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electron multiplierA detection device inside the vacuum of a mass spectrometer which converts ions impacting on its front dynodes into a detectable, amplified electron current at the back lead of the device, with an overall gain (signal out/signal in) as high as 104–108.
Positive ions exiting the mass analyser impact the first dynode’s surface, triggering the release of several electrons, which are then accelerated through a potential to the next electrode, where each electron impact triggers the release of several secondary electrons; these are accelerated into the next dynode, leading to further impact (release events). A cascade of electrons is produced, generating a current that is further amplified and then sampled by an analog-to-digital converter to be recorded by the data system.
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