  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
shows that these 3D sensors perform as expected with full efficiency at bias
voltages between 5 and 15V.
