Patent ID: 7372024
Filing Date: 2008-05-13
Classification: H01J

Abstract:
1. A method for trapping ions in a 2-D ion trap comprising: generating an RF quadrupole field in a trapping volume; generating an octopole field in the trapping volume; providing ions in the trapping volume; generating a first excitation wave in the trapping volume wherein the first excitation wave has a first excitation wave frequency and wherein the first excitation wave frequency changes from a higher frequency to a lower frequency over time and changes from a lower amplitude to a higher amplitude over time, wherein the first excitation wave forces motion of ions in the trapping volume in a first direction; and generating a second excitation wave wherein the second excitation wave has a second wave excitation frequency and wherein the second excitation wave frequency changes from a lower frequency to a higher frequency over time and changes from a higher amplitude to a lower amplitude over time, wherein the second excitation wave forces motion of ions in the trapping volume in a second direction and wherein the first and the second excitation waves are generated independently and sequentially.