Development of wavelength shifter coated reflectors for the ArDM argon dark matter detector

To optimise the design of the light readout in the ArDM 1-ton liquid argon dark matter detector, a range of reflector and WLS coating combinations were investigated in several small setups, where argon scintillation light was generated by radioactive sources in gas at normal temperature and pressure and shifted into the blue region by tetraphenyl butadiene (TPB). Various thicknesses of TPB were deposited by spraying and vacuum evaporation onto specular 3MTM-foil and diffuse Tetratex® (TTX) substrates. Light yields of each reflector and TPB coating combination were compared. Reflection coefficients of TPB coated reflectors were independently measured using a spectroradiometer in a wavelength range between 200 and 650 nm. WLS coating on the PMT window was also studied. These measurements were used to define the parameters of the light reflectors of the ArDM experiment. Fifteen large 120 × 25 cm2 TTX sheets were coated and assembled in the detector. Measurements in argon gas are reported providing good evidence of fulfilling the light collection requirements of the experiment

Implementazione del modello SWAT per uno studio metodologico sull'utilizzo dei dati di un modello meteorologico a scala regionale in un modello idrologico a scala di bacino

In questo lavoro si è cercato di accostare due campi di ricerca tradizionalmente separati: la meteorologia, che verrà introdotta nella prima parte, e l’idrologia, di cui si parlerà nella seconda. Entrambe hanno come scopo la previsione di eventi naturali, quali, per esempio, gli uragani e le alluvioni per la meteorologia e le onde di piena, per l’idrologia. In questo lavoro utilizzeremo una gerarchia di applicazioni: limited area model (LAM), per quanto riguarda la meteorologia, geographic information systems (GIS), per la gestione della topografia e l’utilizzo del suolo ed il modello Soil and Water Assesment Tool (SWAT), per l’idrologia, mediante le quali, a partire dalla scala globale, saremo in grado di simulare un vento di precipitazione intensa e a simulare i suoi effetti in termini di deflusso al suolo. Il caso di studio è relativo ad un evento di precipitazione particolarmente intenso verificatosi nel novembre del 1999 in Sardegna. Le numerose problematiche legate all’integrazione dei tre strumenti applicativi e dei risultati provenienti da ognuno di essi (si pensi al downscaling dei campi di precipitazione per passare dalla scala regionale a quella di bacino) non verranno affrontate perché non sono lo scopo di questo lavoro. Si sono effettuate una serie di simulazioni idrologiche usando l’interfaccia GIS di SWAT2000 partendo dai dati di precipitazione generati dal modello atmosferico sulla Sardegna e effettuando un confronto con i risultati ottenuti mediante dati di precipitazione misurati al suolo e dati costruiti teoricamente

role of the Wikidata librarian in a renewed Bibliographical Universe: "next generation metadata", next generation librarians

Starting from a brief analysis of the OCLC Research report "Next generation metadata", the contribution proposes a reflection on the librarian metadata and the new centrality of its role in the LIS; among the various declinations that can assume such professional figure, One of the most interesting is the Wikidata librarian, of which a first definition is outlined. Following some international experiences of the use of Wikidata as a tool for new working methods, already consolidated in many library institutions, and as a particularly suitable environment for experimentation, thanks to its features of open, free, collaborative, easy to understand and use system. While information professionals and a large part of the academic and scientific environment have understood the potential of Wikidata, some weaknesses of this instrument have been highlighted, which must be corrected and recalibrated in the name of universally accessible and reusable knowledge, also taking into account the requirements contained in the Semantic Web Manifesto by the Cataloging and Indexing Study Group of the Italian Association of Libraries

Study of nuclear recoils in liquid argon with monoenergetic neutrons

For the development of liquid argon dark matter detectors we assembled a setup in the laboratory to scatter neutrons on a small liquid argon target. The neutrons are produced mono-energetically (E_kin=2.45 MeV) by nuclear fusion in a deuterium plasma and are collimated onto a 3" liquid argon cell operating in single-phase mode (zero electric field). Organic liquid scintillators are used to tag scattered neutrons and to provide a time-of-flight measurement. The setup is designed to study light pulse shapes and scintillation yields from nuclear and electronic recoils as well as from {\alpha}-particles at working points relevant to dark matter searches. Liquid argon offers the possibility to scrutinise scintillation yields in noble liquids with respect to the populations of the two fundamental excimer states. Here we present experimental methods and first results from recent data towards such studies.Comment: 9 pages, 8 figures, proceedings of TAUP 2011, to be published in Journal of Physics: Conference Series (JCPS

The Argon Dark Matter Experiment (ArDM)

