SMALL, PRECISE AND POWERFUL: MACHINA, THE ACCELERATOR FOR THE CULTURAL HERITAGE

madonnacardellino leonardoA next-generation accelerator resulting from the collaboration between the National Institute for Nuclear Physics and CERN, dedicated entirely to the cultural heritage. This is the identity card of the MACHINA (Movable Accelerator for Cultural Heritage In-situ Non-destructive Analysis) project for the construction, at the laboratories of the Opificio delle Pietre Dure (OPD) in Florence, of a compact, transportable accelerator, based on radio frequency quadrupole technology(HF-RFQ) developed at CERN, dedicated full-time to non-invasive diagnostic studies for the restoration and study of materials of historical finds and works of art. The project has a funding of 1.7 million euros. In recent years, diagnostic techniques for the study of the cultural heritage have undergone significant technological development that has led to an increase in the demand for scientific support by art historians, archaeologists, restorers, curators and other cultural heritage experts. In parallel, the national INFN-CHNet (Cultural Heritage Network) has been established at INFN which brings together over 15 research groups specialised in this field. Among these, the Laboratory for Nuclear Techniques for the Cultural Heritage and the Environment (LABEC) in Florence where, since 2004, a particle accelerator has been used also for analysis of the cultural heritage, with which, thanks to the collaboration with OPD, many works of art and finds have been studied, including masterpieces by Leonardo, Mantegna, Antonello da Messina, etc. Thanks to the development of new portable instrumentation, researchers are increasingly moving around, avoiding the delicate (and sometimes impossible) transportation of works of art, often however at the expense of analysis performance, normally lower than that obtained in fixed laboratories . Hence the idea to build MACHINA, a new transportable accelerator fully dedicated to cultural heritage applications, based at the Opificio delle Pietre Dure in Florence and which may also be used for short periods in other European laboratories and museums. MACHINA will be implemented with technology developed at CERN for biomedical applications, called radio frequency quadrupole technology, that will allow a high precision and small size (approx. 2 metres long and weighing 300 kg) accelerator to be built, allowing it to be transported in places where large immovable works (e.g. frescoes) or works which cannot be transported due to their fragile preservation conditions are preserved. The project will see the involvement of the INFN-CHNet cultural heritage network and will constitute a first step towards achieving high-performance portable instrumentation. Physics and art, a collaboration that has led to important discoveries The Opificio delle Pietre Dure is a MiBact national institute dedicated to the preservation of works of art through operational activity, research and training. In all these areas, the collaboration between OPD and major research institutes, such as INFN, has proved to be of crucial importance over time and has allowed constant innovations and improvements in the quality of its results. Thanks to the collaboration with OPD, the INFN laboratories have been the protagonists over the years in scientific investigations on works of art by leading Italian artists, mainly by means of particle accelerator measurements (for dating with the carbon-14 method and for ion-band analyses, which are used to discover the constituent chemical elements of a material in a non-destructive manner) and X-ray techniques, such as X-rays, CAT scans and X-ray fluorescence (another technique for analysing the constituent materials of a work). Over the years, many masterpieces of various kinds have been analysed: paintings on canvas and wood such as the Portrait of Trivulzio by Antonello da Messina, the Madonna with Child by Mantegna, the Mute Woman by Raffaello and the Adoration of the Magi by Leonardo, terracottas by Luca della Robbia, drawings by Leonardo and Filippino Lippi and detached frescoes such as the Sant'Agostino in Botticelli's studio.

