HEAVY-ION BEAM PUMPING AS A MODEL FOR NUCLEAR-PUMPED LASERS

Heavy-ion accelerators can provide various beams from protons to urani um ions with energies ranging from a few keV/u to more than 1 GeV/u. T he Munich Tandem van de Graaff accelerator has been used for most of t he experiments described in this article. It can provide continuous or pulsed beams of almost all elements with particle energies of about 3 .5 MeV/u. The pulse width is typically 2 ns. Maximum DC-beam currents of the order of 10 muA can be obtained, for example, for S-32 ions. Wh en the beam is focused to a beam spot of about 3 mm diameter, the flux of the ions is comparable to the flux of fission fragments used for n uclear-pumped lasers. Ion beam pumping is therefore well suited for mo del experiments of nuclear-pumped lasers. Technical aspects of ion bea m-pumped lasers are discussed and the results of the lasers that have thus far been pumped by this method are summarized. As ion beams are a vailable either continuous or at high-pulse repetition rates ranging f rom tens of kHz to MHz, detailed spectroscopic and time-resolved studi es of the emission of light induced by heavy-ion excitation of the tar get material can easily be performed. Experiments in which the emissio n by rare gas excimers and line radiation from atoms and ions has been studied are described. Lifetime measurements of excited levels at dif ferent target densities were used to measure collisional rate constant s.