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The Osservatorio Polifunzionale del Chianti is a new astronomical site located in the neighbourhoods of San Donato in Poggio (Firenze), on top of one of the highest hills of the Chianti area, among the darkest places in Tuscany, and it is managed by the University of Florence. The name takes origin from the different observatories that are hosted in the building. Beside the Astronomical Observatory, Geo-seismic, Meteorological and Environmental Observatories fully operate in a fruitful synergic collaboration among themselves. Presently, the main research activity at OPC concerns the observation and follow-up of transiting exoplanets while the team is involved in national and international collaborations, like TESS SG1 follow-up for the observation of exoplanet candidates and GAPS, which exploits several telescopes and facilities in Italy (Asiago, OAVdA) and Canary Islands (HARPS-North and GIANO instruments as well as their improved combined version) for exoplanetary characterization. OPC researchers perform their activity in the framework of collaborations with Osservatorio Astrofisico di Torino and Osservatorio Autonomo della Val d'Aosta. From July 2017, to date, commissioning observing runs have been done in order to test the telescope and mount capabilities, systematics and limits and to eventually improve the accuracy of the overall system. A software algorithm has been developed1 in order to estimate the accuracy of any transit observation, so that parameters like the integration time and telescope focus can be chosen to obtain a higher signal to noise ratio, and also to understand the observational limits of the instruments. Currently, the system is able to work within+/-1 mmag of accuracy and differential photometry error (refer to the error bars in Figure 6) so that exoplanet transits with (see abstract for symbol _5 mmag) of relative depth can be observed fruitfully. The OPC Research Team also aims at the observation of the optical/visible counterpart of gamma ray bursts afterglows, supernovae and GW ToO (Gravitational Waves events / Targets of Opportunity) follow-up along with transiting exoplanets follow-up. The reason is twofold. First of all, the scientific interest on these events of the researchers supporting OPC, and then the demand of the astronomical community for follow-up observations with small telescopes, around the 1-m class, since larger telescopes are often used for primary targets observations. To pursue the target of observing GRBs and the optical counterpart of GW events, it is planned to improve the main instrument accuracy and to develop a consolidated observation procedure, to be ready for the next LIGO-VIRGO O3 run scheduled for the Autumn, 2018. more...

We built a multi-channel led starlight simulator capable to reproduce the radiation of stars of F, G, K and M spectral types in the wavelength range 365-940 nm. This range overlaps the photosynthetic active interval allowing us to use the simulator for biological experiments under radiation and atmospheric conditions close as much as possible to those expected on extrasolar planets. The simulator is a laboratory tool which is part of the “Atmosphere in a Test Tube” project, aimed to study the photosynthetic efficiency of bacteria under alien environmental conditions and their possible impact on the atmosphere of the host planet. This paper describes the software developed to control the simulator. We begin by presenting a conceptual overview of the instruments and then illustrating the top-level requirements and the architecture of the control software. Finally, we give a description of the graphical user interface. more...

The semi-inclusive deep inelastic electron scattering off transversely polarized $^3$He, i.e. the process, $e + \vec{^3 {\rm He}} \to e' + h+X$, with $h$ a detected fast hadron, is studied beyond the plane wave impulse approximation. To this end, a distorted spin-dependent spectral function of a nucleon inside an A=3 nucleus is actually evaluated through a generalized eikonal approximation, in order to take into account the final state interactions between the hadronizing system and the (A-1) nucleon spectator one. Our realistic description of both nuclear target and final state is a substantial step forward for achieving a reliable extraction of the Sivers and Collins single spin asymmetries of the free neutron. To illustrate how and to what extent the model dependence due to the treatment of the nuclear effects is under control, we apply our approach to the extraction procedure of the neutron single spin asymmetries from those measured for $^3$He for values of the kinematical variables relevant both for forthcoming experiments at Jefferson Lab and, with an exploratory purpose, for the future Electron Ion Collider. more...

The Visible and Near Infrared (VNIR) is one of the modules of EChO, the Exoplanets Characterization Observatory proposed to ESA for an M-class mission. EChO is aimed to observe planets while transiting by their suns. Then the instrument had to be designed to assure a high efficiency over the whole spectral range. In fact, it has to be able to observe stars with an apparent magnitude Mv= 9-12 and to see contrasts of the order of 10-4 - 10-5 necessary to reveal the characteristics of the atmospheres of the exoplanets under investigation. VNIR is a spectrometer in a cross-dispersed configuration, covering the 0.4-2.5 micron spectral range with a resolving power of about 330 and a field of view of 2 arcsec. It is functionally split into two channels respectively working in the 0.4-1 and 1.0-2.5 micron spectral ranges. Such a solution is imposed by the fact the light at short wavelengths has to be shared with the EChO Fine Guiding System (FGS) devoted to the pointing of the stars under observation. The spectrometer makes use of a HgCdTe detector of 512 by 512 pixels, 18 micron pitch and working at a temperature of 45K as the entire VNIR optical bench. The instrument has been interfaced to the telescope optics by two optical fibers, one per channel, to assure an easier coupling and an easier colocation of the instrument inside the EChO optical bench., 26 pages more...

Biological experiments in space and ongoing human space missions devoted to the solar system exploration require significant advancements in the radiation environment monitoring systems. Radiation hazard has to be continuously monitored and the biological damage should be evaluated within short time. In this paper, we review the use of polycrystalline diamond films as dosimeters for space applications. The charge trapped into deep intra-gap defect levels during radiation exposure, and released during a high-temperature thermal scan to give thermally stimulated current (TSC), has been integrated as a function of time to evaluate the absorbed dose. TSC results have been proved to give correct evaluation of the dose absorbed during the space mission, assessing the capabilities of synthetic diamond and TSC read-out system as a proper dosimetry technique for space applications. The capability of diamond films to detect low doses has been demonstrated down to the mGys range. The results of the application of these dosimeters in low Earth orbit space missions are described. more...

