JP4217122B2 - Charged particle mass sorter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for sorting charged particles such as ions and clusters based on mass.
[0002]
[Prior art]
In the case of growth of microcrystals that use specific particles as seeds, or material processing that reacts particles and reactive gases in a state of being isolated in space, particles with specific masses can be selectively captured or taken out. There is a request to use it. In particular, clusters formed by agglomeration of a plurality of atomic molecules exhibit unique physicochemical behavior, and their use in a wide range of fields is being studied.
[0003]
The gas cluster generator generates a cluster having an atomic mass of several thousand upon receiving a pressurized gas. In a cluster generated by a gas cluster generator, the number of gas molecules that aggregate is probabilistically distributed, so there is a wide range of mass. In order to use or study, it is necessary to sort based on, for example, the mass number or mass. There is.
It is convenient to ionize clusters to perform mass-based sorting.
Clusters emitted from the gas cluster generator are charged particles through an ionization electrode, and then used after being classified according to mass using an appropriate mass selection method.
[0004]
Commonly used mass sorting methods or mass spectrometry methods include magnetic field type, quadrupole electric field type, and time-of-flight type. After ionization, ion clusters accelerated by an acceleration electrode are introduced and sorted according to their speed. There are many things.
When the charged particles are accelerated by applying an electric field to the electric charge with the accelerating electrode, the acting force is determined by the electric charge.
[0005]
In the magnetic field type mass sorter, charged particles are passed through a magnetic field generated by a sector magnet, and a force acts in a direction perpendicular to the moving direction of the charged particles and the direction of the magnetic field, so that the trajectory of the charged particles is deflected. At this time, since heavy particles are difficult to bend and light particles are easily bent, charged particles having a desired mass can be obtained by adjusting the extraction position or the magnetic field strength.
[0006]
This device is easy to design and can take out charged particles of the same mass continuously, but the size and weight of the device is large, and the beam trajectory axis and extraction axis have an angle so that it can be used with other devices. Becomes complicated. Furthermore, since the ratio of the unit increase to the total mass decreases as the mass increases, there is also a problem that the resolution is inversely proportional to the mass.
[0007]
A quadrupole electric field type mass sorter is a device that operates using both an alternating current and a direct current electric field, and one example thereof is disclosed in Patent Document 1. As shown in FIG. 8, the device described in Patent Document 1 is composed of a central electrode composed of four or more columnar electrodes arranged symmetrically around a central axis and an external electrode surrounding them. An AC voltage having alternately inverted phases is applied, and a DC bias is applied between the center electrode and the external electrode to move charged particles toward the center electrode.
[0008]
The charged particles existing between the external electrode and the central electrode move in the direction of gathering at the central electrode. On the other hand, the AC electric field strength time-averaged by the alternating voltage applied to the central electrode decreases with increasing distance from the central electrode. Therefore, the charged particles receive a repulsive force in a direction away from the center electrode. The repulsive force due to the AC electric field is proportional to 1 / mf ² where the frequency of the AC is f and the mass of the particle is m. Therefore, the equilibrium position of the charged particle is closer to the center as the mass is larger.
[0009]
Therefore, by adjusting the voltage and frequency, charged particles having a mass greater than or equal to a predetermined value can be collected inside the center electrode and taken out.
A quadrupole electric field type mass sorter can be taken out continuously and is most commonly used in a low energy region, but the resolution decreases as the mass increases. Moreover, high manufacturing accuracy is required for the electrode cross-sectional shape.
[0010]
Further, the time-of-flight mass sorter utilizes the fact that the difference in mass appears as a difference in flight speed when the energy of charged particles moving is equal to the charge. An entrance electrode and an exit electrode are installed in the traveling direction of the charged particles, and a DC voltage is applied to each to block the charged particles. If the voltage at the entrance electrode is cut for a certain time at a certain moment, the charged particles go straight and reach the exit electrode. Therefore, if the exit electrode voltage is turned off in accordance with the time to fly between the two sets of electrodes, a predetermined value is obtained. Since only particles having a mass of 1 pass through the exit electrode, mass selection can be performed.
[0011]
The time-of-flight mass sorter can easily adjust the intensity and resolution by changing the pulse time width. In addition, particles having an arbitrary mass can be selected with a simple apparatus configuration. However, the sorting becomes intermittent, and the sorted particles cannot be continuously supplied.
