Production and use of homogeneous thin actinide targets for neutron induced fission measurements
For measuring the cross section of neutron induced fission for transmutation, thin and monoisotopic targets of 235U,238U,239Pu and 242Pu have to be prepared. This will be done at Johannes-Gutenberg Universität Mainz in the institute of nuclear chemistry. Furthermore thin targets of the long-lived α-emitter 144Nd, which can be measured in the underground laboratory "Felsenkeller" by TU Dresden within the joint research project, will be produced.
The thin layer targets will be prepared via "molecular plating" which is a form of electric deposition. Thereby, the target material is solved as nitrate in nitric acid and given together with isopropyl or isobutanol in an electrolysis system. By applying a voltage of 100V - 1000V, the solved target material is deposited on the cathode as oxide. Aluminium, titanium or carbon can be used as carrier foil.
The institute of nuclear chemistry has produced thin actinide targets for many years. Targets with a thickness of 1mg/cm2 can be prepared.
The deposition yield can be determined by neutron activation analysis or α-spectroscopy. The homogeneity is measured with radiographic methods. For the latter method radioactive isotopes produced at the research reactor TRIGA of Johannes-Gutenberg Universität Mainz can be used as tracer.