411 results about "Drift tube" patented technology

A method and apparatus enabling increased sensitivity in ion mobility spectrometry / mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing a device for transmitting ions from an ion source which allows the transmission of ions without significant delay to an hourglass electrodynamic ion funnel at the entrance to the drift tube and / or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

Particular aspects provide novel methods for analysis of ion populations, the methods comprising filtering and selecting an ion population using a low-field dual-gate ion mobility spectrometer comprising a drift tube, the spectrometer operating at a pressure of at least 100 Torr, to provide mobility-selected ions. Certain aspects comprise: (i) subsequently accumulating the low-field selected ions in an ion trap (e.g., an MS ion trap) and mass spectrometry analysis; (ii) introducing the low-field selected ions into a high-field ion mobility spectrometer for separating thereby (optionally followed by mass spectrometry); and (iii) introducing the low-field selected ions into an ion trap mass spectrometer, and subsequently into a second low-field ion mobility spectrometer (e.g., a non-dual gate spectrometer operating at less than about 100 Torr). Additional aspects provide novel apparatus and combination thereof for performing the disclosed methods.

A time-of-flight ion sensor for monitoring ion species in a plasma includes a housing. A drift tube is positioned in the housing. An extractor electrode is positioned in the housing at a first end of the drift tube so as to attract ions from the plasma. A plurality of electrodes is positioned at a first end of the drift tube proximate to the extractor electrode. The plurality of electrodes is biased so as to cause at least a portion of the attracted ions to enter the drift tube and to drift towards a second end of the drift tube. An ion detector is positioned proximate to the second end of the drift tube. The ion detector detects arrival times associated with the at least the portion of the attracted ions.