Patent ID: 7176454

Claim:
An ion source for a mass analyzer comprising: a sample support having a sample surface; a first electrode spaced apart from the sample support; a second electrode spaced apart from the first electrode in a direction opposite the sample support holder; a third electrode spaced apart from the second electrode in a direction opposite the first electrode; and a power source electrically coupled to the sample support, the first electrode, the second electrode, and the third electrode and configured to: apply a first potential to the sample surface and a second potential to at least one of the first electrode and the second electrode to establish a non-extracting electric field at a first predetermined time substantially prior to striking a sample on the sample surface with a pulse of energy to form sample ions, the non-extracting electrical field substantially not accelerating sample ions in a direction away from the sample surface; change the electrical potential of at least one of the sample surface, and the first electrode to establish a first extraction electric field at a second predetermined time subsequent to the first predetermined time, the first extraction electric field accelerating sample ions in a first direction away from the sample surface; and apply a third potential to the second electrode to establish a second extraction electric field that extracts samples ions substantially in the first direction.