Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Commissariat a L'energie Atomique

Andrea Brambilla

Alexia Gorecki

Alexandra Potop

Marc Arques

Jean-Marc Dinten

Adrien Gasse

Caroline Paulus

Patrice Ouvrier-Buffet

Veronique Rebuffel

Jean Rinkel

Lydie Mathieu

Thierry Pochet

Florent Mougel

Cinzia De Cesare

A method is provided for characterizing a sample, by estimating a plurality of characteristic thicknesses, each being associated with a calibration material. The method includes acquiring an energy spectrum transmitted through the sample, located in an X and/or gamma spectral band; for each spectrum of a plurality of calibration spectra, calculating a likelihood from said calibration spectrum, and from the spectrum transmitted through the sample, each calibration spectrum corresponding to the energy spectrum transmitted through a stack of gauge blocks, each formed of a known thickness of a calibration material; and estimating the characteristic thicknesses associated with the sample according to the criterion of maximum likelihood.

Characterizing a sample by material basis decomposition

The invention is a method for characterizing an object (), comprising the following steps:

Method for characterizing an object using spectral imaging

A method for characterizing a sample, by estimating a plurality of characteristic thicknesses, each being associated with a calibration material, including acquiring an energy spectrum (S) transmitted through this sample, located in an X and/or gamma spectral band; for each spectrum of a plurality of calibration spectra (s(L; L)) calculating a likelihood from said calibration spectrum (S(L; L)), and from the spectrum transmitted through the sample (S), each calibration spectrum (S(L; L)) corresponding to the energy spectrum transmitted through a stack of gauge blocks, each formed of a known thickness of a calibration material; estimating the characteristic thicknesses (L, L) associated with the sample according to the criterion of maximum likelihood.

The invention is a method for processing a pulse generated by a detector of ionizing radiation, the detector being configured to interact with ionizing radiation in order to generate said pulse, the amplitude of which depends on an energy liberated by the ionizing radiation during its interaction in the detector, the method including the following steps:

Method for processing a pulse generated by a detector of ionizing radiation

A method correcting a measured spectrum of X radiation, according to a number of channels Nc, each channel i corresponding to an energy range between Eand Ei+&#x394;E, including: determining function &#x3b4;t(k) determining size of temporal deviation &#x394;t interval separating two interactions with energy Eand E, stacking of which leads to a detected energy value E; determining, from the function &#x3b4;t(k), probability function P(k) that an event counted in a channel k corresponds to a stack of two interactions, respectively of energies Eand E; determining, from the probability function P(k), a stack spectrum as a part of the measured spectrum that corresponds only to the stacks alone; and calculating or estimating at least a first corrected spectrum, by the difference between the measured spectrum and the stack spectrum.

Method for correcting the stacking phenomenon applied to X-ray spectrums acquired using a spectrometric sensor

A device that processes a signal delivered by a radiation detector includes a circuit that delivers a voltage pulse whose amplitude is proportional to a charge detected by the radiation detector. The device also includes an analog to digital converter to digitize the voltage pulse at a given sampling frequency and delivers a corresponding digital signal to a processing circuit. The processing circuit reads the digital signal, computes a temporal variation rate of the digital signal and captures the digital signal when the temporal variation reaches a threshold.

Device for processing a signal delivered by a radiation detector

This device for detecting electromagnetic radiation, in particular X-ray or &#x3b3;-rays, includes: a sensing layer consisting of at least one material capable of interacting with said electromagnetic radiation to be detected, in order to liberate mobile charge carriers, whereof the movement generates an electric current; a substrate provided with a plurality of elementary collectors of the charge carriers thus liberated, said elementary collectors being distributed discretely; a transfer layer suitable for transferring the charge carriers liberated by the sensing layer at the elementary collectors, said layer being connected to the sensing layer; and an insulating adhesive mating layer, suitable for mating the plurality of elementary collectors and the transfer layer.

Device for detecting electromagnetic radiation and ionizing radiation having an isotropic transfer layer

An X-gamma dosimeter responsive to low energy values includes X and gamma radiation detectors responding differently in relation to the dose absorbed at low energy. One detector overestimates the dose absorbed with regard to human tissues, while the other detector underestimates the absorbed dose. An electronic processor combines signals supplied by both detectors, the combination being optimized so as to report accurately the dosimetric quantity within a large energy range.

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Veurey-Voroize, France

Andrea Brambilla