Critical current changes in Nb$sub 3$Sn irradiated with fast neutrons at 6 K

Journal Article · Mon Dec 01 04:00:00 EST 1975 · J. Appl. Phys., v. 46, no. 12, pp. 5163-5168

OSTI ID:4123647

Brown, B S; Blewitt, T H; Wozniak, D G; Suenaga, M

Multifilament copper-clad wires of Nb$sub 3$Sn have been irradiated at 6 K to a dose of 1.8 x 10$sup 18$ n/cm$sup 2$ (E>0.1 MeV). The critical current (J/ sub c/) was measured as a function of dose and applied magnetic field to 33 kOe. After 1.2 x 10$sup 18$ n/cm$sup 2$, an increase of 33% in J/sub c/ occurred at 33 kOe from an initial value of 1.5 x 10$sup 6$ A/cm$sup 2$ at 4.5 K. The increase was smaller at lower applied fields, and J/sub c/ actually decreased for H<8 kOe. For all fields, the increase in J/sub c/ eventually saturated and then decreased as the dose increased, with the saturation dose increasing with increasing applied field. The critical temperature (T/sub c/) changed by <1 K at the highest dose. Approximately 25% of the change in J/sub c/ recovered after a 295 K anneal. The J/sub c/ changes are explained as an increase in flux pinning from radiation-induced defect cascades that leads to an increase in J/sub c/ greater than the decrease in J/sub c/ which results from a decrease in T/sub c/ of 1 K and from the increase in H/sub c/$sub 2$ produced by the increase in normal resistivity. A model is proposed that allows the prediction of the dose dependence of various terms in the pinning-force density and explains the field and dose dependence of the J/sub c/ changes. Measurements of the superconducting- -to--normal-state thermal transition indicate that the decrease in thermal conductivity of the Cu cladding is important when considering the degradation of the thermal transition current that occurs at high doses. (AIP)

• Research Organization: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439
• NSA Number: NSA-33-009912
• OSTI ID: 4123647
• Journal Information: J. Appl. Phys., v. 46, no. 12, pp. 5163-5168, Journal Name: J. Appl. Phys., v. 46, no. 12, pp. 5163-5168; ISSN JAPIA
• Country of Publication: United States
• Language: English

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