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.

An assembly for a mass spectrometer, comprising a housing (106) and a Time of Flight analyser (110), wherein the housing (106) is configured to enclose at least the Time of Flight analyser (110), and the Time of Flight analyser comprises a pusher assembly (120) and a flight tube (160), wherein the Time of Flight mass analyser (110) is cantilevered from the housing.

An MT-TOFMS which is one mode of the present invention includes: a linear ion trap (2) configured to temporarily hold ions to be analyzed, and to eject the ions through an ion ejection opening (211) having a shape elongated in one direction; a loop flight section (3) configured to form a loop path (P) capable of making ions repeatedly fly; and a slit part (5) located on an ion path in which the ions ejected from the linear ion trap (2) travel until the ions are introduced into the loop path, the slit part configured to block a portion of the ions in a longitudinal direction of the ion ejection opening (211).

An electrode assembly, such as for an ion mirror, comprising: a first layer having a plurality of electrodes that are separated by one or more gaps; a second layer arranged to cover said one or more gaps and prevent electric fields passing through said one or more gaps, said second layer having electrically conductive material located to be coincident with said one or more gaps in the first layer.

Improved ion mirrors (10) are proposed for multi-reflecting TOF MS and electrostatic traps at various analyzer topologies. Ion mirrors (10) are constructed of printed circuit boards (11) with improved precision and flatness. To compensate for the remaining geometrical imperfections of mirror electrodes there are proposed electrode sets (17) and field structures in the ion retarding region for electronically adjusting of the ion packets time fronts, for improving the ion injection into the analyzer and for reversing the ion motion in the drift direction.

A no-electric field region (246A) and an electric field region (246B) are formed in a flight tube (246). In the no-electric field region (246A), ions introduced from an ion emission unit fly. In the electric field region (246B), a reflectron (244) is provided and the ions having passed through the no-electric field region (246A) are reflected to the no-electric field region (246A) by an action of an electric field formed on an inner side of a plurality of electrodes (244A, 244B). A through-hole (246D) is formed in at least a part of the flight tube (246) to be closer to the electric field region (246B) than the no-electric field region (246A).

An ion mirror 41 constructed of thin electrodes that are interconnected by resistive dividers 45 with potentials U1-U5 applied to knot electrodes to form segments 41-43 of linear potential distribution between the “knot” electrodes, yet without separating those field regions by meshes. Weak and controlled penetration of electric fields provide for a fine control over the field non linearity and over the equipotential line curvature, thus allowing to reach unprecedented level of ion optical quality: more than twice larger energy acceptance compared to thick electrode mirrors, up to sixth order time per energy focusing, ion spatial focusing and wide spatial acceptance. Novel mirrors can be formed very slim to arrange them into stacks for ion transverse displacement between ion reflections or for multiplexed mirror stacks. Printed circuit boards (PCB) are best suited for making novel ion mirrors, while novel ion mirrors are designed to suit PCB requirements.

Disclosed herein is an ion analysis instrument comprising a Time of Flight (“TOF”) mass analyser comprising a reflectron. The instrument is operable in at least a first mode and a second mode, wherein in said first mode ions are caused to turn around at a first point in the reflectron and wherein in said second mode ions are caused to turn around at a second point in the reflectron such that the distance traveled by ions within the Time of Flight mass analyser is greater in the second mode than the distance traveled by ions within the Time of Flight mass analyser in the first mode. In this way, the operating modes can be selectively optimised for the analysis of ions of different masses.

A flight tube 246 is hollow, and ions emitted from an ion emission unit are introduced into the flight tube 246. A reflectron 244 is provided in the flight tube 246, and is configured by coaxially arranging a plurality of annular electrodes 244A and 244B. A vacuum vessel 247A that becomes in a vacuum state during analysis is formed in the vacuum chamber 247, and the flight tube 246 is provided in the vacuum vessel 247A. A temperature control mechanism 248 controls a temperature of the flight tube 246. An ambient temperature sensor 250 detects an ambient temperature outside the vacuum chamber 247. A target temperature of the temperature control mechanism 248 is set on the basis of the ambient temperature detected by the ambient temperature sensor 250.

A no-electric field region (246A) and an electric field region (246B) are formed in a flight tube (246). In the no-electric field region (246A), ions introduced from an ion emission unit fly. In the electric field region (246B), a reflectron (244) is provided and the ions having passed through the no-electric field region (246A) are reflected to the no-electric field region (246A) by an action of an electric field formed on an inner side of a plurality of electrodes (244A, 244B). A through-hole (246D) is formed in at least a part of the flight tube (246) to be closer to the electric field region (246B) than the no-electric field region (246A).