Abstract: A multi-purpose efficient charge particle detector that by switching bias voltages measures either secondary ions, or secondary electrons (SE) from a sample, or secondary electrons that originate from back scattered electrons (SE3), is described. The basic version of the detector structure and two stripped down versions enable its use for the following detection combinations: 1. The major version is for measuring secondary ions, or secondary electrons from the sample, or secondary electrons due to back-scattered electrons that hit parts other than the sample together or without secondary electrons from the sample. 2. Measuring secondary ions or secondary electrons from the sample (no SE3). 3. Measuring secondary electrons from the sample and/or secondary electrons resulting from back-scattered electrons hitting objects other than the sample (no ions).