Bradbury-Nielsen_shutter
A Bradbury–Nielsen shutter (or Bradbury–Nielsen gate) is a type of electrical ion gate, which was first proposed in an article by Norris Bradbury and Russel A. Nielsen, where they used it as an electron filter.[1] Today they are used in the field of mass spectrometry where they are used in both TOF mass spectrometers and in ion mobility spectrometers [2] , as well as Hadamard transform mass spectrometers (a variant of TOF-MS).[3][4] The Bradbury–Nielsen shutter is ideal for injecting short pulses of ions and can be used to improve the mass resolution of TOF instruments by reducing the initial pulse size as compared to other methods of ion injection.