Axial focusing following low kinetic energy pulsed extraction from a miniature linear ion trap

Using an axial focusing miniature linear ion trap with tubular end cap lenses (MLIT) we have investigated spatial focusing on ion ejection using low kinetic energy pulsed extraction methods. Ion packet widths focused to ca. 1 mm (in both the radial and axial planes) are produced following collisional cooling with helium buffer gas in an MLIT. Small axial and radial packet widths as well as application of DC extraction voltages allow different ion focusing techniques to be used on batch ion extraction. In particular, controlling the position of the space focus plane (commonly used in time-of-flight mass spectrometry) following low kinetic energy ( approximately 10 eV) ion ejection from an MLIT through the application of DC extraction voltages is illustrated. Prior to simultaneous ion ejection, induced axial ion oscillation through a change in the DC potential well shape is also shown to be useful for separating and controlling different mass/charge ion packet spatial distributions in the region of an orthogonal time-of-flight (o-TOF) push pulse.