[0012]
[Patent Document 1]
Japanese Patent Laid-Open No. 2869517
[Problems to be solved by the invention]
Therefore, the problem to be solved by the present invention is to provide a small and lightweight charged particle mass sorting apparatus that can perform continuous extraction without reducing the sorting force even if the mass is large.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, the charged particle mass sorting apparatus of the present invention includes an AC electric field forming unit provided with an AC electric field forming electrode and an exit slit, and the AC electric field forming electrode is charged to be subjected to mass selection. An alternating electric field having a frequency that is an integral multiple of the reciprocal of the time that particles pass is formed. The exit slit is arranged on the traveling axis of the charged particles, and the mass-selected charged particles are collected from the exit slit.
[0015]
The charged particle mass selection apparatus of the present invention performs mass selection based on the fact that the speed of charged particles accelerated by the acceleration electrode corresponds to the mass.
An AC electric field is formed in the AC electric field forming electrode in a direction perpendicular to the traveling axis of the charged particles. The charged particles are subjected to the action of the AC electric field while traveling through the AC electric field forming electrode and generate acceleration in the direction perpendicular to the traveling axis. It has a velocity component in the direction of.
However, when the charged particle crosses the AC electric field for an integer period while passing through the electrode part, the electric field component that acts is equal to the positive and negative phases, so the velocity component perpendicular to the traveling axis of the charged particle at the electrode exit is canceled out. It becomes zero and has only a velocity component parallel to the traveling axis.
[0016]
Therefore, the velocity of the charged particles having the mass to be selected is obtained, and the AC electric field frequency is adjusted so that when the velocity proceeds at this speed, an integer number of AC electric fields are experienced in the AC electric field forming electrode. Then, after passing through the AC electric field forming electrode, the target charged particles travel parallel to the traveling axis, and the non-target charged particles travel at an angle with respect to the traveling axis, so that distinction is possible. When charged particles for sorting enter the AC electric field forming electrode, if the phase of the AC electric field is not zero, the trajectory of the charged particles at the electrode exit is separated from the traveling axis, but only the velocity component parallel to the traveling axis is present. Not having it is the same.
Thus, by providing a slit on the traveling axis, only charged particles for sorting can be taken out.
[0017]
In addition, it is preferable that the frequency of the AC electric field is a value equal to the reciprocal of the time when the charged particles pass through the electrode, since the acting force of the AC electric field becomes the largest and selection becomes easy. In addition, if the frequency of the AC electric field is large and charged particles that are faster than the purpose of selection pass through the AC electric field period by an integer multiple, it becomes difficult to select the target charged particles. From this point of view, it is preferable to select a frequency at which the target charged particle passes exactly one AC electric field.
[0018]
By the way, although the charged particles to be sorted are taken out in parallel to the traveling axis, there are a large number of particles that are separated from the traveling axis, so that only a part of the charged particles to be sorted passes through the slit. Therefore, in the second charged particle mass sorting apparatus of the present invention, the second electrode having the same shape as the AC electric field forming electrode is installed on the downstream traveling axis. In the following description, the first AC electric field forming electrode may be referred to as a first AC electric field forming electrode.
[0019]
By adjusting the phase of the second AC electric field formed on the second AC electric field forming electrode, an electric field completely opposite to the electric field experienced by the charged particles to be selected is experienced at the first AC electric field forming electrode. Then, after passing through the first AC electric field forming electrode, the charged particles to be sorted travel in parallel with the traveling axis in a state where the distribution spreads around the traveling axis, and in the gap between the electrodes parallel to the traveling axis. And then enters the second AC electric field formed in the second AC electric field forming electrode in parallel with the traveling axis. The charged particles to be sorted converge again in the direction of the traveling axis due to the action of the second AC electric field, and are concentrated on the traveling axis after passing through the second AC electric field forming electrode, greatly increasing the recovery rate of the charged particles to be sorted. Can be improved.
[0020]
Depending on the conditions of the charged particle generator, for example, charged particles having a mass that is an integral square of the target particle, the flight speed is a fraction of an integer. In some cases, charged particles other than the charged particles to be sorted that have a velocity parallel to the traveling axis when exiting one AC electric field forming electrode may be included. Such charged particles have a speed parallel to the axis of travel even when they exit the second AC electric field forming electrode, and may be mixed with charged particles for sorting purposes and become noise.
Therefore, in the present invention, it is preferable that the gap between the first AC electric field forming electrode and the second AC electric field forming electrode can be adjusted.
[0021]
If the phase of the second AC electric field is delayed by the time during which the charged particles for sorting fly through the gap width, the second AC electric field when the charged particles arrive at the second AC electric field forming electrode forms the first AC electric field. The phase state is exactly the same as the phase of the first AC electric field when it leaves the electrode.
