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.

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.

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).

An apparatus for amplifying an electron signal caused by the impact of a particle with an electron emissive surface. The apparatus includes: a first electron emissive surface configured to receive an input particle and thereby emit one or more secondary electrons, a series of second and subsequent electron emissive surfaces configured to form an amplified electron signal from the one or more secondary electrons emitted by the first electron emissive surface, and one or more power supplies configured to apply bias voltage(s) to one or more of the emissive surfaces. The bias voltage(s) is sufficient to form the amplified electron signal. The apparatus is configured such that the terminal electron emissive surface(s) of the series of second and subsequent electron emissive surfaces draw a higher electrical current than that of the remainder electron emissive surface(s). The apparatus may be used as part of detector in a mass spectrometer, for example.

A secondary electron multiplier includes: a conversion dynode for emitting a secondary electron in response to an incident ion; a plurality of dynodes configured to have multi-stages from second to final stages for receiving the secondary electron; and a first voltage applying device for applying a first negative voltage to the conversion dynode and sequentially dividing the first negative voltage to apply to each of the second-stage and subsequent dynodes, wherein the secondary electron multiplier is configured to sequentially multiply the emitted secondary electron by the second-stage and subsequent dynodes. In the secondary electron multiplier, any of the second-stage and subsequent dynodes have a second voltage applying device for applying a second negative voltage. The secondary electron multiplier has an improved ion detection efficiency without a large reduction of a usable period thereof, thereby enhancing the sensitivity of a mass spectrometer.

The invention relates to mass spectrometers having secondary electron multipliers with series of discrete dynode stages. The invention particularly relates to an operation with extended dynamic measuring range and extended lifetime. The invention is based on not adapting the dynamic measuring range by control of the gain of the trans-impedance amplifier, nor controlling the multiplier operating voltage, which both are usually too slow, but alternating a number of active and passive dynode stages of a discrete dynode multiplier. Each dynode stage is connected to a discrete voltage supply circuit, being able to be de-energized and short-cut; the multiplier gain is feedback-controlled by energizing or short-cutting dynode stages, serially from the end of the multiplier, as a function of a last measured ion signal; and the multiplier has a single trans-impedance amplifier and a single analog-to-digital converter, measuring and digitizing the output current of the last active dynode stage.

The invention relates to mass spectrometers having secondary electron multipliers with series of discrete dynode stages. The invention particularly relates to an operation with extended dynamic measuring range and extended lifetime. The invention is based on not adapting the dynamic measuring range by control of the gain of the trans-impedance amplifier, nor controlling the multiplier operating voltage, which both are usually too slow, but alternating a number of active and passive dynode stages of a discrete dynode multiplier. Each dynode stage is connected to a discrete voltage supply circuit, being able to be de-energized and short-cut; the multiplier gain is feedback-controlled by energizing or short-cutting dynode stages, serially from the end of the multiplier, as a function of a last measured ion signal; and the multiplier has a single trans-impedance amplifier and a single analog-to-digital converter, measuring and digitizing the output current of the last active dynode stage.

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).

An apparatus for amplifying an electron signal caused by the impact of a particle with an electron emissive surface. The apparatus includes: a first electron emissive surface configured to receive an input particle and thereby emit one or more secondary electrons, a series of second and subsequent electron emissive surfaces configured to form an amplified electron signal from the one or more secondary electrons emitted by the first electron emissive surface, and one or more power supplies configured to apply bias voltage(s) to one or more of the emissive surfaces. The bias voltage(s) is sufficient to form the amplified electron signal. The apparatus is configured such that the terminal electron emissive surface(s) of the series of second and subsequent electron emissive surfaces draw a higher electrical current than that of the remainder electron emissive surface(s). The apparatus may be used as part of detector in a mass spectrometer, for example.