A multi-reflecting time of flight mass analyser is disclosed in which the ion flight path is maintained relatively small and the duty cycle is made relatively high. Spatial focusing of the ions in the dimension (z-dimension) in which the mirrors (36) are elongated can be eliminated whilst maintaining a reasonably high sensitivity and resolution.

An electrostatic linear ion trap has first and second axially aligned ion mirrors separated by a charge detection cylinder axially aligned with each ion mirror. Electric fields are selectively established within the first and second ion mirrors in a manner which causes an ion in the trap to oscillate back and forth through the charge detection cylinder between the first and second ion mirrors with a duty cycle, corresponding to a ratio of time spent by the ion passing through the charge detection cylinder and total time spent traversing a combination of the first and second ion mirrors and the charge detection cylinder during one complete oscillation cycle, of approximately 50%.

A system for trapping ions for measurement thereof may include an electrostatic linear ion trap (ELIT), a source of ions to supply ions to the ELIT, a processor operatively coupled to ELIT, and a memory having instructions stored therein executable by the processor to produce at least one control signal to open the ELIT to allow ions supplied by the source of ions to enter the ELIT, determine an ion inlet frequency corresponding to a frequency of ions flowing from the source of ions into the open ELIT, generate or receive a target ion charge value, determine an optimum threshold value as a function of the target ion charge value and the determined ion inlet frequency, and produce at least one control signal to close the ELIT when a charge of an ion within the ELIT exceeds the optimum threshold value to thereby trap the ion in the ELIT.

An electrostatic linear ion trap (ELIT) array includes multiple elongated charge detection cylinders arranged end-to-end and each defining an axial passageway extending centrally therethrough, a plurality of ion mirror structures each defining a pair of axially aligned cavities and an axial passageway extending centrally therethrough, wherein a different ion mirror structure is disposed between opposing ends of each cylinder, and front and rear ion mirrors each defining at least one cavity and an axial passageway extending centrally therethrough, the front ion mirror positioned at one end of the arrangement of charge detection cylinders and the rear ion mirror positioned at an opposite end of the arrangement of charge detection cylinders, wherein the axial passageways of the charge detection cylinders, the ion mirror structures, the front ion mirror and the rear ion mirror are coaxial to define a longitudinal axis passing centrally through the ELIT array. In a second aspect, an ELIT array comprises a plurality of non-coaxial ELIT regions, wherein ions are selectively guided into each of the ELIT regions.

An MCP detector (620) receives an ion packet along an ion path (601) of mass spectrometer through a hollow central cylindrical tube (621) of the MCP detector. The MCP detector includes coaxial rings (622) of MCPs surrounding the hollow central cylindrical tube. The MCP detector transmits the ion packet along the ion path to an ELIT (610) through holes in the center of a first set of reflectron plates (613) of the ELIT to oscillate the ion packet between the first set and a second set of reflectron plates (614) of the ELIT. The ELIT transmits the oscillated ion packet back to the MCP detector along the ion path through the holes of the first set. The MCP detector detects ions of the oscillated ion packet that are radially deflected from the ion path using the rings of MCPs. The MCP detector allows ions to be transmitted to or from either port of the ELIT.

Embodiments provide methods of disambiguating the spectra produced by cyclic ion analysers. Systems, methods, and computer readable media described herein can compare two sets of ion data that have been obtained using different analyser settings such that the number of passes N through the cyclic segment of the ion path taken by ions contributing to an ion peak can be determined. As a result of the determination of the number of passes N taken by ions, the physicochemical property of those ions can be unambiguously assigned to the ion peak.

A voltage supply and a method for calibrating the voltage supply are provided. The voltage supply is for providing a reference voltage to supply a voltage to at least one electrode. The voltage supply comprises: an ultra-stable DC voltage source, an accurate DC voltage source, a tuning unit, a comparator, and a control unit. An ultra-stable voltage is applied to the tuning unit, which is provided based on a supplied voltage of the ultra-stable DC voltage source. The tuning unit provides an output voltage. A voltage based on the output voltage of the tuning unit is compared by the comparator with an accurate voltage. The accurate voltage is provided based on a supplied voltage of the accurate DC voltage source. The comparator provides a signal resulting from the comparison to the control unit, wherein the control unit is tuning the tuning unit during a tuning period according to the signal provided by the comparator to minimize the absolute difference between the voltage based on the output voltage of the tuning unit and the accurate voltage. The reference voltage of the voltage supply is provided based on the output voltage of the tuning unit after the tuning period.

Systems, methods, and computer-readable media described provide multi-reflection time-of-flight analyser (e.g. of a type in which the ion beam is allowed to spread out relatively broadly) and methods for use in a zoom mode, in which time-of-flight perturbations induced by reflections at the deflector are cancelled out or removed, such that they do not give rise to a significant increase in the arrival time spread of ions at the detector. This accordingly facilitates high resolution operation of the analyser in the zoom mode. Furthermore, this is done in a way which allows the analyser to remain drift focussed, which in turn means that the analyser can be straightforwardly and seamlessly switched between its normal mode of operation and the zoom mode of operation.

Improved ion mirrors 30 (FIG. 3) are proposed for multi-reflecting TOF MS and electrostatic traps. Minor and controlled variation by means of arranging a localized wedge field structure 35 at the ion retarding region was found to produce major tilt of ion packets time fronts 39. Combining wedge reflecting fields with compensated deflectors is proposed for electrically controlled compensation of local and global misalignments, for improved ion injection and for reversing ion motion in the drift direction. Fine ion optical properties of methods and embodiments are verified in ion optical simulations.

Improved pulsed ion sources and pulsed converters are proposed for multi-pass time-of-flight mass spectrometer, either multi-reflecting (MR) or multi-turn (MT) TOF. A wedge electrostatic field (45) is arranged within a region of small ion energy for electronically controlled tilting of ion packets (54) time front. Tilt angle γ of time front (54) is strongly amplified by a post-acceleration in a flat field (48). Electrostatic deflector (30) downstream of the post-acceleration (48) allows denser folding of ion trajectories, whereas the injection mechanism allows for electronically adjustable mutual compensation of the time front tilt angle, i.e. γ=0 for ion packet in location (55), for curvature of ion packets, and for the angular energy dispersion. The arrangement helps bypassing accelerator (40) rims, adjusting ion packets inclination angles α.sub.2 and what is most important, compensating for mechanical misalignments of the optical components.