The possibility of improving the description of the semi-inclusive deep inelastic electron scattering off polarized 3He, that provides information on the neutron single spin asymmetries, is illustrated. In particular, the analysis at finite momentum transfers in a Poincare' covariant framework is outlined and a generalized eikonal approach to include final state interaction is presented., 4 pages, 2 figures, presented at The 22nd European Conference on Few Body Problems in Physics, Krakow, Poland, 9 - 13 September 2013 more...

In this work we report preliminary tests aimed at the implementation of a Silicon-On-Diamond (SOD) radiation sensor. SOD materials have been prepared by continuously scanning a 20 ps pulsed 355 nm laser beam on the silicon–diamond interface. A pixel monolithic sensor has also been bonded to diamond with the same technique and tested to show that a complex electronic chip can undergo the process without any damage. Through silicon vias have been fabricated by laser drilling on the silicon side of the SOD samples and their insulation from the silicon bulk has been tested. The charge collection efficiency of a diamond sensor with laser-written graphitic contacts has been measured, to demonstrate a reliable and simple way to fabricate ohmic contacts on the diamond side of the SOD devices. Finally, a SOD material with electric contacts on the silicon and on the diamond sides has been tested as a particle sensor to demonstrate the electrical continuity of the silicon–diamond interface after the bonding. more...

A polycrystalline Chemical Vapour Deposited (pCVD) diamond film has been processed to implement a bidimensional dosimeter for applications in clinical radiotherapy. The detector, with an area of 2.5×2.5 cm 2 and a thickness of 300 μ m , has been equipped with a matrix of electrical contacts (12×12 pixels) on the upper surface. The matrix of pixels has been electrically characterized in dark showing uniformity and very low leakage current. This study demonstrates that when applied bias is in the range 0–5 V, the pCVD diamond film provides very accurate measurement of dose and dose-rates under clinical 62 MeV proton beam, conventional 6–10 MeV photon beams, and Intensity Modulated Radiotherapy (IMRT) beams. more...

Simultaneous photon beam position and intensity monitoring is becoming of increasing importance for new generation synchrotron radiation sources and free electron lasers (FEL). Thus, novel concepts of beam diagnostics are required in order to keep such beams under control. From this perspective diamond is a promising material for the production of semitransparent in situ photon beam monitors, which can withstand the high dose rates occurring in such radiation facilities. Here, we report on the development of freestanding, single-crystal chemical-vapor-deposited diamond detectors with segmented electrodes. Due to their direct, low-energy band gap, InGaAs quantum well devices operated at room temperature may also be used as fast detectors for photons ranging from visible to X-ray. These features are valuable in low-energy and time-resolved FEL applications. In particular, a novel segmented InGaAs/InAlAs device has been developed and will be discussed. Dedicated measurements carried out on both these devices at the Elettra Synchrotron show their capability to monitor the position and the intensity of the photon beam with bunch-by-bunch temporal performances. Furthermore, preliminary tests have been performed on diamond detectors at the Fermi EEL, extracting quantitative intensity and position information for 100-fs-wide FEL pulses with a photon energy of 28.8 eV. (C) 2013 Elsevier B.V. All rights reserved more...

The interaction between electromagnetic radiation and bio-molecules in heterogeneous environments is a prebiotically relevant process. Minerals may have a pivotal role in the prebiotic evolution of complex chemical systems, mediating the effects of electromagnetic radiation, influencing the photostability of bio-molecules, catalyzing important chemical reactions and/or protecting molecules against degradation. In particular, nucleobases are relevant bio-molecules to investigate both in the prebiotic context, because they are coding components of nucleic acids, and from the standpoint of the survival of biological systems in space conditions. Several studies on the photodynamics of nucleobases suggest that their structure could have been naturally selected for the ability to dissipate electronic energy through ultrafast photophysical decay. Considering the putative involvement of minerals in the prebiotic chemistry, it is necessary to study the photostability of nucleobases under space conditions in the presence of mineral matrices, to investigate both the prebiotic processes that might have had a role in the development of the first living entities on Earth and the physical and chemical processes occurring in extraterrestrial environments. We focused our study on the characterization of the nature of the interaction between nucleobases and the surface of the minerals magnesium oxide and forsterite by infrared vibrational spectroscopy. We observed that most of the characteristic bands of pure nucleobases vanished when adsorbed on magnesium oxide. On the contrary, in the case of adenine and uracil adsorbed on forsterite, very intense nucleobase absorption peaks appeared. This phenomenon pertains to the surface selection rules changes related to molecular orientation. Moreover, based on the vibrational shifts, we deduced the molecular interaction sites with the mineral surfaces. Furthermore, we investigated the photostability of nucleobases adsorbed on such minerals through in situ UV irradiation experiments. Experimental results confirm the high intrinsic photostability of such molecules, because a rather low probability of interaction between UV radiation and nucleobases was estimated, and furthermore indicate that cytosine and hypoxanthine have a greater photostability compared to adenine and uracil, both pure and adsorbed onto magnesium oxide and forsterite. more...

article i nfo Diamond is one of the most promising materials for developing innovative electronic devices. Chemical va- pour deposition (CVD) homoepitaxial growth allows the synthesis of high quality single crystal diamond plates. However, the use of these crystals for electronic applications is hampered by their small area (typically of the order of 10 mm 2 ). Large areas are desired to ensure efficient particle or radiation detection with pixelated devices. By growing a thick CVD layer it is possible to enlarge the initial area of the substrate by a factor of 2 since growth also occurs laterally from the substrate. In this work, by using an X-ray collimated synchrotron radiation beam, the detection and charge collection properties of an enlarged CVD single-crystal diamond are used as a point-to-point probe to study the material quality. It was found that stress and dislocation density are correlated with the detection properties of the enlarged regions. The sensitivity of the device is affected by the vertical-to-lateral growth interface and the enlarged material quality seems to be correlated with the distance from this interface. more...

ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three present candidates for the next ESA medium-class science mission (M4) to be launched in 2026. During its 3.5 years of scientific operations from L2 orbit, this mission will observe spectroscopically in the infrared (IR) a large population of known transiting planets in the neighbourhood of the Solar System. The aim is to enable a deep understanding of the physics and chemistry of these exoplanets. ARIEL is based on a 1-m class telescope ahead of a suite of instruments: two spectrometer channels covering the band 1.95 to 7.80 µm and four photometric channels (two wide and two narrow band) in the range 0.5 to 1.9 μm. The ARIEL optical design is conceived as a fore-module common afocal telescope that will feed the spectrometer and photometric channels. The telescope optical design is based on an eccentric pupil two-mirror classic Cassegrain configuration coupled to a tertiary paraboloidal mirror. An all-aluminum structure has been considered for the telescope layout, and a detailed tolerance analysis has been conducted to assess the telescope feasibility. This analysis has been done including the different parts of the realization and life of the instrument, from integration on-ground to in-flight stability during the scientific acquisitions. The primary mirror (M1) temperature will be monitored and finely tuned via an active thermal control system based on thermistors and heaters. The heaters will be switched on and off to maintain the M1 temperature within ±1K thanks to a proportional-integral-derivative (PID) controller. more...

ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three present candidates for the next ESA medium-class science mission (M4) to be launched in 2026. During its 3.5 years of scientific operations from L2 orbit, this mission will observe spectroscopically in the infrared (IR) a large population of known transiting planets in the neighbourhood of the Solar System. The aim is to enable a deep understanding of the physics and chemistry of these exoplanets. ARIEL is based on a 1-m class telescope ahead of a suite of instruments: two spectrometer channels covering the band 1.95 to 7.80 µm and four photometric channels (two wide and two narrow band) in the range 0.5 to 1.9 μm. The ARIEL optical design is conceived as a fore-module common afocal telescope that will feed the spectrometer and photometric channels. The telescope optical design is based on an eccentric pupil two-mirror classic Cassegrain configuration coupled to a tertiary paraboloidal mirror. An all-aluminum structure has been considered for the telescope layout, and a detailed tolerance analysis has been conducted to assess the telescope feasibility. This analysis has been done including the different parts of the realization and life of the instrument, from integration on-ground to in-flight stability during the scientific acquisitions. The primary mirror (M1) temperature will be monitored and finely tuned via an active thermal control system based on thermistors and heaters. The heaters will be switched on and off to maintain the M1 temperature within ±1K thanks to a proportional–integral–derivative (PID) controller. more...

Jefferson Lab (JLab) is starting a wide experimental program aimed at studying the neutron's structure, with a great emphasis on the extraction of the parton transverse-momentum distributions (TMDs). To this end, Semi-inclusive deep-inelastic scattering (SiDIS) experiments on polarized $^3$He will be carried out, providing, together with proton and deuteron data, a sound flavor decomposition of the TMDs. Given the expected high statistical accuracy, it is crucial to disentangle nuclear and partonic degrees of freedom to get an accurate theoretical description of both initial and final states. In this contribution, a preliminary study of the Final State Interaction (FSI) in the standard SiDIS, where a pion (or a Kaon) is detected in the final state is presented, in view of constructing a realistic description of the nuclear initial and final states. more...

ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three candidates for the next ESA medium-class science mission (M4) expected to be launched in 2026. This mission will be devoted to observing spectroscopically in the infrared (IR) a large population of known transiting planets in the neighborhood of the Solar System, opening a new discovery space in the field of extrasolar planets and enabling the understanding of the physics and chemistry of these far away worlds. ARIEL is based on a 1-m class telescope ahead of two spectrometer channels covering the band 1.95 to 7.8 microns. In addition there are four photometric channels: two wide band, also used as fine guidance sensors, and two narrow band. During its 3.5 years of operations from L2 orbit, ARIEL will continuously observe exoplanets transiting their host star. The ARIEL optical design is conceived as a fore-module common afocal telescope that will feed the spectrometer and photometric channels. The telescope optical design is composed of an off-axis portion of a two-mirror classic Cassegrain coupled to a tertiary off-axis paraboloidal mirror. The telescope and optical bench operating temperatures, as well as those of some subsystems, will be monitored and fine tuned/stabilised mainly by means of a thermal control subsystem (TCU-Telescope Control Unit) working in closed-loop feedback and hosted by the main Payload electronics unit, the Instrument Control Unit (ICU). Another important function of the TCU will be to monitor the telescope and optical bench thermistors when the Payload decontamination heaters will be switched on (when operating the instrument in Decontamination Mode) during the Commissioning Phase and cyclically, if required. Then the thermistors data will be sent by the ICU to the On Board Computer by means of a proper formatted telemetry. The latter (OBC) will be in charge of switching on and off the decontamination heaters on the basis of the thermistors readout values. more...

ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three present candidates as an M4 ESA mission to be launched in 2026. During its foreseen 3.5 years operation, it will observe spectroscopically in the infrared a large population of known transiting planets in the neighborhood of the Solar System. The aim is to enable a deep understanding of the physics and chemistry of these exoplanets. ARIEL is based on a 1-m class telescope ahead of a suite of instruments: two spectrometer channels covering the band 1.95 to 7.8 μm and four photometric channels (two wide and two narrow band) in the range 0.5 to 1.9 μm. The ARIEL optical design is conceived as a fore-module common afocal telescope that will feed the spectrometer and photometric channels. The telescope optical design is based on an eccentric pupil two-mirror classic Cassegrain configuration coupled to a tertiary paraboloidal mirror. The temperature of the primary mirror (M1) will be monitored and finely tuned by means of an active thermal control system based on thermistors and heaters. They will be switched on and off to maintain the M1 temperature within ±1 K thanks to a proportional-integral-derivative (PID) controller implemented within the Telescope Control Unit (TCU), a Payload electronics subsystem mainly in charge of the active thermal control of the two detectors owning to the spectrometer. TCU will collect the housekeeping data of the controlled subsystems and will forward them to the spacecraft (S/C) by means of the Instrument Control Unit (ICU), the main Payload's electronic Unit linked to the S/C On Board Computer (OBC). more...

Poincar\'e covariant definitions for the spin-dependent spectral function and for the momentum distributions within the light-front Hamiltonian dynamics are proposed for a three-fermion bound system, starting from the light-front wave function of the system. The adopted approach is based on the Bakamjian--Thomas construction of the Poincar\'e generators, which allows one to easily import the familiar and wide knowledge on the nuclear interaction into a light-front framework. The proposed formalism can find useful applications in refined nuclear calculations, such as those needed for evaluating the European Muon Collaboration effect or the semi-inclusive deep inelastic cross sections with polarized nuclear targets, since remarkably the light-front unpolarized momentum distribution by definition fulfills both normalization and momentum sum rules. Also shown is a straightforward generalization of the definition of the light-front spectral function to an $A$-nucleon system. more...

The VSiPMT (Vacuum Silicon Photomultiplier Tube) is an innovative design for a revolutionary hybrid photodetector. The idea consists in replacing the classic dynode chain of a classic PMT with a SiPM. This new device aims at extending SiPM technology to large detection volumes. In this configuration, we match the large sensitive area of a photocathode with the performance of SiPM technology, which thererefore acts like an electron detector and current amplifier. The excellent photon counting capability, fast response, low power consumption and great stability are among the most attractive features of the VSiPMT. Hamamatsu realized two VSiPMT industrial prototypes with a photocathode of 3 mm diameter. In this work we present the progresses on the realization of a 1-inch prototype based on CsI photocathode and the preliminary tests we are performing on it. more...

The exoplanet revolution is well underway. The last decade has seen order-of-magnitude increases in the number of known planets beyond the Solar system. Detailed characterization of exoplanetary atmospheres provide the best means for distinguishing the makeup of their outer layers, and the only hope for understanding the interplay between initial composition chemistry, temperature-pressure atmospheric profiles, dynamics and circulation. While pioneering work on the observational side has produced the first important detections of atmospheric molecules for the class of transiting exoplanets, important limitations are still present due to the lack of systematic, repeated measurements with optimized instrumentation at both visible (VIS) and near-infrared (NIR) wavelengths. It is thus of fundamental importance to explore quantitatively possible avenues for improvements. In this paper we report initial results of a feasibility study for the prototype of a versatile multi-band imaging system for very high-precision differential photometry that exploits the choice of specifically selected narrow-band filters and novel ideas for the execution of simultaneous VIS and NIR measurements. Starting from the fundamental system requirements driven by the science case at hand, we describe a set of three opto-mechanical solutions for the instrument prototype: 1) a radial distribution of the optical flux using dichroic filters for the wavelength separation and narrow-band filters or liquid crystal filters for the observations; 2) a tree distribution of the optical flux (implying 2 separate foci), with the same technique used for the beam separation and filtering; 3) an 'exotic' solution consisting of the study of a complete optical system (i.e. a brand new telescope) that exploits the chromatic errors of a reflecting surface for directing the different wavelengths at different foci. In this paper we present the first results of the study phase for the three solutions, as well as the results of two laboratory prototypes (related to the first two options), that simulate the most critical aspects of the future instrument. more...

ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three candidates for the next ESA medium-class science mission (M4) expected to be launched in 2026. This mission will be devoted to observe spectroscopically in the infrared (IR) a large population of known transiting planets in our Galaxy. ARIEL is based on a 1-m class telescope ahead of two spectrometer channels covering the band 1.95 to 7.8 microns. In addition there are four photometric channels: two wide band, also used as fine guidance sensors, and two narrow band. During its 3.5 years operations from L2 orbit, ARIEL will continuously observe exoplanets transiting their host star. The ARIEL design is conceived as a fore-module common afocal telescope that will feed the spectrometer and photometric channels. The telescope optical design is an off-axis portion of a two-mirror classic telescope coupled to a tertiary off-axis paraboloidal mirror providing a collimating output beam. The telescope and optical bench operating temperatures, as well as those of some subsystems, will be monitored and fine tuned/stabilised mainly by means of a thermal control subsystem (TCU - Telescope Control Unit) working in closed-loop feedback and hosted by the main Payload electronics unit, i.e. the Instrument Control Unit (ICU). In this paper the telescope requirements will be given together with the foreseen design. The technical solution chosen to passively cool the telescope unit will be detailed discussed. more...

