A multi-pass time-of-flight mass spectrometer is disclosed having an elongated orthogonal accelerator (30). The orthogonal accelerator (30) has electrodes (31) that are transparent to the ions so that ions that are reflected or turned back towards it are able to pass through the orthogonal accelerator (30). The electrodes (31) of the orthogonal accelerator (30) may be pulsed from ground potential in order to avoid the reflected or turned ion packets being defocused. The spectrometer has a high duty cycle and/or space charge capacity of pulsed conversion.

A method of analysing labelled analyte ions comprises fragmenting labelled analyte ions to produce analyte fragment ions and reporter ions or complementary ions, analysing the analyte fragment ions using a time-of-flight mass analyser operating in a first mode of operation, and analysing the reporter ions or the complementary ions using the time-of-flight mass analyser operating in a second mode of operation. In the first mode of operation, ions are caused to travel along a flight path having a first length, and in the second mode of operation, ions are caused to travel along a flight path having a second length, wherein the second length is greater than the first length.

A multi-reflection mass spectrometer comprising two ion mirrors spaced apart and opposing each other in a direction X, each mirror elongated generally along a drift direction Y, the drift direction Y being orthogonal to the direction X, a pulsed ion injector for injecting pulses of ions into the space between the ion mirrors, the ions entering the space at a non-zero inclination angle to the X direction, the ions thereby forming an ion beam that follows a zigzag ion path having N reflections between the ion mirrors in the direction X whilst drifting along the drift direction Y, a detector for detecting ions after completing the same number N of reflections between the ion mirrors, and an ion focusing arrangement at least partly located between the opposing ion mirrors and configured to provide focusing of the ion beam in the drift direction Y, such that a spatial spread of the ion beam in the drift direction Y passes through a single minimum at or immediately after a reflection having a number between 0.25N and 0.75N, wherein all detected ions are detected after completing the same number N of reflections between the ion mirrors.

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.

Apparatus and method are proposed for the strong improvement of dynamic range (DR) of detectors and of data systems for time-of-flight mass spectrometers (TOF MS) with periodically repetitive signals. TOF separated ions are converted into secondary particles, primarily electrons, and the flow of secondary particles is controllably attenuated to sustain the data acquisition system in a counting mode above the electronic noise threshold. The acquisition time is split between at least two time segments, characterized by alternated transmission efficiency SE of secondary particles. Using strong electron suppression (SE1) is employed for recording intense ion peak, while counting ions with either ADC, or TDC, or ADC with extracting peak centroids. A longer time segment employs an efficient electron transfer (SE=1) for detecting weak ion species. In another independent aspect, an ion-optical element is provided upstream of the ion detector and is configured to deflect, reflect or retard ions such that ions that have been scattered or fragmented in the time of flight region do not impact on the ion detector.

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 apparatus configured to produce an image charge/current signal representative of trapped ions undergoing oscillatory motion. The apparatus includes: an electrostatic ion trap configured to trap ions such that the trapped ions undergo oscillatory motion in the electrostatic ion trap; an image charge/current detector configured to obtain an image charge/current signal representative of trapped ions undergoing oscillatory motion in the electrostatic ion trap, wherein the electrostatic ion trap configured to trap ions such that the image charge/current signal in the time domain repeats, for ions of a given mass/charge ratio m, at a frequency f.sub.sig(m) [Hz] with a signal period T.sub.sig(m) [s]. The image charge/current detector includes one or more pickup electrodes configured to obtain the image charge/current signal. The one or more pickup electrodes are arranged to detect two signal pulses caused by ions having the given mass/charge ratio m within each signal period T.sub.sig(m). The one or more pickup electrodes are further arranged such that the time separation t.sub.sep(m) between the two signal pulses caused by ions having the given mass/charge ratio m within each signal period T.sub.sig(m) is approximately equal to 2p+1/2.n.f.sub.sig(m) so as to suppress a predetermined nth harmonic within the image charge/current signal, where n is an integer that is 1 or more, and where p is an integer that is 0 or more.

One or more ions are received along a central axis through a first set of reflectron plates of an ELIT. Voltages are applied to the first set of plates and to a second set of reflectron plates in order to trap and oscillate the one or more ions. A first induced current is measured from a cylindrical pickup electrode between the first set of reflectron plates and the second set of reflectron plates. A second induced current is measured from one or more plates of the first set of reflectron plates. A third induced current is measured from one or more plates of the second set of reflectron plates. The first measured induced current, second measured induced current and third measured induced current are combined to reduce higher order frequency harmonics of the induced current.

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 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. =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 .sub.2 and what is most important, compensating for mechanical misalignments of the optical components.

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.