DAMPE: IN SEARCH OF DARK MATTER IN COSMIC RAYS

DAMPE LAncio2 The scientific journal Nature has published the first results of the DAMPE (DArk Matter Particle Explorer) experiment, in orbit on a satellite since December 2015. The experiment measures the flow of very high energy cosmic electrons and positrons (from 55 GeV to 4.6 TeV). For the first time, the direct measurement of these particles in space highlights and measures a sharp change, in jargon "break", in their flow according to energy: at energies exceeding 0.9 TeV, the electron and positron flow changes and "dips", decreasing more rapidly with increasing energy. This phenomenon had recently been measured only by ground experiments, with indirect observations, with much greater uncertainty and results still partly preliminary. DAMPE, the first Chinese astrophysical satellite, is one of the five space mission projects of the Strategic Pioneer Program on Space Science of the Chinese Academy of Science (CAS). It is an international collaboration involving more than 100 scientists, technicians and students from Chinese, Italian and Swiss institutions led by the CAS Purple Mountain Observatory (PMO). Italy is involved with a research group of approx. twenty scientists form the Perugia, Bari and Lecce sections of the National Institute for Nuclear Physics and the Universities of Perugia, Bari and Salento. The detector has been designed to measure the flows of electrons, photons, protons and nuclei, with a greater precision and energy range than the already active experiments. The importance of the recent DAMPE measurement is related to the research and study of the electron and positron sources at TeV energies, whether they are objects of an astrophysical nature - for example, pulsars - or whether their presence is partly due to dark matter, as it would seem possible given the characteristics of the positron flow observed up to those energies by the AMS-02 experiment on the International Space Station. Launched on 17 December 2015 from the Chinese Jiuquan Satellite Launch Center in the Gobi Desert, DAMPE orbits at a distance of approx. 500 km, from which it tries to detect possible signals of the presence of dark matter by studying the characteristics of ordinary cosmic particles. In its first 530 days of scientific activity, starting from 8 June of this year, it has detected 1.5 million cosmic electrons and positrons with energies exceeding 25 GeVs: data characterised by an unprecedented energy resolution and level of contamination from background particles. Thanks to these characteristics, the detector is able to measure the direction of arrival of the cosmic photons with great accuracy and, at the same time, to differentiate the nuclear species that make up the cosmic rays and their trajectory. DAMPE is also capable of measuring the flow of nuclei in the range between 100 GeV and 100 TeV, thus providing new data and information to understand the origin and propagation of high energy cosmic rays. DAMPE has a total weight of approx. 1900 kg, of which 1400 kg are represented by the four scientific experiments, including the heart of the detector, the silicon tracker, entirely built by Italian researchers with the coordination of the INFN. The technology of this detector - originally developed in the 80's for elementary particle physics experiments in accelerators - was used for the first time in space by Italian physicists with the AMS-01 experiment, which flew for ten days on the Discovery Space Shuttle in 1998. This was followed by other experiments - such as PAMELA and FERMI on satellites, and AMS-02 on the ISS - all operating since many years in orbit around the Earth. DAMPE is part of a programme of space missions, such as those mentioned above, but also of terrestrial such as CTA-MAGIC, AUGER and Advanced VIRGO, or submarine observatories, such as Km3net, with the aim of studying all the messengers of the cosmos. It will thus be possible to study the most hidden properties of the universe with a strongly synergistic approach.

INAUGURATION OF CUORE: THE COLD GIANT STUDYING NEUTRINOS

cuore2On 23 October, at the Gran Sasso National Laboratories (LNGS) of INFN, the CUORE (Cryogenic Underground Observatory for Rare Events) experiment, the largest cryogenic detector ever built, designed to study the properties of neutrinos, was inaugurated. In the first two months of data collection, the experiment has operated with extraordinary precision, fully satisfying the expectations of the physicists who built it and significantly restricting, already at this very first phase, the region in which to look for the rare phenomenon of double beta decay without neutrino emission, the main scientific objective of the experiment. Detecting this process would make it possible not only to determine the mass of neutrinos, but also to demonstrate their potential nature as Majorana particles, providing a possible explanation for the prevalence of matter over antimatter in the universe. The CUORE detector is a 741 kilogram giant implemented with a technology based on ultra cold cubic tellurite crystals designed to operate at very low temperatures: 10 thousandths of a degree above absolute zero (-273.15°C). Its structure comprises19 towers each consisting of 52 tellurite crystals purified from any contaminants. The most difficult technological challenge faced by the experiment was the implementation of the cryostat, able to keep the 19 towers suspended inside it at a few thousandths of a degree above absolute zero. The experiment works in extremely pure environmental conditions, in particular with very low levels of radioactivity. The cryostat is, in fact, shielded from the shower of particles coming from the cosmos both by the 1400 metres of rock of the Gran Sasso massif and by a special protective shield, made by casting lead ingots recovered from a Roman ship sunk over 2000 years ago, off the coast of Sardinia. CUORE therefore uses a technology unique in the world for unprecedented precision, a result that has required more than ten years of work. The prototype called Cuore-0, consisting of a single tower in operation from 2013 to 2015, preceded CUORE and whose first results were announced in April 2015.