High resolution multi-reflection time-of-flight mass analyser

A method of operating a multi-reflection time-of-flight mass analyser that comprises:

• two ion mirrors spaced apart and opposing each other in a first direction X, each mirror elongated generally along a drift direction Y between a first end and a second end, the drift direction Y being orthogonal to the first direction X;
• an ion injector for injecting ions into a space between the ion mirrors, the ion injector located in proximity with the first end of the ion mirrors;
• a detector for detecting ions after they have completed a plurality of reflections between the ion mirrors, the detector located in proximity with the first end of the ion mirrors;
• and
• a deflector located in proximity with the first end of the ion mirrors;
• the method comprising:
• (i) injecting ions from the ion injector into the space between the ion mirrors, wherein the ions complete a first cycle in which the ions follow a zigzag ion path having plural reflections between the ion mirrors in the direction X whilst:
• (a) drifting along the drift direction Y from the deflector towards the second end of the ion mirrors, (b) reversing drift direction velocity in proximity with the second end of the ion mirrors, and (c) drifting back along the drift direction Y to the deflector;
• (ii) using the deflector to reverse the drift direction velocity of the ions such that the ions are caused to complete a further cycle in which the ions follow a zigzag ion path having plural reflections between the ion mirrors in the direction X whilst:
• (a) drifting along the drift direction Y from the deflector towards the second end of the ion mirrors, (b) reversing drift direction velocity in proximity with the second end of the ion mirrors, and (c) drifting back along the drift direction Y to the deflector;
• and
• (iii) causing the ions to travel from the deflector to the detector for detection.