The use of a capacitor (22) to serve as the principal impedance in a negative feed-back loop in a voltage amplifier component (21) of a trans-impedance amplifier and actively controlling the amount of charge accumulated within the capacitor appropriately to improve the responsiveness and/or dynamic range of the amplifier. A switch (25) is electrically coupled to the inverting input terminal of the voltage amplifier and electrically isolated from the output terminal (23) of the voltage amplifier. The output voltage of the amplifier is proportional to the accumulation of charge, and the switch is operable to ‘reset’ the charge/voltage on the feedback capacitor, as desired. This arrangement decouples the structure of the switch from the output port of the voltage amplifier, and so avoids leakage currents and/or interfering voltage signals emanating from the switch structure and being felt at the output port of the voltage amplifier.

A mass spectrometer is disclosed comprising a system control module (1715) for controlling the operation of the mass spectrometer. The system control module (1715) comprises one or more functional modules, each functional module being operable to perform a predetermined function of the mass spectrometer. The system control module (1715) and/or one or more functional modules are operable to communicate non-time information with each other using a time code of a communications protocol.

A method of performing time-of-flight secondary ion mass spectrometry on a sample includes the step of directing a beam of primary ions to the sample, and stimulating the migration of ions within the sample while the beam of primary ions is directed at the sample. The stimulation of the ions is cycled between a stimulation state and a lower stimulation state. Secondary ions emitted from the sample by the beam of primary ions are collected in a time-of-flight mass spectrometer. Time-of-flight secondary ion mass spectrometry is then performed on the secondary ions. A system for performing time-of-flight secondary ion mass spectrometry on a sample is also disclosed.

An ion detector (4) includes a shield electrode (42) between an aperture plate (41) and a conversion dynode (43). The shield electrode (42) has a rectilinearly-moving particle block wall (42a) positioned on an extension line (C′) extending from the central axis (C) of a quadrupole mass filter (3), and an ion attracting electric field adjustment wall (42b) inclined by a predetermined angle θ (acute angle) with respect to the extension line (C′). In the ion attracting electric field adjustment wall (42b) is provided an ion passing aperture (42c). The rectilinearly-moving particles, such as neutral particles, which are ejected from the quadrupole mass filter (3), are blocked by the rectilinearly-moving particle block wall (42a), thereby reducing noises caused by the rectilinearly-moving particles. Meanwhile, the potential of the ion attracting electric field adjustment wall (42b) corresponds to equipotential surfaces in a strong electric field formed by the conversion dynode (43), and thus the condition of the strong electric field is not remarkably changed from the state where no shield electrode (42) is provided. Therefore, the effect of drawing ions is exhibited, thereby maintaining the high ion-detection efficiency.

A positive high voltage, a first terminal of a semiconductor element, and a first terminal of a first resistance element are connected to a first terminal of a first current controller. A current input terminal of a first active element is connected to a second terminal of the first current controller, and a second terminal of the semiconductor element and a second terminal of the first resistance element are connected to a control terminal of the first active element. A second resistance element is connected between a current output terminal and a control terminal of the first active element. The first current controller allows a drive current corresponding to an input signal to flow in the first active element and allows the drive current output from the first active element to flow into a load, thereby generating an output voltage.

A method of analysis using mass and/or ion mobility spectrometry or ion mobility spectrometry is disclosed comprising: using a first device to generate aerosol, smoke or vapour from one or more regions of a first target of biological material; and el mass and/or ion mobility analysing and/or ion mobility analysing said aerosol, smoke, or vapour, or ions derived therefrom so as to obtain first spectrometric data. The method may use an ambient ionisation method.

A method for characterizing or quantifying one or more proteins in visible and/or sub-visible particles formed in a sample by detecting the at least one visible or sub-visible particle in the sample, isolating and capturing the at least one visible or sub-visible particle to identify a presence of a protein, and using a mass spectrometer to characterize the protein.

A method for characterizing or quantifying one or more proteins in visible and/or sub-visible particles formed in a sample by detecting the at least one visible or sub-visible particle in the sample, isolating and capturing the at least one visible or sub-visible particle to identify a presence of a protein, and using a mass spectrometer to characterize the protein.

A mass spectrometry (MS) apparatus is provided. The MS apparatus includes a mass spectrometer, an ionization source coupled to the mass spectrometer, and a flow injection system (FIS) coupled to the ionization source. The ionization source is configured to provide an ionized gas flow of an analyte towards an entrance of the mass spectrometer. The ionization source is further configured to provide a second gas flow of a second gas. The MS apparatus is configured to measure a mass spectrometer (MS) signal of the analyte. The MS apparatus is further configured to analyze a dependency of the MS signal of the analyte versus a parameter of the second gas flow or a state of the second gas flow and to determine a condition of the apparatus based on the analyzed dependency.

A mass spectrometer comprising: a multi-reflecting time of flight (MRTOF) mass analyser or mass separator having two gridless ion mirrors 2 that are elongated in a first dimension (Z-dimension) and configured to reflect ions multiple times in a second orthogonal dimension (X-dimension) as the ions travel in the first dimension; the spectrometer configured to operate in: (i) a first mode for ions having a first rate of interaction with background gas molecules in the mass analyser or separator, such that the ions are reflected a first number of times between the ion mirrors 2; and (ii) a second mode for ions having a second, higher rate of interaction with background gas molecules in the mass analyser or separator, such that ions are reflected a second, lower number of times between the ion mirrors 2.