In order to evaluate the conformation of a single chain in mixed solutions of sodium salts of hydrogenated and deuterated poly(vinyl sulfuric acid) (PVSNa(H) and PVSNa(D)) without added salts, measurements of time-of-flight neutron small angle scattering (NSAS) were performed while making use of a wide band chopper. By means of the deuterium labeling, the scattering law, S(Q), of the polymer solution can be separated into two parts: the intrapolymer scattering law, S1(Q), and the interpolymer one, S2(Q). Using the Kratky plot, it is concluded that at Q values larger than 0.04 Å-1, the polyelectrolyte can be regarded as a rod-like molecule. It has also been shown that the wide band chopper could be useful for NSAS studies of polymer solutions as well as crystalline aggregates of metals. © 1980.