Transverse time-of-flight cluster mass selector and method of using the same

Abstract

The present invention discloses a transverse time-of-flight cluster mass selector and a method for using the same. A pair of parallel plate electrodes is used to replace the complex structure of three groups of electrodes, namely, a cluster ion forward deflection zone, a free flight zone, and a reverse deflection zone, in the currently common cluster time-of-flight mass selector, thereby greatly simplifying the selector structure. There is a simple linear relationship between the cluster mass selected by the selector and the amplitude of the acceleration and deceleration pulse voltage applied to the parallel plate electrodes. Therefore, the cluster mass can be selected simply by adjusting the pulse voltage amplitude, making the debugging and operation of the selector intuitive and simple, with constant mass resolution and rapid calibration. By reasonably setting the time logic of the voltage pulse, the cluster mass selection can achieve a high pass rate of 50%. In addition, its electric field distribution structure constrains ions to converge toward the axis, which is more conducive to improving the beam quality compared with the electric field distribution configuration of the currently common cluster time-of-flight mass selector that causes ion divergence.

Description

Technical Field

[0001] The invention belongs to the field of atomic and molecular physics and nanoscience technology, and relates to a device widely used in cluster physics, chemical property research and cluster beam controllable deposition, specifically a lateral flight time cluster mass selector and a method for using the same. Background Art

[0002] The selection of cluster beam size and the real-time measurement of cluster size distribution are critical in basic cluster research and in the process of cluster beam deposition to prepare cluster-assembled nanostructured materials and devices, and are an indispensable component of various cluster beam systems.

[0003] The size selection of cluster beams can be divided into two categories: neutral clusters and ionized clusters. The size selection of neutral clusters mainly uses gas dynamic lenses, rotary wheel dividers, etc., while the devices used for the size selection of ionized clusters mainly include quadrupole mass filters, time-of-flight mass selectors and differential mobility analyzers. The mass selection range of quadrupole mass filters is limited, and generally can only achieve the size selection of small clusters with a mass less than several thousand atoms. Differential mobility analyzers cannot achieve atomic precision cluster size selection resolution and are generally used for the size selection of large clusters (nanoparticles) with a diameter of more than 1 nanometer. Time-of-flight mass selectors can achieve atomic precision size selection from single atoms to large clusters with an atomic mass number of more than 100,000. They have both a large size selection range and high size selection accuracy, and are widely used in cluster research and cluster deposition applications.

[0004] Time-of-flight mass spectrometry (TOF-MS) and mass selection are key components in cluster size and size distribution measurement, physical and chemical property research, and single-size cluster beam acquisition and deposition devices. They are widely used in basic research in atomic and molecular physics and nanoscience and nanoparticle lattice vapor deposition. TOF-MS consists of three parts: ion source, field-free drift tube, and detection area. Ions are generated in the ionization region, and after being accelerated, they leave the source region and enter the field-free drift tube. The speed of ions in the field-free drift space is a function of the charge-to-mass ratio Q / M. Therefore, when they pass through the drift tube and reach the detection region, they are separated in time according to Q / M. Assuming that the generated ions are all single-charged, the mass spectrum can be obtained based on the ion flight spectrum. The initial position of ions in the ionization region and the distribution of initial kinetic energy are the main factors affecting the resolution of mass spectrometry measurement. In 1955, Wiley and McLaren used a dual-field ion source [Wiley, WC, McLaren, IH, Time-of-Flight Mass Spectrometer with Improved Resolution, Rev. Sci. Instrum, 1955, 26: 1150-1157.] to compensate for the discreteness of ion flight time caused by the initial ionization position distribution through spatial focusing, thereby improving the resolution of time-of-flight measurement and making time-of-flight mass spectrometry practical.