The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for the detection of dark matter particles which can scatter off the spinless argon nuclei. These events producing a recoiling nucleus will be discerned by their light to charge ratio, as well as the time structure of the scintillation light. The experiment is presently under construction and will be commissioned on surface at CERN. Here we describe the detector concept and give a short review on the main detector components.Comment: Proceedings of 4th Patras workshop (DESY) on Axions, Wimps and Wisps (4 pages, 4 figures

Dust signatures observed in atmospheric aerosols and related to radiative transfer algorithms

The Natural Sources of pollutants, such as Sahara desert dust outbreaks or ashes from vulcanoes, in many cases, could grow the bad air quality forecast and PM limits values measured could exeed the European Law recomendations, in that case the country have to pay to the Community if an evidence of that is a Natural Pollutant is not brought to the European Court. The goal to control air quality could be reached studying the pollution sources, the dispersion with atmospheric model, the chemical reactions occurring and also the study of air depositions. Exeedences of air quality limit value represent breaches of Community law which can have significant legal consequences for the European Member States. For some existing limit values, such as those in the directive 1999/30/EC (first daughter Directive), an exeedence which is caused by particular natural sources can be ignored for the purpose of ensuring compliance with Community law; article 2.15 of the first daughter directive defines “natural events” as volcanic eruptions, seismic activities, geothermal activities, wild-land fires, high wind events or the atmospheric resuspension or transport of natural particles from dry regions. The next air quality directive will likely extend this principle to natural (i.e. Non anthropogenic) sources of pollution generally so long as the “natural contribution” can be quantified and documented. Particle Matters (PM) emissions sources are sea-spray, soil moved by wind, biogenic aerosols, volcanic emissions, forest fires, and anthropogenic sources. The EU legislation give limits for mobile emission, there are many like the Euro X limitation for private cars (gasoline and diesel). To control the road transport emissions there is a common trend of modification of the engines technology, the reduction of traffic in big city centre, the use of Pb and S free fuel, the promotion of the use of renewable energy and the use of alternative fuel. A cure strategy is post combustion treatment. The aim of this PhD work is to present a new way to approach radiative tranfer on air when dust episodes occurs, and to start a study/work group able to inform, with quality and quantity data, on natural sources of air pollution, capable to discuss with other governative and regional organizations such as ARPAS (with monitoring in site stations or mobile devices), and POLARIS 's entrerprises, which main topic is dealing with Environmental Science and Air quality. It is globally achieved that dust is part of natural aerosols quantity in air, with dimension from 1 to 10 microns, and could affect both human health, for breath disease, and local climate system, or global as well. Dust could reach Mediterranean and South European countries because of the local meteorology, the source points are often in the Sahara desert. Using Satellites Spectroradiometry we could detect and visualise dust over land and oceans. We used three Modis combination bands into the multispectral data analysis toolkit HYDRA (HYperspectral data viewer for Development if Research Application): a simple algorithm is showed with the help of HYDRA software, that help scientists to see dust easly without any other processed data. A case study is showed over the South West Mediterranean Area, near Tunisia and Lybia, but could be used for any other case and area of the world

Damage of calcarenite stone in archaeological site: relationship between wheathering, pollution and biological agents

For thousand of years, when magnificence and beauty were the goals of architecture, stones were the most widely used durable materials. The deterioration of building stones causes irreparable damages to our cultural heritage, not only as loss of architecture and ancient art, but especially as loss of symbols of human cultural identity and continuity. Sun, frost, wind, rain, pollution etc. contribute to a gradual process of weathering. Biological activity also plays a role and its association with physico-chemical phenomena should be considered essential for understanding long term deterioration. In this contest appear necessary to understand the weight of each single environmental parameter in order to assess and to plan not only a suitable restoration project and a preventive maintenance but also to test natural products (specific biocides) to be used to limit the degradation caused by bio deterioration agents We studied the influence and synergistic effects of climatic parameters (temperature, light irradiation, wind intensity, humidity), pollution (SO2, CO, NO2, Ozone and heavy metals), and biological attacks on a building placed between an archaeological site of Lavello, a little town located in the Basilicata Region, and the industrial area surrounding this town. Moreover, X-ray diffraction, X-ray induced photoelectron spectroscopy (XPS), X-ray fluorescence spectrometry (XRF), ground penetrating radar and geo-electrical measurements (GPR and MGE), Fourier Transform Infrared spectroscopy (FT-IR) and biological investigations were carried out on powdered calcarenite and on stones samples. Preliminary results show that climatic parameters and pollution undermine the structure and the compactness of stones (i.e. micro-fractures, increase of salts’ concentration) favouring the biological colonization (bacteria, mushrooms and lichens) especially in south–east direction of prevailing winds