Capture Cross Sections and Gamma-Ray Spectra from the Interaction of 0.5- to 3.0-MeV Neutrons with Nuclei in the Mass Range A = 63 to 209

Absolute neutron capture cross sections for natural elements of copper, yttrium, zirconium, niobium, lanthanum, gadolinium, terbium, tantalum, tungsten, rhenium, platinum, thallium, bismuth, and separated isotopes of ⁶³Cu, ⁶⁵Cu, ¹⁵⁵Gd, ¹⁵⁶Gd, ¹⁵⁷Gd, ¹⁵⁸Gd, ¹⁶⁰Gd, ¹⁸²W, ¹⁸³W, ¹⁸⁴W, ¹⁸⁶W, ²⁰³Tl, ²⁰⁵Tl have been measured in the 0.5- to 3.0-MeV energy range. For most of these nuclides and isotopes, available data were scarce and discrepant, especially for neutron energies above 0.7 MeV. A spectrum-fitting method was developed to deduce the radiative capture cross section from prompt gamma rays emitted by the sample. The gamma rays were recorded by a NaI scintillator surrounded by an annular detector and the capture gamma-ray spectrum was obtained by unfolding the observed pulse-height distribution with the response function of the detector. Gamma-ray spectra emitted in the capture of 0.5-MeV neutrons as well as the multiplicity of the gamma-ray transitions are presented.