Project: Fiber Bragg Grating monitoring system for cryogenic applications

The present project aims at fully developing a Structural Health Monitoring system based on Fiber Bragg Grating (FBG) technology for application in cryogenic environments. _x000D__x000D_Cryogenic applications include Liquefied Natural Gas (LNG) transportation and storage, superconducting magnet monitoring (ITER, CERN,LHC, ...) and thermal vacuum testing for space structures, among others. Such applications are rapidly increasing and so are the monitoring demands associated to them. These applications usually involve large number of strain and temperature sensors, and commonly involve high electro-magnetic fields (such as the case of superconducting magnets). In such environments conventional electronic based systems present problems in terms cumbersome cabling, lack of signal integrity due to the high EM fields and channel crosstalk, and low sensitivity at cryogenic temperatures. Fiber Bragg Grating sensors are thus an optimum candidate for replacing these conventional monitoring solutions. _x000D__x000D_Fiber optic sensor technology presents long recognized advantages over conventional electric sensors, such as: multiplexing capability, immunity to EMI/RFI, remote monitoring, small size and weight, electrical and thermal insulation, intrinsically safe operation, high sensitivity and long-term reliability. These characteristics enable fiber optic sensors to mitigate well-known deficient performance of conventional technology in hazard-environments common in cryogenic monitoring applications. The implementation of centralized distributed fiber optic sensing systems would greatly benefit large scale thermal mapping along large cryogenic infrastructures. Fiber Bragg Grating (FBG) sensors share the benefits of any fiber optic sensor technology, and add to these features multiplexing and self-referencing intrinsic capabilities that make Bragg grating technology particularly competitive for medium and large scale (+20 sensors) monitoring applications, such as those dealing with cryogenic environments. _x000D__x000D_The goal of the project is to design and test a full FBG based strain and temperature monitoring system suitable for application in cryogenic environments. For achieving such a system, FBG based strain and temperature sensors, which have been well proven for operation at room temperature, will be redesigned and tested for cryo environments. Challenges on the new designs include optimized sensitivity at temperatures as low as 4K, long-term reliability analysis at cryogenic temperatures and radiation effect evaluation. Components such as the optical cable, fiber vacuum feedthroughs and adhesives will have to be selected and validated for this environment. Also an analysis of the adaptations required on the data acquisition equipment for each identified market application will be provided. _x000D__x000D_In order to achieve these goals, FiberSensing and SMARTEC have formed a consortium to address the application of FBG technology to cryo environments. Both companies have extensive experience in the design, implementation, testing, commercialization and installation of fiber optic monitoring solutions, and are thus in an optimum position to undertake the proposed work._x000D_

Acronym CryoBRAGG (Reference Number: 6393)
Duration 01/09/2011 - 31/08/2013
Project Topic CryoBRAGG aims at developing a structural health monitoring solution for cryogenic applications based on Fiber Bragg Grating technology. The EM/RF immunity, electrical passivity and reduced cabling requirements of the technology make it an ideal candidate for application in cryo environments.
Project Results
(after finalisation)
A complete array of sensors, readout unit and accesories (fibers and vacuum feedtroughts) for use in cryogenic environments has been developed and qualified. The system designs target the three CO identified cryogenic applications: instrumentation of supermagnet coils, instrumentation of thermal ground testing of space structures and leak detection in LNG applications.
Network Eurostars
Call Eurostars Cut-Off 6

Project partner

Number Name Role Country
2 SMARTEC SA Partner Switzerland
2 FiberSensing - Sistemas Avançados de Monitorização, S.A. Coordinator Portugal