Laser sources of multiply charged heavy ions

Intense studies of laser ion sources (LIS) at present are motivated mainly by the growing demand for high current beams of multiply charged heavy ions for large accelerators [1,2]. It was demonstrated [3,4], confirmed [5,6] and generally accepted that LIS can produce by 1–2 orders of magnitude higher current densities and also higher ion charges than the electron cyclotron resonance (ECR) sources, which are presently favored as heavy ion injectors. However, LIS can also be utilized for various technological purposes, like for a material modification, VLSI circuit fabrication, ion implantation, laser mass spectrometry etc. Depending on parameters of the laser used LIS can deliver ions of different atomic mass from A= 1 to A ∼ 200 amu (any materials can be evaporated and ionized) with charge states from z= 1 up to z ∼ 50 and with energies from hundreds eV up to even about 10 MeV [6–8]. Experiments performed so far with Nd:glass and iodine lasers proved that the short wavelengths (∼1 µm) and short pulse lengths (∼ 1 ns) lasers are more suitable for production of highly charged ions than the CO
2
lasers [9].