Abstract: A signal processing unit comprises: at least one data signal input line adapted to receive a measured data signal generated by an image current, the measured data signal comprising an added crosstalk signal induced by a source of electromagnetic disturbance; at least one disturbance signal input line adapted to receive a decoupled disturbance signal, extracted from the source of electromagnetic disturbance; an output line adapted to supply a compensated data signal; a conditioning module, to which the decoupled disturbance signal is supplied via the disturbance signal input line and which provides a compensation signal; and an adding module, to which the measured data signal and the compensation signal are provided and in which the measured data signal and the compensation signal are superposed, whereby the decoupled disturbance signal is conditioned by the conditioning module such that the compensation signal essentially corresponds to an inverted added crosstalk signal.

Abstract: A mass spectrometer comprises: a first ion optical device in a relatively low gas pressure region; a second ion optical device in a relatively high gas pressure region, the first and second ion optical devices receiving respective RF voltages from respective RF power supplies for generating respective RF fields that confine ions in respective trapping regions of the ion optical devices; and a gas conductance restriction, restricting gas flow from the relatively high gas pressure region to the relatively low gas pressure region, the gas conductance restriction having an aperture to allow ions to pass from the second to the first ion optical device. The first and second RF power supplies are independent to allow the RF voltages for generating the first RF field to have a different amplitude from the RF voltages for generating the second RF field.

Abstract: A signal processing unit comprises: at least one data signal input line adapted to receive a measured data signal generated by an image current, the measured data signal comprising an added crosstalk signal induced by a source of electromagnetic disturbance; at least one disturbance signal input line adapted to receive a decoupled disturbance signal, extracted from the source of electromagnetic disturbance; an output line adapted to supply a compensated data signal; a conditioning module, to which the decoupled disturbance signal is supplied via the disturbance signal input line and which provides a compensation signal; and an adding module, to which the measured data signal and the compensation signal are provided and in which the measured data signal and the compensation signal are superposed, whereby the decoupled disturbance signal is conditioned by the conditioning module such that the compensation signal essentially corresponds to an inverted added crosstalk signal.

Abstract: There is disclosed a method for eliminating an added crosstalk signal from a measured data signal, which is generated by an image current. There is further disclosed a signal processing unit for carrying out the method. There is still further disclosed a mass spectrometer and a mass analyser comprising the signal processing unit for carrying out the method. There is yet still further disclosed a Fourier transform mass spectrometer configured to eliminate the added crosstalk signal from a measured data signal.

Abstract: A method for controlling the filling of an ion trap with a predetermined quantity of ions. The method comprises generating an ion current by transmitting ions along an ion path to an ion trap, such that ions are accumulated in the ion trap over a transmission time period, wherein the magnitude of the ion current varies in time. The method further comprises detecting at an ion detector at least some ions from the source of ions during a plurality of distinct sampling time intervals interspersed within the transmission time period, and setting the duration of the transmission time period based on the detection of ions at the ion detector. The time difference between the start of a sampling time interval and the start of an immediately subsequent sampling time interval is less than a timescale for variation of the magnitude of the ion current. A controller for controlling the filling of an ion trap with a predetermined quantity of ions and a mass spectrometer comprising the controller is also described.

Abstract: There is disclosed a method for eliminating an added crosstalk signal from a measured data signal, which is generated by an image current. There is further disclosed a signal processing unit for carrying out the method. There is still further disclosed a mass spectrometer and a mass analyser comprising the signal processing unit for carrying out the method. There is yet still further disclosed a Fourier transform mass spectrometer configured to eliminate the added crosstalk signal from a measured data signal.

Abstract: There is disclosed a method for eliminating an added crosstalk signal from a measured data signal, which is generated by an image current. There is further disclosed a signal processing unit for carrying out the method. There is still further disclosed a mass spectrometer and a mass analyser comprising the signal processing unit for carrying out the method. There is yet still further disclosed a Fourier transform mass spectrometer configured to eliminate the added crosstalk signal from a measured data signal.

