Carbon nanotubes are allotropes of carbon with a cylindrical nanostructure. When they randomly bond with each other by van der Waals forces, so-called carbon nanotube foam (CNF) is formed. The average density of CNFs lies in the range of a few mg/cm^3 to tens of mg/cm^3. If fully ionized, such a thin foam can turn to a plasma slab with critical density. Here we report the recent progress on the fabrication and the applications of CNF as near-critical-density targets for laser-driven ion acceleration and X-ray/Gamma-ray generation. Our recent experimental results show that highly energetic carbon ions can be obtained by shooting a CNF-coated ultrathin solid foil with PW laser pulses. Ions in the solid foil undergo a cascaded accelerations process if the density of CNF is lower than 3 mg/cm^2. Our simulation study also reveals that such double-layer targets can be employed to efficiently generate bright X-ray/Gamma-ray pulses with currently available PW lasers in a very simple way. Preliminary experimental results using a 100 TW laser will be presented.
|Working group||Laser-driven ion acceleration|