Controllability of intense-laser ion acceleration

Abstract

An ion beam has the unique feature of being able to deposit its main energy inside a human body to kill cancer cells or inside material. However, conventional ion accelerators tend to be huge in size and cost. In this paper, a future intenselaser ion accelerator is discussed to make the laser-based ion accelerator compact and controllable. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching, and the ion particle energy control. In the study, each component is designed to control the ion beam quality by particle simulations. The energy efficiency from the laser to ions is improved by using a solid target with a fine sub-wavelength structure or a near-critical-density gas plasma. The ion beam collimation is performed by holes behind the solid target or a multi-layered solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching are successfully realized by a multi-stage laser-target interaction.

Towards laser ion acceleration with holed targets

“…Not long after the first MeV laser generated protons were demonstrated by laser irradiation of flat foils, simulations proposed that a curved foil could collimate the proton beam (Bulanov et al 2000;Sentoku et al 2000;Wilks et al 2001) and an experimental demonstration came soon after (Patel et al 2003), setting the new path of laser irradiated microstructured targets. A few notable target proposals include a foil doped with a proton-rich region Esirkepov et al 2002;Schwoerer et al 2006), a hollow microsphere (Burza et al 2011), foils with solid microspheres attached on their front surface (Klimo et al 2011;Margarone et al 2012), foils attached to hollow cones (Bartal et al 2012;Qiao et al 2013), foils with a series of microslits (Nagashima et al 2013;Kawata et al 2014), atomic clusters (Ditmire et al 1997), microwires developed on the target front surface (Jiang et al 2016;Bargsten et al 2017;Rocca et al 2017) and laser irradiated microtubes/microchannel plates Ji, Snyder & Shen 2019;Snyder et al 2019). Fabrication of microstructures is now considered a routine process and features of ∼100 nm can be created by direct laser writing (Fischer & Wegener 2013).…”

Effective laser driven proton acceleration from near critical density hydrogen plasma

“…Kawata et al (2014) discussed the compact and controllable laser baser ion accelerator by using a solid target with a fine sub-wavelength structure or a near critical density gas plasma. The energy efficiency from laser to ion is improved by employing such hybrid target.…”

Density measurements of laser interaction with ordered structured ‘snow’ targets

“…Enhancement of the energy of the generated protons using a compact laser source (moderate intensity, ) is a challenging but rewarding task due to the fact that the proton energy in traditional schemes scales as the electric field employed on the target [3] . One of the promising ways to increase the ion energy is the use of structured targets [4] , mainly nanotargets [5] . In this kind of target the energy conversion efficiency from the laser to the proton beam is increased [6] .…”