Investigation of Electron-beam Production of Neutron-Rich Radioactive Ion Beams

Photo-fission has been proposed for production of neutron-rich radioactive isotopes because potentially attractive absolute fission yields may be achieved with a modest-cost electron accelerator, and because the relative production of the most neutron-rich isotopes should be substantially enhanced in photo-fission compared to fission induced by protons and other light-ion beams. We intend to carry out measurements of isotopic yields in bremsstrahlung induced photo-fission of $^{238}$U at the Oak Ridge Electron Linear Accelerator (ORELA) at ORNL as part of an evaluation of this production method. A target for high-power electron beam irradiation at has been fabricated and tested. Fission products will be stopped in a closed-circuit, NaCl-loaded helium gas system and transported to a gamma ray detection system in order to measure the production of specific fission products. Measurements using a $^{252}$Cf source have confirmed that the transport efficiency is about 40{\%} through a 30 meter, 0.75 mm diameter stainless steel tube. The target assembly is to be mounted in the ORELA target room operated with up to 10 kW of $\sim $150 MeV electrons.