We present our first results of ionizing radiation measurement using optical fibers and LYSO scintillator. The LYSO scintillator was used to detect the radiation and the silica optical fibers with 1 mm fiber core was used to deliver scintillation radiation from LYSO to single photon counter. We present our setups and measurement results of several ionizing sources Co-60, Cs-134, Cs-137 and Am-241 with different level of the activities. Focus to measurement gamma radiation of these nuclides was motivated by the research of measurement possibilities in the nuclear power plants by optical fibers. Used nuclides have different level of radiation energies and can be used to design and optimize of the measurement setup. We used one and four optical fibers with different types of collimation at both ends of the optical fibers to deliver scintillation radiation to the single photon counter. The comparison of these setups of the measurement is presented. Our measurement confirmed the optical fibers can be used to measure radiation of these nuclides with activities from tenths up to hundreds kBq. Next will be verified the measurement of higher level of radiation activities.
We present development and first measurement with new ionizing radiation sensors with silica optical fibers. Our research is focused to merge silica optical fibers and some scintillation materials. The ionizing radiation has a minimal effect to silica optical fibers in comparison with plastic optical fibers which are usually used to these measurements. In combination with the right scintillation materials we created first set-up of sensor to measurement beta and gamma radiation. Our sensors are prepared for the most types of scintillation materials structures. The structure can be in liquid, powdered or crystalline state. The advantages of each type of structure are presented with focus to type of ionizing radiation measurement.
We present the development of new methods and techniques of splicing and forming optical fibers with focusing on the development of new ionizing radiation sensors. Optical fiber-based ionizing sensors can be prepared by the combination of scintillation material and optical fibers. The type of optical fibers forming depends on the scintillation material structure. The type of scintillation material to ionizing radiation sensor preparation which can be used primary depends on the efficiency of ionizing radiation to scintillation radiation conversion. The standard types of optical fibers with different core diameters can be used for the powdered or crystalline structure of scintillation material. On the other side, the liquid scintillation material can be used in combination with microstructure fiber mainly. We prepared techniques for splicing and closing special hollow-core Photonic Crystal Fibers (PCF) and theirs cross splicing methods with standard optical fibers to using with this liquid scintillation materials. To powdered scintillation materials we prepared forming technology to optical fibers narrowing, etching etc. These techniques of fibers forming are presented.
KEYWORDS: Calibration, Interferometers, Field programmable gate arrays, Interferometry, Sensors, Monte Carlo methods, Homodyne detection, Distance measurement, Signal processing, Signal detection, Laser interferometry
We report on a traceable calibration system for a 3500mm-long console that carries a measurement system for inspecting the diameter of a circular reactor chassis. The system uses two single-pass laser interferometers with homodyne fringe detection for measurement in two degrees of freedom. The hybrid FPGA-microcontroller control module carries out the fringe detection together with the application-specific scale linearization approach and the compensation of environmental influences such as thermal elongation and the refractive index of air fluctuations. We demonstrated the system feasibility with an accuracy of a few microns and translation velocity higher than 0:1 metre per second.
Optical fiber links in Europe are with growing importance utilized in comparison campaigns of experimental optical clocks to verify their ultimate relative stability. We present a 306 km long optical fiber link established in the Czech Republic between ISI CAS Brno and CESNET Prague. This link will to deliver stable optical frequencies from laser standards located at ISI CAS in Brno to prospective academic and industrial partners in the Prague area. Our contribution reports on the current state of the fiber link for phase-coherent transfer of optical frequency. The long-haul link operates on an internet communication fiber in a dedicated 1540-1546nm DWDM window. A narrow-linewidth laser (Koheras BASIK) working at 1540.5 nm locked to a high-finesse optical cavity (Q = 300 000) serves as the optical frequency standard and source of highly coherent laser light at the transmitting side.
We present the development of new methods and techniques of splicing and forming optical fibers with focusing on the development of new ionizing radiation sensors. Optical fiber-based ionizing sensors can be prepared by the combination of scintillation material and optical fibers. The type of optical fibers forming depends on the scintillation material structure. The type of scintillation material to ionizing radiation sensor preparation which can be used primary depends on the efficiency of ionizing radiation to scintillation radiation conversion. The standard types of optical fibers with different core diameters can be used for the powdered or crystalline structure of scintillation material. On the other side, the liquid scintillation material can be used in combination with microstructure fiber mainly. We prepared techniques for splicing and closing special hollow-core Photonic Crystal Fibers (PCF) and theirs cross splicing methods with standard optical fibers to using with this liquid scintillation materials. To powdered scintillation materials we prepared forming technology to optical fibers narrowing, etching etc. These techniques of fibers forming are presented.
We present construction development of new ionizing radiation sensors based on silica optical fibers. Optical fiber based ionizing sensors can be prepared from silica optical fibers by adding a scintillation material. Scintillation material can be in liquid, powdered or crystalline structure. Then the sensor construction has to be prepared with focus to the scintillation material structure and to efficiency of ionizing radiation to scintillation radiation conversion. The best conversion efficiency is usually for the crystalline or powdered types of scintillation material structure. The liquid scintillation material has smaller efficiency conversion and can be used in combination with microstructure fiber mainly. Our first set-ups of silica optical fiber based ionizing radiation sensors with powdered and crystalline structure of the scintillation material are presented.