International audience; The Atmospheric Remote-Sensing Infrared Exoplanet Large-survey (ARIEL) is one of the three candidate missions selected by the European Space Agency (ESA) for its next medium-class science mission due for launch in 2026. The goal of the ARIEL mission is to investigate the atmospheres of several hundred planets orbiting distant stars in order to address the fundamental questions on how planetary systems form and evolve. During its four (with a potential extension to six) years mission ARIEL will observe 500+ exoplanets in the visible and the infrared with its meter-class telescope in L2. ARIEL targets will include gaseous and rocky planets down to the Earth-size around different types of stars. The main focus of the mission will be on hot and warm planets orbiting close to their star, as they represent a natural laboratory in which to study the chemistry and formation of exoplanets. The ARIEL mission concept has been developed by a consortium of more than 50 institutes from 12 countries, which include UK, France, Italy, Germany, the Netherlands, Poland, Spain, Belgium, Austria, Denmark, Ireland and Portugal. The analysis of the ARIEL spectra and photometric data in the 0.5-7.8 micron range will allow to extract the chemical fingerprints of gases and condensates in the planets' atmospheres, including the elemental composition for the most favorable targets. It will also enable the study of thermal and scattering properties of the atmosphere as the planet orbit around the star. ARIEL will have an open data policy, enabling rapid access by the general community to the high-quality exoplanet spectra that the core survey will deliver. more...

A new technique, named “laser comb”, was tested during the last SPARC run. It is able to produce electron pulse trains with a charge of some hundreds pC, a repetition rate of some terahertz, and a sub-picosecond length. This technique is based on the velocity bunching configuration of the SPARC injector. It can be useful to drive pump and probe free-electron laser experiments, to generate coherent excitation of plasma waves in plasma accelerators, and to produce narrow band terahertz radiation. In this paper, we describe the experimental results achieved so far and provide a comparison with simulations. more...

A 250-TW laser system (FLAME - Frascati laser for acceleration and multidisciplinary experiments) is now in its commissioning phase in a new laboratory at LNF-INFN in the framework of the PLASMONX (Plasma acceleration and monochromatic X-ray generation) project. The laser will deliver < 25 fs duration pulses with an energy up to 6J, at a 10Hz repetition rate. An ad hoc target area has also been designed and is currently being set up, allowing the first test experiments of electron laser wakefield acceleration to be carried out over the next few months in a safe, radiation-protected environment. An overview of the main features of the laser system and target area is given, along with a survey of the design and set-up of the self-injection test experiment, which is expected to reach the production of sub-GeV electron bunches. © 2010 Taylor and Francis. more...

Due to its exceptional physical properties, synthetic diamond is an ideal material for the realization of UV and X-ray detectors to be used for the characterization of laser-generated plasmas. Diamond detectors are able to operate at high temperatures and in the presence of high fluxes of ionizing radiation, where traditional silicon-based detectors usually fail. In this paper, we report on Raman and electro-optical characterization of a structure consisting of intrinsic diamond/boron-doped diamond homoepitaxially grown by chemical vapor deposition onto a commercial high pressure high temperature Ib-type diamond substrate using a 1% CH4/H2 gas mixture. A metal–insulator–semiconductor (MIS) diode was obtained by thermally evaporating an aluminum contact on the growth surface of the intrinsic layer. The detection capability of this device operating in transverse configuration was measured in the deep UV spectral range. The device sensitivity has been estimated at different biasing voltages and at two wavele... more...

Biological experiments in space and ongoing human space missions devoted to the solar system exploration require significant advancements in the radiation environment monitoring systems. Radiation hazard has to be continuously monitored and the evaluation of the biological damage suffered should be calculated within short time. In this paper we demonstrate the feasibility of using polycrystalline diamond films as dosimeters for space applications. The charge trapped into deep intra-gap defect levels during radiation exposure, and released during a high-temperature thermal scan to give thermally stimulated current (TSC), has been integrated as a function of time to evaluate the absorbed dose. The capability of diamond films to detect low doses has been demonstrated down to the mGys range. First application of these dosimeters in a real twelve-day, low Earth orbit, space mission has been carried out. TSC results have been proved to give correct evaluation of the dose absorbed during the space mission, assessing the capabilities of synthetic diamond and TSC read-out system as a proper dosimetry technique for space applications. more...

The WSO-UV space observatory, an UV-optimized 1.7 m Ritchey-Chretien telescope, will investigate many astrophysical phenomena from planetary science to cosmology. The Field Camera Unit is a multi-spectral radial instrument on the focal plane of WSO-UV. It will have three channels covering the wide spectral range from 115 nm to 800 nm and it will be operated in imaging, low-resolution spectroscopic, polarimetric and spectro-polarimetric modes. This paper will discuss and review the main characteristics and the present status of this instrument. more...

We extend the investigation of the Generalized Parton Distribution for a charged pion within a fully covariant constituent quark model, in two respects: (i) calculating the tensor distribution and (ii) adding the treatment of the evolution, needed for achieving a meaningful comparison with both the experimental parton distribution and the lattice evaluation of the so-called generalized form factors. Distinct features of our phenomenological covariant quark model are: (i) a 4D Ansatz for the pion Bethe-Salpeter amplitude, to be used in the Mandelstam formula for matrix elements of the relevant current operators, and (ii) only two parameters, namely a quark mass assumed to hold $m_q=~220$ MeV and a free parameter fixed through the value of the pion decay constant. The possibility of increasing the dynamical content of our covariant constituent quark model is briefly discussed in the context of the Nakanishi integral representation of the Bethe-Salpeter amplitude., Pages 20, figure 11 and table 8. Minor changes. To be published in EPJC more...

A distorted spin-dependent spectral function for 3He is considered for the extraction of the transverse-momentum dependent parton distributions in the neutron from semi-inclusive deep inelastic electron scattering off polarized 3He at finite momentum transfers, where final state interactions are taken into account. The generalization of the analysis to a Poincar\'e covariant framework within the light-front dynamics is outlined., Comment: 4 pages, 2 figures, talk given at the 21st International Conference on Few-Body Problems in Physics, Chicago, IL, May 18th-22nd, 2015; EPJ Web of Conference, in press more...

