Developments at the CERN laser ion source

Abstract

Articles you may be interested inPhysics research and technology developments of electron string ion sourcesa) Rev. Sci. Instrum. 83, 02A512 (2012); 10.1063/1.3678660 H − source developments at CERN Rev. Sci. Instrum. 77, 03A521 (2006);The high current, high charge-state ion beam which can be extracted from a laser produced plasma is well suited, after initial acceleration, for injection into synchrotrons. At CERN, the production of a heavy ion beam using a CO 2 laser ion source is studied. The latest results of experiments with a tantalum ion beam with charge states up to 23ϩ and accelerated by a radio frequency quadrupole from 6.9 to 100 keV/u, are presented along with simulations of the low energy beam transport. The ion yield at the desired charge state, the pulse to pulse stability of the ion beam, and the system reliability are all of major interest. Work is under way to replace the low repetition rate free-running laser oscillator by a master oscillator and power amplifier system. The master oscillator is operational and the first results of measurements of its beam quality and stability are presented.

Spark discharge coupled laser multicharged ion source

“…This is achieved through the use of larger laser pulse energies, shorter pulse widths, and shorter laser wavelengths to penetrate the formed dense plasma. [20][21][22][23][24][25][26][27][28] High laser intensity (≥10 14 W cm −2 ) causes nonlinear interactions, e.g., self-focusing, with the plasma formed by a pre-pulse or the initial part of the laser pulse resulting in higher charge state generation. 20,21 Laska et al observed charge state of >50 for Ta with high kinetic energies (up to 100 keV/amu) using a high power iodine photo-dissociation laser (λ = 1315 nm, pulse energy 40-750 J, τ ∼400 ps, intensity ≤6 × 10 16 W cm −2 ).…”

“…27 At CERN, production of high current and high charge state ion beam with maximum charge state of Ta 23+ was reported using a CO 2 laser (λ = 10.6 µm, τ = 70 ns, pulse energy ≤50 J). 28 Clearly, using lasers with large pulse energies is effective in increasing the plasma density and temperature resulting in higher ionization states and more ion production. However, this approach requires expensive lasers that are typically available only in limited laser laboratories.…”

CO2 laser ion source: Comparison between mode-locked and free-running laser beams

“…Most of the measurements are performed with tantalum targets mainly for its isotopic purity and high melting point~which reduces target damage and sputtering onto optical components!. To satisfy the specified parameters, an upgraded laser system consisting of a Master Oscillator~MO; Haseroth et al, 1998! and a new power amplifier able to deliver 100-J, 20-ns laser pulses at a repetition rate of 1 Hz~l ϭ 10.6 mm!…”

Aberrations due to solenoid focusing of a multiply charged high-current ion beam

“…On the CERN Laser Ion Source (LIS), solenoids were used in the transport line from the source outlet to the input of the Radio Frequency Quadrupole (RFQ) accelerator. The beam from the source has a range of charge-state [1], with the most abundant being Ta 20+ and the highest Ta 24+ .…”