Tow-stage extraction ion diode experiments on Reiden-SHVS for light ion fusion

Key issues of light‐ion‐beam fusion research are an improvement of beam divergence and a demonstration of target heating to achieve an intense and uniform soft x‐ray radiation in the Hohlraum. A two‐stage diode is proposed and demonstrated to reduce the beam divergence on Reiden‐SHVS, an eight‐stage induction adder accelerator. The two‐stage diode is only an active method to reduce the beam divergence. Divergences of carbon beam at the first and the second stage diode were measured by shadow‐boxes. The results show that the divergence improvement agrees with prediction until the current density is less than about 5 times of the space charge limited value. On an annular two‐stage proton diode, a distribution of radial and azimuthal beam divergence were measured simultaneously by 2‐dimensional arrayed pinhole camera. The results show that the azimuthal divergence was larger than the radial one.