We present method for the improvement of the measurement accuracy in the optical frequency spectra
measurements based on tunable optical filters. The optical filter was used during the design and realization of the
measurement system for the inspection of the fiber Bragg gratings. The system incorporates a reference block for the
compensation of environmental influences, an interferometric verification subsystem and a PC - based control software
implemented in LabView. The preliminary experimental verification of the measurement principle and the measurement
system functionality were carried out on a testing rig with a specially prepared concrete console in the UJV Řež. The
presented system is the laboratory version of the special nuclear power plant containment shape deformation
measurement system which was installed in the power plant Temelin during last year.
On the base of this research we started with preparation other optical fiber sensors to nuclear power plants
measurement. These sensors will be based on the microstructured and polarization maintaining optical fibers. We started
with development of new methods and techniques of the splicing and shaping optical fibers. We are able to made optical
tapers from ultra-short called adiabatic with length around 400 um up to long tapers with length up to 6 millimeters.
We developed new techniques of splicing standard Single Mode (SM) and Multimode (MM) optical fibers and
splicing of optical fibers with different diameters in the wavelength range from 532 to 1550 nm. Together with
development these techniques we prepared other techniques to splicing and shaping special optical fibers like as
Polarization-Maintaining (PM) or hollow core Photonic Crystal Fiber (PCF) and theirs cross splicing methods with focus
to minimalize backreflection and attenuation. The splicing special optical fibers especially PCF fibers with standard
telecommunication and other SM fibers can be done by our developed techniques. Adjustment of the splicing process has
to be prepared for any new optical fibers and new fibers combinations. The splicing of the same types of fibers from
different manufacturers can be adjusted by several tested changes in the splicing process. We are able to splice PCF with
standard telecommunication fiber with attenuation up to 2 dB. The method is also presented.
Development of these new techniques and methods of the optical fibers splicing are made with respect to using
these fibers to another research and development in the field of optical fibers sensors, laser frequency stabilization and
laser interferometry based on optical fibers. Especially for the field of laser frequency stabilization we developed and
present new techniques to closing microstructured fibers with gases inside.
We present development of new methods and techniques of the splicing and shaping optical fibers. We developed new techniques of splicing for standard Single Mode (SM) and Multimode (MM) optical fibers and optical fibers with different diameters in the wavelength range from 532 to 1550 nm. Together with development these techniques we prepared other techniques to splicing and shaping special optical fibers like as Polarization-Maintaining (PM) or hollow core Photonic Crystal Fiber (PCF) and theirs cross splicing methods with focus to minimalize backreflection and attenuation. The splicing special optical fibers especially PCF fibers with standard telecommunication and other SM fibers can be done by light adjustment of our developed techniques. Adjustment of the splicing process has to be prepared for any new optical fibers and new fibers combinations. The splicing of the same types of fibers from different manufacturers has to adjust too. We are able to splice PCF with standard telecommunication fiber with attenuation up to 2 dB. The method is also presented. In the next step we developed techniques to tapering optical fibers. We are able to made optical tapers from ultra-short called adiabatic with length around 400 um up to long tapers with length up to 6 millimeters. Development of these new optical fibers splicing techniques and methods are made with respect to using these fibers to another research and development in the field of optical fibers sensors, laser frequency stabilization and laser interferometry based on optical fibers. Especially for the field of laser frequency stabilization we developed and present new techniques to closing microstructured fibers with gases inside.
We present system of structure health measurement by optical fiber sensors based on fiber Bragg gratings. Our system is focused to additionally install to existing buildings. We prepared first set-up of the system to monitoring of the nuclear power plant containment shape deformation. The presented system can measure up to several tens of sensors simultaneously. Each sensor contains optical fiber grating to measurement of change of length and the other independed fiber grating to monitor the temperature and the other ineligible effects.
We present optical fiber sensors to measurement strain and vibration. The sensors are based on fiber Bragg gratings (FBG). We prepared construction of strain sensors with respect to its implementation on the outer surface of concrete structures and with compensation of potential temperature drifts. These sensors are projected with look forward to maximal elongation and strength which can be applied to the sensor. Each sensor contains two optical fibers with FBGs. One FBG is glued into the sensor in points of fixation which are in the line with mounting holes. This FBG is prestressed to half of measurement range, than the stretching and pressing can be measured simultaneously by one FBG. The second FBG is placed inside the sensor without fixation to measure temperature drifts. The sensor can be used to structure health monitoring. The sensors to measurement vibration are based on tilted fiber Bragg grating (TFBG) with fiber taper. The sensor uses the TFBG as a cladding modes reflector and fiber taper as a bend-sensitive recoupling member. The lower cladding modes (ghost), reflected from TFBG, is recoupled back into the fiber core via tapered fiber section. We focused on optimization of TFBG tilt angle to reach maximum reflection of the ghost and taper parameters. In this article we present complete set-up, optical and mechanical parameters of both types of sensors.
We present system of structure health measurement by optical fiber sensors based on fiber Bragg gratings. Our system is focused to additionally install to existing buildings. We prepared first set-up of the system to monitoring of the nuclear power plant containment shape deformation. The presented system can measure up to several tens of sensors simultaneously. Each sensor contains optical fiber grating to measurement of change of length and the other independed fiber grating to monitor the temperature and the other ineligible effects.
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