[0005] The principle of time-of-flight mass spectrometry is also used for the size selection of cluster ions. In 1999, von Issendorff and Palmer of the University of Birmingham, UK [B.von Issendorff,REPalmer,A new high transmission infinite range mass selector for cluster and nanoparticle beams,Rev.Sci.Instrum,1999,70:4497-4501] proposed a design of a transverse time-of-flight mass selector, which consists of three parts: a cluster ion forward deflection zone, a free flight zone, and a reverse deflection zone. The selection is made according to the principle of matching the transverse flight time of the cluster with the pulse period. By introducing a pair of accelerating and decelerating pulse electric fields perpendicular to the flight direction of the cluster beam, the cluster is caused to fly transversely perpendicular to the original beam direction. After accelerating in the acceleration zone, the cluster enters the field-free flight zone, and after flying at a uniform speed, it enters the deceleration zone to decelerate. By controlling the time logic between the acceleration pulse and the deceleration pulse, only clusters that meet the mass selection conditions can resume flight parallel to the original beam flight direction in the deceleration zone, and thus be selected. This mass selector can maintain an ion pass rate of about 50% while maintaining a high mass selection resolution. This transverse time-of-flight mass selector is widely used in current cluster research, especially in controllable size cluster beam deposition. However, the electrode structure of this mass selector is relatively complex, and the requirements for cluster beam quality are high, and the construction cost is high; the functional relationship between cluster mass and acceleration and deceleration electric field pulse period is complex, and there are many influencing factors, making it difficult to adjust and calibrate, and inconvenient to use. Moreover, its electric field distribution structure causes cluster ions to tend to diverge off-axis in the flight path, resulting in a decrease in cluster beam quality after selection. Summary of the invention

[0006] Technical problem to be solved: Cluster (nanoparticle) beams are widely used in basic research in nanoscience and preparation of nanostructured materials. In the above research and application, the control of the size and size distribution of clusters is a basic requirement. The clusters generated by the existing cluster beam source have a wide size distribution, and in many cases, a mass (size) selector is required to obtain clusters of a single size. Therefore, cluster mass selectors are widely needed in the precise measurement of cluster properties and the controllable deposition of cluster beams. The present invention provides a novel transverse flight time cluster mass selector composed of a pair of parallel plate electrodes and a method for using the same, which is used to replace the currently common cluster flight time mass selector composed of three groups of electrodes, namely, a cluster ion forward deflection zone, a free flight zone, and a reverse deflection zone, so that the mass selector structure is greatly simplified, and there is a simple linear relationship between the selected cluster mass and the acceleration and deceleration pulse voltage amplitude applied to the parallel plate electrodes, so that the mass selector is easy to debug and operate, the mass resolution is constant, the calibration is rapid, and the ion pass rate is high. Moreover, its electric field distribution structure constrains the ions to converge toward the axis, which is conducive to improving the beam quality.

[0007] Technical solution: A transverse time-of-flight cluster mass selector, the selector comprising a parallel plate electrode 1 and a parallel plate electrode 2 which are parallel to each other, an entrance slit plate and an exit slit plate which are arranged in parallel, the parallel plate electrode being perpendicular to and fitting with the slit plate; wherein the parallel plate electrode 1 and the parallel plate electrode 2 are respectively connected to an external high-voltage pulse power supply, the entrance slit plate is provided with an entrance slit at one end close to the parallel plate electrode 1, and the exit slit plate is provided with an exit slit at one end close to the parallel plate electrode 2; the high-voltage pulses V1 and V2 outputted to the two electrodes by the high-voltage pulse power supply are both square waves with the same period, and one period contains three synchronized potential states of t0-t1, t1-t2, and t2-t3, wherein: in the time period t0-t1, the potentials of V1 and V2 are both kept at zero; in the time period t1-t2, V1 is the amplitude potential, and V2 is the zero potential; in the time period t2-t3, V1 is the zero potential, and V2 is the amplitude potential; the selector is placed in a vacuum chamber.

[0008] Preferably, the parallel plate electrodes and the slit plates are made of stainless steel or aluminum, and are electrically insulated from each other.

[0009] Preferably, the parallel plate electrodes are rectangular flat plates with a length of 100 mm to 1000 mm, a width of 50 mm to 200 mm, a thickness of 2 mm to 10 mm, and a spacing between the inner surfaces of the two parallel plate electrodes of 50 mm to 500 mm.

[0010] Preferably, the width of the two slit plates is consistent with the width of the parallel plate electrodes, the length is consistent with the distance between the outer surfaces of the two parallel plate electrodes, and the thickness is 0.5 mm-3 mm.

[0011] Preferably, the inlet slit and the outlet slit are strips of the same size and are parallel to the parallel plate electrodes. The slit length is 10 mm-50 mm and the width is 2 mm-10 mm.

[0012] Preferably, the distance between the center line of the inlet slit and the parallel plate electrode 1 and the distance between the center line of the outlet slit and the parallel plate electrode 2 are equal.

