Methods and apparatus for trapping and accumulation of ions

A method of ion accumulation, comprising:

• introducing ions into an apparatus for ion accumulation having a first region, a second region adjacent to the first region, and a third region adjacent to the second region;
• generating a drive potential within the first region for guiding the ions across the first region in a first direction;
• transferring the ions from the first region to the second region with the drive potential;
• generating a first electric field within the second region when in a first state for preventing the ions from entering the third region using a segmented electrode which extends axially across the second region, the first electric field including a second drive potential and a gate potential generated by the segmented electrode;
• accumulating ions in the second region using the gate potential;
• and
• switching the first electric field generated by the segmented electrode within the second region to a second electric field for guiding the accumulated ions in the first direction toward the third region.

An ion accumulation device, comprising:

• an ion accumulation section having a first width and being configured to receive ions, switch between a first state and a second state, generate a first electric field when in the first state using one more segmented electrodes which extend axially across a length of the ion accumulation section, and generate a second electric field using the one more segmented electrodes when in the second state;
• an outlet section having a second width less than the first width, the outlet section being configured to generate a third electric field configured to guide the ions across the outlet section;
• and
• an outlet transition section extending between the ion accumulation section and the outlet section, and having a tapering width that reduces from the first width adjacent the ion accumulation section to the second width adjacent the outlet section, the outlet transition section being configured to generate the third electric field to guide the ions across the outlet transition section to the outlet section;
• wherein the first electric field is configured to accumulate ions in the ion accumulation section and prevent the ions from moving in a first direction and entering the outlet transition section, the first electric field including a drive potential and a gate potential,
• wherein the second electric field is configured to guide the ions in the first direction toward the outlet transition section, and
• wherein when the ion accumulation section is in the first state the first electric field prevents ions in the ion accumulation section from exiting the ion accumulation section and causes the ions to accumulate in the ion accumulation section, and when the ion accumulation section is in the second state the second electric field causes the ions to move in the first direction toward the outlet transition section.