Fiber Bragg Grating Cryosensors for Superconducting Accelerator Magnets

Chiuchiolo, A.; Bajko, M.; Pérez, Juan Carlos; Bajas, Hugues; Consales, M.; Giordano, M.; Breglio, G.; Cusano, A.

doi:10.1109/jphot.2014.2343994

Cited by 44 publications

(15 citation statements)

References 16 publications

(15 reference statements)

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“…In addition to the temperature sensors, also optical fibers with Bragg gratings [35,36], a relatively new temperature monitoring technique, were used on inductive backing wire the outside of the coil to map the temperature of important components, such as the joints and the top of the coil. The temperature as measured by the optical fibers was in good agreement with the classical temperature sensors, showing that the system is working correctly.…”

Section: Instrumentation and Noise Levelsmentioning

confidence: 99%

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Nugteren

Kirby

Bajas

et al. 2018

Supercond. Sci. Technol.

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This paper describes the standalone magnet cold testing of the high temperature superconducting magnet Feather-M2.1-2. This magnet was constructed within the European funded FP7-EUCARD2 collaboration to test Roebel type HTS cable, and is one of the first high temperature superconducting dipole magnets in the world. The magnet was operated in forced flow helium gas with temperatures ranging between 5 to 85 K. During the tests a magnetic dipole field of 3.1 T was reached inside the aperture at a current of 6.5 kA and a temperature of 5.7 K. These values are in agreement with the self-field critical current of the used SuperOx cable assembled with Sunam tapes (lowperformance batch), thereby confirming that no degradation occurred during winding, impregnation, assembly and cool-down of the magnet. The magnet was quenched many tens of times by ramping over the critical current and no degradation nor training was evident. During the tests the voltage over the coil was monitored in the micro-volt range. An inductive cancellation wire was used to remove the inductive component, thereby significantly reducing noise levels. Close to the quench current, drift was detected both in temperature and voltage over the coil. This drifting happens in a time scale of minutes and is a clear indication that the magnet has reached its limit. All quenches happened approximately at the same average electric field and thus none of the quenches occurred unexpectedly.

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Section: Instrumentation and Noise Levelsmentioning

confidence: 99%

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Nugteren

Kirby

Bajas

et al. 2018

Supercond. Sci. Technol.

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“…This section provides a brief description of the physics underlying the two fiber optic thermometry sensors installed and tested on the VIPER cables during the SULTAN test: the FBG system from CERN [19]; and the ULFBG system from RRI [20].…”

Section: Background: Fbgsmentioning

confidence: 99%

Fiber optic quench detection for large-scale HTS magnets demonstrated on VIPER cable during high-fidelity testing at the SULTAN facility

Salazar

Badcock

Bajko

et al. 2021

Supercond. Sci. Technol.

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Fiber-optic thermometry has the potential to provide rapid and reliable quench detection for emerging large-scale, high-field superconducting magnets fabricated with high-temperature-superconductor (HTS) cables. Developing non-voltage-based quench detection schemes, such as fiber Bragg grating (FBG) technology, are particularly important for applications such as magnetic fusion devices where a high degree of induced electromagnetic noise impose significant challenges on traditional voltage-based quench detection methods. To this end, two fiber optic quench detection techniques-FBG and ultra-long FBG (ULFBG)-were incorporated into two vacuum pressure impregnated, insulated, partially transposed, extruded, and roll-formed (VIPER) high-current HTS cables and tested in the SULTAN facility, which provides high-fidelity operating conditions to large-scale superconducting magnets. During surface heater induced quench-like events under a variety of operating conditions, FBG and ULFBG demonstrated strong signal-to-noise ratios (SNRs) ranging from 4 to 32 and measured single-digit temperature excursions; both the SNR and temperature sensitivity increase with temperature. Fiber thermal response times ranged between effectively instantaneous to a few seconds depending on the operating temperature. Strain sensitivity dominates the thermal sensitivity in the conditions achievable at SULTAN; however, measurements at higher quench evolution temperatures, coupled to future work to increase the thermal-to-strain signal, show promise for quench detection capability in full-scale magnets where temperature and strain may occur simultaneously. Overall, FBG and ULFBG were proven capable to quickly and reliably detect small temperature disturbances which induced quench initiation events for high current VIPER HTS conductors in realistic operating conditions, motivating further work to develop FBG and ULFGB quench detection systems for full-scale HTS magnets.

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“…Second, reduce the time span when the hot-spot temperature increases with a sensitive quench detection, a significant challenge for instrument and measurement. New quench detection techniques measuring the temperature rise in the normal zone are under investigation [161][162][163][164][165][166][167]. Compared to the voltage-based detection technique, these new optic and acoustic techniques are more immune to electromagnetic interference, attractive for fusion applications.…”

Section: How Do Rebco Accelerator Magnets Transit From Superconductinmentioning

confidence: 99%

Dipole Magnets above 20 Tesla: Research Needs for a Path via High-Temperature Superconducting REBCO Conductors

2019

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To enable the physics research that continues to deepen our understanding of the Universe, future circular colliders will require a critical and unique instrument—magnets that can generate a dipole field of 20 T and above. However, today’s maturing magnet technology for low-temperature superconductors (Nb-Ti and Nb 3 Sn) can lead to a maximum dipole field of around 16 T. High-temperature superconductors such as REBCO can, in principle, generate higher dipole fields but significant challenges exist for both conductor and magnet technology. To address these challenges, several critical research needs, including direct needs on instrumentation and measurements, are identified to push for the maximum dipole fields a REBCO accelerator magnet can generate. We discuss the research needs by reviewing the current results and outlining the perspectives for future technology development, followed by a brief update on the status of the technology development at Lawrence Berkeley National Laboratory. We present a roadmap for the next decade to develop 20 T-class REBCO accelerator magnets as an enabling instrument for future energy-frontier accelerator complex.

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Fiber Bragg Grating Cryosensors for Superconducting Accelerator Magnets

Cited by 44 publications

References 16 publications

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Powering of an HTS dipole insert-magnet operated standalone in helium gas between 5 and 85 K

Fiber optic quench detection for large-scale HTS magnets demonstrated on VIPER cable during high-fidelity testing at the SULTAN facility

Dipole Magnets above 20 Tesla: Research Needs for a Path via High-Temperature Superconducting REBCO Conductors

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