For the preparation of isotopic accelerator targets by means of an evaporation-condensation process, laser heating is a method with high efficiency and thus low consumption of expensive isotope materials. A Q-switched, pulsed Nd: YAG laser is utilized for the ablation of refractory metals, which are deposited on substrates in a vacuum of 10-5 Pa. Even for metals with low vapor pressures at their melting points, high ablation rates nearly independent of the vapor pressure can be obtained with laser pulses of 300 mJ within 10 ns. With an average laser power of 3 W, deposition rates for various metals were measured. With a source to substrate distance of 5 cm, condensation rates varied only from 70-300 ngcm-2 s-1 for the wide range of elements with lower vapor pressures from boron to uranium.    «

For the preparation of isotopic accelerator targets by means of an evaporation-condensation process, laser heating is a method with high efficiency and thus low consumption of expensive isotope materials. A Q-switched, pulsed Nd: YAG laser is utilized for the ablation of refractory metals, which are deposited on substrates in a vacuum of 10-5 Pa. Even for metals with low vapor pressures at their melting points, high ablation rates nearly independent of the vapor pressure can be obtained with las...    »