Strategic dynamic range control for time-of-flight mass spectrometry

A mass spectrometer comprising:

• ion optics for receiving ionized sample material from an ion source and conveying at least some of the ions from the ion source through the ion optics;
• a time-of-flight mass analyzer coupled to the ion optics for receiving at least some of the ions conveyed by the ion optics, the mass analyzer comprising a time-of-flight chamber, an ion pulsing system for periodically generating an electrical field to direct groups of the received ions into the time-of-flight chamber, and an ion detector arranged to receive ions that have traveled through the time-of-flight chamber for generating a signal indicative of the number of ions arriving at the ion detector as a function of time, the signal including information about mass spectra of the groups of ions produced by the pulsing system;
• a digitizing system adapted to receive and digitize the signal from the ion detector, the digitizing system being adapted to sample and digitize the signal in a first dynamic range during a first time period, sample and digitize the signal in a second dynamic range larger than the first dynamic range at a second time period for providing extended dynamic range data during the second time period, and then sample and digitize data from a third dynamic range different from the second dynamic range at a third time period, wherein each of the first, second, and third time periods corresponds to expected times of arrival at the ion detector of ions within each mass spectrum.

A method of operating a time-of-flight mass spectrometer, the method comprising:

• conveying ionized sample material from an ion source to a time-of-flight mass analyzer comprising, a time-of-flight chamber, an ion detector, and an ion pulsing system;
• periodically generating an electrical field using the ion pulsing system to direct a plurality of groups of the ions received by the mass analyzer through the time-of-flight chamber to the ion detector,
• outputting a signal from the ion detector indicative of the number of ions arriving at the ion detector as a function of time, the signal including information about mass spectra of the groups of ions produced by the pulsing system;
• sampling and digitizing the signal from the ion detector in a first dynamic range during a first time period, sampling and digitizing the signal in a second dynamic range larger than the first dynamic range at a second time period for providing extended dynamic range data during the second time period, and then sampling and digitizing the signal in a third dynamic range different from the second range at a third time period, wherein each of the first, second, and third time periods corresponds to expected times of arrival at the ion detector of ions within each mass spectrum.