Nuclear microscopy uses a device called a microprobe. A microprobe is a device that uses electromagnetic or electrostatic lenses to focus an ion beam. In this way a microprobe is very similar to a scanning electron microscope. Some difference are that the nuclear microprobes beam is composed of usually, but not exclusively protons and alpha (He ions) particles. Some of the most advanced nuclear microprobes have beam energies 1MeV and up. This gives the device very high sensitivity to minute concentrations of elements around 1ppm at beam sizes <1 micro-meter. This elemental sensitivity is due to the fact that as the beam interacts with the a sample it gives off characteristic x-rays of each element present in the sample. This type of detection of radiation is called PIXE. Other analysis techniques are applied to nuclear microscopy including RBS, STIM , etc.