[0013] Preferably, the distance between the center line of the inlet slit and the center line of the outlet slit is 45 mm-495 mm, and the spacing between the center line of the slit and the corresponding parallel plate electrode is not less than 1 / 2 of the slit width and not more than 40 mm.

[0014] Preferably, the periods of the high voltage pulses V1 and V2 are both 3 μs-1000 μs, wherein the time period t0-t1 accounts for 30%-50%, and the time period t1-t2 is equal to the time period t2-t3.

[0015] Preferably, the voltage pulse amplitudes of the high voltage pulses V1 and V2 are equal, and the amplitude is 100V-5000V.

[0016] A method for using any of the above transverse time-of-flight cluster mass selectors, the method comprising the following steps:

[0017] S1. Place the transverse time-of-flight cluster mass selector in a vacuum chamber and connect it to an external cluster source. Pump down the above device to a vacuum of 1×10 -4 -1×10 -5 Vacuum degree Pa;

[0018] S2, operating the cluster source to generate a cluster beam, and the cluster beam enters the cluster mass selector through the entrance slit;

[0019] S3, start the high-voltage pulse power supply, select the pulse period and the percentage of the time period t0-t1, output synchronized high-voltage square wave pulses V1 and V2 to the parallel plate electrode 1 and the parallel plate electrode 2, and the cluster flies along the lateral flight path;

[0020] S4. According to the mass of the cluster to be selected, the pulse voltage amplitude is adjusted to obtain the selected cluster of predetermined mass from the exit slit. There is the following linear relationship between the mass of the selected cluster and the pulse voltage amplitude:

[0021] M=eV / (2dH)Δt 2, where M is the mass of the cluster, e is the electron charge, V is the pulse voltage amplitude, d is the distance between the inner surfaces of the two parallel plate electrodes, H is the distance between the center lines of the entrance slit and the exit slit, and Δt is the length of the time period t1-t2. According to the selected high-voltage pulse period and the length of the t0-t1 time period, Δt is determined. Therefore, the corresponding relationship table or curve between the mass of the selected cluster and the pulse voltage amplitude can be calculated according to the above formula, which is used to select clusters by adjusting the voltage amplitude. Since there is a linear relationship between the mass of the cluster and the pulse voltage amplitude, in actual operation, as long as the voltage corresponding to a specific mass is remembered, the voltage corresponding to other masses can be simply estimated.

[0022] The working principle of the transverse flight time cluster mass selector described in the present invention is that under a constant electric field, charged particles of all masses follow the same flight path between parallel electrodes, so the mass separation of charged particles cannot be achieved by a constant transverse electric field. However, the time required for charged particles of different masses to fly through a certain path is related to their mass. This means that under a pulsed electric field with a certain pulse width, the actual flight path of the charged particles between the parallel plate electrodes is related to their mass. Figure 1As shown, a pulse voltage V1 is applied to the parallel plate electrode 1, and a pulse voltage V2 is applied to the parallel plate electrode 2. In the time period t0-t1, the potential difference between the two plates is zero. After the cluster ions enter the parallel plate electrode area from the entrance slit, they fly parallel to the electrode plane. In the time period t1-t2, V1 is higher than V2, and the positively charged clusters will undergo a lateral acceleration flight perpendicular to the electrode plane. In the time period t2-t3, V1 is lower than V2, and the positively charged clusters will undergo a lateral deceleration flight perpendicular to the electrode plane, and their lateral flight speed will be reduced to zero at the end of the pulse cycle t3, and then they will maintain flight parallel to the electrode plane at the beginning of the next pulse cycle, and finally they will either pass through the exit slit or be deposited on the surface of the exit slit plate or electrode 2. Since clusters of different masses have different lateral flight accelerations, their lateral flight distances are different in the same flight time, which results in the flight paths of clusters of different masses no longer coinciding after the moment t2. The lateral flight distance of the charged clusters in the time period t1-t3 is proportional to the ratio of the pulse voltage amplitude to its mass V / m. Among them, the clusters with larger mass fly along path 2, the clusters with smaller mass fly along path 3, and only the clusters with moderate mass can fly along path 1. During the time period t1-t3, their lateral flight distance is exactly equal to the lateral distance between the entrance slit and the exit slit, so that they can be selected through the exit slit. Since clusters with the same V / m ratio have the same lateral flight distance within the given lateral flight time t1-t3, under the fixed pulse time logic, the linear selection of cluster mass can be achieved simply by changing the pulse voltage amplitude. Clusters that meet the selection conditions (mass) and enter the entrance slit during the time period t0-t1 can be selected through the exit slit. Among them, as Figure 2As shown, the cluster entering the entrance slit at time t0 has a lateral velocity of zero during the time period t0-t1 because there is no electric field between electrode 1 and electrode 2, and the original flight direction remains unchanged. From time t1, it is laterally accelerated and deflected toward electrode 2 by the electric field generated by voltage V1 applied to electrode 1. From time t2, it is decelerated by the electric field generated by voltage V2 applied to electrode 2. At time t3, the lateral velocity is restored to zero, so that it flies along path 1 and passes through the exit slit; the cluster entering the entrance slit at time t1 is laterally accelerated and deflected toward electrode 2 by the electric field generated by voltage V1 applied to electrode 1 as soon as it enters the slit. From time t2, it is decelerated by the electric field generated by voltage V2 applied to electrode 2. At time t3, the lateral velocity is restored to zero, and it continues to fly along the center line of the exit slit at the beginning of the next pulse cycle, and finally flies out through the exit slit, forming a flight path 2. The clusters that enter the entrance slit after time t1 are only partially accelerated by the V1 pulse voltage, but fully decelerated by the V2 pulse voltage, causing the lateral velocity to become negative near time t3, so that they fly along path 3 and cannot pass through the exit slit. The ratio of the t0-t1 time period to the pulse period determines the percentage of clusters with a given mass that can be selected in the total number of clusters of this mass generated by the cluster source, that is, the pass rate of mass selection. The pass rate can be calculated by the following formula: T = Δt 0-1 / Δt 0-3 , where T is the passing rate, Δt 0-1 is the length of the time period t0-t1, Δt 0-3 It is the length of time period t0-t3.

