measured in several irradiation campaigns is discussed, and the timing performances during a test beam at CERN-H2 with 120-GeV electrons. Additionally, a description of the latest prototype, Proto-1, is provided together with the results of the latest low-energy beam test at the LNF beam test facility (BTF) with 450 MeV electrons.
Laser-induced fluorescence (LIF), Raman spectroscopy and X-ray (XRF) fluorescence were used to study two frescoes at the S. Alexander catacombs complex, in Rome. LIF analysis has shown the presence ...of a transparent protective material probably deposited in previous restoration treatments and allowed to clearly distinguish the areas undergoing the current restoration process from the ones which still have to be treated. Raman and XRF analysis allowed to non-destructively characterizing most of the pictorial materials used for the artworks, including calcite (CaCO3), red ochre (Fe2O3), minium (Pb3O4), yellow ochre (α-FeOOH) and others. Therefore, thanks to the complementarity of the above-mentioned techniques, it was possible to obtain a detailed characterization of the studied frescoes. Finally, the whole ensemble of results constituted a valid tool to effectively plan the restoration of the frescoes.
Highlights•Multi-analytical non-invasive in-situ study of IV A.C. Roman frescoes performed.•Former transparent consolidants of previous restorative intervention identified.•The current restorative intervention assessed by means of multispectral (LIF) imaging.•Pigments from the Roman period identified by means of Raman and X-ray fluorescence spectroscopy. Display omitted
Analysis and understanding of wall erosion, material transport and fuel retention are among the most important tasks for ITER and future devices, since these questions determine largely the lifetime ...and availability of the fusion reactor. These data are also of extreme value to improve the understanding and validate the models of the in vessel build-up of the T inventory in ITER and future D-T devices. So far, research in these areas is largely supported by post-mortem analysis of wall tiles. However, access to samples will be very much restricted in the next-generation devices (such as ITER, JT-60SA, W7-X, etc) with actively cooled plasma-facing components (PFC) and increasing duty cycle. This has motivated the development of methods to measure the deposition of material and retention of plasma fuel on the walls of fusion devices in situ, without removal of PFC samples. For this purpose, laser-based methods are the most promising candidates. Their feasibility has been assessed in a cooperative undertaking in various European associations under EFDA coordination. Different laser techniques have been explored both under laboratory and tokamak conditions with the emphasis to develop a conceptual design for a laser-based wall diagnostic which is integrated into an ITER port plug, aiming to characterize in situ relevant parts of the inner wall, the upper region of the inner divertor, part of the dome and the upper X-point region.
The Mu2e experiment at Fermilab searches for the charged-lepton flavor violating (CLFV) conversion of a negative muon into an electron in the field of an aluminum nucleus, with a distinctive ...signature of a monoenergetic electron of energy slightly below the muon rest mass (104.967 MeV). The Mu2e goal is to improve by four orders of magnitude the search sensitivity with respect to the previous experiments. Any observation of a CLFV signal will be a clear indication of new physics. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter, and an external veto for cosmic rays surrounding the solenoid. The calorimeter plays an important role in providing particle identification capabilities, a fast online trigger filter, a seed for track reconstruction while working in vacuum, in the presence of 1-T axial magnetic field and in a harsh radiation environment. The calorimeter requirements are to provide a large acceptance for 100-MeV electrons and reach at these energies: 1) a time resolution better than 0.5 ns; 2) an energy resolution <10%; and 3) a position resolution of 1 cm. The calorimeter design consists of two disks, each one made of 674-undoped cesium iodine crystals read by two large area arrays of UV-extended silicon photomultipliers (SiPMs). We report here the construction and the test of the Module-0 prototype. The Module-0 has been exposed to an electron beam in the energy range around 100 MeV at the Beam Test Facility in Frascati. Preliminary results of timing and energy resolution at normal incidence are shown. A discussion of the technical aspects of the calorimeter engineering is also reported in this paper.
Single and double pulse laser-induced breakdown spectroscopy (LIBS) was carried out on aluminum samples in air. In the case of double pulse excitation, experiments were conducted by using the same ...laser source operated at the same wavelength (1064 nm in most cases here presented). A lowering of the second pulse plasma threshold was observed, together with an overall enhancement in line emission for the investigated time delay between the two pulses (40–60 μs). The laser-induced plasma originated by a single and double pulse was investigated near ignition threshold with the aim to study possible dynamical mechanisms in different regimes. Currently available spectroscopic diagnostics of plasma, such as the line broadening and shift due Stark effects, have been used in the characterization in order to retrieve electron densities, while standard temperature measurements were based on Boltzmann plot. Plasma relevant parameters, such as temperature and electron density, have been measured in the plasma decay on a long time scale, and compared with crater shape (diameter and inferred volume). The comparison of double with single pulse laser excitation was carried out while keeping constant the energy per pulse; the influence of laser energy was investigated as well. Results here obtained suggest that use of the double pulse technique could significantly improve the analytical capabilities of LIBS technique in routine laboratory experiments.
