Extraction of radioactive positive ions across the surface of superfluid helium: A new method to produce cold radioactive nuclear beamsW. X. Huang, P. Dendooven, K. Gloos, N. Takahashi, J. P. Pekola and J. ÄystöEurophys. Lett., 63 5 (2003) 687-693DOI: https://doi.org/10.1209/epl/i2003-00576-1