423 research outputs found
PICsIT Detector for Gamma-Ray Astronomy: Pixels Qualification Campaign
No full textPosition sensitive detectors coupled to coded masks are used for imaging in high energy astronomy. PICsIT is the gamma-ray position sensitise detector of the IBIS telescope to be flown onboard the INTEGRAL satellite in 2001. PICsIT detector functionalities and scientific performances as a whole are described in details elsewhere in this Conference (Labanti et at. (Nucl. Instr. and Meth. A. this conference)). In this work. we present the aim. methodology, and results of the tests and calibrations performed on the first qualification lot of 136 PICsIT pixels carried out at SCIONIX laboratories in The Netherlands in April 1999. Before being accepted for PICsIT. each detection unit has in fact to be fully characterized in terms of energy resolution and lower energy threshold. The principal aim of PICsIT pixel qualification campaign described in this work has been to measure the key parameters of each CsI(T1) + photodiode detection unit: CsI(T1) crystals light Output, gain variation with temperature, energy resolution degradation due to scintillation light production and collection, inhomogeneity in the crystal, and the variation of these quantities after a thermo-vacuum stress treatment
"Performance of a Silicon drift Chamber as Fast Scintillator Photodetector for Gamma-Ray Spectroscopy"
No full text"Submillimeter resolution in one-dimensional position measurements of γ-ray photons by using a CsI(TI) scintillator coupled to a linear array of silicon drift detectors"
No full textThe ORION Chipset for the X-Gamma Imaging Spectrometer Onboard of the THESEUS Space Mission
No full textWe present the design of a multichip Application Specific Integrated Circuit (ASIC), named ORION, for the front-end readout of the X-Gamma Imaging Spectrometer (XGIS) on-board the Transient High Energy Sky and Early Universe Surveyor (THESEUS) space mission. The XGIS instrument is composed by two cameras that operate as a wide field deep sky monitors with a broad energy range from 2 keV to 20 MeV, and it is based on a position sensitive double-detection mechanism for image reconstruction, in which a single pixel is constituted by a Thallium activated Cesium Iodide (CsI(Tl)) scintillator crystals and two Silicon Drift Detectors (SDDs) glued at both crystal ends, whose signal is collected, reconstructed and digitized by the presented ORION chipset. In each camera, the ORION chipset is organized in a constellation of 12 800 analog front-end chips (ORION-FE), closely connected to the SDD anodes, and 800 mixed signal multi-channel back-end chips (ORION-BE) for signal processing and digitalization, for a total 25 600 ORION-FE and 1 600 ORION-BE in the complete instrument. The back-end chips have two parallelized X and Gamma signal processors, for low-energy and high-energy photons respectively, which allow a tailored optimization on the noise and energy range requirements for each type of event. The chipset has an input dynamic range of 32 fC that allows to process signals with a linearity error below ±1.2% on the Gamma processor, and below ±0.1% on the X processor. The nominal Equivalent Noise Charge (ENC) of the system at -20 °C for an estimated detector leakage current of 0.7 pA is 12.5 el. r.m.s at 1 μs peaking time for the X processor, and 32.9 el. r.m.s. at 3 μs peaking time for the Gamma processor. The simulated power consumption is of 1.55 mW per pixel
First Prototype of a Gamma-Camera Based on a Single-CsI(T1) Scintillator Coupled to a Silicon Drift Detector Array
No full text
"Performance of a Silicon Drift Chamber as fast scintilator photodetector for ray spectroscopy".
No full textFirst results with a novel x-ray source for dual-energy angiography
No full textn angiographic practice an iodate contrast medium is injected in patient vessels with a catheter. The iodine is used because its linear absorption coefficient shows a K-edge at 33.169 keV. In digital subtraction angiography (DSA), some images are acquired before and during the injection of the contrast medium. The vessels' morphology is obtained by subtracting the live images from the first (mask) image. A new approach is presented where two quasimonochromatic beams, having mean energies lower and higher than the iodine K-edge, are produced simultaneously-starting from an X-ray tube-by means of a pyrolytic graphite crystal monochromator. These two thin parallel beams impinge on the phantom simulating patient vessels and are detected with solid-state array detectors. The image results as the difference between the remaining intensities of the two beams. Performance-in terms of spatial resolution, contrast and reduction of iodine concentration in an invasive perfusion medium-are presented and compared with the full spectra subtraction method in use
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