Patent ID: 8637815

Claim:
A method of separating charged particles comprising the steps of: providing an analyser comprising two opposing mirrors each mirror comprising inner and outer field-defining electrode systems elongated along an axis z, the outer system surrounding the inner and defining therebetween an analyser volume, whereby when the electrode systems are electrically biased the mirrors create an electrical field within the analyser volume comprising opposing electrical fields along z, the strength along z of the electrical field being a minimum at a plane z=0; causing a beam of charged particles to fly through the analyser, orbiting the charged particles around the z axis within the analyser volume, reflecting the charged particles from one mirror to the other at least once thereby defining a maximum turning point within each of the mirrors; the strength along z of the electrical field at the maximum turning point being X and the absolute strength along z of the electrical field being less than |X|/2 for not more than ⅔ of the distance along z between the plane z=0 and the maximum turning point in each mirror; separating the charged particles according to their flight times; and ejecting at least some of the charged particles having a plurality of m/z from the analyser or detecting the at least some of charged particles having a plurality of m/z, the ejecting or detecting being performed after the particles have undergone the same number of orbits around the axis z.