A time-of-flight (ToF) mass spectrometer, comprising: a pulsed ion injector for forming an ion beam that travels along an ion path; a detector for detecting ions in the ion beam that arrive at the detector at times according to their m/z values; an ion focusing arrangement located between the ion injector and the detector for focusing the ion beam in at least one direction orthogonal to the ion path; and a variable voltage supply for supplying the ion focusing arrangement with at least one variable voltage that is dependent on a charge state and/or an amount of ions of at least one species of ions in the ion beam. A corresponding method of mass spectrometry is provided. The charge state and/or an amount of ions may be acquired from a pre-scan, or predicted. Tuning of the spectrometer based on a charge state and/or an amount of ions of at least one species of ions in the ion beam may be performed on the fly.

A constructed unit is fixed to a base by means of a plurality of support posts while being spaced from the base. The constructed unit includes an orthogonal acceleration unit. An incidence regulator unit is fixed to the base by a pair of support posts while being spaced from the base and the constructed unit. The incidence regulator unit includes, among others, a pair of blades that define a slit, and heaters for heating the pair of blades.

When a Q-TOF type mass spectrometer is operated in an MS.sup.1 mode, a controller (40), at the time of measurement, controls voltage generators (31 to 33) such that only a V voltage (radio-frequency voltage for mass separation) and a direct-current bias voltage are applied to main rod electrodes of a quadrupole mass filter (12) without application of a U voltage (direct-current voltage for mass separation). During a measurement preparation period between a plurality of measurements to obtain one mass spectrum, the controller (40) controls a U voltage generator (31) so as to apply the U voltage to the main rod electrodes of the quadrupole mass filter (12). Accordingly, a direct-current electric field is formed between adjacent main rod electrodes around an ion optical axis (C) due to a potential difference, and electric charges accumulated in rod holders (122) holding the main rod electrodes are rapidly removed by an effect of this electric field. As a result, it is possible to eliminate a charge-up that has not been eliminated by a conventional method in which a polarity of a direct-current bias voltage applied to the rod electrodes is merely reversed.

An ion detection system is disclosed that comprises one or more first devices 11 configured to produce secondary electrons in response to incident ions. The one or more first devices 11 comprise a first ion collection region and a second ion collection region and are configured to produce first secondary electrons in response to one or more ions incident at the first ion collection region and to produce second secondary electrons in response to one or more ions incident at the second ion collection region. The ion detection system also comprises a first output device 14 configured to output a first signal in response to first secondary electrons produced by the one or more first devices 11 and a second output device 15 configured to output a second signal in response to second secondary electrons produced by the one or more first devices 11.

A transfer electrode unit (240) is configured by coaxially arranging a plurality of loop electrodes (241A, 241B, 241C), and guides ions to an orthogonal acceleration region (242C) by allowing the ions to pass through an inner side of the plurality of electrodes (241A, 241B, 241C) each of which is applied with a voltage. A voltage having a higher absolute value than the voltage applied to the plurality of electrodes (241A, 241B, 241C) is applied to a flight tube (246), and the ions accelerated in the orthogonal acceleration region (242C) are introduced to a flight space formed in the flight tube (246). A shield portion (241F) is provided between the transfer electrode unit (240) and the flight tube (246), and suppresses that an electric field derived from the voltage applied to the flight tube (246) enters the transfer electrode unit (240).

The present disclosure relates to a device for filtering at least one selected ion from an ion beam includes a unit for creating an electric field for accelerating the ions of the ion beam along a flight path of predefinable length, and a controllable ion optical system, which delimits the flight path in one direction, and which is used to deflect the selected ion from a flight path of the ion beam. The device is further designed to control the ion optical system subject to a flight time of the selected ion along the flight path. The present disclosure also relates to a mass spectrometer having a device according to the present disclosure, and to a method for filtering at least one selected ion from an ion beam.

When a Q-TOF type mass spectrometer is operated in an MS.sup.1 mode, a controller (40), at the time of measurement, controls voltage generators (31 to 33) such that only a V voltage (radio-frequency voltage for mass separation) and a direct-current bias voltage are applied to main rod electrodes of a quadrupole mass filter (12) without application of a U voltage (direct-current voltage for mass separation). During a measurement preparation period between a plurality of measurements to obtain one mass spectrum, the controller (40) controls a U voltage generator (31) so as to apply the U voltage to the main rod electrodes of the quadrupole mass filter (12). Accordingly, a direct-current electric field is formed between adjacent main rod electrodes around an ion optical axis (C) due to a potential difference, and electric charges accumulated in rod holders (122) holding the main rod electrodes are rapidly removed by an effect of this electric field. As a result, it is possible to eliminate a charge-up that has not been eliminated by a conventional method in which a polarity of a direct-current bias voltage applied to the rod electrodes is merely reversed.

To acquire a mass spectrum for a wide mass range, a normal analysis execution controlling unit controls components to repeatedly perform measurement while changing setting m/z by a predetermined m/z at a time, and a mass spectrum summarizing processing unit summarizes data pieces each obtained by each time of measurement to generate the mass spectrum. Radio-frequency voltage applied to an ion guide and the like is changed based on the setting m/z. The radio-frequency voltage for the setting m/z is determined using a table in which a relationship between a position on an axis between upper and lower limits of the mass range and the radio-frequency voltage is substantially the same regardless of the mass range.

An acceleration voltage generator (7) generates a high-voltage pulse to be applied to an electrode in an orthogonal accelerator by turning on/off a high DC voltage generated by a high-voltage power source through MOSFETs (741) in a switch circuit (74). A controller (6) sends driving pulse signals to the switch circuit (74) through a primary-side driver section (71), transformer (72) and secondary driver section (73). An adjustment circuit (742) formed by a gate resistor (742a) and gate capacitor (742b) is provided between the secondary-side driver section (73) and the MOSFET (741). The resistance value of the resistor (742a) and the capacitance value of the capacitor (742b) are determined so as to suppress an overshoot of the gate voltage due to the resonance while preventing a decrease in steepness of the waveform in its rising and falling phases.

Elongation of orthogonal accelerators is assisted by ion spatial transverse confinement within novel confinement means, formed by spatial alternation of electrostatic quadrupolar field (22). Contrary to prior art RF confinement means, the static means provide mass independent confinement and may be readily switched. Spatial confinement defines ion beam (29) position, prevents surfaces charging, assists forming wedge and bend fields, and allows axial fields in the region of pulsed ion extraction, this way improving the ion beam admission at higher energies and the spatial focusing of ion packets in multi-reflecting, multi-turn and singly reflecting TOF MS or electrostatic traps.