Abstract: An ion trap 1 comprises one ejection electrode 2 for ion trapping having an opening 4, through which ions in the ion trap 1 can be ejected in an ejection direction E and further electrodes 3 for ion trapping, wherein the ejection electrode 2 and the further electrodes 3 are elongated in a longitudinal direction L. The angle ? between the longitudinal direction L and the ejection direction E is nearly 90°. The ion trap 1 comprises a primary winding 5 connected to an RF power supply 6, a secondary winding 7 coupling with the primary winding 5 for transforming the RF voltage of the RF power supply 6 supplying the transformed RF signals to the ejection electrode 2 and secondary windings 7? coupling with the primary winding 5 for transforming the RF voltage of the RF power supply 6 supplying the transformed RF signals to the further electrodes 3.

Abstract: A method for controlling the filling of an ion trap with a predetermined quantity of ions. The method comprises generating an ion current by transmitting ions along an ion path to an ion trap, such that ions are accumulated in the ion trap over a transmission time period, wherein the magnitude of the ion current varies in time. The method further comprises detecting at an ion detector at least some ions from the source of ions during a plurality of distinct sampling time intervals interspersed within the transmission time period, and setting the duration of the transmission time period based on the detection of ions at the ion detector. The time difference between the start of a sampling time interval and the start of an immediately subsequent sampling time interval is less than a timescale for variation of the magnitude of the ion current. A controller for controlling the filling of an ion trap with a predetermined quantity of ions and a mass spectrometer comprising the controller is also described.

Abstract: There is disclosed a method for eliminating an added crosstalk signal from a measured data signal, which is generated by an image current. There is further disclosed a signal processing unit for carrying out the method. There is still further disclosed a mass spectrometer and a mass analyser comprising the signal processing unit for carrying out the method. There is yet still further disclosed a Fourier transform mass spectrometer configured to eliminate the added crosstalk signal from a measured data signal.

Abstract: A method of switching between two modes of power supply to a mass analyzer is provided. In a first mode of operation, operated for a first predefined time duration, a first power supply, coupled to the mass analyzer, generates a first non-zero potential, while a second power supply, disconnected from the mass analyzer, generates a second non-zero potential. In a second mode of operation, operated for a second predefined time duration, the second potential is coupled to the mass analyzer, while the first power supply, disconnected from the mass analyzer, generates the first potential. These predefined time durations are selected such that only one of: the first potential; and the second potential is coupled to the mass analyzer at any time, and such that the first and second modes of operation are carried out at least once within a predetermined length of time.

Abstract: A method of mass analysis and a mass spectrometer are provided wherein a batch of ions is accumulated in a mass analyzer; the batch of ions accumulated in the mass analyzer is detected using image current detection to provide a detected signal; the number of ions in the batch of ions accumulated in the mass analyzer is controlled using an algorithm based on a previous detected signal obtained using image current detection from a previous batch of ions accumulated in the mass analyzer; wherein one or more parameters of the algorithm are adjusted based on a measurement of ion current or charge obtained using an independent detector located outside of the mass analyzer.

Abstract: A detection system and a method for detecting ions which have been separated in a time-of-flight (TOF) mass analyzer, comprising an amplifying arrangement for converting ions into packets of secondary particles and amplifying the packets of secondary particles, wherein the amplifying arrangement is arranged so that each packet of secondary particles produces at least a first output and a second output separated in time and so that during the delay between producing the first and second output the first output produced by a packet of secondary particles is used for modulating the second output produced by the same packet. An increased dynamic range of detection and protection of the detection system against intense ion pulses is thereby provided.

