A micro ion pump based on pyroelectric principle

Abstract

The present application relates to a kind of micro ion pump based on pyroelectric principle, belong to ion pump technical field.The micro ion pump includes vacuum chamber, one side of the vacuum chamber is equipped with radio frequency ion trap module and the other side is equipped with pyroelectric electron source;The pyroelectric electron source includes the first pyroelectric crystal of being arranged in the bottom of vacuum chamber and the temperature control module for adjusting the temperature of first pyroelectric crystal;The radio frequency ion trap module includes the electric feedthrough of being fixed in the top of vacuum chamber in a sealed manner and the first polar plate and the second polar plate of being oppositely arranged in the inside of vacuum chamber.The first polar plate and the second polar plate of the present application form ion trap, first pyroelectric crystal is discharged while temperature changes, and the ion generated by ionization is absorbed by polar plate, ion pump structure is simple, small and exquisite, can be applied in small atomic system, can remove gas in vacuum chamber and does not need external high-voltage power supply.

Description

Technical Field

[0001] This invention belongs to the field of ion pump technology, specifically relating to a micro ion pump based on the principle of pyroelectricity. Background Technology

[0002] Ion pumps are commonly used in ultra-high vacuum systems, typically utilizing the structure of a Penning source to trap electrons. A Penning source, also known as a Penning ion source, generally consists of two cathodes, an anode cylinder, and a magnet. The cathodes of the ion pump are symmetrically distributed at both ends of the anode cylinder, with the magnet encasing the cathodes. By generating a high electric field between the cathode and the anode cylinder, the ion pump emits free electrons from the cathode towards the anode cylinder. Under the combined influence of the electric and magnetic fields, the electrons are trapped within the anode cylinder and undergo a long-trajectory helical motion. Due to the influence of the electric field, the electrons accumulate kinetic energy during this motion, until their energy is sufficient to ionize air molecules through collision. The ionized gas ions move towards the cathode, colliding and sputtering to produce new titanium atoms. Reactive gas molecules such as oxygen and hydrogen are absorbed by the cathode through the adsorption of titanium, while inert gas atoms such as helium and argon are ionized and injected into the cathode.

[0003] Existing ion pumps with Penning source structures still contain magnets even after miniaturization, making them relatively large compared to small atomic systems, thus limiting their application in such systems. Furthermore, existing micro-ion pumps typically use electron guns or field emission electron sources. Electron guns are too large to be integrated into a vacuum chamber, while field emission electron sources have low discharge currents and require a large voltage to discharge. Summary of the Invention

[0004] The purpose of this invention is to provide a simple and rationally designed micro ion pump based on the pyroelectric principle in order to solve the above problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] A micro ion pump based on the pyroelectric principle includes a vacuum chamber. A radio frequency (RF) ion trap module is located on one side of the vacuum chamber, and a pyroelectric electron source is located on the other side. The pyroelectric electron source emits high-energy electrons required for ionization, and the RF ion trap module adsorbs ions formed by ionized gas. The pyroelectric electron source includes a first pyroelectric crystal located at the bottom of the vacuum chamber and a temperature control module for adjusting the temperature of the first pyroelectric crystal. The first pyroelectric crystal releases electrons as its temperature changes. The RF ion trap module includes an electrical feedthrough sealed and fixed to the top of the vacuum chamber, and a first electrode plate and a second electrode plate opposite to each other inside the vacuum chamber. An ion trap is formed between the first and second electrode plates. The ion trap traps electrons released by the first pyroelectric crystal, which collide with air molecules inside the vacuum chamber, causing ionization.

[0007] As a further optimization of the present invention, the temperature control module of the pyroelectric electronic source includes a heat dissipation component fixed to the bottom end of the first pyroelectric crystal and a first thermocouple for detecting the temperature of the first pyroelectric crystal.

[0008] As a further optimization of the present invention, the radio frequency ion trap module also includes a radio frequency power supply that is electrically connected to the power supply.

[0009] As a further optimization of the present invention, the radio frequency ion trap module further includes an adsorption layer fixed on the top of the first electrode plate, the first electrode plate and the second electrode plate are vertically disposed inside the vacuum chamber, and the second electrode plate is located directly below the first electrode plate.

