A mass spectrometer comprising: an ion energy filter 14 arranged and configured to filter ions according to their kinetic energy and so as to only transmit ions having a component of kinetic energy in a first dimension (z-dimension) that is within a selected range; and a multi-reflecting time of flight mass analyser or mass separator 1 having an ion accelerator 6, and two gridless ion mirrors 2 that are elongated in the first dimension (z-dimension) and configured to reflect ions multiple times in a second orthogonal dimension (x-dimension), wherein the ion accelerator 6 is arranged to receive ions from the energy filter 14 and accelerate the ions into one of the ion mirrors 2.

Each of one or more unknown compounds are separated from a sample over a separation time period. Separated compounds are ionized, producing one or more compound precursor ions for each of the unknown compounds and a plurality of background precursor ions. A precursor ion mass spectrum is measured for the combined compound and background precursor ions at each time step of a plurality of time steps spread across the separation time period, producing a plurality of precursor ion mass spectra. One or more background precursor ions are selected from the plurality of precursor ion mass spectra that have a resolving power in a range below a threshold expected resolving power. A separation time is detected for an unknown compound when a decrease in an intensity measurement of the selected background precursor ions over a time period exceeds a threshold decrease in intensity with respect to time.

Inside a chamber (10) evacuated by a vacuum pump, a flight tube (12) is held via a support member (11) that is of insulation. The outside of the chamber (10) is surrounded by a temperature control unit (16) including a heater. A body (10a) of the chamber (10) is made of aluminum, and a coating layer (10b) by a black nickel plating is formed on the inner wall surface of the body (10a) of the chamber (10). Due to this, the radiation factor of the chamber (10) becomes higher than that of a conventional apparatus using only aluminum, and the thermal resistance of the radiation heat transfer path between the chamber (10) and the flight tube (12) becomes low, thus improving the temperature stability of the flight tube (12). Furthermore, the time constant of the temperature change of the flight tube (12) becomes small, thus reducing the time for the flight tube (12) to stabilize to a constant temperature.

An example system includes an ion detector and a signal processing apparatus in communication with the ion detector. The ion detector is arranged to detect ions during operation of the system and to generate a signal pulse in response to the detection of an ion. The signal pulse has a peak amplitude related to at least one operational parameter of the system. The signal processing apparatus is configured to analyze signal pulses from the ion detector and determine information about the detected ions during operation of the system based on the signal pulses. The signal processing apparatus includes a discriminator circuit. The signal processing apparatus is programmed to vary a threshold of the discriminator circuit based on the at least one operational parameter of the system during operation of the system.

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.

For an automatic adjustment of a detector voltage, a measurement of a standard sample is performed, in which a reflection voltage generator under the control of an autotuning controller applies, to a reflector, voltages which are different from those applied in a normal measurement and do not cause temporal conversion of ions. Ions having the same m/z simultaneously ejected from an ejector are dispersed in the temporal direction and reach a detector. Therefore, a plurality of low peaks corresponding to individual ions are observed on a profile spectrum. A peak-value data acquirer determines a wave-height value of each peak. A wave-height-value list creator creates a list of wave-height values. A detector voltage determiner searches for a detector voltage at which the median of the wave-height values in the wave-height-value list falls within a reference range.

Inside a chamber (10) evacuated by a vacuum pump, a flight tube (12) is held via a support member (11) that is of insulation. The outside of the chamber (10) is surrounded by a temperature control unit (16) including a heater. A body (10a) of the chamber (10) is made of aluminum, and a coating layer (10b) by a black nickel plating is formed on the inner wall surface of the body (10a) of the chamber (10). Due to this, the radiation factor of the chamber (10) becomes higher than that of a conventional apparatus using only aluminum, and the thermal resistance of the radiation heat transfer path between the chamber (10) and the flight tube (12) becomes low, thus improving the temperature stability of the flight tube (12). Furthermore, the time constant of the temperature change of the flight tube (12) becomes small, thus reducing the time for the flight tube (12) to stabilize to a constant temperature.

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 time-of-flight mass spectrometer includes a beam irradiation unit that generates an ionized particle by emitting an ion beam in a pulse form to a sample, a mass spectrometry unit that causes the ionized particle to fly, an MCP disposed in the mass spectrometry unit to measure a mass by amplifying the ionized particle, an MCP power source that applies a voltage to the MCP, and an MCP gain adjustment unit that adjusts a gain of the voltage. The MCP gain adjustment unit adjusts the gain of the voltage until a subsequent pulse is emitted after the beam irradiation unit emits a first pulse of the ion beam.

A time-of-flight mass spectrometer includes a beam irradiation unit that generates an ionized particle by emitting an ion beam in a pulse form to a sample, a mass spectrometry unit that causes the ionized particle to fly, an MCP disposed in the mass spectrometry unit to measure a mass by amplifying the ionized particle, an MCP power source that applies a voltage to the MCP, and an MCP gain adjustment unit that adjusts a gain of the voltage. The MCP gain adjustment unit adjusts the gain of the voltage until a subsequent pulse is emitted after the beam irradiation unit emits a first pulse of the ion beam.