Luminescence and Structural Characterization of Gd2O2S Scintillators Doped with Tb3+, Ce3+, Pr3+ and F for Imaging Applications

none14siRadiodiagnostic technologies are powerful tools for preventing diseases and monitoring the condition of patients. Medicine and sectors such as industry and research all use this inspection methodology. This field demands innovative and more sophisticated systems and materials for improving resolution and sensitivity, leading to a faster, reliable, and safe diagnosis. In this study, a large characterization of gadolinium oxysulfide (Gd2O2S) scintillator screens for imaging applications has been carried out. Seven scintillator samples were doped with praseodymium (Pr3+), terbium (Tb3+) activators and co-doped with praseodymium, cerium, and fluorine (Gd2O2S:Pr,Ce,F). The sample screens were prepared in the laboratory in the form of high packing density screens, following the methodology used in screen sample preparation in infrared spectroscopy and luminescence. Parameters such as quantum detection efficiency (QDE), energy absorption efficiency (EAE), and absolute luminescence efficiency (ALE) were evaluated. In parallel, a structural characterization was performed, via XRD and SEM analysis, for quality control purposes as well as for correlation with optical properties. Spatial resolution properties were experimentally evaluated via the Modulation Transfer Function. Results were compared with published data about Gd2O2S:Pr,Ce,F screens produced with a standard method of a sedimentation technique. In particular, the ALE rose with the X-ray tube voltage up to 100 kVp, while among the different dopants, Gd2O2S:Pr exhibited the highest ALE value. When comparing screens with different thicknesses, a linear trend for the ALE value was not observed; the highest ALE value was measured for the 0.57 mm thick Gd2O2S:Pr,Ce,F sample, while the best MTF values were found in the thinner Gd2O2S:Pr,Ce,F screen with 0.38 mm thickness.De Martinis, Alessia; Montalto, Luigi; Scalise, Lorenzo; Rinaldi, Daniele; Mengucci, Paolo; Michail, Christos; Fountos, George; Martini, Nicki; Koukou, Vaia; Valais, Ioannis; Bakas, Athanasios; Fountzoula, Christine; Kandarakis, Ioannis; David, StratosDe Martinis, Alessia; Montalto, Luigi; Scalise, Lorenzo; Rinaldi, Daniele; Mengucci, Paolo; Michail, Christos; Fountos, George; Martini, Nicki; Koukou, Vaia; Valais, Ioannis; Bakas, Athanasios; Fountzoula, Christine; Kandarakis, Ioannis; David, Strato

IXPE instrument integration, testing and verification

The Imaging X-ray Polarimetry Explorer (IXPE) is a scientific observatory with the purpose of expand observation space adding polarization property to the X-ray source's currently measured characteristics. The mission selected in the context of NASA Small Explorer (SMEX) is a collaboration between NASA and ASI that will provide to observatory the instrumentation of focal plane. IXPE instrument is composed by three photoelectric polarimeters based on the Gas Pixel Detector (GPD) design, integrated by INFN inside the detector unit (DU) that comprises of the electrical interfaces required to control and communicate with the GPD. The three DUs are interfaced with spacecraft through a detector service unit (DSU) that collect scientific and ancillary data and provides a basically data handling and interfaces to manage the three DUs. AIV has been planned to combine calibration of DUs and Instrument integration and verification activities. Due the tight schedule and the scientific and functional requirements to be verified, in IAPS/INAF have been assembled two equipment's that work in parallel. The flight model of each DU after the environmental tests campaign was calibrated on-ground using the Instrument Calibration Equipment (ICE) and subsequently integrated in the instrument in the AIV-T process on a AIV and Calibration Equipment (ACE), both the facilities managed by Electrical Ground Support Equipment (EGSE) that emulate the spacecraft interfaces of power supply, functional and thermal control and scientific data collection. AIV activities test functionalities and nominal/off-nominal orbits activities of IXPE instrument each time a calibrated DU is connected to DSU flight model completing step by step the full instrument. Here we describe the details of instrumentation and procedures adopted to make possible the full integration and test activities compatibly with calibration of IXPE Instrument

