Development and operation of laser source of highly charged ions for ITEP terraWatt accumulator facility

Abstract

Laser ion source (LIS) is the most intense source of highly charged ions to fill the synchrotron rings in a single turn injection mode. For this reason LIS is used for ITEP TerraWatt Accumulator (TWAC) facility aiming at the production of TerraWatt power level (100 kJ/100 ns) of intense ion beams. Total current density, charge state distribution, and emittance of carbon ion beam generated by the 5 J/0.5 Hz rep-rate CO2 laser were measured at the exit of the source. A low energy beam transport line (LEBT) consisting of Einzel lenses and a buncher were used to match the source to 2 MV/2.5 MHz injector I-3. The C+4 ion beam with current up to 5 mA was accelerated by injector I–3 and about half of this amount have been injected into booster synchrotron. LIS was operated with rep-rate of 0.25 Hz during more than one year with few short breaks. Prolongation of intervention free period of LIS operation up to 3 months was achieved by using of CO2 laser gas mixture regeneration circuit.