  We prepared three types of non-Cu RHQ-Nb3Al wire samples with different
matrix structures: an all-Ta matrix,a composite matrix of Nb and Ta with a Ta
inter filament, and an all-Nb matrix. Neutron diffraction patterns of the wire
samples were measured at room temperature in J-PARC "TAKUMI". To obtain
residual strains of materials, we estimated lattice constant a by multi-peak
analysis in the wire. Powder sample of each wire was measured, where the powder
was considered to be strain-free. The grain size of all the powder samples was
below 0.02 mm. For wire sample with the all-Nb matrix, we also obtained lattice
spacing d by a single-peak analysis. Residual strains of Nb3Al filament were
estimated from the two analysis results and were compared. Result, residual
strains obtained from the multi-peak analysis showed a good accuracy with small
standard deviation. The multi-peak analysis results for the residual strains of
Nb3Al filament in the three samples were all tensile residual strain in the
axial direction, they are 0.12%, 0.12%, and 0.05% for the all-Ta matrix, the
composite matrix, and the all-Nb matrix, respectively. Difference in the
residual strain of Nb3Al filament between the composite and all-Nb matrix
samples indicates that type of inter-filament materials show a great effect on
the residual strain. In this paper, we report the method of measurement, method
of analysis, and results for residual strain in the tree types of non-Cu
RHO-Nb3Al wires.
