The second type of AMS system employs an electrostatic tandem accelerator. Typically, TAMS (tandem accelerator mass spectrometry) is used to refer to this type of AMS system."Tandem" here refers to the fact that particle acceleration in electrostatic systems is accomplished in a two-step "pull-push" process. For example, negative ion can be accelerated to a positive terminal ("pull") and then "stripped", i.e., electrons removed form the outer shells, to produce a positive ion which is then accelerated away from the terminal ("push").