[0023] Beneficial effects: The present invention provides a transverse time-of-flight cluster mass selector, which uses a pair of parallel plate electrodes to replace the complex structure of the current common cluster time-of-flight mass selector composed of three groups of electrodes, namely, the cluster ion forward deflection zone, the free flight zone, and the reverse deflection zone, thereby greatly simplifying the mass selector structure. There is a simple linear relationship between the cluster mass selected by the mass selector and the amplitude of the acceleration and deceleration pulse voltage applied to the parallel plate electrodes. Therefore, the cluster mass can be selected simply by adjusting the pulse voltage amplitude, making the debugging and operation of the mass selector intuitive and simple, with constant mass resolution and rapid calibration. By reasonably setting the time logic of the voltage pulse, the cluster mass selection can achieve a high pass rate of 50%. In addition, its electric field distribution structure constrains the ions to converge toward the axis, which is more conducive to improving the beam quality compared with the electric field distribution configuration of the current common cluster time-of-flight mass selector that causes ion divergence. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1It is a schematic diagram of the structure, principle and use method of the transverse time-of-flight cluster mass selector of the present invention;

[0025] Figure 2 is a schematic diagram of the flight path of a cluster having a mass equal to a preset selection value when the lateral time-of-flight cluster mass selector of the present invention is used;

[0026] Figure 3 is a structural diagram of the transverse time-of-flight cluster mass selector used in Example 1 of the present invention;

[0027] Among them, 1 is parallel plate electrode 1, 2 is parallel plate electrode 2, 3 is entrance slit plate, 4 is exit slit plate, 5 is entrance slit, 6 is exit slit, 7 is high voltage pulse V1 applied to parallel plate electrode 1, 8 is high voltage pulse V2 applied to parallel plate electrode 2, 9 is flight path 1 of clusters with mass equal to preset selection value, 10 is flight path 3 of clusters with mass less than preset selection value, 11 is flight path 2 of clusters with mass greater than preset selection value, 12 is time period t0-t1, 13 is t1 -t2 time period, 14 is t2-t3 time period, 15 is flight path 1 of the cluster whose mass entering the entrance slit at time t0 is equal to the preset selection value, 16 is flight path 2 of the cluster whose mass entering the entrance slit at time t1 is equal to the preset selection value, 17 is flight path 3 of the cluster whose mass entering the entrance slit after time t1 is equal to the preset selection value, 18 is the lateral flight time cluster mass selector, 19 is the vacuum chamber, 20 is the vacuum pump, A is the center line of the outlet slit, and B is the center line of the entrance slit. DETAILED DESCRIPTION

[0028] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and essence of the present invention, modifications and substitutions made to the method, steps or conditions of the present invention all belong to the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0029] Example 1