The ARIEL mission has been proposed to ESA by an European Consortium as the first space mission to extensively perform remote sensing on the atmospheres of a well defined set of warm and hot transiting gas giant exoplanets, whose temperature range between ~600 K and 3000 K. ARIEL will observe a large number (~500) of warm and hot transiting gas giants, Neptunes and super-Earths around a range of host star types using transit spectroscopy in the ~2-8 μm spectral range and broad-band photometry in the NIR and optical. ARIEL will target planets hotter than 600 K to take advantage of their well-mixed atmospheres, which should show minimal condensation and sequestration of high-Z materials and thus reveal their bulk and elemental composition. One of the major motivations for exoplanet characterisation is to understand the probability of occurrence of habitable worlds, i.e. suitable for surface liquid water. While ARIEL will not study habitable planets, its major contribution to this topic will results from its capability to detect the presence of atmospheres on many terrestrial planets outside the habitable zone and, in many cases, characterise them. This represents a fundamental breakthrough in understanding the physical and chemical processes of a large sample of exoplanets atmospheres as well as their bulk properties and to probe in-space technology. The ARIEL infrared spectrometer (AIRS) provides data on the atmospheric composition; these data are acquired and processed by an On-Board Data Handling (OBDH) system including the Cold Front End Electronics (CFEE) and the Instrument Control Unit (ICU). The Telescope Control Unit (TCU) is also included inside the ICU. The latter is directly connected to the Control and Data Management Unit (CDMU) on board the Service Module (SVM). The general hardware architecture and the application software of the ICU are described. The Fine Guidance Sensor (FGS) electronics and the Cooler Control Electronics are also presented. more...

PLATO 2.0 has been selected by ESA as the third medium-class Mission (M3) of the Cosmic Vision Program. Its Payload is conceived for the discovery of new transiting exoplanets on the disk of their parent stars and for the study of planetary system formation and evolution as well as to answer fundamental questions concerning the existence of other planetary systems like our own, including the presence of potentially habitable new worlds. The PLATO Payload design is based on the adoption of four sets of short focal length telescopes having a large field of view in order to exploit a large sky coverage and to reach, at the same time, the needed photometry accuracy and signalto- noise ratio (S/N) within a few tens of seconds of exposure time. The large amount of data produced by the telescope is collected and processed by means of the Payload’s Data Processing System (DPS) composed by many processing electronics units. This paper gives an overview of the PLATO 2.0 DPS, mainly focusing on the architecture and processing capabilities of its Instrument Control Unit (ICU), the electronic subsystem acting as the main interface between the Payload (P/L) and the Spacecraft (S/C). more...

ARIEL (the Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three candidates for the next ESA medium-class science mission (M4) expected to be launched in 2026. This mission will be devoted to observing spectroscopically in the infrared a large population of warm and hot transiting exoplanets (temperatures from ~500 K to ~3000 K) in our nearby Galactic neighborhood, opening a new discovery space in the field of extrasolar planets and enabling the understanding of the physics and chemistry of these far away worlds. The three candidate missions for M4 are now in a Phase A study which will run until mid-2017 at which point one mission will be selected for implementation. ARIEL is based on a 1-m class telescope feeding both a moderate resolution spectrometer covering the wavelengths from 1.95 to 7.8 microns, and a four channel photometer (which also acts as a Fine Guidance Sensor) with bands between 0.55 and 1.65 microns. During its 3.5 years of operation from an L2 orbit, ARIEL will continuously observe exoplanets transiting their host star. more...

Beam diagnostic is a fundamental constituent of any particle accelerators either dedicated to high-energy physics or to synchrotron radiation experiments. All storage rings emit radiations. Actually they are high brilliant sources of radiation: the synchrotron radiation emission covers from the infrared range to the X-ray domain with a pulsed structure depending on the temporal characteristics of the stored beam. The time structure of the emitted radiation is extremely useful as a tool to perform time-resolved experiments. However, this radiation can be also used for beam diagnostic to determine the beam stability and to measure the dimensions of the e − or e + beam. Because of the temporal structure of the synchrotron radiation to perform diagnostic, we need very fast detectors. Indeed, the detectors required for the diagnostics of the stored particle bunches at third generation synchrotron radiation sources and FEL need response times in the sub-ns and even ps range. To resolve the bunch length and detect bunch instabilities, X-ray and visible photon detectors may be used achieving response times of a few picoseconds. Recently, photon uncooled infrared devices optimized for the mid-IR range realized with HgCdTe semiconductors allowed to obtain sub-nanosecond response times. These devices can be used for fast detection of intense IRSR sources and for beam diagnostic. We present here preliminary experimental data of the pulsed synchrotron radiation emission of DAΦNE, the electron positron collider of the LNF laboratory of the INFN, performed with new uncooled IR detectors with a time resolution of a few hundreds of picoseconds. more...

Due to its unique physical properties, diamond is a very appealing material for the development of electronic devices and sensors. Its wide band gap (5.5 eV) endows diamond based devices with low thermal noise, low dark current levels and, in the case of radiation detectors, high visible-to-X-ray signal discrimination (visible blindness) as well as high sensitivity to energies greater than the band gap. Furthermore, due to its radiation hardness diamond is very interesting for applications in extreme environments, or as monitor of high fluency radiation beams. In this work the use of diamond based detectors for X-ray sensing is discussed. On purpose, some photo-conductors based on different diamond types have been tested at the DAFNE-L synchrotron radiation laboratory at Frascati. X-ray sensitivity spectra, linearity and stability of the response of these diamond devices have been measured in order to evidence the promising performance of such devices. more...

