Electron multipliers (EMT) are used for the detection and measurement of electrons, charged particles such as ions, VUV radiation and soft X-rays. Hamamatsu electron multipliers have high gain and low noise, making them suitable for the detection of very small or low energy particles. An EMT has CuBeO dynodes for producing gain via secondary emission. The dynodes are connected by a built-in voltage divider (1M ohm per stage) and are supplied in an evacuated glass bulb. The first dynode can be replaced by a photocathode of CsI or KBr for use in VUV photometry. Microchannel Plates (MCP) can also be used as electron multipliers. EMTs are used in applications such as mass spectroscopy, field ion microscopy, electron or VUV spectroscopy, Auger spectroscopy, AES and ESCA.