[0030] like Figure 1 and 3As shown, a transverse time-of-flight cluster mass selector comprises a parallel plate electrode 1 and a parallel plate electrode 2 which are parallel to each other, an entrance slit plate 3 and an exit slit plate 4 which are arranged in parallel, the parallel plate electrode is perpendicular to and fits the slit plates, and the mass selector is installed in a vacuum chamber 19. The parallel plate electrode, the entrance slit plate 3 and the exit slit plate 4 are all made of aluminum; the parallel plate electrode is a rectangular plate with a length of 740 mm, a width of 100 mm and a thickness of 3 mm; the two parallel plate electrodes are placed in parallel, the spacing between the inner surfaces of the plates is 150 mm, and the plates are electrically insulated; the entrance slit plate 3 and the exit slit plate 4 are placed at both ends of the long sides of the parallel plates, perpendicular to the plane of the parallel plate electrodes, and the width of the two slit plates is 100 mm, the length is 156 mm and the thickness is 3 mm. The entrance slit plate 3 and the exit slit plate 4 are electrically insulated from the two parallel plate electrodes; an entrance slit 5 and an exit slit 6 are respectively provided on the entrance slit plate and the exit slit plate, and the slit lengths are both 30 mm and the widths are both 8 mm; the distance between the center line of the entrance slit 5 and the inner surface of the parallel plate electrode 1 is 12 mm, the distance between the center line of the exit slit 6 and the inner surface of the parallel plate electrode 2 is 12 mm, and the distance between the center lines of the entrance slit 5 and the exit slit 6 is 128 mm; the parallel plate electrode 1 is connected to the high voltage pulse power supply 1 through a vacuum lead flange, and the parallel plate electrode Pole 2 is connected to the high-voltage pulse power supply 2 through a vacuum lead flange; the high-voltage pulse power supplies 1 and 2 apply synchronized high-voltage pulses V1 and V2 with a period of 10μs to the electrode plates 1 and 2 respectively. One cycle of the high-voltage pulse consists of three time periods. The length of the first time period is 43.4μs, and the potentials of V1 and V2 are both zero; the length of the second time period is 21.8μs, V1 is a square wave pulse with an amplitude potential, and V2 is zero potential; the length of the third time period is 21.8μs, V1 is zero potential, and V2 is a square wave pulse with an amplitude potential.

[0031] The method for using the transverse time-of-flight cluster mass selector comprises the following steps:

[0032] Step 1: evacuate the vacuum chamber 19 in which the transverse time-of-flight cluster mass selector 18 is installed and the magnetron plasma gas cluster source connected thereto to a vacuum of 1×10 -4 Vacuum degree Pa;

[0033] Step 2: operate the cluster source to generate a Ag cluster beam, and the cluster beam enters the cluster mass selector through the entrance slit 5;

[0034] Step 3: Start the high-voltage pulse power supply and output synchronized high-voltage square wave pulses V1 and V2 to the parallel plate electrode 1 and the parallel plate electrode 2 according to the aforementioned parameters, and the cluster flies along the lateral flight path;

[0035] Step 4: Adjust the pulse voltage amplitude to 1800 V, and obtain the selected single-size Ag cluster with a mass of 20 silver atoms from the exit slit 6, and the pass rate of mass selection is 50%.