Accordingly, since the charged particles for sorting are subjected to the opposite action to that received by the first AC electric field forming electrode at the second AC electric field forming electrode, when the second AC electric field forming electrode exits, the charged particles return to just above the traveling axis. That is, all the charged particles for selection are collected on the traveling axis when leaving the second AC electric field forming electrode, regardless of the phase when entering the first AC electric field forming electrode.
[0022]
In addition, the charged particles that are not selected for the purpose have different flight times in the gap and the flight direction has an angle with respect to the traveling axis, so that when the second AC electric field forming electrode is reached, the phase of the second AC electric field is different. The electric field recorded in the second AC electric field forming electrode is shifted. For this reason, when charged particles other than the target exit the second AC electric field forming electrode, they do not travel on the traveling axis parallel to the axis.
Charged particles having a special flight speed travel parallel to the traveling axis after passing through the second AC electric field forming electrode, but the spread of the distribution from the traveling axis is the same as that of the first AC electric field forming electrode. It can be adjusted by adjusting the gap of the second AC electric field forming electrode.
[0023]
In other words, the charged particles other than the selection target charged particles do not match the phase of the first AC electric field when exiting the first AC electric field forming electrode and the phase of the second AC electric field when reaching the second AC electric field electrode. The velocity of the charged particles exiting the second AC electric field forming electrode has only a component parallel to the traveling axis, but is distributed in a direction perpendicular to the axis and does not collect on the traveling axis.
The distribution state perpendicular to the advancing axis is changed by adjusting the relationship between the gap between the electrodes and the phase of the two AC electric fields. Since the exit slit is provided on the traveling axis, only charged particles traveling along the traveling axis along the axis pass through the exit slit, and other charged particles cannot pass through the slit. Therefore, the amount of charged particles other than the selection target charged particles that pass through the exit slit can be reduced by adjusting the gap between the electrodes.
Even if the gap between the electrodes is changed, the recovery rate of the selection target charged particles does not change as long as the phase difference of the AC electric field is adjusted so that the selection target charged particles are always concentrated on the traveling axis.
[0024]
In this way, charged particles for sorting can be distinguished and extracted from other charged particles. For example, when a cluster generated by a gas cluster generator is ionized and accelerated by an accelerator, the speed of the cluster is inversely proportional to the mass. Therefore, the component having the velocity corresponding to the period of the AC electric field is discriminated from the other components. A component having the target mass can be selected and supplied.
As described above, according to the charged particle mass sorting apparatus of the present invention, charged particles having a uniform mass can be supplied almost continuously by sorting charged particles at a predetermined speed.
[0025]
A shield may be provided on the charged particle traveling axis in the gap between the first AC electric field forming electrode and the second AC electric field forming electrode.
Depending on the conditions of the cluster generation device, there may be a case where the exit speed of the charged particle mass sorter has the same deflection speed and deflection position as the target particle despite having a mass different from that of the target charged particle. For example, in a cluster that is heavier than the target cluster, the flight speed is slow, so that it may pass through the AC electric field for several cycles and eventually return to the original traveling axis and output from the sorting device may appear.
[0026]
In such heavy particles, the effect of the electric field of the AC electric field forming electrode on the acceleration in the direction perpendicular to the axis is small, so there are many cases in which the deviation from the traveling axis is not large, and the particles gather near the axis. . The target charged particles are in a zero acceleration state at the position where they exit the first AC electric field forming electrode, but are distributed in a direction perpendicular to the traveling axis according to the phase difference when entering the AC electric field forming electrode.
Therefore, if a shield of any shape such as a shield plate or a shield block is provided on the shaft to trap and remove impurities with a large mass, a part of the target charged particles will be trapped by the shield. Enters the subsequent AC electric field forming electrode, so that the purity of the selected particles can be improved.
[0027]
Further, the exit slit may be configured by arranging two or more slits on the traveling axis.
In the state where the target particles are free of deflection speed and deflection, that is, along the axis of travel, they fly along the axis, reach the exit slit, and are taken out to the outside. Separated from. However, some unintended particles with different velocities and waves of alternating electric fields may reach the exit slit with a complex trajectory. Non-target particles that enter the exit slit do not enter the traveling axis, and charged particles that have returned to the traveling axis always enter the slit obliquely.
Therefore, if two or more slits are arranged on the axis, the obliquely incident particles cannot pass through the rear slit, so that the last slit can only pass through the axis at a speed parallel to the axis. Only the particles will be separated.
