A magnetic photomultiplier tube (PMT) system, including a PMT. The PMT including a photocathode for converting an impinging photon to a photoelectron, an anode, and at least two or a series of oppositely facing pairs of dynodes, wherein each pair is spaced apart from an adjacent pair, a first electric field being generated intermediate at least one pair of oppositely facing dynodes and a second electric field generated intermediate at least one adjacent pairs of dynodes. The PMT system includes a magnetic field generated by a magnetic system, the PMT being positioned within the magnetic field.

A method for correcting mass spectral m/z values comprises: detecting mass spectra for different amounts of sample ions within an ion trapping mass analyzer; evaluating an observable difference of relative m/z shift from the detected mass spectra of at least two of the different amounts of ions induced by space charge; evaluating a visible total charge Q.sub.v and/or the difference of a visible total charge Q.sub.v from the detected mass spectra; determining, from the evaluated observable differences of relative m/z shift and the evaluated visible total charges Q.sub.v and/or differences of the visible total charge Q.sub.v, a slope of a linear correlation between relative m/z shift and visible total charge Q.sub.v; determining a relative m/z shift of sample ions detected in a mass spectrum by multiplying visible total charge Q.sub.v with the determined slope; and correcting the m/z values in the mass spectrum using its determined relative m/z shift.

A method of analysis using mass spectrometry and/or ion mobility spectrometry is disclosed. The method comprises: using a first device to generate smoke, aerosol or vapour from a target comprising or consisting of a microbial population; mass analysing and/or ion mobility analysing said smoke, aerosol or vapour, or ions derived therefrom, in order to obtain spectrometric data; and analysing said spectrometric data in order to analyse said microbial population.

A mass spectrometer comprises an interface for receiving an ion beam from an ion source, a mass analyzer unit for selecting from the received ion beam, in two or more time periods, ions having different ranges of mass-to-charge ratios, a first detection unit for detecting, in each of said time period, ions within a selected range and producing first detection signals representative of quantities of detected ions having respective mass-to-charge ratios, and a second detection unit arranged between the interface and the mass analyzer unit for producing a second detection signal representative of a total intensity of the ion beam received from the ion source as a function of time. The mass spectrometer further comprises a processing unit for normalizing the first detection signals by using the second detection signal, which processing unit may output a ratio of normalized first detection signals.

A method of mass and/or ion mobility spectrometry is disclosed that comprises accumulating ions for a first period of time (T1) one or more times so as to form one or more first groups of ions, accumulating ions for a second period of time (T2) one or more times so as to form one or more second groups of ions, wherein the second period of time (T2) is less that the first period of time (T1), analysing the one or more first groups of ions to generate one or more first data sets, analysing the one or more second groups of ions to generate one or more second data sets, and determining whether the one or more first data sets comprise saturated and/or distorted data. If it is determined that the one or more first data sets comprise saturated and/or distorted data, then the method further comprises replacing the saturated and/or distorted data from the one or more first data sets with corresponding data from the one or more second data sets.

A method of separating a sample of ions according to their ion mobilities is provided. The method comprises receiving the sample of ions into a drift tube; applying a first electric field component within the drift tube so as to cause the sample of ions to move along a path within the drift tube, whereby the sample of ions separates along the path; and applying a second electric field component within the drift tube. The first and second electric field components have a combined electric field strength to modify the ion mobility of at least a portion of the sample of ions and to increase the separation of at least a portion of the sample of ions along the path The second electric field component substantially does not cause a net change in the velocity of the sample of ions perpendicular to the path. An apparatus for separating a sample of ions according to their ion mobilities is also provided.

A method for removing deposits in a mass spectrometer ion source housing includes delivering a liquid from a liquid source to a surface within the ion source housing. The surface including an ultrasonic transducer embedded within the surface. The method further includes activating the ultrasonic transducer to ultrasonically remove the deposit.

An apparatus (100, 300, 700) is described, comprising: a linear ion trap (102) comprising two pairs of pole electrodes and a radiofrequency, RF, electrical potential supply (117) configured to apply respective RF waveforms to the pairs of pole electrodes, thereby forming a RF trapping field component to trap analyte ions (116) radially in a trapping region (115) of the linear ion trap for processing of the analyte ions (116) therein; a charged particle source (101) comprising a pulse valve (103), a conduit (106, 107), having an entrance in fluid communication therewith and an exit, wherein the conduit (106, 107) extends in the direction of the trapping region (115), and a discharge device (108) electrically coupled to an electrical potential supply (109) and disposed between the entrance and the exit of the conduit (106, 107), wherein the pulse valve (103) is configured to release a gas pulse from a gas supply into the entrance of the conduit (106, 107) and wherein the electrical potential supply (109) is configured to apply a high voltage to the discharge device (108) to generate a discharge (110) in the gas pulse in the conduit (106, 107), thereby generating charged particles (114) from the gas and accelerating the generated charged particles in the direction of the trapping region (115). A method is also described.

The present invention comprises novel methods of continuously monitoring the performance of an atmospheric pressure ionization (API) system. The methods of the invention allow for improved quality monitoring of the processes that leads to the formation of ions at atmospheric pressure. The methods of the invention further allow for continuously monitoring for the quality of the ion formation process in API without the addition of extraneous material (such as labelled compounds or control known compounds) to the system being monitored.

A protection device for an Optical Emission Spectrometer (OES) and a method of protecting a detector to which purge gas is supplied, in an OES, are disclosed. The protection device comprises a timer, which measures a parameter, such as a humidity value, indicative of a shut down time period following cessation of application of purge gas to the detector. The protection device comprises a processor, which determines a start-up time period, based on the parameter, during which purge gas is supplied to the detector prior to cooling of the detector. The processor may selectively trigger commencing or maintaining application of purge gas to the detector or cooling of the detector in dependence on the parameter.