[0036] Example 2

[0037] like Figure 1 and 3 As shown, a transverse time-of-flight cluster mass selector comprises a parallel plate electrode 1 and a parallel plate electrode 2 which are parallel to each other, an inlet slit plate 3 and an outlet slit plate 4 which are arranged in parallel, the parallel plate electrode is perpendicular to and fits the slit plate, and the mass selector is installed in a vacuum chamber. The parallel plate electrode, the inlet slit plate 3 and the outlet slit plate 4 are all made of stainless steel; the parallel plate electrode is a rectangular plate with a length of 600 mm, a width of 120 mm and a thickness of 2 mm; the two parallel plate electrodes are placed in parallel, the spacing between the inner surfaces of the plates is 200 mm, and the plates are electrically insulated; the inlet slit plate 3 and the outlet slit plate 4 are placed at both ends of the long sides of the parallel plates, perpendicular to the plane of the parallel plate electrodes, and the width of the two slit plates is 120 mm, the length is 204 mm and the thickness is 1 mm. The entrance slit plate 3 and the exit slit plate 4 are electrically insulated from the two parallel plate electrodes; an entrance slit 5 and an exit slit 6 are respectively provided on the entrance slit plate 3 and the exit slit plate 4, and the slit lengths are both 25 mm and the widths are both 5 mm; the distance between the center line of the entrance slit 5 and the inner surface of the parallel plate electrode 1 is 12 mm, the distance between the center line of the exit slit 6 and the inner surface of the parallel plate electrode 2 is 12 mm, and the distance between the center lines of the entrance slit 5 and the exit slit 6 is 170 mm; the parallel plate electrode 1 is connected to the high voltage pulse power supply 1 through a vacuum lead flange, and the parallel The plate electrode 2 is connected to the high-voltage pulse power supply 2 through a vacuum lead flange; the high-voltage pulse power supplies 1 and 2 respectively apply synchronous high-voltage pulses V1 and V2 with a period of 100μs to the electrode plates 1 and 2. One cycle of the high-voltage pulse consists of three time periods. The length of the first time period is 200μs, and the potentials of V1 and V2 are both zero; the length of the second time period is 155μs, V1 is a square wave pulse with an amplitude potential, and V2 is zero potential; the length of the third time period is 155μs, V1 is zero potential, and V2 is a square wave pulse with an amplitude potential.

[0038] The method for using the transverse time-of-flight cluster mass selector comprises the following steps:

[0039] Step 1: evacuate the vacuum chamber 19 in which the transverse time-of-flight cluster mass selector 18 is installed and the magnetron plasma gas cluster source connected thereto to a vacuum of 5×10 -5 Vacuum degree Pa;

[0040] Step 2: operate the cluster source to generate a Pd cluster beam, and the cluster beam enters the cluster mass selector through the entrance slit 5;

[0041] Step 3: Start the high-voltage pulse power supply and output synchronized high-voltage square wave pulses V1 and V2 to the parallel plate electrode 1 and the parallel plate electrode 2 according to the aforementioned parameters, and the cluster flies along the lateral flight path;

[0042] Step 4: Adjust the pulse voltage amplitude to 2500 V, and obtain the selected single-size Pd cluster with a mass of 1600 Pd atoms from the exit slit 6, and the pass rate of mass selection is 39%.

[0043] Example 3

[0044] like Figure 1 and 3 As shown, a transverse time-of-flight cluster mass selector comprises a parallel plate electrode 1 and a parallel plate electrode 2 which are parallel to each other, an entrance slit plate 3 and an exit slit plate 4 which are arranged in parallel, the parallel plate electrode is perpendicular to and fits the slit plate, and the mass selector is installed in a vacuum chamber 19. The parallel plate electrode, the entrance slit plate 3 and the exit slit plate 4 are all made of aluminum; the parallel plate electrode is a rectangular plate with a length of 250 mm, a width of 40 mm and a thickness of 2 mm; the two parallel plate electrodes are placed in parallel, the spacing between the inner surfaces of the plates is 50 mm, and the plates are electrically insulated; the entrance slit plate 3 and the exit slit plate 4 are placed at both ends of the long sides of the parallel plates, perpendicular to the plane of the parallel plate electrodes, and the width of the two slit plates is 40 mm, the length is 54 mm and the thickness is 2 mm. The entrance slit plate 3 and the exit slit plate 4 are electrically insulated from the two parallel plate electrodes; an entrance slit 5 and an exit slit 6 are respectively provided on the entrance slit plate and the exit slit plate, and the slit lengths are both 20 mm and the widths are both 2 mm; the distance between the center line of the entrance slit 5 and the inner surface of the parallel plate electrode 1 is 10 mm, the distance between the center line of the exit slit 6 and the inner surface of the parallel plate electrode 2 is 10 mm, and the distance between the center lines of the entrance slit 5 and the exit slit 6 is 30 mm; the parallel plate electrode 1 is connected to the high voltage pulse power supply 1 through a vacuum lead flange, and the parallel plate electrode Pole 2 is connected to the high-voltage pulse power supply 2 through a vacuum lead flange; the high-voltage pulse power supplies 1 and 2 apply synchronized high-voltage pulses V1 and V2 with a period of 3μs to the electrode plates 1 and 2 respectively. One cycle of the high-voltage pulse consists of three time periods. The length of the first time period is 1.2μs, and the potentials of V1 and V2 are both zero; the length of the second time period is 0.90μs, V1 is a square wave pulse with an amplitude potential, and V2 is zero potential; the length of the third time period is 0.90μs, V1 is zero potential, and V2 is a square wave pulse with an amplitude potential.

