The ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}(n, \gamma )$ cross section has been measured at the electron linear accelerator capture facility. This very high resolution experiment has allowed the extraction of capture areas for some 139 resonances for incident neutron energies 2.5-215 keV. The capture data combined with spin and parity assignments and a few neutron widths from the literature provide full sets ($E_{\gamma }, {\Gamma }_{\gamma }, {\Gamma }_n$) of the resonance parameters for 45 $s$-wave resonances. Analysis of these parameters has yielded values for the $s$-wave strength function ${{〈S〉}^{l=0\mathrm{}}}_{J=3\mathrm{}}=\left({8.3}_{-2.5\mathrm{}}^{+4.0\mathrm{}}\right)\times {10}^{-4\mathrm{}}$ and ${{〈S〉}^{l=0\mathrm{}}}_{J=4\mathrm{}}=\left({7.0}_{-2.2\mathrm{}}^{+3.8\mathrm{}}\right)\times {10}^{-4\mathrm{}}$ (10-90% confidence interval). The mean level spacing found for the $J^{\pi }=4^{-}$ levels is ${{〈D〉}^{l=0\mathrm{}}}_{J=4\mathrm{}}=\left({9.8}_{-0.5\mathrm{}}^{+0.8\mathrm{}}\right)$ keV. The $J^{\pi }=3^{-}$ mean level spacing ${{〈D〉}^{l=0\mathrm{}}}_{J=3\mathrm{}}=\left({7.8}_{-1.7\mathrm{}}^{+0.5\mathrm{}}\right)$ keV derived from this work is less well determined than that for the $4^{-}$ levels because of an apparent change in mean level spacing near 100 keV. This effect is probably due to levels with widths too small compared to the resolution width for parity to be determined and/or to levels not seen in this work. The $s$-wave total radiation widths are large and fluctuate widely; ${{〈{\Gamma }_{\gamma }〉}^{l=0\mathrm{}}}_{J=3\mathrm{}}=1467\mathrm{}\pm 183$ meV and ${{〈{\Gamma }_{\gamma }〉}^{l=0\mathrm{}}}_{J=4\mathrm{}}=1629\mathrm{}\pm 352$ meV. The variance of these distributions are consistent with ${\chi }^2$ distributions of 5 degrees of freedom for the $3^{-}$ resonances and 2 degrees of freedom for the $4^{-}$ resonances. The reduced neutron widths and the total radiative widths for the $4^{-}$ $s$-wave resonances exhibit strong correlation ($\rho =0.93\mathrm{}$, significant at >99.9% confidence level), but the $3^{-}$ $s$ waves are less significantly correlated ($\rho =0.42\mathrm{}$ significant at the 96% confidence level). The contribution of these resonances to the thermal capture cross section is determined to be 3.95 b, approximately 80% of the measured thermal value. The capture resonance integral derived from this work is in good agreement with the published value. The 30 keV Maxwellian averaged cross section (41±3) mb is of interest in stellar nucleosynthesis.

NUCLEAR REACTIONS ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}(n, \gamma )$, $E=2.6-215\mathrm{}$ keV; measured ${\sigma }_{\gamma }\mathrm{}\left(E\right)\mathrm{}$; deduced (${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$+$n$) resonance parameters, $S_0$, $D$, ${\Gamma }_{\gamma }$ for $J=3^{-}, 4^{-}$ separately, (${\Gamma }_n^0{\Gamma }_{\gamma }$) correlation coefficients significant for $J=4^{-}$, resonance integral, stellar average cross sections. 25.40.Lw

• Received 28 November 1977

DOI:https://doi.org/10.1103/PhysRevC.18.2092