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US 8,013,296 B2Granted
Charged-particle condensing device
AssigneeShimadzu Corporation
InventorsHermann Wollnik, Yoshihiro Ueno
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AssigneeShimadzu Corporation
InventorsHermann Wollnik, Yoshihiro Ueno
Estimating the term…
Ions and charged droplets move from the nozzle (6) towards the orifice (22) of a charged-particle transport device or the desolvation pipe (7). This particle motion is governed by the distribution of the pseudo-potential along particle trajectories. There are RF-voltages applied to neighboring electrodes (241-246) of the electrode array (24) cause the charged particles to substantially hover above the electrode array (24). Right before the ions come to the electrode array (24) they thus experience a repelling force “F” perpendicular to the surface of the electrode array (24). This force “F” causes an effective barrier (B) right before the electrode array (24) and consequently a pseudo-potential well (A) where the charged particles stop their motion parallel to the plume axis (D). Thus they accumulate around the center line (C) of this well (A). Applying additionally to the RF-potentials also DC-potentials to neighboring electrodes within the electrode array (24) small DC-fields can be formed within the well area (23). These additional DC-fields drive the charged particles towards the axis of symmetry (C) and thus towards the orifice (22) of a charged-particle transport device or the desolvation pipe (7). Thus, many of the charged particles which would normally impinge on the wall (21) around the orifice (22) can now be analyzed.
A charged-particle condensing device that operates in a gas of approximately one atmosphere in which charged particles have been formed and are accelerated towards a surface that contains at least one orifice through which they can move to an evacuated mass spectrometer or a gas-filled mobility spectrometer characterized by the fact that the charged-particle condensing device comprises an array of many closely spaced electrodes or conductive surface strips placed on said surface or positioned a short distance above said surface such that an opening is left for the charged particles to move to said at least one orifice with RF-voltages being applied between neighboring said electrodes or conductive strips causing RF-fields that keep the charged particles hovering above said electrodes or conductive strips so that they can be pushed towards said orifice by fields caused by additional DC-potentials being applied to neighboring said electrodes or conductive strips.
Dependencies are inferred from the claim text.