Patent ID: 8304715

Claim:
A method of operating a measuring cell of an ICR mass spectrometer, said an ICR cell having a first compartment and a second compartment positioned spatially along a direction of a magnetic field of said mass spectrometer, the method comprising: trapping ions in the first compartment of the ICR cell by generating an electric potential well in the direction of said magnetic field with a minimum of said electric potential well located inside said first compartment; exciting cyclotron motion of said ions trapped in the first compartment; transferring at least a part of the ions having cyclotron motion excited during the said above excitation step from said first compartment to the second compartment by a displacement of a position of the minimum of said electric potential well from the first compartment to the second compartment; and detecting an ion cyclotron motion of at least a part of the ions in said second compartment, wherein said transferring comprises displacing the position of the minimum of said electric potential well from the first compartment to the second compartment preferably over a period of time equal to or longer than a characteristic period of ion oscillations along the direction of said magnetic field in said electric potential well.