X-ray absorption near-edge structures of chloroferrates [FeIICl4]2−^{II}Cl_4]^{2-} [FeIIICl4]−^{III}Cl_4]^- and [FeIIICl6]3−^{III}Cl_6]^{3-} - experimental and MS-LSD computational studies

The influence of electronic and structural effects in FeCL and FeCl6 entities has been investigated through X-ray absorption spectroscopy and theoretical calculations of electronic transition energies using the MSLSD method. The relative importance of the formal oxidation degree of the metal, the metal-ligand distance, and the symmetry of the site on the energy of near-edge structures are studied. The principal effect is the stabilization of the iron 1s orbital in the ground state when the oxidation degree increases. The accuracy of the theoretical determination regarding the experimental spectra is discussed. The incidence of the same electronic parameters on the intensities of near-edge structures is also investigated through a transition cross section calculation

A standalone Monte Carlo simulation toolkit at the micro-cell level to mimic SiPMs signals

International audienceRecently, a SiPM digitizer has been implemented in GATE version 8.2 and has been made available as open source code. A standalone version of this experimentally-validated digitizer is presented here, which allows to simulate a SiPM offline or with data not specifically generated with GATE. It is composed of a C++ class with a default implemention including several functions modeling the SiPM detection efficiency, geometry, noise properties (crosstalk, afterpulse), timing response (SPTR and micro-cell signal shape generation). All parameters can be modified by the user to match with a desired experimental or simulated setup. The SiPM class allows Mont Carlo simulation at the micro-cell scale and is based on the generation of a signal for each impinging photon (also called pulse) onto a micro-cell

A standalone Monte Carlo simulation toolkit at the micro-cell level to mimic SiPMs signals

International audienceRecently, a SiPM digitizer has been implemented in GATE version 8.2 and has been made available as open source code. A standalone version of this experimentally-validated digitizer is presented here, which allows to simulate a SiPM offline or with data not specifically generated with GATE. It is composed of a C++ class with a default implemention including several functions modeling the SiPM detection efficiency, geometry, noise properties (crosstalk, afterpulse), timing response (SPTR and micro-cell signal shape generation). All parameters can be modified by the user to match with a desired experimental or simulated setup. The SiPM class allows Mont Carlo simulation at the micro-cell scale and is based on the generation of a signal for each impinging photon (also called pulse) onto a micro-cell

First images from a CeBr 3 /LYSO:Ce Temporal Imaging portable Compton camera at 1.3 MeV

International audienceDuring nuclear decommissioning or waste management operations, there is a need for imaging the contamination field while identifying and quantifying the contaminants. Our objective is to test a Compton camera within the energy range 300 keV-2 MeV that uses both light and timing distribution of fast scintillating monolithic crystals. In this experiment we use a 5 mm thick CeBr3 scatterer plate and a 20 mm thick LYSO absorber plate. Our algorithms record for each scintillation event the full position and energy of the event including DOI, even in the thin plate and the relative timing between the detection in the two plate. Our CRT was measured at 293 ps FWHM in coincidence mode without DOI correction. This good time resolution allows for a stringent veto on real Compton event that must be recorded simultaneously in both the scatterer and the absorber plates, thus reducing background very efficiently. Acquisitions were performed with a Phillips Digital Photon Counter SiPM 3200 matrix with a delay-time correction map applied pixel by pixel. After accurate detection of gamma interaction coordinates (x,y,z) and energy in each plate, a list-mode maximum likelihood iterative reconstruction algorithm is applied to better estimate the gamma source activity distribution. Our Compton camera is a promising device for imaging high energy gamma rays, moreover, it can be also suitable for on-line monitoring due to its timing performance. The project TEMPORAL is funded by the ANDRA/PAI under the grant No. RTSCNADAA160019

Malaria asymptomatic carriage in the Sahelian region: the challenge associated to young adults

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