[0028]
Furthermore, it is preferable to provide an acceleration / deceleration electrode for accelerating / decelerating charged particles on the traveling axis.
For the selection of charged particles, it is preferable that the speed of charged particles is not so high. On the other hand, the energy of the selected cluster is preferably high in order to cause some reaction in the cluster. Therefore, it is preferable to provide an acceleration / deceleration electrode for accelerating / decelerating the cluster at a position after selection. Needless to say, the acceleration / deceleration electrode may be installed before sorting or at an intermediate position in the sorting area when there is no problem in sorting the particles.
[0029]
If the first AC electric field forming electrode and the second AC electric field forming electrode are combined, and a plurality of sets are arranged along the traveling axis, there is an effect that the purity of the selection is improved by repeating the mass selection.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
The charged particle mass sorting apparatus of the present invention will be described in detail with reference to the drawings based on the embodiments.
FIG. 1 is a block diagram showing an apparatus in which a charged particle mass sorting apparatus according to one embodiment of the present invention is combined with a gas cluster apparatus to process cluster ions and act on a target. FIG. 3 is a block diagram showing the configuration of the particle mass sorting apparatus, FIG. 3 is a diagram for explaining the operation of the charged particle mass sorting apparatus, and FIG. 4 depicts a locus calculated for charged particles flying at the same speed as the traveling wave phase velocity. Drawing, FIG. 5 is a locus diagram of charged particles having different flight speeds, FIG. 6 is a diagram showing a case where a shield is placed between the traveling wave forming electrode on the entrance side and the traveling wave forming electrode on the exit side, and FIG. It is drawing explaining the effect of a thing.
[0031]
When the charged particle mass sorting apparatus of the present invention is used in combination with a gas cluster generator, the utility of the gas cluster apparatus is enhanced and the application field of the gas cluster apparatus is further expanded.
In the gas cluster generator, a cluster generation unit 1, an ionization acceleration unit 2, a mass selection unit 3, and a process unit 4 are arranged in series. The cluster generation unit 1 includes a main body 11, a nozzle 12 provided at the main body outlet, and a skimmer 13 provided at the outlet of the cluster generation unit 1 as main components. When a pressurized gas of about 2.5 to 4 atm is introduced into the main body 11, a glass nozzle in which gas molecules are pseudo-collected to form a cluster, and the diameter of the tube is gradually expanded after a pore of about 0.1 mm. 11 is ejected, and a cluster in which a large number of molecules are gathered is selected by the skimmer 12 and ejected. For example, when argon gas is clustered, abundant clusters aggregated to an atomic weight of about 500 to 10,000 can be generated.
[0032]
The ionization acceleration unit 2 is provided with an ionization electrode 21 and an acceleration electrode 22. The mass selection unit 3 is ionized by a cluster included in the cluster beam supplied from the cluster generation unit 1 and accelerated by the electric field of the acceleration electrode 22. To supply. Since the cluster usually has a monovalent cation and is accelerated by a direct current electric field, the cluster flows into the mass selector 3 at a speed inversely proportional to the mass.
The mass sorting unit 3 is provided with a charged particle mass sorting device 31 according to the present invention, where cluster ions having a target mass are sorted and supplied to the process unit 4. In the process unit 4, a desired process is performed on the selected cluster and, for example, it is deposited on the target 41.
[0033]
As shown in FIG. 2, the charged particle mass sorting device 31 includes a first AC electric field forming electrode 32, a first AC power source 33, a second AC electric field forming electrode 34, a second AC power source 35, and an outlet slit 36. The first alternating current power supply 33 has a sinusoidal wave Asin (ωt) such that the time for the target charged particles to pass through the first alternating current electric field forming electrode 32 is an integral multiple of the period of the alternating electric field, preferably one. An alternating electric field is formed.
FIG. 3 is a diagram for explaining the relationship of the alternating electric field. The upper graph shows the electric field waveform at the first AC electric field forming electrode 32 with the horizontal axis taking time. The lower graph shows the electric field waveform at the second AC electric field forming electrode 34.
[0034]
If the velocity of the target charged particle is Vt and the length of the first AC electric field forming electrode (EL1) 32 is Le,
1 / f = Le / Vt
To be. Here, f is a wave number, and ω = 2πf.
Then, the charged particles pass through the electrode through the first AC electric field for one period. Therefore, the charged particles that have reached the electrode when the first AC electric field is zero receive the force perpendicular to the traveling axis due to the electric field in the positive and negative directions and reach the outlet of the electrode, so that the charged particles at the outlet are on the traveling axis. And fly along the axis of travel.
