Abstract: Apparatus for monitoring a reactor surface with a sensor cable, which is during operation at least partially arranged in the region of the reactor surface, has at least two optical fibers (1, 2) arranged in the sensor cable, has at least one laser light source whose light is coupled at least partially into the optical fibers (1, 2) during the operation of the apparatus, and evaluation means, in which portions of the light coupled out of the optical fibers (1, 2) are evaluated during the operation of the apparatus, for monitoring at least partially the reactor surface with respect to at least one physical size in a spatially resolved manner. The apparatus includes magnetic retaining means (8) for attaching the sensor cable (10) on the reactor surface.

Abstract: A device for spatially resolved measuring of a physical variable has a device for generating a first electrical signal with a first frequency and a device for generating a second electrical signal with a second frequency. The second frequency differs from the first frequency by a difference frequency. An optical radiation source generates an optical signal modulated by the first frequency. The optical signal can interact with a test object and be modified in the process. A mixer can mix an electrical signal emerging from the optical signal with the second signal. A device, particularly embodied as a DDS system, generates a third electrical signal with a third frequency that corresponds to the difference frequency or a multiple of the difference frequency. A digital/analog converter digitizes the at least one mixed signal by sampling the mixed signal at the third frequency in order to digitize it.

Abstract: A device for calibrating a fiber-optic temperature measuring system has a broadband light source, a coupling-in device, which can couple light generated by the light source for calibration into an optical fiber of the temperature measuring system, a coupling-out device, which can couple components of the light source-generated light that are backscattered in the optical fiber out of the optical fiber. An evaluation device performs a calibration of the temperature measuring system on the basis of the backscattered components of the light.

Abstract: A device for spatially resolved measuring of a physical variable has a device for generating a first electrical signal with a first frequency and a device for generating a second electrical signal with a second frequency. The second frequency differs from the first frequency by a difference frequency. An optical radiation source generates an optical signal modulated by the first frequency. The optical signal can interact with a test object and be modified in the process. A mixer can mix an electrical signal emerging from the optical signal with the second signal. A device, particularly embodied as a DDS system, generates a third electrical signal with a third frequency that corresponds to the difference frequency or a multiple of the difference frequency. A digital/analog converter digitizes the at least one mixed signal by sampling the mixed signal at the third frequency in order to digitize it.