Longitudinal and transverse quark momentum distributions in the nucleon are calculated from a phenomenological quark-nucleon vertex function obtained through an investigation of the nucleon electromagnetic form factors within a light-front framework., Comment: 6 pages, 11 figs. proceedings of LC2009, to appear in Nucl. Phys. B more...

A simple, but fully-covariant model for describing neutral Vector Mesons, in both light and heavy sectors, is briefly illustrated. The main ingredients of our relativistic constituent model are i) an Ansatz for the Bethe-Salpeter vertex for Vector Mesons, and ii) a Mandelstam-like formula for the electromagnetic decay widths. The free parameters of our approach are fixed through a comparison with the valence transverse-momentum distribution, $n(k_\perp)$, obtained within phenomenological Light-Front Hamiltonian Dynamics models reproducing the mass spectra. Preliminary results for the transverse-momentum distributions, the parton distribution and the electromagnetic decay constants are shown., 6 pages, 4 figures. Proceedings of LC2009, to appear in Nucl. Phys. B suppl more...

We present a preliminary calculation of the electromagnetic form factors of $^3$He and $^3$H, performed within the Light-Front Hamiltonian Dynamics. Relativistic effects show their relevance even at the static limit, increasing at higher values of momentum transfer, as expected., 6 pages, 4 figures. Proceedings of 20th European Conference on Few-Body Problems in Physics; to be published in Few-Body Systems more...

This work reports on the development and characterization of bi-dimensional deep-UV sensor arrays based on synthetic diamond to address the requirements of space-born astrophysical experiments. The material was synthesized at the University of Rome “Tor Vergata” where both heteroepitaxial polycrystalline diamond films and homoepitaxial single-crystal diamonds are grown using a tubular MWCVD reactor. The quality of chemical vapour deposited diamond was characterized by cathodoluminescence, photoluminescence, Raman spectroscopy and thermally stimulated currents. Then, suitable samples were selected and used to fabricate photoconductive single-pixel and 2D array devices by evaporating metal contacts on the growth surface. The electro-optical characterization of the devices was carried out in a wide spectral region, ranging from 120 to 2400 nm. A deuterium lamp and a 0.5 m vacuum monochromator were used to measure the detector responsivity under continuous monochromatic irradiation in the 120–250 nm spectral range, while an optical parametric oscillator tunable laser producing 5 ns pulses was used as light source from 210 up to 2400 nm. Time response, signal-to-noise ratio, responsivity and visible rejection factor were evaluated and the results are hereafter summarized. more...

CVD diamond, as other wide energy gap semiconductors or insulators, is known to present polarization effects when used as a nuclear particle detector, which are due to the building up of an internal space-charge electric field and are responsible for “memory” effects if the polarization is not erased. Polarization effects are larger when the thickness of the sample is longer than the drift length of carriers and give rise to a shortening of the electric field region inside the sample. In this work, IBIC (Ion Beam Induced Charge) measurements with 1 and 2 MeV proton beams have been carried out on a relatively thin CVD diamond sample with the conclusion that no memory or hysteresis effects were present even by switching from one polarity to the opposite one in subsequent measurements. However, it resulted that the values of the charge collection efficiency (cce) did depend on counting rate and the lowering at large counting rates was attributed to a local polarization due to trapping. Finally, in some cases cce turned out to be larger than 1, a result which could be either due to local detrapping or to non-blocking contacts. more...

Radiation hardness, mass and power budget constraints as well as high detection efficiency are strong requirements for detectors devoted to space applications. Progress in material deposition and device fabrication technologies presently makes diamond photoconductors the most sensitive among deep ultraviolet photodetectors, but still some problems, related to the signal response dynamic and reproducibility, prevent such devices from a full exploitation. The aim of our work is to study the effects of photon irradiation on the time response of detectors based on single crystal diamonds. The improved performance of these deep ultraviolet photo-conductors enables the analysis of effects that are usually hidden by the persistence of the photocurrent and by excess charge trapping–detrapping at defects. Negligible or reduced impact of the persistence of photocurrent makes possible the analysis of the signal response time evolution in consecutive photocurrent transient. In this paper, a deep ultraviolet detector based on a 300-μm thick high-pressure high-temperature 1b-type single crystal diamond was irradiated with photons in the spectral region around the band gap energy corresponding to 110–250 nm spectral range. Photocurrent transients at different energies were measured in vacuum. The results show that current transient shapes and the time response depend on the energy and probably on the irradiation intensity. A possible explanation of this behaviour is discussed. more...

We suggest the use of deep UV photons as a probe to investigate the photoelectrical properties of different depths in the diamond films. The penetration depth of UV photons decreases rapidly towards shorter wavelengths in the region of and just below the band gap energy, achieving ∼2 nm at wavelengths approximately 100 nm. Therefore, they are suitable for probing the bulk properties and the surface proximity of diamond layers. We have irradiated different CVD diamond samples with UV laser pulses at 193, 213 and 266 nm as well as continuous radiation emitted by a UV source in the 140–250 nm wavelength range. We have analysed the photoconductivity at different depths as a function of material thickness, electric field value and polarity, radiation intensity, time response to laser pulses and to illumination transients. We have observed different behaviours above and below the band gap energy that could be due to polarization effects and a photo-response quenching above the band gap that is enhanced by reversing the electric field. more...

The pion electromagnetic form factor is calculated in the space- and time-like regions from -10 $(GeV/c)^2$ up to 10 $(GeV/c)^2$, within a front-form model. The dressed photon vertex where a photon decays in a quark-antiquark pair is depicted generalizing the vector meson dominance ansatz, by means of the vector meson vertex functions. An important feature of our model is the description of the on-mass-shell vertex functions in the valence sector, for the pion and the vector mesons, through the front-form wave functions obtained within a realistic quark model. The theoretical results show an excellent agreement with the data in the space-like region, while in the time-like region the description is quite encouraging., 9 pages + 4 figures. To appear in Phys. Lett. B more...

