Abstract: A mass spectrometer having a mass filter which applies a transient voltage profile to accelerate ion packets. The voltage profile is chosen to have a functional form which imparts each ion species with a kinetic energy which is larger the larger the mass-to-charge ratio and a velocity which is smaller the larger the mass-to-charge ratio. The ions are detected in an ion detector which discriminates between different ion species based on their kinetic energy and taking account of the functional form of the voltage profile. Suitable voltage profiles include periodic functions such as sinusoids, triangles and sawtooths, which allow the amplification of drive pulses in the mass filter to be carried out with narrow band amplification stages, which are simple and inexpensive to construct.
Type:
Grant
Filed:
March 2, 2011
Date of Patent:
March 10, 2015
Assignee:
Ilika Technologies Limited
Inventors:
David Bream, Christopher Newman, Brian Christopher Webb
Abstract: A mass spectrometer comprises an ion source which provides a beam of ions; a mass filter comprising a pair of electrodes and a drive circuit, the drive circuit operable to apply a time varying voltage to the electrodes having a profile that accelerates the ions to equal velocities irrespective of their mass: charge ratios; and an ion detector for detecting the proportions of ions according to their mass-to-charge ratios. In one embodiment, the voltage profile is exponential. In another embodiment, the voltage profile is a sequence of constant amplitude and increasing repetition frequency pulses. The novel mass filter thus imparts equal velocities to all ion species irrespective of their mass. This allows the ion species to be discriminated at the detector by energy, enabling simple and compact detection schemes to be used.
Type:
Grant
Filed:
May 29, 2002
Date of Patent:
July 24, 2007
Assignee:
ILIKA Technologies Limited
Inventors:
Brian Christopher Webb, Donald Clifford Young