The spatial and energy response of a 3d architecture silicon detector measured with a synchrotron X-ray microbeam

3D processed silicon detectors offer several advantages over conventional, planar processed devices. The electric fields between the electrodes of a 3D detector are parallel to its surface, and for a given applied bias, stronger than those found in a planar device of equivalent dimensions. We have investigated the spatial response of a first generation 3D detector using a synchrotron X-ray microbeam as a probe. The microbeam was of cross-section ∼10 μm, commensurate with the dimensions of the electrode structures. The detector showed excellent charge collection, as verified by the energy spectra acquired at various probe positions. Variations in the energy spectra provided a sensitive indicator of the charge splitting that inevitably occurs at the boundaries between adjacent pixel cells, and for measuring the expected loss of sensitivity at the 3D electrodes themselves.