[0010] As a further optimization of the present invention, the radio frequency ion trap module further includes a mounting plate disposed above the adsorption layer and a fixing member uniformly distributed along the upper circumferential side of the mounting plate. The fixing member is fixedly installed on the top of the vacuum chamber and fixed together with the mounting plate, the adsorption layer, the first electrode plate and the second electrode plate, so that the distance between the first pyroelectric crystal and the adsorption layer, the first electrode plate and the second electrode plate is fixed.

[0011] As a further optimization of the present invention, both the first electrode plate and the second electrode plate are provided with uniformly distributed through holes.

[0012] As a further optimization of the present invention, the temperature control module of the pyroelectric electronic source also includes a pulsed laser located directly below the first pyroelectric crystal.

[0013] As a further optimization of the present invention, the temperature control module of the pyroelectric electronic source further includes an insulating pad fixed between the heat dissipation component and the bottom wall of the vacuum chamber, and the first pyroelectric crystal is directly attached to the second electrode plate.

[0014] As a further optimization of the present invention, both the first electrode plate and the second electrode plate are made of titanium, and the adsorption layer is made of tantalum.

[0015] As a further optimization of the present invention, the first electrode plate and the second electrode plate are horizontally disposed inside the vacuum chamber. The radio frequency ion trap module also includes a DC power supply. The temperature control module of the pyroelectric electron source also includes two mutually symmetrical Pole elements fixed on the inner side wall of the vacuum chamber and a second pyroelectric crystal fixed at one end opposite to the two Pole elements. The first electrode plate and the second electrode plate are respectively fixed to the two second pyroelectric crystals.

[0016] The beneficial effects of this invention are as follows:

[0017] 1) In this invention, when the electrode plates are vertically arranged, an ion trap is formed between the cathode and anode through micro-perforations. A temperature control module regulates the temperature of the first pyroelectric crystal within the vacuum chamber, allowing the crystal to provide a large discharge current to the ion trap while its temperature changes, ionizing the gas between the cathode and anode. The pyroelectric crystal accumulates charge on its surface and conducts it to the anode, giving the anode a high voltage. Ions are formed in the ion trap, and these air ions are adsorbed through the cathode and adsorption layer. The ion pump has a simple structure, is compact, and can be applied to small atomic systems, effectively removing gas from a vacuum chamber without requiring an external high-voltage power supply.

[0018] 2) When the electrode plates are set horizontally, the present invention forms a transverse ion trap in the vacuum chamber. Electrons are emitted to the center of the ion trap by the first pyroelectric crystal. A second pyroelectric crystal and a Pole element are set on the side of the first and second electrode plates that are far apart from each other. The pyroelectric crystal is divided into a +Z surface and a -Z surface according to its charge. The +Z surface of one second pyroelectric crystal and the -Z surface of another second pyroelectric crystal are respectively attached to the two electrode plates, so that the two electrode plates can carry high voltages with different charges, thereby improving the ionization efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the internal structure of the first embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the overall structure of the radio frequency ion trap module according to the first embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the split structure of the pyroelectric electron source according to the first embodiment of the present invention;

[0022] Figure 4 This is a cross-sectional structural diagram of the first embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the internal structure of the second embodiment of the present invention;

[0024] Figure 6This is a cross-sectional structural diagram of the second embodiment of the present invention.

[0025] In the diagram: 1. Vacuum chamber; 2. Radio frequency ion trap module; 3. Pyroelectric electron source; 21. Electrical feedthrough; 22. First electrode plate; 23. Second electrode plate; 24. Radio frequency power supply; 25. Adsorption layer; 26. Mounting plate; 27. Fixing component; 28. DC power supply; 31. First pyroelectric crystal; 32. Heat dissipation component; 33. First thermocouple; 34. Pulsed laser; 35. Insulating pad; 36. Pole element; 37. Second pyroelectric crystal; 38. Second thermocouple. Detailed Implementation

[0026] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0027] First Embodiment

