Patent ID: 8735811

Claim:
A mass spectrometer comprising: an electrode arrangement for causing charged particles in a beam to undergo at least three reflections; a detection arrangement, arranged to detect a first portion of the charged particle beam that has travelled a first path length through the mass spectrometer and that has undergone at least one reflection, and to provide a first output based upon the intensity of the detected first portion of the charged particle beam, the detection arrangement further arranged to detect a second portion of the charged particle beam that has travelled a second path length through the mass spectrometer, the second path length being greater than the first path length, and to provide a second output based upon the detected second portion of the charged particle beam; and a controller, arranged to adjust the parameters of at least one of the charged particle beam and the detection arrangement, based upon the first output of the detection arrangement, so as to adjust the second output of the detection arrangement; wherein the detection arrangement is arranged to detect the first portion of the charged particle beam at a temporal focusing region; and wherein the electrode arrangement defines a flight path for the charged particle beam and wherein the detection arrangement is located substantially along the last 50% of the flight path.