Low-Temperature Operation of a Bulk HTSC Staggered Array Undulator

Kii, Toshiteru; Kinjo, Ryota; Kimura, N.; Shibata, M.; Bakr, Mahmoud; Choi, Yong Woon; Omer, Mohamed; Yoshida, Kyohei; Ishida, K.; Komai, Takuya; Shimahashi, Kyohei; Sonobe, Taro; Zen, H.; Masuda, Kai; Ohgaki, Hideaki

doi:10.1109/tasc.2011.2180498

Cited by 41 publications

(30 citation statements)

References 8 publications

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“…Higher J c 2.3×10 9 0.8 2.0×10 9 4.5 1.0 Best fit J c 2.3×10 9 0.8 1.57×10 9 4.5 1.0 Lower J c 2.3×10 9 0.8 1.3×10 9 4.5 1.0 J c (B, T) characteristics of the bulk; this is because the stress is closely related to the Lorentz force F L . In a previous simulation paper [23], the J c (B) characteristics, which were estimated by the magnetic moment hysteresis (M-H) loop using a small piece cut from the bulk, were typically used. Bean's critical state model [24] or the Kim model [25] were also used.…”

Section: Resultsmentioning

confidence: 99%

Promising effects of a new hat structure and double metal ring for mechanical reinforcement of a REBaCuO ring-shaped bulk during field-cooled magnetisation at 10 T without fracture

Fujishiro¹,

Naito²,

Yanagi³

et al. 2019

Supercond. Sci. Technol.

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PAPERPromising effects of a new hat structure and double metal ring for mechanical reinforcement of a REBaCuO ring-shaped bulk during fieldcooled magnetisation at 10 T without fracture AbstractWe have investigated a new reinforcement hat structure for a RE-Ba-Cu-O (REBaCuO, RE: rare earth element or Y) ring-shaped bulk superconductor (ring bulk) shrink-fitted with a double Al alloy ring and set on the cold stage of a cryogenic refrigerator prior to field-cooled magnetisation (FCM). With the hat structure, a ring bulk having an outer diameter of 64 mm, inner diameter of 40 mm, and height of 20.5 mm achieved a trapped field as high as 6.8 T at 50 K during FCM with an applied magnetic field at B app =10 T without fracture; a similar ring bulk without the hat structure broke during FCM at B app =8.8 T. Using a numerical simulation for electromagnetic and mechanical properties, the potential benefit of the hat structure was confirmed. The magnetic field dependence of the average critical current density J c (B) of the ring bulk used in the simulation was determined by experimental results of time step dependence of the trapped field B z at the bulk centre. As a result, the total hoop stress σ θ total in the ring bulk including the resulting stress of cooling from 300 K to 50 K and subsequent FCM at B app =10 T is lower than the fracture strength of a typical Ag-doped REBaCuO bulk material. The effect of double Al alloy ring reinforcement was also analysed using a numerical simulation and compared with that of the conventional single Al alloy ring reinforcement. These results suggest that the double ring provides only a limited benefit, whereas the hat structure is fairly effective in reducing the electromagnetic hoop stress during FCM at B app =10 T. Using this reinforcement method, a 400 MHz (9.4 T) nuclear magnetic resonance bulk magnet system could be realised.

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Section: Resultsmentioning

confidence: 99%

Promising effects of a new hat structure and double metal ring for mechanical reinforcement of a REBaCuO ring-shaped bulk during field-cooled magnetisation at 10 T without fracture

Fujishiro¹,

Naito²,

Yanagi³

et al. 2019

Supercond. Sci. Technol.

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“…Superconducting bulk magnets are suitable for new compact-magnet applications such as desktop NMR, MRI, motors, and particle accelerators [9][10][11] , which require very strong fields that cannot be obtained by conventional permanent magnets and flexible magnet-shape design. State-of-the-art texturing growth techniques overcome the electromagnetic weak-link problem in quasi-single-crystal forms of HTS rare-earth barium copper oxide (HTS-REBCO), and a record high field of 17 T was trapped in a 1-inch compact bulk [2,8] .…”

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confidence: 99%

Permanent magnet with MgB2 bulk superconductor

Yamamoto

Ishihara

Tomita

et al. 2014

Applied Physics Letters

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Abstract:Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging (MRI). The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)-materials that can be used without conventional liquid-helium cooling to 4.2 K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB 2 ) makes an excellent permanent bulk magnet, maintaining 3 T at 20 K for 1 week with an extremely high stability (<0.1 ppm/h). The magnetic field trapped in this magnet is uniformly distributed, as for single-crystalline neodymium-iron-boron. Magnetic hysteresis loop of the MgB 2 permanent bulk magnet was detrmined. Because MgB 2 is a simple-binary-line compound that does not contain rare-earth metals, polycrystalline bulk material can be industrially fabricated at low cost and with high yield to serve as strong magnets that are compatible with conventional compact cryocoolers, making MgB 2 bulks promising for the next generation of Tesla-class permanent-magnet applications.

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“…where Jc1 = 9.0 × 10 9 A/m 2 , BL = 1.5 T, Jc2 = 5.4 × 10 9 A/m 2 , Bmax = 8.0 T and k = 0.5 are used for the fitting parameters at 20 K [6,9].Elastic behavior can be expressed by Hooke's law, in which the stress tensor, , is linearly proportional to strain tensor, , as follows,…”

Section: Numerical Simulation Frameworkmentioning

confidence: 99%

Design Optimization of a Hybrid Trapped Field Magnet Lens (HTFML)

Namba

Fujishiro

Ainslie

et al. 2019

IEEE Trans. Appl. Supercond.

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The concept of a hybrid trapped field magnet lens (HTFML) was recently proposed by the authors, which consists of a trapped field magnet (TFM) cylinder exploiting the "vortex pinning effect," combined with a superconducting bulk magnetic lens exploiting the "diamagnetic shielding effect." This HTFML can generate, within its bore, a magnetic field higher than the applied magnetic field, even after external field decreases to zero. In this paper, a design optimization of the inner GdBaCuO magnetic lens within the GdBaCuO TFM cylinder was carried out using numerical simulations based on the finite element method, in order to maximize the concentrated magnetic field. The HTFML with an optimized shape and size achieved a concentrated magnetic field of Bc = 5.6 and 12.8 T at the center of the lens for applied magnetic fields of Bapp = 3 and 10 T, respectively. A maximum tensile stress of +135 MPa exists in the outer GdBaCuO TFM cylinder during the magnetizing process for Bapp = 10 T, which exceeds the fracture strength of the bulk. This result suggests that mechanical reinforcement is necessary to avoid mechanical fracture under such high magnetic field conditions.  Index Terms-Hybrid trapped field magnet lens (HTFML), mechanical stress, numerical simulation, REBaCuO bulk superconductor, trapped field magnets

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Low-Temperature Operation of a Bulk HTSC Staggered Array Undulator

Cited by 41 publications

References 8 publications

Promising effects of a new hat structure and double metal ring for mechanical reinforcement of a REBaCuO ring-shaped bulk during field-cooled magnetisation at 10 T without fracture

Promising effects of a new hat structure and double metal ring for mechanical reinforcement of a REBaCuO ring-shaped bulk during field-cooled magnetisation at 10 T without fracture

Permanent magnet with MgB2 bulk superconductor

Design Optimization of a Hybrid Trapped Field Magnet Lens (HTFML)

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