Abstract: A measuring system includes a detector having an optical waveguide including a primary dopant capable of transmuting, by neutron capture, into a stable secondary dopant that is less neutron-absorbent than the primary dopant, a moderation layer suitable for slowing down fast neutrons, and an analysis device connected to the detector. The analysis device is configured to inject, into the waveguide, an interrogation wave having a wavelength corresponding to an absorption peak of the secondary dopant, detect a response wave emitted by the waveguide, calculate, from the detected response wave, a piece of information relating to a concentration of secondary dopant in the waveguide, and, based on the information relating to the calculated concentration of secondary dopant, determine a fluence of fast neutrons during a predetermined secondary period.

Abstract: A flatness roller includes a body having at least one cavity opening onto an outer surface of the body through a plurality of slots, two successive slots defining a lamella between them, each lamella being connected to the body by two connection portions. The flatness roller also includes at least one optical fibre having at least one strain sensor having a measurement axis. Each strain sensor is housed in a cavity and attached at a connection portion of a lamella, the measurement axis forming an angle less than or equal to 20° with a plane orthogonal to the axis of revolution of the body. Each strain sensor is configured to send an optical response wave representative of a strain of the strain sensor according to the measurement axis thereof.

Abstract: A radiation-detecting device including at least two radiation detectors distributed in series along a support cable, each detector including an optically stimulated luminescence detection element which is optically coupled to at least one optical fiber, each optically stimulated luminescence detection element being held opposite a first end of the optical fiber by a mechanical part fixed to the support cable, the mechanical part being held in a flexible cable by a holding mechanism, second ends of each optical fiber leading to the same first end of the flexible cable.

Abstract: A radiation-detecting device including at least two radiation detectors distributed in series along a support cable, each detector including an optically stimulated luminescence detection element which is optically coupled to at least one optical fiber, each optically stimulated luminescence detection element being held opposite a first end of the optical fiber by a mechanical part fixed to the support cable, the mechanical part being held in a flexible cable by a holding mechanism, second ends of each optical fiber leading to the same first end of the flexible cable.

Abstract: Device for measuring corrosion in a structure. It comprises: at least one assembly comprising a metallic part (2) intended to be fixed to the structure and able to deform under the effect of corrosion and/or a thermomechanical variation, and transduction means (4) comprising an optical fibre (3) fixed to the metallic part in a prestressed state, the transduction means being able to modify light propagating in the fibre under the effect of a stress applied to the fibre; means for measuring and processing the spectral responses supplied by the transduction means of said at least one assembly. The metallic part is segmented longitudinally in order to form an alternation of segments covered by a corrosion-protection material (8) and uncovered segments, in order to distinguish the thermomechanical influence of the structure from the mechanical effects caused by corrosion.

Abstract: Device for measuring corrosion in a structure. It comprises: at least one assembly comprising a metallic part (2) intended to be fixed to the structure and able to deform under the effect of corrosion and/or a thermomechanical variation, and transduction means (4) comprising an optical fibre (3) fixed to the metallic part in a prestressed state, the transduction means being able to modify light propagating in the fibre under the effect of a stress applied to the fibre; means for measuring and processing the spectral responses supplied by the transduction means of said at least one assembly. The metallic part is segmented longitudinally in order to form an alternation of segments covered by a corrosion-protection material (8) and uncovered segments, in order to distinguish the thermomechanical influence of the structure from the mechanical effects caused by corrosion.

Abstract: The invention relates to an instrumented tubular device for transporting a pressurized fluid notably in the field of oil exploration and in that of the transport of gas or hydrocarbons. This device comprises a tube in which this fluid flows, with which are associated means for measuring the main deformations of this tube, and means for measuring the temperature of the fluid in the tube. This tube is equipped with measurement means integral with its surface and offset by at least one remote optical cable towards an electronic measurement system. These measurement means are means for assembling at least two non-parallel optical fibers which comprise at least three assemblies of at least two optical gages with Bragg gratings attached to at least three measurement locations and connected to the remote optical cable via optical fibers. At least one assembly further comprises a temperature gage.

Abstract: The invention relates to a system for distributed or dispersed measurement of axial and bending deformations of a structure including at least one threadlike device (10) equipped for the distributed or dispersed measurement of these axial and bending deformations, and means for processing measurement signals generated by said device, in which each device includes a cylindrical reinforcement (11) supporting, at its periphery, at least three optical fibres (12) locally parallel to the axis of the reinforcement, and in which the processing means implement means for spectral or time division multiplexing of signals coming from optical fibres.

Abstract: The invention relates to an instrumented tubular device for transporting a pressurized fluid notably in the field of oil exploration and in that of the transport of gas or hydrocarbons. This device comprises a tube (20) in which this fluid flows, with which are associated means for measuring the main deformations of this tube, and means for measuring the temperature of the fluid in the tube. This tube is equipped with measurement means integral with its surface and offset by at least one remote optical cable towards an electronic measurement system. These measurement means are means for assembling at least two non-parallel optical fibers which comprise at least three assemblies (B1, B2, B3) of at least two optical gages with Bragg gratings attached to at least three measurement locations (22) and connected to the remote optical cable (23) via optical fibers. At least one assembly further comprises a temperature gage.

Abstract: A sensor including at least one element made out of a radiation detection material, capable of emitting a luminescence radiation and transparent to this radiation, and two radiation filtration screens, one thin and placed opposite one end of the element, the other thick and placed at the periphery of the element. The sensor may be coupled with a flexible optical wave guide designed to collect and convey the luminescence radiation.

Abstract: This spectrometer comprises at least one elementary spectrometer that comprises an optical phase array comprising a microguide assembly (12) and formed on a cleaved planar optical guide (14), reflecting means (24, 30, 32, 34) capable of successively reflecting radiation sent from the microguide assembly, for propagating this radiation in the folded form and in free space, means (26) for photodetecting the radiation so reflected and means (28) for focusing radiation on said photodetection means.

Abstract: This device comprises a device (DD) for demultiplexing these lines in terms of wavelength, a device (DM) for measuring, by filtering, the wavelengths of the demultiplexed lines, comprising, for each of these lines, a measuring channel (VM) provided with a filter and a reference channel (VR), and means (MP) for the photodetection, for each line, of the light intensity transmitted by the corresponding measuring and reference channels. The wavelength of each of these lines is determined by calculating the ratio of the intensities thus detected. Application to the monitoring of structures.

Abstract: Energy compensation, wide beam width radiation sensor, for remote dosimetry, and dosimetry device using this sensor.

Abstract: The present invention relates to a device for demultiplexing spectrum lines contained in an optical spectrum. This device comprises a energy separator (2a, 2b, 2c) and selective wavelength light reflectors (12), each selective wavelength light reflector having a wavelength bandpass that contains the spectral region associated with one of the lines and that, therefore, reflects only this particular line. Applications to surveying constructions, such as buildings and aircraft.

Abstract: The present invention relates to a planar, rosette-type, optical microsystem with strain gauges having dielectric guides used for measuring a system of strains or stresses applied to a part, in which the part is under purely longitudinal strain, at least one rosette being formed by at least two strain gauges with dielectric guides (J1, J2, J3) and in which a calculating circuit makes it possible to determine said strain by resolving a system of equations.

Abstract: The present invention relates to a high capacity, high signal-to-noise ratio sensor incorporating an array of Bragg grating transducers photoinscribed on a dielectric guide and a feedback loop incorporating a wavelength selective element which is time modulated making it possible to obtain a laser sensor selectively switched by each Bragg grating.Application to monitoring strains or temperatures in a structure.