[0035]
The frequency may be such that charged particles pass through the electrode through an integer multiple of the period of the alternating electric field. However, as the number of cycles through which the charged particles pass increases, the acting force of the AC electric field that moves in the direction perpendicular to the axis of the charged particles decreases.
In addition, if the velocity is the same when entering with a phase difference from the first AC electric field, the force in the direction perpendicular to the traveling axis due to the electric field cancels out and reaches the electrode outlet. The charged particles fly in parallel with the traveling axis even if they are separated from the traveling axis. Needless to say, even if the charged particles pass through the integer period of the AC electric field, they also fly along the traveling axis at the exit.
[0036]
The second AC electric field formed in the second AC electric field forming electrode has a phase difference opposite to that of the first AC electric field, and has a phase difference corresponding to the time when the target charged particles fly through the gap. If the gap width is Dl and the phase difference is φ,
φ = ωD1 / Vt = 2πD1 / Le
The second exchange is
-Asin (ωt-φ)
It is represented by
[0037]
The phase position of the first AC electric field when the target charged particle exits the first AC electric field forming electrode is the same as the phase position of the second AC electric field when the target charged particle reaches the second AC electric field forming electrode. When exiting the two AC electric field forming electrodes, the action received by the first AC electric field forming electrode is just offset by the second AC electric field having the opposite phase, and the velocity component perpendicular to the return axis is also zero on the traveling axis. .
[0038]
FIG. 4 is a drawing depicting the locus in the alternating electric field forming unit calculated for charged particles flying at the speed of the selection target. Charged particles that have entered the first AC electric field forming electrode at various phases are distributed in a direction perpendicular to the axis when exiting the electrode based on the difference in action received in the electrode, but the velocity has only a component parallel to the axis. Absent.
When each charged particle flies through the gap and reaches the second AC electric field forming electrode, the second phase having the opposite phase to the first AC electric field is in the same phase as the first AC electric field when exiting the first AC electric field forming electrode. Enter the AC electric field. Therefore, the action received by the first AC electric field forming electrode during traveling inside the second AC electric field forming electrode is just canceled, and when leaving the electrode, the charged particles return to the position of the traveling axis, and the slit moves along the axis. Proceed toward.
On the other hand, FIG. 5 shows trajectories of charged particles having different flight speeds. Neither diverges and returns to the original axis.
[0039]
FIG. 6 is a view showing a case where a shielding object 37 is placed in a gap provided between the first AC field forming electrode 32 on the entrance side and the second AC field forming electrode 34 on the exit side.
When the AC forming unit 31 of the present embodiment is used, particularly in a large cluster, the acceleration formed by the first AC electric field forming electrode 32 is small, and the vehicle may travel around the traveling axis without being sufficiently separated from the traveling axis. The shielding object 37 shields particles flying in a position close to such a traveling axis. Most of the particles having the target mass enter the second AC electric field forming electrode 34 while avoiding the shield 37, and gather on the traveling axis again by the action of the electric field, and are output through the exit slit 36.
[0040]
FIG. 7 is a diagram for explaining the effect of the shielding object. FIG. 7 (a) shows the mass distribution of the sorted particles when there is no shielding object, and FIG. 7 (b) shows the sorting result when the shielding block is placed on the shaft. When there is no shielding block, a larger amount of particles having a larger amount of impurities than the target cluster having an atomic weight of 5000 are contained as impurities, whereas when there is a shielding block, the clusters having a large atomic weight are significantly reduced.
The shield may be plate-shaped or massive. Further, a spindle type along the ion flow path can also be used.
[0041]
As can be seen from FIG. 5, particles with an unintended mass may enter and pass through the exit slit 36 depending on conditions.
Therefore, as shown by the dotted line in FIG. 6, by arranging the same slits 38 so as to be coaxial with the slits 36, it is possible to output only the particles traveling straight.
[0042]
Even if particles other than the charged particles to be sorted are on the traveling axis at the position of the exit slit 36, the charged particles have a velocity component perpendicular to the axis, so that the slit 38 located at a position away from the traveling axis. Cannot pass through.
Therefore, by providing the slits side by side on the traveling axis, particles having an unintended mass can be eliminated and the selectivity can be improved. Needless to say, the number of slits is not limited to two but may be three or more.
[0043]
Moreover, the traveling wave formation part of a present Example may provide the acceleration / deceleration electrode 39 on a traveling axis, as represented by the dotted line in FIG.