Laser-induced breakdown spectroscopy (LIBS) has been performed on immersed solid samples with different grades of surface roughness and material homogeneity and on bulk water solutions. The ...underwater plasma was produced by applying double-pulse excitation at 1064 nm, with different sets of laser pulse energies. LIBS spectra were recorded separately for each couple of laser pulses in order to monitor shot-to-shot plasma behavior and to apply signal post processing. The latter was aimed at improving the detection limits for elemental analyses. Except in the case of flat homogeneous solid samples at high laser pulse energies, the measurements were affected by strong shot-to-shot signal oscillations. Automatic elimination of low intensity spectra reduced the detection limit up to a factor of seven. The optimum level for spectral filtering depends strongly on sample properties. For bulk water, a poor correlation was observed between the peak line intensities and the plasma continuum emission, making the peak-to-background ratio unsuitable for internal standardization purposes. The analytical performance of LIBS for bulk liquid was also affected by the spatial fluctuations of the breakdown location, a phenomenon known as “moving breakdown” in the literature, which was responsible for the signal depletion in the detection region. In preliminary measurements on water solutions, the detection limit of 0.2 mg/l for magnesium has been obtained after applying data post processing.
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► Description of a LIBS set-up as remote diagnostics in new generation fusion machines. ► Identification of the atomic composition of samples simulating plasma facing components. ► ...Submicrometric resolution in depth profiling the elemental composition of the samples. ► Identification of elements present in traces or as impurities on the sample surface. ► Discussion on the applicability of the Calibration Free method for quantitative analysis.
The occurrence of several plasma-wall interaction processes, eventually affecting the overall system performances, is expected in a working fusion device chamber. Monitoring the changes in the composition of the plasma facing component (PFC) surface layer, as a result of erosion and redeposition mechanisms, can provide useful information on the possible plasma pollution and fuel retention. To this aim, suitable diagnostic techniques able to perform depth profiling analysis of the superficial layers on the PFCs have been developed. Due to the constraints commonly found in fusion devices, the measuring apparatus must be non invasive, remote and sensitive to light elements. These requirements make LIBS (Laser Induced Breakdown Spectroscopy) an ideal candidate for on-line monitoring the walls of current and of next generation (as ITER) fusion devices. LIBS is a well established tool for qualitative, semi-quantitative and quantitative analysis of surfaces, with micro-destructive characteristics and some capabilities for stratigraphy.
In this work, LIBS depth profiling capability has been verified for the determination of the composition of multilayer structures simulating plasma facing components covered with deposited impurity layers. A new experimental setup has been designed and realized in order to optimize the characteristics of a LIBS system working in vacuum conditions and remotely, two noticeable properties for an ITER-relevant diagnostics.
A quantitative analysis has been carried out in determining the elemental composition of the ITER-like samples.
Abstract
The measurement of physics processes at new energy frontier
experiments requires excellent spatial, time, and energy resolutions
to resolve the structure of collimated high-energy jets. In a ...future
Muon Collider, the beam-induced backgrounds (BIB) represent the main
challenge in the design of the detectors and of the event
reconstruction algorithms. The technology and the design of the
calorimeters should be chosen to reduce the effect of the BIB, while
keeping good physics performance. Several requirements can be
inferred: i) high granularity to reduce the overlap of BIB particles
in the same calorimeter cell; ii) excellent timing (of the order of
100 ps) to reduce the out-of-time component of the BIB; iii)
longitudinal segmentation to distinguish the signal showers from the
fake showers produced by the BIB; iv) good energy resolution (less
than 10%/
√E
) to obtain good physics performance, as has
been already demonstrated for conceptual particle flow calorimeters.
Our proposal consists of a semi-homogeneous electromagnetic
calorimeter based on lead fluoride crystals (PbF
2
) read out by
surface-mount UV-extended Silicon Photomultipliers (SiPMs): the
Crilin calorimeter. In this paper, the performance of the Crilin
calorimeter in the Muon Collider framework for hadron jets
reconstruction has been analyzed. We report the characterisation of
individual components together with the development of a small-scale
prototype, consisting of 2 layers of 3 × 3 crystals each.
The study of plasma-wall interactions is of paramount importance for continuous and fault free operations in thermonuclear fusion research to monitor the damages of plasma facing components (PFCs), ...plasma pollution from impurities and wall retention of hydrogen isotopes, like tritium. These needs make laser-induced-breakdown-spectroscopy (LIBS) a suitable candidate for a real time monitoring of PFCs in the current and next generation fusion devices, like ITER. It is also worthwhile for the quantitative analysis of surfaces, with micro-destructivity of the sample and depth profiling capabilities with sub-micrometric sensitivity. In this paper LIBS spectroscopy is exploited as a valid diagnostic tool for PFCs at the ENEA Research Center in Frascati (Italy) and at the Institute of Plasma Physics and Laser Microfusion (IPPLM) of Warsaw (Poland). The activities have been focused on LIBS characterization of samples simulating PFCs surfaces eroded/redeposited or contaminated from nuclear fuel after or during the normal operation of the reactor.
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