Invited Review Article: The electrostatic plasma lens

Abstract

The fundamental principles, experimental results, and potential applications of the electrostatic plasma lens for focusing and manipulating high-current, energetic, heavy ion beams are reviewed. First described almost 50 years ago, this optical beam device provides space charge neutralization of the ion beam within the lens volume, and thus provides an effective and unique tool for focusing high current beams where a high degree of neutralization is essential to prevent beam blow-up. Short and long lenses have been explored, and a lens in which the magnetic field is provided by rare-earth permanent magnets has been demonstrated. Applications include the use of this kind of optical tool for laboratory ion beam manipulation, high dose ion implantation, heavy ion accelerator injection, in heavy ion fusion, and other high technology.

A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

“…As the guiding magnetic coil has features of a plasma lens [233,234], its optics is designed to transport positive ions through the radial electrical field (Fig. 20).…”

Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

“…The beam envelopes reach a maximum at the accelerating column exit. A plasma lens located at this exit controls the beam envelopes and limits the emittance growth [13]. A magnetic quadrupole triplet lens will be used to focus the beam and adjust the beam spot size on the rotating target surface.…”

A FIB induced boiling mechanism for rapid nanopore formation

“…According to prior estimates [14], these fluxes would correspond to beam currents of 225 pA and higher, which are approximately a factor of 10 higher than typical experimental conditions. We note that a precise conversion from ion beam flux to current is difficult due to uncertainty in the extent of charge neutralization in such beams [16–18]. Without accounting for charge neutralization, one would typically find a three order of magnitude difference between flux and inferred current [19–21], (and thus the assertion that with charge neutralization 1.8 × 10 24 cm −2 s −1 is equivalent to approximately 225 pA) but we refer to flux in the present work because it is neutralization independent and can thus be precisely calculated.…”