In the selection of particles using an alternating electric field in this embodiment, the particles are selected by the action of the electric field in the electrode, so it is preferable that the speed of the charged particles is not so high. On the other hand, it is preferable that the energy of the cluster is high in order to cause some kind of reaction in the selected cluster. Therefore, an acceleration / deceleration electrode 39 for accelerating / decelerating the ion cluster is provided behind the second AC electric field forming electrode 34 so that the cluster after selection can be accelerated / decelerated and supplied to the subsequent process.
The acceleration / deceleration electrode 39 may be installed before the first AC electric field forming electrode 32 or between the first AC electric field forming electrode 32 and the second AC electric field forming electrode 36 if there is no problem in particle selection. Good.
[0044]
【The invention's effect】
As described above, the charged particle mass sorter of the present invention can select a cluster of the target mass and separate it with high purity. In a wide range of fields, such as formation of crystals and materials, clusters of any mass can be easily supplied and used in large quantities.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an apparatus in which a charged particle mass sorting apparatus according to one embodiment of the present invention is combined with a gas cluster apparatus.
FIG. 2 is a block diagram showing a configuration of a charged particle mass sorting apparatus according to the present embodiment.
FIG. 3 is a diagram illustrating the operation of the charged particle mass sorting apparatus in the present embodiment.
FIG. 4 is a trajectory diagram calculated for charged particles having a target mass in this example.
FIG. 5 is a trajectory diagram calculated for a non-target charged particle in this example.
FIG. 6 is a view showing a case where a shielding object is placed between a traveling wave forming electrode on the entrance side and a traveling wave forming electrode on the exit side in the present embodiment.
FIG. 7 is a drawing for explaining the effect of a shielding object in the present embodiment.
FIG. 8 is a conceptual diagram showing an example of a conventional charged particle mass sorting apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cluster production | generation part 2 Ionization acceleration part 3 Mass selection part 4 Process part 11 Cluster production | generation body main body 12 Nozzle 13 Skimmer 21 Ionization electrode 22 Acceleration electrode 31 Charged particle mass selection apparatus 32 1st alternating current electric field formation electrode 33 1st alternating current power supply 34 1st 2 AC electric field forming electrode 35 2nd AC power source 36 Exit slit 37 Shielding object 38 Slit 39 Acceleration / deceleration electrode

Claims (7)

A charged particle mass sorting apparatus including an AC electric field forming unit that introduces charged particles accelerated by an accelerating electrode and sorts based on mass, the AC electric field forming unit sharing an advancing axis and an AC electric field forming electrode An AC power source having an exit slit and an electrode power source adjuster that adjusts an AC power source applied to the AC electric field forming electrode, and the AC electric field forming electrode has a deflection electric field perpendicular to a traveling axis of charged particles An electric field is formed, and the exit slit is disposed on the traveling axis of the charged particles, and the frequency of the AC electric field is adjusted to an integral multiple of the reciprocal of the time required for the charged particles to pass through the AC electric field forming electrode. The charged particle mass sorting apparatus, wherein the charged particles are sorted and collected from the exit slit.   A second AC electric field forming electrode of the same shape sharing the traveling axis with the AC electric field forming electrode, further comprising an electrode gap between the AC electric field forming electrode and the second AC electric field forming electrode, and adjusting the electrode power supply A first electrode is formed on the AC electric field forming electrode, a second AC electric field is formed on the second AC electric field forming electrode, and a phase difference between the first AC electric field and the second AC electric field is adjusted. The charged particles for the purpose of selection receive an action that is completely opposite to the electric field that is applied while passing through the first AC electric field forming electrode while passing through the second AC electric field forming electrode. The charged particle mass sorting apparatus according to claim 1.   The charged particle mass sorting apparatus according to claim 2, wherein a width of the electrode gap is adjustable.   The charged particle mass sorting apparatus according to claim 2, wherein a shielding object is disposed on the traveling axis of the electrode gap.   5. The charged particle mass sorting apparatus according to claim 2, wherein two or more sets of the AC electric field forming electrode and the second AC electric field forming electrode are arranged in series. Sorting device.   The charged particle mass sorting apparatus according to any one of claims 1 to 5, wherein the exit slit is configured by arranging two or more slits on the traveling axis.   The charged particle mass sorting apparatus according to any one of claims 1 to 6, wherein an acceleration / deceleration electrode for accelerating and decelerating the charged particles in the traveling direction is provided on the charged particle traveling axis.

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