New results from experimental and numerical investigations of the self-magnetically BΘ-insulated ion diode

Due to its reliability and reproducibility the BΘ-Diode is now used routinely for testing new diagnostics and experimental set-ups. The numerical simulations and the experimental investigations of the BΘ-Diode described at the BEAMS-90-Conference [1] were continued. Using a numerically optimized anode shape did not improve the focusing properties; as the main reason the large beam divergence of ±3° was identified. Reducing the electric field parallel to the plastic anode surface by decreasing the distance of the metal pins had no effect on the divergence. Experiments using a thin film Pd covered Ti-hydride-anode to improve the divergence and to increase the focused power density beyond the presently achieved value of about 0.3 TW/cm² will be described. Numerical simulations suggesting a possible improvement of the focusing at the edges of the anode will be presented.