Acceleration of intense beams of highly-charged ions using direct plasma injection scheme

Laser Ion Source (LIS) is the most intense source of highly-charged ions of different elements capable of being providing beams with current 10-100 mA and pulse duration 1-10 μs. Such parameters well meet the requirements of single turn injection into synchrotron and FFAG rings. A few years ago the Direct Plasma Injection Scheme (DPIS) was proposed to extract and accelerate intense beams of highly-charged ions from laser produced plasma. By this approach extraction of ions from plasma happens almost inside the first cell of an RFQ, eliminating severe space charge problems in a low-energy-beam-transport (LEBT) and the LEBT itself. About 35 mA/1.5 μs (6x1010 ions/pulse) of 12C4+ ions were accelerated by RFQ up to 100 keV/u using DPIS with amplitude of total current up to 60 mA. 17 mA/0.4 μs (6x109 ions/pulse) of 12C6+ ions has been accelerated up to 100 keV/u as well. The results obtained well meet the requirements of small scale synchrotron or FFAG accelerators for carbon cancer therapy. The latest results on 27Al ions acceleration using DPIS are presented. The results obtained show that DPIS is, probably, the best choice as high current injector of highly-charged ions for FFAG accelerator. (author)