Radioactive targets for nuclear astrophysics research at LANSCE

During the past few years we have made measurements of (n,p) and (n,α) cross sections on several radioactive nuclei of importance to nuclear astrophysics. The measurements were made at the Manuel Lujan, Jr. Neutron Scattering Center (LANSCE) from thermal neutron energy to approximately 100 keV. Successful measurements have been completed on the radioisotopes 7Be, 22Na and 36Cl while preliminary data have been taken on targets of 54Mn and 55Fe. Similar measurements have also been made on the stable isotopes 14N, 17O and 35Cl. We are currently assembling a 4π barium fluoride (BaF2) detector which will allow us to expand our program to (n,γ) measurements. The (n,γ) (and in some cases future (n,p)) measurements will require targets with higher specific activity and greater chemical purity than we have so far been able to use. We discuss the fabrication techniques used for the samples produced so far, the requirements the future (n,γ) targets must meet and our current plans for producing them, and the physics motivations for the measurements. (orig.)