Daly detector operable in negative ion and positive ion detection modes

A method of ion detection comprising:

• (a) setting electrical potentials of a dynode and a scintillator electrode of a Daly detector and of a focusing lens disposed at an ion inlet of the Daly detector so as to detect positively charged ions received at the ion inlet from a mass analyzer or mass filter;
• (b) transferring the positively charged ions from the mass analyzer or mass filter to the Daly detector through the focusing lens and detecting a first signal that corresponds to detection of the positively charged ions by a photodetector of the Daly detector;
• (c) setting electrical potentials of the dynode, the scintillator electrode and the focusing lens of the Daly detector so as to detect negatively charged ions received at the ion inlet from the mass analyzer or mass filter;
• and
• (d) transferring the negatively charged ions from the mass analyzer or mass filter to the Daly detector through the focusing lens and detecting a second signal that corresponds to detection of the negatively charged ions by the photodetector of the Daly detector
• wherein the dynode has a surface configured to intercept, within a zone of interception, the positively charged ions upon the passing of the ions through the ion focusing lens, wherein a plane that is tangent to the dynode surface at the zone of interception is disposed at an angle of twenty degrees to thirty degrees, inclusive, to a line that passes through the center of the dynode surface and the center of the focusing lens.