Abstract: A method for detecting chemical species present in a condensed medium including determining characteristic wavelengths and intensity values of back-scattered electromagnetic emission signals due to fluorescence of chemical species excited in response to a multiplicity of electromagnetic excitations of distinct wavelengths of at least one chemical species that could be contained in the condensed medium; successively exciting a multiplicity of surface elements of a surface portion of the condensed medium with a laser beam having tunable wavelength capable of taking on at least one of value of the distinct wavelengths of the multiplicity of electromagnetic excitations; successively recording wavelengths and intensity values of the electromagnetic emission signals back-scattered by each of the surface elements in response to the electromagnetic excitations produced by the beam; comparing at least one excitation wavelength and at least one corresponding emission wavelength of the recorded intensity value of the el

Abstract: The invention relates to a device for detecting chemical species present in a condensed medium, comprising means for determining the wavelength and the intensity values which are characteristic of electromagnetic transmission signals which are backscattered in response to a plurality of electromagnetic excitations, which have distinct wavelengths, of at least one chemical species which can be contained in the condensed medium; laser means producing a beam in order to excite the condensed medium; means for recording the wavelengths and the intensity values of backscattered electromagnetic transmission signals; and comparing and determining means for comparing the recorded intensity value of the electromagnetic signal, which is backscattered by the medium at a determined characteristic intensity value, with at least one corresponding transmission wavelength and excitation wave length.

Abstract: A pin (101) for alignment of two elements (1, 3) each comprising at least one orifice (2, 4) to be positioned coaxially with each other, the first element (1) being stationary and the second element (3) being radially displaceable. The alignment pin comprises a cage (11) having a diameter smaller than the diameter of the orifices (2, 4) of the two elements (1, 3) and intended to be placed in these orifices (2, 4). The cage (11) comprises radial expansion blocks (13) for centering the pin (10) in the orifice (2) of the first stationary element (1) forming a reference and for displacement of the second element (3) in relation to the first element (1). The pin is used for centering a cover on a nuclear reactor vessel.