Contour plot of ﹩{\chi }^{2}﹩ fit for a disk-like model with halo size of ﹩{z}_{{\rm{h}}}=1\,\mathrm{kpc}﹩ and diffusion coefficient of ﹩{D}_{0}=4\times {10}^{27}﹩ cm² s⁻¹. The red contours correspond to the ⁵¹V/⁵¹Cr fit, the blue contours correspond to the ⁴⁹Ti/⁴⁹V fit, and the dashed purple lines correspond to the combined ﹩{\chi }^{2}﹩ calculation. Note the discrepancy between the ⁵¹V/⁵¹Cr and the ⁴⁹Ti/⁴⁹V fits: while the observation for ⁵¹V/⁵¹Cr requires high normalization and a low power-law index, the observation for ⁴⁹Ti/⁴⁹V requires a smaller normalization and a higher power-law index. The green point denotes the electron attachment cross section derived by Letaw et al. (1985), based on the lab measurements of Crawford (1979) and Wilson (1978), which is required to explain experimental data.