Preliminary calculations of the inclusive electromagnetic responses by a polarized 3He target, including final state interaction effects, relativistic kinematics and a relativistic electron-nucleon cross section, are presented. The features of our approach will be briefly illustrated, in order to yield an insight on the model dependence affecting the extraction of the neutron magnetic form factor, G n M , from the inclusive scattering of polarized electrons by a polarized 3He target, recently explored at TJLAB for $0.1 ~(GeV/c)^2 \le Q^2 \le 0.6 ~(GeV/c)^2$ . more...

This work reviews some general results obtained by our group in the framework of a programme focused on the development and the characterisation of Vacuum-UV (VUV) CVD diamond photodetectors to address the requirements of space missions where pixel and 2-D arrays are used. We discuss the performance of detectors based on single crystal diamond films and CVD polycrystalline diamond films. The performance of these devices in the dark and under illumination was investigated and the results were compared to those from CCD and MCP detectors. The status of diamond detector technology is finally described in order to highlight its advantages over more traditional detectors and the aspects requiring further developments. more...

Preliminary results for the proton and neutron electromagnetic form factors, calculated within a front-form constituent quark model, are presented. A Poincare covariant electromagnetic current operator for systems of interacting particles has been used and an effective quark mass at the photon-quark vertex has been introduced for a first insight of many body effects in the electromagnetic current. more...

EChO is a three-modules (VNIR, SWIR, MWIR), highly integrated spectrometer, covering the wavelength range from 0.55 $\mu$m, to 11.0 $\mu$m. The baseline design includes the goal wavelength extension to 0.4 $\mu$m while an optional LWIR module extends the range to the goal wavelength of 16.0 $\mu$m. An Instrument Control Unit (ICU) is foreseen as the main electronic subsystem interfacing the spacecraft and collecting data from all the payload spectrometers modules. ICU is in charge of two main tasks: the overall payload control (Instrument Control Function) and the housekeepings and scientific data digital processing (Data Processing Function), including the lossless compression prior to store the science data to the Solid State Mass Memory of the Spacecraft. These two main tasks are accomplished thanks to the Payload On Board Software (P-OBSW) running on the ICU CPUs., Comment: Experimental Astronomy - EChO Special Issue 2014 more...

A simple compact temperature sensor and microheater in a wide temperature range has been developed, realizing a laser-patterned resistive structure on the surface of a synthetic polycrystalline diamond plate. Imaging and spectroscopy techniques used to investigate morphology, structure, and composition of the pattern showed that it incorporates different nondiamond carbon phases. Transport experiments revealed the semiconducting behavior of this microresistor. Thermal power measurements versus temperature are presented. A possible application of this device that may easily match compact experimental layouts avoiding both thermal anchoring offset and mechanical stress between sample and sensor is discussed. The patterned structure undergoes testing as a microthermometer, providing fast response and excellent stability versus time. It exhibits a good sensitivity that coupled to an easy calibration procedure minimizes errors and guarantees high accuracy. Plot of temperature versus input power of the resistive patterned line used as microheater shows a linear behavior in an extended temperature range. more...

The Exoplanet Characterisation Observatory (EChO) is a space mission dedicated to investigate exoplanetary atmospheres by undertaking spectroscopy of transiting planets in a wide spectral region from the visible to the mid-InfraRed (IR). The high sensitivity and the long exposures required by the mission need an extremely stable thermo-mechanical platform. The instrument is passively cooled down to approximately 40 K, together with the telescope assembly, by a V-Groove based design that exploits the L2 orbit favourable thermal conditions. The visible and short-IR wavelength detectors are maintained at the operating temperature of 40 K by a dedicated radiator coupled to the cold space. The mid-IR channels, require a lower operating temperature and are cooled by an active refrigerator: a 28 K Neon Joule-Thomson (JT) cold end, fed by a mechanical compressor. Temperature stability is one of the challenging issues of the whole architecture: periodical perturbations must be controlled before they reach the sensitive units of the instrument. An efficient thermal control system is required: the design is based on a combination of passive and active solutions. In this paper we describe the thermal architecture of the payload with the main cryo-chain stages and their temperature control systems. The requirements that drive the design and the trade-offs needed to enable the EChO exciting science in a technically feasible payload design are discussed. Thermal modelling results and preliminary performance predictions in terms of steady state and transient conditions are also reported. This paper is presented on behalf of the EChO Consortium. more...

BOLD (Blind to the Optical Light Detectors) is an international initiative dedicated to the development of novel imaging detectors for UV solar observations. It relies on the diamond and nitride materials that have lately undergone key advances. The investigation is proposed in view of Solar Orbiter UV instruments, for which the expected properties of the new sensors—visible blindness and radiation hardness—will be highly beneficial. Solar Orbiter is a selected Flexi mission of the European Space Agency (ESA). Despite various improvements over the last few decades, the present UV detectors exhibit limitations inherent to their actual technology. Yet the utmost spatial resolution, temporal cadence, sensitivity, and photometric accuracy will be decisive for the forthcoming space solar missions. The advent of imagers made of a large bandgap semiconductor would surmount many weaknesses, thus opening up new prospects and making the instruments cheaper. As for the ESA Solar Orbiter, the aspiration for wide bandgap semiconductor-based UV detectors is still more sensible, for the spacecraft will approach the Sun where the heat and the radiation fluxes are high. We depict motivations and present activities and programme to achieve revolutionary flight cameras within the Solar Orbiter schedule. more...