Abstract: A mass analyzer in which ions form packets that oscillate with a period has an ion detector comprising: a detection arrangement; and compensation circuitry. The detection arrangement may comprise: a plurality of detection electrodes detecting image current signals from ions in the mass analyzer; and a preamplifier, providing an output based on the image current signals. The compensation circuitry provides a compensation signal to a respective compensatory part of the detection arrangement, based on one or more of the image current signals. A capacitance between each of the compensatory parts of the detection arrangement and a signal-carrying part of the detection arrangement affects the signal-to-noise ratio of the preamplifier output. A generator may provide a trapping field defining an ion trapping volume and a shielding conductor may be positioned between two detection electrodes, with a controller applying a voltage to the shielding conductor based on a detected image current.

Abstract: The present invention provides a radio frequency (RF) power supply in a mass spectrometer. The power supply provides an RF signal to electrodes of a storage device to create a trapping field. The RF field is usually collapsed prior to ion ejection. In an illustrative embodiment the RF power supply includes a RF signal supply; a coil arranged to receive the signal provided by the RF signal supply and to provide an output RF signal for supply to electrodes of an ion storage device; and a shunt including a switch operative to switch between a first open position and a second closed position in which the shunt shorts the coil output.

Abstract: A mass analyser in which ions form packets that oscillate with a period has an ion detector comprising: a detection arrangement; and compensation circuitry. The detection arrangement may comprise: a plurality of detection electrodes detecting image current signals from ions in the mass analyser; and a preamplifier, providing an output based on the image current signals. The compensation circuitry provides a compensation signal to a respective compensatory part of the detection arrangement, based on one or more of the image current signals. A capacitance between each of the compensatory parts of the detection arrangement and a signal-carrying part of the detection arrangement affects the signal-to-noise ratio of the preamplifier output. A generator may provide a trapping field defining an ion trapping volume and a shielding conductor may be positioned between two detection electrodes, with a controller applying a voltage to the shielding conductor based on a detected image current.

Abstract: A method of mass analysis and a mass spectrometer are provided wherein a batch of ions is accumulated in a mass analyser; the batch of ions accumulated in the mass analyser is detected using image current detection to provide a detected signal; the number of ions in the batch of ions accumulated in the mass analyser is controlled using an algorithm based on a previous detected signal obtained using image current detection from a previous batch of ions accumulated in the mass analyser; wherein one or more parameters of the algorithm are adjusted based on a measurement of ion current or charge obtained using an independent detector located outside of the mass analyser.

Abstract: A mass analyzer in which ions form packets that oscillate with a period has an ion detector comprising: a detection arrangement; and compensation circuitry. The detection arrangement may comprise: a plurality of detection electrodes detecting image current signals from ions in the mass analyzer; and a preamplifier, providing an output based on the image current signals. The compensation circuitry provides a compensation signal to a respective compensatory part of the detection arrangement, based on one or more of the image current signals. A capacitance between each of the compensatory parts of the detection arrangement and a signal-carrying part of the detection arrangement affects the signal-to-noise ratio of the preamplifier output. A generator may provide a trapping field defining an ion trapping volume and a shielding conductor may be positioned between two detection electrodes, with a controller applying a voltage to the shielding conductor based on a detected image current.

Abstract: A method of mass analysis and a mass spectrometer are provided wherein a batch of ions is accumulated in a mass analyzer; the batch of ions accumulated in the mass analyzer is detected using image current detection to provide a detected signal; the number of ions in the batch of ions accumulated in the mass analyzer is controlled using an algorithm based on a previous detected signal obtained using image current detection from a previous batch of ions accumulated in the mass analyzer; wherein one or more parameters of the algorithm are adjusted based on a measurement of ion current or charge obtained using an independent detector located outside of the mass analyzer.

Abstract: A detection system and a method for detecting ions which have been separated in a time-of-flight (TOF) mass analyzer, comprising an amplifying arrangement for converting ions into packets of secondary particles and amplifying the packets of secondary particles, wherein the amplifying arrangement is arranged so that each packet of secondary particles produces at least a first output and a second output separated in time and so that during the delay between producing the first and second output the first output produced by a packet of secondary particles is used for modulating the second output produced by the same packet. An increased dynamic range of detection and protection of the detection system against intense ion pulses is thereby provided.