The complex magnetic permeability of Nbhyphen;44 at.percnt; Ti has been measured using a modified Hartshorn ac bridge and a lockhyphen;in amplifier. The outhyphen;ofhyphen;phase signal can be directly related to the energy losses, and critical current can be calculated using the Bean model. Samples were irradiated in a fission neutron spectrum to a dose of 3.2times;1018neutronsol;cm2. All measurements were takenin situat approximately 4.5 deg;K in an external magnetic field continuously swept to 6.7 kOe while applying ac magnetic fields at 88 Hz with amplitudes between 8 and 500 Oe. Irradiations and measurements were performed on an annealed and a coldhyphen;worked sample of the alloy. For the annealed sample, no changes were observed inVLand thus inJcafter 8.2times;1017neutronsol;cm2and after an anneal to 320 deg;K. A decrease of approximately 8percnt; was observed inJcfor the coldhyphen;worked sample after 3.2times;1018neutronsol;cm2. Onehyphen;half of this decrease was recovered by 270 deg;K.
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