Internal strain measurement for Nb ₃Sn wires using synchrotron radiation

The internal strain of the practical Nb ₃Sn wires under tensile strain were measured by synchrotron radiation. The x-ray energy of 72keV was selected to obtain the diffraction from the Nb ₃Sn in the composite wire. The axial and lateral strains of the as-reacted and prebent wire were investigated. The Nb ₃Sn 321 and 320 diffraction peaks were measured to obtain accurate strain data because of their high intensity. It was found that the relationship between internal and external strain under the tensile strain is slightly different. The strain of the Nb ₃Sn 321 plane reveals the similar total strain applied to the Nb ₃Sn wire. The ratio of lateral/axial strain for the as-reacted and prebent wires is 0.34 and 0.30, respectively.