[0045] The method for using the transverse time-of-flight cluster mass selector comprises the following steps:

[0046] Step 1: evacuate the vacuum chamber 19 in which the transverse time-of-flight cluster mass selector 18 is installed and the magnetron plasma gas cluster source connected thereto to a vacuum of 1×10 -4 Vacuum degree Pa;

[0047] Step 2: operate the cluster source to generate a Pd cluster beam, and the cluster beam enters the cluster mass selector through the entrance slit 5;

[0048] Step 3: Start the high-voltage pulse power supply and output synchronized high-voltage square wave pulses V1 and V2 to the parallel plate electrode 1 and the parallel plate electrode 2 according to the aforementioned parameters, and the cluster flies along the lateral flight path;

[0049] Step 4: The pulse voltage amplitude is adjusted to 3940 V, and a cluster with a mass of 2 palladium atoms is selected from the outlet slit 6, and the pass rate of mass selection is 40%.

[0050] Example 4

[0051] like Figure 1 and 3As shown, a transverse time-of-flight cluster mass selector comprises a parallel plate electrode 1 and a parallel plate electrode 2 which are parallel to each other, an entrance slit plate 3 and an exit slit plate 4 which are arranged in parallel, the parallel plate electrode is perpendicular to and fits the slit plates, and the mass selector is installed in a vacuum chamber 19. The parallel plate electrode, the entrance slit plate 3 and the exit slit plate 4 are all made of aluminum; the parallel plate electrode is a rectangular plate with a length of 1000 mm, a width of 150 mm and a thickness of 3 mm; the two parallel plate electrodes are placed in parallel, the spacing between the inner surfaces of the plates is 400 mm, and the plates are electrically insulated; the entrance slit plate 3 and the exit slit plate 4 are placed at both ends of the long sides of the parallel plates, perpendicular to the plane of the parallel plate electrodes, and the width of the two slit plates is 150 mm, the length is 406 mm and the thickness is 2 mm. The entrance slit plate 3 and the exit slit plate 4 are electrically insulated from the two parallel plate electrodes; an entrance slit 5 and an exit slit 6 are respectively provided on the entrance slit plate and the exit slit plate, and the slit lengths are both 50 mm and the widths are both 10 mm; the distance between the center line of the entrance slit 5 and the inner surface of the parallel plate electrode 1 is 15 mm, the distance between the center line of the exit slit 6 and the inner surface of the parallel plate electrode 2 is 15 mm, and the distance between the center lines of the entrance slit 5 and the exit slit 6 is 370 mm; the parallel plate electrode 1 is connected to the high voltage pulse power supply 1 through a vacuum lead flange, and the parallel plate The electrode 2 is connected to the high-voltage pulse power supply 2 through a vacuum lead flange; the high-voltage pulse power supplies 1 and 2 apply synchronized high-voltage pulses V1 and V2 with a period of 1000μs to the electrode plates 1 and 2 respectively. One cycle of the high-voltage pulse consists of three time periods. The length of the first time period is 500μs, and the potentials of V1 and V2 are both zero; the length of the second time period is 250μs, V1 is a square wave pulse with an amplitude potential, and V2 is zero potential; the length of the third time period is 250μs, V1 is zero potential, and V2 is a square wave pulse with an amplitude potential.

[0052] The method for using the transverse time-of-flight cluster mass selector comprises the following steps:

[0053] Step 1: evacuate the vacuum chamber 19 in which the transverse time-of-flight cluster mass selector 18 is installed and the magnetron plasma gas cluster source connected thereto to a vacuum of 1×10 -5 Vacuum degree Pa;

[0054] Step 2: operate the cluster source to generate a Ag cluster beam, and the cluster beam enters the cluster mass selector through the entrance slit 5;

[0055] Step 3: Start the high-voltage pulse power supply and output synchronized high-voltage square wave pulses V1 and V2 to the parallel plate electrode 1 and the parallel plate electrode 2 according to the aforementioned parameters, and the cluster flies along the lateral flight path;

[0056] Step 4: The pulse voltage amplitude is adjusted to 130 V, and a cluster with a mass of 50 silver atoms is selected from the outlet slit 6, and the pass rate of mass selection is 50%.

