title: Laser ion acceleration toward future ion beam cancer therapy - Numerical simulation study -.
abstract: BACKGROUND
  Ion beam has been used in cancer treatment, and has a unique preferable feature to deposit its main energy inside a human body so that cancer cell could be killed by the ion beam. However, conventional ion accelerator tends to be huge in its size and its cost. In this paper a future intense-laser ion accelerator is proposed to make the ion accelerator compact.
  
  
  METHODS
  An intense femtosecond pulsed laser was employed to accelerate ions. 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 particle computer simulations were performed to solve the issues, and each component was designed to control the ion beam quality.
  
  
  RESULTS
  When an intense laser illuminates a target, electrons in the target are accelerated and leave from the target; temporarily a strong electric field is formed between the high-energy electrons and the target ions, and the target ions are accelerated. The energy efficiency from the laser to ions was improved by using a solid target with a fine sub-wavelength structure or by a near-critical density gas plasma. The ion beam collimation was realized by holes behind the solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching were successfully realized by a multi-stage laser-target interaction.
  
  
  CONCLUSIONS
  The present study proposed a novel concept for a future compact laser ion accelerator, based on each component study required to control the ion beam quality and parameters.
authors.affiliation: Department of Advanced Interdisciplinary Sciences, Utsunomiya University, Japan ; CORE (Center for Optical Research and Education), Utsunomiya University, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Kawata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Izumiyama
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nagashima
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takano
authors.forename: Daisuke
authors.initials: D
authors.lastname: Barada
authors.forename: Qing
authors.initials: Q
authors.lastname: Kong
authors.forename: Yan Jun
authors.initials: YJ
authors.lastname: Gu
authors.forename: Ping Xiao
authors.initials: PX
authors.lastname: Wang
authors.forename: Yan Yun
authors.initials: YY
authors.lastname: Ma
authors.forename: Wei Min
authors.initials: WM
authors.lastname: Wang
keywords: Intense pulsed laser; laser ion acceleration; laser ion beam cancer therapy; laser plasma interaction