The possibility of a relevant contribution of biomass burning for domestic heating to PM10 in the urban area of Rome was explored. The concentration of levoglucosan was determined for 31 months in ...Rome and in a nearby peri-urban area. During the cold season it reached several hundreds of ng/m3 at both sites, with a clear inverse relationship with air temperature. During the summer it remained well below 100 ng/m3. Although at the peri-urban station the concentration was about 50% higher than at the urban site, the two seasonal patterns show a very good agreement (R2 = 0.95), pointing at a main contribution of biomass burning in both areas.
Additional information came from the comparison of the 2-h time pattern of levoglucosan and the mixing conditions of the atmosphere, evaluated by monitoring natural radioactivity. During the summer levoglucosan concentration followed the pattern of natural radioactivity, indicating a contribution from many small sources scattered on a wide area (wildfires, barbecues, agricultural fires). During the heating season the activity of a source that switched in the early afternoon and switched off before midnight was highlighted. A 2-h delay between levoglucosan time patterns at the peri-urban and the urban site suggests that biomass burning mainly occurs outside Rome and the combustion products are then transported towards the city centre.
Biomass burning contribution to PM10 was estimated as 12% at the peri-urban site and 6.7% inside the city, with relevant implications for the health of the about 2.800.000 citizens living in the urban area of Rome.
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•During the winter we measured high levoglucosan concentrations in the area of Rome.•The concentration increased in the early afternoon and decreased after midnight.•In the peri-urban area we measured higher values and a 2-h shift with respect to Rome.•A substantial transport from the peri-urban area to the city centre was recognized.•The average contribution of biomass burning to PM10 in the urban area was 6.7%.
The seasonal variability in the mass concentration and chemical composition of atmospheric particulate matter (PM₁₀ and PM₂.₅) was studied during a 2-year field study carried out between 2010 and ...2012. The site of the study was the area of Ferrara (Po Valley, Northern Italy), which is characterized by frequent episodes of very stable atmospheric conditions in winter. Chemical analyses carried out during the study allowed the determination of the main components of atmospheric PM (macro-elements, ions, elemental carbon, organic matter) and a satisfactory mass closure was obtained. Accordingly, chemical components could be grouped into the main macro-sources of PM: soil, sea spray, inorganic compounds from secondary reactions, vehicular emission, organics from domestic heating, organics from secondary formation, and other sources. The more significant seasonal variations were observed for secondary inorganic species in the fine fraction of PM; these species were very sensitive to air mass age and thus to the frequency of stable atmospheric conditions. During the winter ammonium nitrate, the single species with the highest concentration, reached concentrations as high as 30 μg/m³. The intensity of natural sources was fairly constant during the year; increases in natural aerosols were linked to medium and long-range transport episodes. The ratio of winter to summer concentrations was roughly 2 for combustion product, close to 3 for secondary inorganic species, and between 2 and 3 for organics. The winter increase of organics was due to poorer atmospheric dispersion and to the addition of the emission from domestic heating. A similar winter to summer ratio (around 3) was observed for the fine fraction of PM.
The Electron-Ion collider (EIC) will be the ultimate facility to study the dynamics played by colored quarks and gluons in the phenomenology of nucleons and nuclei, described by Quantum ...Chromodynamics. The physics programs will greatly rely on efficient particle identification (PID) in both the forward and the backward regions. The forward and the backward RICHes of the EIC have to be able to cover wide acceptance and momentum ranges; in the forward region a dual radiator RICH (dRICH) is foreseen and in the backward region a proximity-focusing RICH can be foreseen to be employed. The geometry and the performance studies of the dRICH have been performed as prescribed in the EIC Yellow Report using the ATHENA software framework. This part of our work reports the effort following the call for EIC detector proposal and the studies related to the forward and the backward RICH performance. In the forward region, the dRICH performance showed a pion- kaon separation from around 1 GeV/c to 50 GeV/c at a three sigma level; the proximity focusing RICH (pfRICH) foreseen for the backward region can reach three sigma separation up to 3 GeV/c for e/π and up to 10 GeV/c for π/K mass hypotheses.
The next generation of gaseous photon detectors is requested to overcome the limitations of the available technology, in terms of resolution and robustness. The quest for a novel photocathode, ...sensitive in the far vacuum ultra violet wavelength range and more robust than present ones, motivated an R&D programme to explore nanodiamond based photoconverters, which represent the most promising alternative to cesium iodine. A procedure for producing the novel photocathodes has been defined and applied on THGEMs samples. Systematic measurements of the photo emission in different Ar/CH4 and Ar/CO2 gas mixtures with various types of nanodiamond powders have been performed. A comparative study of the response of THGEMs before and after coating demonstrated their full compatibility with the novel photocathodes.
The COMPASS RICH-1 detector has undergone a major upgrade in 2016 with the installation of four novel MPGD-based photon detectors. They consist of large-size hybrid MPGDs with multi-layer ...architecture composed of two layers of Thick-GEMs and bulk resistive MicroMegas. A dedicated high voltage power supply system, based on CAEN HV modules, has been built and put in operation: it controls more than 100 HV channels. The system is required to protect the detectors against errors by the operator, monitor voltages and currents at a 1 Hz rate and automatically react to detector misbehavior. It includes also a HV compensation system against environmental pressure and temperature variation to grant the detector stability. The operation of a MPGD based single photon detector poses challenging requirements to the high voltage power supply systems employed in terms of high-resolution diagnostic features and dynamic voltage control. Systems satisfying all the needed features are not commercially available; for this reason a novel single channel high voltage system matching the MPGD needs has been designed and realized. In this article the COMPASS RICH-1 MPGD HV system implementation is described as well as its performance in terms of stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS. The design, implementation and performance of a novel HV power supply system based on DC to DC converters and controlled by a FPGA device is presented. The capabilities of the first prototype of the new single HV channel power supply are illustrated when operated with a MPGD based single photon detector during a test beam exercise. The preliminary result of the multi channel system are briefly discussed.
