Abstract:
An ion guide is disclosed comprising a plurality of electrodes. A first device is arranged and adapted to apply a RF voltage 103 to at least some of the electrodes in order to form, in use, a pseudo-potential well which acts to confine ions in a first (y) direction within the ion guide. A second device is arranged and adapted to apply a DC voltage to at least some of the electrodes in order to form, in use, a DC potential well which acts to confine ions in a second (z) direction within the ion guide. A third device is arranged and adapted to cause ions having desired or undesired mass to charge ratios to be mass to charge ratio selectively ejected from the ion guide in the second (z) direction.
Abstract:
An ion trap includes an electrode structure, including a first and a second opposed mirror electrodes and a central lens therebetween, that produces an electrostatic potential in which ions are confined to trajectories at natural oscillation frequencies, the confining potential being anharmonic. The ion trap also includes an AC excitation source having an excitation frequency f that excites confined ions at a frequency of about twice the natural oscillation frequency of the ions, the AC excitation frequency source preferably being connected to the central lens. In one embodiment, the ion trap includes a scan control that mass selectively reduces a frequency difference between the AC excitation frequency and about twice the natural oscillation frequency of the ions.
Abstract:
A method of separating ions according to their time of flight is provided comprising: a. providing an analyser comprising two opposing ion mirrors, each mirror comprising inner and outer field-defining electrode systems elongated along an analyser axis with the outer field-defining electrode system surrounding the inner field-defining electrode system and creating therebetween an analyser volume; b. injecting ions into the analyser volume or creating ions within the analyser volume so that they separate according to their time of flight as they travel along a main flight path whilst undergoing a plurality of axial oscillations in the direction of the analyser axis and a plurality of radial oscillations whilst orbiting about one or more inner field-defining electrodes; c. the plurality of axial oscillations and plurality of radial oscillations causing the separated ions to intercept an exit port after a predetermined number of orbits. Also provided is an analyser for performing the method, comprising: the two opposing ion mirrors which abut at a first plane, wherein the outer field-defining electrode system of one mirror comprises two sections, the sections abutting at a second plane, comprising a first section between the first plane and the second plane, and a second section adjacent the first section and wherein the first section has at least a portion which extends radially from the analyser axis a greater extent than an adjacent portion of the second section at the second plane.
Abstract:
A novel method and mass spectrometer apparatus is introduced to spatially and temporally resolve images of one or more ion exit patterns of a multipole instrument. In particular, the methods and structures of the present invention measures the ion current as a function of time and spatial displacement in the beam cross-section of a quadrupole mass filter via an arrayed detector. The linearity of the detected quadrupole ion current in combination with it reproducible spatial-temporal structure enables the deconvolution of the contributions of signals from individual ion species in complex mixtures where both sensitivity and mass resolving power are essential.
Abstract:
An apparatus for providing power to a multipole in a mass spectrometer is provided. The apparatus comprises a first resonant LC circuit; at least one inductor for forming a second resonant LC circuit with the multipole, the second resonant LC circuit connected in cascade with the first resonant LC circuit, when the at least one inductor is connected to the multipole; an RF power source for providing an RF signal; and a step-up transformer connected in parallel to the RF power source on a primary side and the first resonant LC circuit on a secondary side, the step-up transformer providing voltage gain for the RF signal thereby reducing the loaded Q of the resonant LC circuits.