Ion injection method into side-on FT-ICR mass spectrometers

A method for injecting charged particles in a focusing region of an electric field in a side-on injection Penning trap, comprising:

• applying a quadrupole electric field to a cylindrical gap between a first set of electrodes printed on a first printed circuit board (PCB) and a second set of electrodes that correspond in shape and size to the first set of electrodes printed on a second PCB using the first set of electrodes and second set of electrodes,
• wherein the first set of electrodes and the second set of electrodes each include a central disk electrode and one or more concentric segmented ring electrodes, the central disk electrode and the next adjacent concentric segmented ring electrode are separated by a circular non-conducting path and each concentric segmented ring electrode is separated by the next adjacent concentric segmented ring electrode by a circular non-conducting path, and each of the one or more concentric segmented ring electrodes is segmented by at least two radial non-conducting paths extending from the circular non-conducting path around the central disk electrode to the outer edge of the outermost segmented ring electrode,
• wherein the second PCB is placed in parallel with the first PCB so that the second set of electrodes and the first of electrodes are coaxial and so that each electrode and non-conducting path of the first set of electrodes faces a corresponding electrode and non-conducting path of the second set of electrodes,
• wherein the space between the first set of electrodes and the second set of electrodes is a cylindrical gap used to trap charged particles, and
• wherein the first set of electrodes and the second set of electrodes are biased to apply a quadrupole electric field to the cylindrical gap;
• applying a magnetic field to the cylindrical gap that is coaxial with the cylindrical gap using at least one permanent magnet that is placed coaxially with the first set of electrodes and the second set of electrodes but outside of the cylindrical gap,
• wherein the effects of the magnetic field and the quadrupole electric field combine to trap charged particles in the cylindrical gap;
• and
• injecting charged particles into the cylindrical gap in a direction perpendicular to the magnetic field and parallel to a radial non-conducting path of the first set of electrodes and a corresponding radial non-conducting path of the second set of electrodes using a charged particle injection device,
• wherein in injection mode, segments of the concentric segmented ring electrodes of the first set of electrodes on opposite sides of the radial non-conducting path are oppositely biased and segments of the concentric segmented ring electrodes of the second set of electrodes on opposite sides of the corresponding radial non-conducting path are correspondingly oppositely biased, producing an electric field in the cylindrical gap between the radial non-conducting path and the corresponding radial non-conducting path that has a focusing region and a defocusing region and
• wherein in injection mode, the charged particle injection device injects charged particles into the cylindrical gap along an axis of injection that is shifted from the axis of the radial non-conducting path and the axis of the corresponding radial non-conducting path towards segments of the concentric segmented ring electrodes of the first set of electrodes and towards segments of the corresponding concentric segmented ring electrodes of the second set of electrodes that are biased with the same polarity as the polarity of the charged particles so that the charged particles are injected in the focusing region.

A side-on injection Penning trap that includes a charged particle injection device that is biased to compensate for a Lorentz force experienced by charged particles flowing through the charged particle injection device, comprising:

• a first printed circuit board (PCB) on which is printed a first set of two or more concentric circular or semi-circular electrodes;
• a second PCB on which is printed a second set of two or more concentric circular or semi-circular electrodes that correspond in shape and size to the first set of electrodes, wherein the second PCB is placed in parallel with the first PCB so that the second set of electrodes faces and is coaxial with the first set of electrodes, wherein the space between the first set of electrodes and the second set of electrodes is a cylindrical gap used to trap charged particles, and wherein the first set of electrodes and the second set of electrodes apply a quadrupole electric field to the cylindrical gap;
• at least one permanent magnet that is placed coaxially with the first set of electrodes and the second set of electrodes but outside of the cylindrical gap that applies a magnetic field to the cylindrical gap that is coaxial with the cylindrical gap, wherein the effects of the first magnetic field and the quadrupole electric field combine to trap charged particles in the cylindrical gap;
• and
• a charged particle injection device configured to inject charged particles into the cylindrical gap in a direction perpendicular to the magnetic field and biased to apply an electric field to the flow of charged particles in the charged particle injection device that compensates for a Lorentz force applied to the flow of charged particles in the charged particle injection device by the magnetic field outside of the cylindrical gap, wherein the charged particle injection device comprises a third set of trapezoidal electrodes printed outside of the first set of electrodes on the first PCB, and a fourth set of trapezoidal electrodes printed outside of the second set of electrodes on the second PCB, wherein the third set of trapezoidal electrodes and the fourth set of trapezoidal electrodes are tapered radio frequency (RF) quadrupole electrode pads for providing a dipolar electric field to compensate for the Lorentz force applied to the flow of charged particles in the charged particle injection device by the magnetic field outside of the cylindrical gap.