Neutron Capture<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>-Rays from Scandium, Vanadium, Manganese, Cobalt, and Copper

Abstract

The neutron capture $\ensuremath{\gamma}$-ray spectrum from scandium consists of an exceptionally large number of $\ensuremath{\gamma}$-rays, and those of highest energy are only partially resolved when the line width in the coincidence spectrum is 130 kev. The $\ensuremath{\gamma}$-ray corresponding to the direct transition to the ground state in ${\mathrm{Sc}}^{46}$ (8.85\ifmmode\pm\else\textpm\fi{}0.08 Mev), if correctly identified, has an intensity of 0.3 photon per 100 captures. Vanadium produces several strong $\ensuremath{\gamma}$-rays with intensities of about 10 photons per 100 captures. Of these, the $\ensuremath{\gamma}$-ray with the highest energy, 7.305\ifmmode\pm\else\textpm\fi{}0.007 Mev, can be identified with the transition to the ground state of ${\mathrm{V}}^{52}$. A group of partially resolved $\ensuremath{\gamma}$-rays with energies between 7.6 and 8.0 Mev are tentatively ascribed to capture in the rare isotope ${\mathrm{V}}^{50}$. If this interpretation is correct, the isotopic capture cross section of ${\mathrm{V}}^{50}$ probably lies between 40 and 400 barns. The transition to the ground state in ${\mathrm{V}}^{51}$ was not detected. In manganese the transition to the ground state (7.261\ifmmode\pm\else\textpm\fi{}0.006 Mev) is stronger than any other $\ensuremath{\gamma}$-ray in the spectrum (12 photons per 100 captures). With a line width of 100 kev it is only partially resolved from another strong $\ensuremath{\gamma}$-ray with an energy of 7.15\ifmmode\pm\else\textpm\fi{}0.02 Mev. The remainder of the manganese spectrum is complex. From cobalt, about six $\ensuremath{\gamma}$-rays are produced each with intensities of the order of 5 photons per 100 captures. The $\ensuremath{\gamma}$-ray with the highest energy (7.486\ifmmode\pm\else\textpm\fi{}0.006 Mev) may be identified with either the transition to the ground state or to the isomeric state at 59 kev. The copper spectrum is dominated by the strong $\ensuremath{\gamma}$-ray producing the ground state in ${\mathrm{Cu}}^{64}$. Its energy is 7.914\ifmmode\pm\else\textpm\fi{}0.006 Mev and its intensity is 24 photons per 100 captures in ${\mathrm{Cu}}^{63}$. Another strong $\ensuremath{\gamma}$-ray at 7.634\ifmmode\pm\else\textpm\fi{}0.006 Mev may be the transition to the ground state of ${\mathrm{Cu}}^{66}$.