Abstract
For the purpose of withstanding very high radiation doses, silicon pixel sensors with a `3D' electrode geometry are being developed. Detectors of this kind are highly interesting for harch radiation environments such as expected in the High Luminosity LHC, but also for space physics and medical applications. In this paper, prototype sensors developed at SINTEF are presented and results from tests in a pion beam at CERN are given. These tests show that these 3D sensors perform as expected with full efficiency at bias voltages between 5 and 15V.