Dual Ion Species Plasma Expansion from Isotopically Layered Cryogenic Targets

Abstract

A dual ion species plasma expansion scheme from a novel target structure is introduced, in which a nanometer-thick layer of pure deuterium exists as a buffer species at the target-vacuum interface of a hydrogen plasma. Modeling shows that by controlling the deuterium layer thickness, a composite H^{+}/D^{+} ion beam can be produced by target normal sheath acceleration (TNSA), with an adjustable ratio of ion densities, as high energy proton acceleration is suppressed by the acceleration of a spectrally peaked deuteron beam. Particle in cell modeling shows that a (4.3±0.7) MeV per nucleon deuteron beam is accelerated, in a directional cone of half angle 9°. Experimentally, this was investigated using state of the art cryogenic targetry and a spectrally peaked deuteron beam of (3.4±0.7) MeV per nucleon was measured in a cone of half angle 7°-9°, while maintaining a significant TNSA proton component.

Enhanced laser-driven proton acceleration via improved fast electron heating in a controlled pre-plasma

“…Ion acceleration driven by ultraintense lasers using Target Normal Sheath Acceleration (TNSA) 1 is establishing itself as a powerful technique to access relatively high energy ion beams in a compact and affordable layout. Since the original investigations, effort has been dedicated 2 , 3 to enhance the cut-off energy and the flux of the accelerated ions via a number of advances of laser and target specifications using plasma mirror for ultra-high laser contrast with ultra-thin targets 4 , cryogenic 5 or nano-structured targets 6 . To date, however, practical exploitation of laser-driven ion acceleration relies heavily on the original TNSA configuration based on thin foil targets and optimized contrast without plasma mirror, possibly operating at the repetition rate required for applications like radiobiology 7 , 8 , where high dose irradiation is needed for meaningful studies.…”

Enhanced laser-driven proton acceleration via improved fast electron heating in a controlled pre-plasma

“…Ion acceleration driven by ultraintense lasers using Target Normal Sheath Acceleration (TNSA) 1 is establishing itself as a powerful technique to access relatively high energy ion beams in a compact and affordable layout. Since the original investigations, effort has been dedicated 2,3 to enhance the cut-off energy and the flux of the accelerated ions via a number of advances of laser and target specifications using plasma mirror for ultra-high laser contrast with ultra-thin targets 4 , cryogenic 5 or nano-structured targets 6 . To date, however, practical exploitation of laser-driven ion acceleration relies heavily on the original TNSA configuration based on thin foil targets and optimized contrast without plasma mirror, possibly operating at the repetition rate required for applications like radiobiology 7,8 , where high dose irradiation is needed for meaningful studies.…”

Influence of Pre-Plasma on Accelerated Protons in Ultraintense Laser Interaction with Not-So-Thin Foils

“…Ion acceleration driven by ultraintense lasers using Target Normal Sheath Acceleration (TNSA) 1 is establishing itself as a powerful technique to access relatively high energy ion beams in a compact and affordable layout. Since the original investigations, effort has been dedicated 2,3 to enhance the cut-off energy and the flux of the accelerated ions via a number of advances of laser and target specifications using plasma mirror for ultra-high laser contrast with ultra-thin targets 4 , cryogenic 5 or nano-structured targets 6 . To date, however, practical exploitation of laser-driven ion acceleration relies heavily on the original TNSA configuration based on thin foil targets and optimized contrast without plasma mirror, possibly operating at the repetition rate required for applications like radiobiology 7,8 , where high dose irradiation is needed for meaningful studies.…”