Claims

1. A transverse time-of-flight cluster mass selector, characterized in that: The selector comprises a parallel plate electrode 1 (1) and a parallel plate electrode 2 (2) which are parallel to each other, an entrance slit plate (3) and an exit slit plate (4) which are arranged in parallel, and the parallel plate electrode is perpendicular to and fits with the slit plate; wherein the parallel plate electrode 1 (1) and the parallel plate electrode 2 (2) are respectively connected to an external high-voltage pulse power supply, the entrance slit plate (3) is provided with an entrance slit (5) at one end close to the parallel plate electrode 1 (1), and the exit slit plate (4) is provided with an exit slit (6) at one end close to the parallel plate electrode 2 (2). 6); the high-voltage pulses V1 and V2 outputted by the high-voltage pulse power supply to the two electrodes are both square waves with the same period, and one period includes three synchronous potential states of t0-t1, t1-t2, and t2-t3, wherein: in the t0-t1 time period, the potentials of V1 and V2 are both kept at zero; in the t1-t2 time period, V1 is the amplitude potential and V2 is the zero potential; in the t2-t3 time period, V1 is the zero potential and V2 is the amplitude potential; the selector is placed in the vacuum chamber (19); The method for using the transverse time-of-flight cluster mass selector comprises the following steps: S1. Place the transverse time-of-flight cluster mass selector (18) in a vacuum chamber (19), connect an external cluster source, and evacuate the vacuum chamber to a vacuum of 1×10 -4 -1×10 -5 Vacuum degree Pa; S2, operating the cluster source to generate a cluster beam, and the cluster beam enters the cluster mass selector through an entrance slit (5); S3, start the high-voltage pulse power supply, select the pulse period and the percentage of the time period t0-t1, output synchronized high-voltage square wave pulses V1 and V2 to the parallel plate electrode 1 (1) and the parallel plate electrode 2 (2), and the cluster flies along the lateral flight path; S4. According to the mass of the cluster to be selected, the pulse voltage amplitude is adjusted to obtain the selected cluster of predetermined mass from the exit slit (6); there is the following linear relationship between the mass of the selected cluster and the pulse voltage amplitude: M = eV / (2dH)Δt 2 , where M is the mass of the cluster, e is the electron charge, V is the pulse voltage amplitude, d is the distance between the inner surfaces of the two parallel plate electrodes, H is the distance between the center lines of the entrance slit and the exit slit, and Δt is the length of the time period t1-t2.

2. The lateral time-of-flight cluster mass selector according to claim 1, characterized in that: The parallel plate electrodes and the slit plate are made of stainless steel or aluminum and are electrically insulated from each other.

3. The lateral time-of-flight cluster mass selector according to claim 1, characterized in that: The parallel plate electrode is a rectangular flat plate with a length of 100mm-1000mm, a width of 50mm-200mm, a thickness of 2mm-10mm, and a spacing between the inner surfaces of the two parallel plate electrodes of 50mm-500mm.

4. The lateral time-of-flight cluster mass selector according to claim 1, characterized in that: The width of the two slit plates is consistent with the width of the parallel plate electrodes, the length is consistent with the distance between the outer surfaces of the two parallel plate electrodes, and the thickness is 0.5mm-3mm.

5. The transverse time-of-flight cluster mass selector according to claim 1, characterized in that: The inlet slit (5) and the outlet slit (6) are strips of the same size and are parallel to the parallel plate electrodes. The slit length is 10 mm to 50 mm and the width is 2 mm to 10 mm.

6. The transverse time-of-flight cluster mass selector according to claim 1, characterized in that: The distance between the center line of the inlet slit (5) and the parallel plate electrode 1 (1), and the distance between the center line of the outlet slit (6) and the parallel plate electrode 2 (2) are equal.

7. The transverse time-of-flight cluster mass selector according to claim 1, characterized in that: The distance between the center line of the inlet slit (5) and the center line of the outlet slit (6) is 45 mm-495 mm, and the spacing between the center line of the slit and the corresponding parallel plate electrode is not less than 1 / 2 of the slit width and not more than 40 mm.

8. The transverse time-of-flight cluster mass selector according to claim 1, characterized in that: The periods of the high voltage pulses V1 and V2 are both 3 μs-1000 μs, wherein the time period t0-t1 accounts for 30%-50%, and the time period t1-t2 is equal to the time period t2-t3.

9. The transverse time-of-flight cluster mass selector according to claim 1, characterized in that: The voltage pulse amplitudes of the high voltage pulses V1 and V2 are equal, and the amplitude ranges from 100V to 5000V.

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