The IXPE Instrument Calibration Equipment

The Imaging X-ray Polarimetry Explorer is a mission dedicated to the measurement of X-ray polarization from tens of astrophysical sources belonging to different classes. Expected to be launched at the end of 2021, the payload comprises three mirrors and three focal plane imaging polarimeters, the latter being designed and built in Italy. While calibration is always an essential phase in the development of high-energy space missions, for IXPE it has been particularly extensive both to calibrate the response to polarization, which is peculiar to IXPE, and to achieve a statistical uncertainty below the expected sensitivity. In this paper we present the calibration equipment that was designed and built at INAF-IAPS in Rome, Italy, for the calibration of the polarization-sensitive focal plane detectors on-board IXPE. Equipment includes calibration sources, both polarized and unpolarized, stages to align and move the beam, test detectors and their mechanical assembly. While all these equipments were designed to fit the specific needs of the IXPE Instrument calibration, their versatility could also be used in the future for other projects

CMS physics technical design report : Addendum on high density QCD with heavy ions

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Intervento di replica

First response to Dimenticare Pasolini by Pierpaolo Antonello.Quel che m’ha dato gusto nel divorare Dimenticare Pasolini è stato prima di tutto il titolo. Intorno al Santo/Poeta, al Martire/Veggente si è detto e scritto talmente tanto che vien la nausea solo a parlarne. Sono stati in molti, in troppi a massacrare il ‘cadavere’ di Pasolini, troppi a ballare una danza funebre infinita attorno alla sua tomba, troppi a usarlo a proprio gusto senza il minimo rispetto filologico e politico. Pasolini, che era quel che a Roma si chiama ‘un gran filone’, ha meriti che poco hanno a che vedere con i suoi sciocchi ammiratori e presunti esegeti

S-MIM: A Novel Radio Interface for Efficient Messaging Services over Satellite

This article presents a radio interface recently standardized by ETSI under the name of S-band Mobile Interactive Multimedia (S-MIM) and especially designed to provide ubiquitous messaging services over S-band GEO satellites using low-power terminals. Thanks to low terminal cost and high bandwidth efficiency, this standard allows the development of new satellite services, particularly for vehicular and machine-to machine applications. The S-MIM standard relies on a broadcasting radio interface such as DVB-SH or ETSI SDR in the forward link, and reuses 3GPP W-CDMA technology properly adapted to the scope in the return link. Thanks to the use of spread spectrum ALOHA, terminals can access the channel in a totally asynchronous manner. The use of a packet-optimized iterative successive interference cancellation (i- SIC) algorithm at the receiver allows exploiting the inherent power imbalance among terminals in order to boost the throughput with respect to conventional SSA systems. In addition, advanced packet transmission control techniques have been adopted to maximize the probability of successful packet reception in the challenging land mobile satellite channel. Finally, the S-MIM link layer provides efficient and reliable transport of IP datagrams over the forward and return link radio interfaces

Inspection of birefringent media by photoelasticity: from diffuse light polariscope to laser conoscopic technique

A reliable and noninvasive measurement method for the inspection of naturally birefringent transparent media is presented in this paper. It allows us to achieve a spatially resolved analysis of the stress state of birefringent materials. The developed system is based on photoelasticity and exploits a controlled laser conoscopy technique and a scanning system to perform local measurements in the volume dimensions of the media, which can be displaced over a grid of points. The configuration of the proposed laser conoscopic system is presented, and a dedicated algorithm, designed to perform digital analysis of the fringe patterns, is also described. The design and the realization of the system are discussed, as well as the advantages of the proposed system over the classic diffuse light polariscope technique. The method has been experimentally validated through laboratory tests on birefringent samples with known induced stress. The system has demonstrated its sensitivity to stress and its capability to achieve a spatial resolution on the order of 0.1 mm to resolve stress gradients (uncertainty on the stress amplitude of +/-0.1 MPa)