High Energy Proton Irradiation Induced Pinning Centers in Bi-2212 and Bi-2223 Superconductors

Willis, J. O.; Safar, H.; Cho, J.H.

doi:10.1007/978-4-431-66871-8_111

Cited by 7 publications

(5 citation statements)

References 8 publications

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“…That the I c increases for low irradiation levels can also be inferred by comparing the I c (5T) for sections A (220 A) and C (202 A) of sample 5 which receive a lower dose than section B (232 A). For sample 6 irradiated to 2x10 An increase in the critical current density, J c has been observed in single crystal Bi-2212 when irradiated with high energy protons [3], and heavy ions [4,5]. This has been attributed to the creation of columnar pinning sites by the latent fission tracks, which increases J c .…”

Section: Resultsmentioning

confidence: 96%

Effect of proton irradiation on the critical current and critical temperature of Bi-2212 wires

Ghosh¹,

Greene²

2012

AIP Conference Proceedings

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Section: Resultsmentioning

confidence: 96%

Effect of proton irradiation on the critical current and critical temperature of Bi-2212 wires

Ghosh¹,

Greene²

2012

AIP Conference Proceedings

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“…The 85 filament tapes have final dimensions of 0.25 x 2.5 mm with filament dimensions of 15 µm thick and 120 µm wide and a 28% fill factor. These tapes were of an older generation to allow comparison with results of earlier experiments [4][5]. The critical current I c of the tape stock is about 30 A at 77 K, 0 T; the J c and J e are 20 and ~4.5 kA/cm 2 , respectively, under the same conditions.…”

Section: Experimental Tape Fabricationmentioning

confidence: 96%

“…This was followed shortly by an investigation of proton-irradiated Bi-2223/Ag sheathed tapes by the Los Alamos group [4][5][6]. For magnetic fields up to ~1 T at 75 K, large enhancements were seen in the critical current for the magnetic field oriented along the normal to the tape plane.…”

Section: Introductionmentioning

confidence: 99%

Enhanced critical currents in Bi-2223/Ag sheathed tapes by high energy proton irradiation

Willis¹,

Coulter²,

Maley³

et al. 2002

AIP Conference Proceedings

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We irradiated Bi-2223/Ag sheathed tapes with high-energy protons, causing fission reactions with Bi and Pb nuclei and generating in situ splayed columnar defects in the superconductor core of the tapes. We find that the best 75 K critical-current density J c performance in an applied magnetic field B perpendicular to the tape plane is achieved at a matching field, for which the flux-quantum density equals the columnar-defect density, of about 1 T. At this defect density, the J c at 75 K and 1 T perpendicular to the tape plane is almost 100 times larger than that for an unirradiated tape. For higher proton doses, there is increasingly greater grain-boundary damage, lowering the self-field J c and ultimately degrading the in-field performance. However, much of this damage can be repaired with a short anneal at 400°C. Decreasing the incident proton energy from 800 to 500 MeV has little effect on the enhanced J c performance and has beneficial side effects. Irradiation of a stack of tapes demonstrates the high penetration power and uniform generation of columnar defects throughout a substantial volume of material. The application of this technique to improved device performance will be discussed.

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“…It is widely accepted that the current in the Bi-2212 round wire generally transports through the grain boundary and the a-b plane within the grain, while the current flow can be readily inhibited by the lattice distortion due to the presence of defects [15][16][17][18][19][20][21]. As demonstrated by the heavily disordered atomic arrangement in the irradiated sample (figures 6(b) and (d)), it can be briefly concluded that the irradiation defects could disrupt the connectivity of the Bi-2212 superconducting region, thereby resulting in the J C degradation of Bi-2212 round wire, consistent well with the previous reports [12,18,19].…”

Section: Superconducting Performancementioning

confidence: 99%

“…Nevertheless, HTS is generally required to be exposed to different levels and types of irradiation. There were some previous studies to report the influences of ion irradiation [13][14][15], neutron irradiation [16,17], electron irradiation [18] or proton irradiation [19,20] on the microstructure and property of the Bi-2212 superconducting materials, mainly aiming to evaluate the applicability of the Bi-2212 as a strong magnet operated in an irradiation environment. Some investigations [11-14, 19, 20] have verified that the irradiation could lead to the creation of columnar pinning sites by the latent fission tracks, and thus the flux pinning effect could be enhanced by increasing irradiation defects.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of irradiation effects on the microstructure and properties of Ag-sheathed Bi-2212 superconducting round wire for future application in CFETR

Zhu

Qiu

et al. 2020

Supercond. Sci. Technol.

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The Chinese Fusion Engineering Test Reactor (CFETR) is designed to build a fusion engineering Tokamak reactor generating fusion power of 200–1500 MW, and to test the breeding tritium during fusion reaction. This may require a maximum magnetic field up to 15 T in the central solenoid and toroidal field coils. New superconducting materials should be developed for satisfying the next-generation fusion reactors with critical requirements. Recently, Bi2Sr2CaCu2Ox (denoted as Bi-2212) is considered as one of the most promising potential superconductors to be used as the magnets in CFETR, however, they will be subjected to harsh irradiation under operating conditions. The irradiation effects of the high-energy helium ions on the Ag-sheathed Bi-2212 superconducting round wire have been explored for the first time in this work. The microstructure and the critical current at 4.2 K of the superconducting wire before and after irradiation have been carefully investigated. Room-temperature x-ray diffraction (XRD) profiles showed that all the peaks shifted rightward significantly with a broadened (111)Ag peak, indicating that the high-energy He+ irradiation resulted in appreciable defects and strain in the superconducting wire. Meanwhile, the in-situ high-temperature XRD tests showed that the lattice constant and the thermal expansion coefficient were deduced in the irradiated sample to be due to the presence of the generated defects. After irradiation, the grain size of the Ag sheath was refined, and the lattice of Bi-2212 superconductor was distorted obviously, as confirmed by transmission electronic microscopy. The critical current IC at 4.2 K of the superconducting wires in the field of 0–12T determined by the four-probe technique, decreased substantially after irradiation because of the lattice distortion and the consequently induced strain in the Bi-2212 superconductor. This work provides a solid basis for evaluating and understanding the irradiation effects upon the Ag-sheathed Bi-2212 superconducting wire, more promising for future application in CFETR.

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High Energy Proton Irradiation Induced Pinning Centers in Bi-2212 and Bi-2223 Superconductors

Cited by 7 publications

References 8 publications

Effect of proton irradiation on the critical current and critical temperature of Bi-2212 wires

Effect of proton irradiation on the critical current and critical temperature of Bi-2212 wires

Enhanced critical currents in Bi-2223/Ag sheathed tapes by high energy proton irradiation

Evaluation of irradiation effects on the microstructure and properties of Ag-sheathed Bi-2212 superconducting round wire for future application in CFETR

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