Semantic dementia is a progressive, relatively selective disorder affecting the semantic system with involvement of the verbal and non-verbal functions. The clinical picture is well characterised ...despite the confusion that may be generated by the different ways of classifying it. AIM. To determine the clinical, neurolinguistic, imaging and pathological features of this progressive language disorder.
Evaluation of language reveals above all the existence of semantic paraphasias, disorders affecting the comprehension of isolated words and surface dyslexia. Flow of speech, complex syntactic comprehension and grammar are preserved. Both episodic and autobiographic memory are close to normality. Both the clinical signs and symptoms and imaging studies agree on the fact that the most heavily affected area is the anteroinferomedial region of the temporal lobe on a bilateral scale but with predominance of the left-hand side. Pathologically, in most cases positive intraneuronal ubiquitin inclusions are observed like those described in motor neuron diseases.
Semantic dementia constitutes a diagnosis challenge, mainly from the neuropsychological point of view. Further advances towards reaching a diagnosis would allow us to determine which area is mainly affected and, in the future, to find an effective treatment for this progressive, degenerative disorder.
Gamma beam collimation system and profile imager for ELI-NP Cardarelli, P.; Paternò, G.; Di Domenico, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
Odprti dostop
ELI-NP-GBS is a high-brilliance gamma source that will produce monochromatic beams in the energy range 0.2–19.5 MeV through inverse Compton scattering. In order to obtain a monochromatic beam a ...collimation of the emission is necessary. Depending on the energy, the angular aperture required to provide the design bandwidth ΔE/E=0.5% is between 70 and 700 μrad. This collimation is provided by a stack of 14 tungsten slits, arranged with a relative rotation around the beam axis, so that the overlap will be a continuously adjustable aperture. To monitor the operation and alignment of the collimation, a set of detectors will provide a complete characterization of the gamma beam, including the measurement of the transverse spatial distribution. For this task a gamma beam profile imager based on a thin scintillator screen and a high-resolution CCD-camera was developed. In this work we briefly present the status of the collimation system and beam profile imager, which were designed, assembled and are currently under test at INFN-Ferrara laboratories.
A γ calorimeter for the monitoring of the ELI-NP beam Veltri, M.; Adriani, O.; Albergo, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
The ELI-NP facility will provide a monochromatic, high brilliance γ beam with tunable energy up to 19.5 MeV. The time structure of the beam consists of 32 pulses of 105 photons separated by 16 ns and ...delivered at repetition rate of 100 Hz. In order to match such unprecedented beam specifications and to measure its energy spectrum, intensity and space profile, a characterization system has been developed. This paper will focus on the working principle, the expected performances and the results of tests carried out on a low-Z sampling calorimeter, made of silicon detectors and polyethylene absorbers, which will measure the average beam energy and its intensity. The results of tests performed with an infrared pulsed laser have shown the capability of the detector to cope with the time structure of ELI-NP beam. Further tests carried out at the LABEC facility in Firenze have shown the excellent linearity of the silicon detectors in the energy range relevant to ELI-NP beam.
Performance of second generation BABAR resistive plate chambers Anulli, F.; Baldini, R.; Calcaterra, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2005, Letnik:
552, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The BABAR detector has operated nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector, for the past two years. The RPCs experience widely ...different background and luminosity-driven singles rates (0.01–10
Hz/cm
2) depending on position within the endcap. Some regions have integrated over 0.3
C/cm
2. RPC efficiency measured with cosmic rays is high and stable. The average efficiency measured with beam is also high. However, a few of the highest rate RPCs have suffered efficiency losses of 5–15%. Although constructed with improved techniques and minimal use of linseed oil, many of the RPCs, which are operated in streamer mode, have shown increased dark currents and noise rates that are correlated with the direction of the gas flow and the integrated current. Studies of the above aging effects are presented and correlated with detector operating conditions.
The ELI-NP facility, currently being built in Bucharest, Romania, will deliver an intense and almost monochromatic γ beam with tunable energy between 0.2 MeV and 19.5 MeV in two different beamlines. ...An articulated beam characterization system will be installed downstream of the collimator of each line. The system will use, as calibration candles, a few selected nuclear levels whose fluorescence condition will be monitored by a Nuclear Resonance Scattering System (NRSS). The NRSS will use a peculiar double-readout approach in order to detect resonant events overwhelming background: both scintillation and Cherenkov photons produced inside the same crystals will be separately read.
•The NRS system will play a crucial role in the characterization of the Eli-NP beam.•It will be able to give a precise absolute energy calibration of the gamma beam.•The determination of the resonance will be achieved using a matrix of BaF/LYSO crystals.•A novel double readout technique shows a very good background rejection power.
A gamma beam profile imager for ELI-NP Gamma Beam System Cardarelli, P.; Paternò, G.; Di Domenico, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2018, Letnik:
893
Journal Article
Recenzirano
Odprti dostop
The Gamma Beam System of ELI-Nuclear Physics is a high brilliance monochromatic gamma source based on the inverse Compton interaction between an intense high power laser and a bright electron beam ...with tunable energy. The source, currently being assembled in Magurele (Romania), is designed to provide a beam with tunable average energy ranging from 0.2 to 19.5 MeV, rms energy bandwidth down to 0.5% and flux of about 108 photons/s. The system includes a set of detectors for the diagnostic and complete characterization of the gamma beam. To evaluate the spatial distribution of the beam a gamma beam profile imager is required. For this purpose, a detector based on a scintillator target coupled to a CCD camera was designed and a prototype was tested at INFN-Ferrara laboratories. A set of analytical calculations and Monte Carlo simulations were carried out to optimize the imager design and evaluate the performance expected with ELI-NP gamma beam. In this work the design of the imager is described in detail, as well as the simulation tools used and the results obtained. The simulation parameters were tuned and cross-checked with the experimental measurements carried out on the assembled prototype using the beam from an x-ray tube.
Experiment E835 at Fermilab Garzoglio, G.; Gollwitzer, K.; Hahn, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2004, Letnik:
519, Številka:
3
Journal Article
Recenzirano
We provide a comprehensive description of experiment E835 at Fermilab, a high-precision experimental study of charmonium bound states. The
c
̄
c
states are formed in
p
̄
p
annihilations of cooled ...antiprotons stored in the Fermilab Antiproton Accumulator using a dense internal hydrogen gas-jet target. We describe the experimental strategies adopted for detecting the tiny
c
̄
c
resonant signals in the huge non-resonant hadronic background, and for measuring resonance parameters with high precision.
A Gamma Beam Characterisation System has been designed by the EuroGammaS association for the commissioning and development of the Extreme Light Infrastructure-Nuclear Physics Gamma Beam System ...(ELI-NP-GBS) to be installed in Magurele, Romania. The characterisation system consists of four elements: a Compton spectrometer, a sampling calorimeter, a nuclear resonant scattering spectrometer (NRSS) and a beam profile imager. In this paper, the nuclear resonant scattering spectrometer system, designed to perform an absolute energy calibration for the gamma beam, will be described.
•Gamma Beam Characterisation System.•Fast detection system based on BaF2 crystals.•Absolute Gamma energy calibration based on Nuclear Resonant Scattering.
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