The proposed new Electron–Ion Collider poses a technical and intellectual challenge for the detector design to accommodate the long-term diverse physics goals envisaged by the program. This requires ...a 4π detector system capable of reconstructing the energy and momentum of final state particles with high precision. The Electron-Ion Collider also requires identification of particles of different masses over a wide momentum range.
A diverse spectrum of Particle IDentification detectors has been proposed. Of the four types of detectors for hadron identification, three are based on Ring Imaging Cherenkov Counter technologies, and one is realized by the Time of Flight method. The quest for a novel photocathode, sensitive in the far vacuum ultraviolet wavelength range and more robust than cesium iodide, motivated an R&D programme to explore nano-diamond (ND) based photocathodes, started by a collaboration between INFN and CNR Bari and INFN Trieste. Systematic measurements of the photoemission in different Ar:CH4 and Ar:CO2 gas mixtures with various types of ND powders and Hydrogenated ND (H-ND) powders are reported. A first study of the response of THGEMs coated with different photocathode materials is presented.
The progress of this R&D programme and the results obtained so far by these exploratory studies are described.
A ten-month field study aimed to determine the contribution of natural events (i.e. sea-salt and mineral dust events) to urban PM concentration was carried out at six sampling sites in Central Italy ...(Lazio region). Four indicators have been used to identify natural events during the period of the study. The first one is constituted by the ratio between number of particles in the coarse to the accumulation mode. It is simple, cheap, and the information are given in quasi-real time, but the nature of the event (sea-salt or mineral dust) is not detectable. The second indicator relies on the chemical analysis of the collected PM by X-ray fluorescence (XRF) and allows a robust identification of sea-salt and crustal components. The third one is based on diagnostic ratios of elemental fractions: Mg
extractable/Ti
residue for sea-salt and Ti
residue/Sb
residue for mineral dust. It requires skilled staff but it is most accurate and sensible. The last indicator, constructed on the basis of natural radioactivity data, is not diagnostic for the nature of the event but it is able to estimate the increase in PM concentration with respect to the expected concentration in the absence of natural events.
The relevance of natural events and the variations in PM concentration and composition during the study are discussed. The joined use of the four indicators allowed the identification of about 20 natural PM episodes. In general, sea-salt aerosol events did not cause exceedance of the daily EU limit value for PM
10. Saharan dust events, instead, were in most cases responsible for the exceedance of the limit value at all stations.
The novel MPGD-based photon detectors of COMPASS RICH-1 consist of large-size hybrid MPGDs with multi-layer architecture including two layers of Thick-GEMs and a bulk resistive MicroMegas. The top ...surface of the first THGEM is coated with a CsI film which also acts as photo-cathode. These detectors have been successfully in operation at COMPASS since 2016. Concerning bias-voltage supply, the Thick-GEMs are segmented in order to reduce the energy released in case of occasional discharges, while the MicroMegas anode is segmented into pads individually biased with positive voltage while the micromesh is grounded. In total, there are about ten different electrode types and more than 20000 electrodes supplied by more than 100 HV channels, where appropriate correlations among the applied voltages are required for the correct operation of the detectors. Therefore, a robust control system is mandatory, implemented by a custom designed software package, while commercial power supply units are used. This sophisticated control system allows to protect the detectors against errors by the operator, to monitor and log voltages and currents at 1 Hz rate, and automatically react to detector misbehavior. In addition, a voltage compensation system has been developed to automatically adjust the biasing voltage according to environmental pressure and temperature variations, to achieve constant gain over time. This development answers to a more general need. In fact, voltage compensation is always a requirement for the stability of gaseous detectors and its need is enhanced in multi-layer ones.
In this paper, the HV system and its performance are described in details, as well as the stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS.
In high momenta range, the construction of a Ring Imaging CHerenkov (RICH) detector for the particle identification at the future Electron Ion Collider (EIC) is a complicated task. A compact collider ...setup imposes to construct a RICH with a short radiator length, hence limiting the number of photons. The number of photons can be increase by choosing to work in far UV region. However, as standard fused-silica windows are opaque below 165 nm, therefore, a windowless RICH approach could be a possible choice. In the far UV range, CsI is a widely used photo-cathode (PC) to detect photons, but because of its hygroscopic nature, it is very delicate to handle. Its Quantum Efficiency (QE) degrades in high intensity ion fluxes. These are the key reasons to search a novel, less delicate PC with sensitivity in the far UV region. Hydrogenated nanodiamond films are proposed as an alternative PC material and shown to have promising characteristics. The performance of nanodiamond PC coupled to THGEM-based detectors is the objects of our ongoing R & D.
The first phase of these studies includes the characterization of THGEMs coated with nanodiamont PC, the comparison of the effective QE in vacuum and in gaseous atmospheres, the hardness respect to the PC bombardment by ions from the multiplication process. The approach is described in detail as well as all the results obtained so far with these exploratory studies.
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