[0028] like Figure 1-3 As shown, a micro ion pump based on the pyroelectric principle includes a vacuum chamber 1. A radio frequency ion trap module 2 is located on one side of the vacuum chamber 1, and a pyroelectric electron source 3 is located on the other side. The pyroelectric electron source 3 is used to ionize the gas inside the vacuum chamber 1, and the radio frequency ion trap module 2 is used to adsorb the ions formed by the ionized gas. The pyroelectric electron source 3 includes a first pyroelectric crystal 31 located at the bottom of the vacuum chamber 1 and a temperature control module for adjusting the temperature of the first pyroelectric crystal 31. The first pyroelectric crystal 31 releases electrons as its temperature changes. The temperature control module regulates the temperature of the first pyroelectric crystal 31 inside the vacuum chamber 1, allowing the first pyroelectric crystal 31 to release electrons to the radio frequency ion trap module 2 as its temperature changes. The radio frequency ion trap module 2 includes an electrical feed 21 that is sealed and fixed to the top of the vacuum chamber 1, and a first electrode 22 and a second electrode 23 that are disposed opposite to each other inside the vacuum chamber 1. A vertical ion trap is formed between the first electrode 22 and the second electrode 23. The ion trap is used to capture electrons released by the first pyroelectric crystal 31 and ionize them by collision with air molecules in the vacuum chamber 1. The first pyroelectric crystal 31 provides a large discharge current to the ion trap to ionize the air in the ion trap. The ion trap is used to capture electrons released by the first pyroelectric crystal 31 and adsorb and bury the air ions generated after the electrons collide with and are ionized by air molecules. The adsorption layer 25 is used to adsorb the air ions in the ion trap. The ion pump in this embodiment is small in size and simple in structure, can be applied to small atomic systems and can successfully remove gas in the vacuum chamber 1 without the need for an external high-voltage power supply.

[0029] like Figure 3 and Figure 4As shown, the temperature control module of the pyroelectric electronic source 3 includes a heat dissipation component 32 fixed to the bottom of the first pyroelectric crystal 31 and a first thermocouple 33 for detecting the temperature of the first pyroelectric crystal 31. The heat dissipation component 32 is preferably a heat sink with high thermal conductivity. The heat sink is fixed together with the first pyroelectric crystal 31. The first thermocouple 33 is an armored thermocouple used to detect the temperature change of the first pyroelectric crystal 31. The first thermocouple 33 is fixed to the vacuum chamber 1 through a vacuum flange. The detection end of the first thermocouple 33 passes through the vacuum flange. The detection end of the first thermocouple 33 is bent and fixed to the side of the first pyroelectric crystal 31 with conductive adhesive.

[0030] like Figure 2 and Figure 4 As shown, the radio frequency ion trap module 2 also includes a radio frequency power supply 24 electrically connected to the power supply 21. The radio frequency ion trap module 2 also includes an adsorption layer 25 fixed on the top of the first electrode plate 22. The first electrode plate 22 and the second electrode plate 23 are vertically disposed inside the vacuum chamber 1. The second electrode plate 23 is located directly below the first electrode plate 22. The first electrode plate 22 is the cathode and the second electrode plate 23 is the anode. The power supply 21 is electrically connected to the cathode through the adsorption layer 25.

[0031] like Figure 3 and Figure 4 As shown, the temperature control module of the pyroelectric electronic source 3 includes a pulsed laser 34 located directly below the first pyroelectric crystal 31, which assists the heat dissipation component 32 in providing periodic heating to the first pyroelectric crystal 31.

[0032] Furthermore, the temperature control module of the pyroelectric electronic source 3 also includes a heat sink fixed to the bottom of the first pyroelectric crystal 31 and an insulating pad 35 fixed between the heat sink and the bottom wall of the vacuum chamber 1. The bottom wall of the vacuum chamber 1 is provided with an optical window corresponding to the pulsed laser 34, and the heat sink is provided with through holes corresponding to the optical path channel. The pulsed laser 34 provides periodic heating to the first pyroelectric crystal 31, and the heat sink makes the first pyroelectric crystal 31 cool down faster during heat dissipation, providing a larger discharge current. The first thermocouple 33 monitors the temperature of the first pyroelectric crystal 31 to achieve the optimal temperature change range. The first pyroelectric crystal 31 is directly attached to the second electrode plate 23, which maximizes the discharge current of the first pyroelectric crystal 31 and can provide a high voltage to the first electrode plate 22.

[0033] It should be noted that a vertical ion trap is formed between the first electrode plate 22 and the second electrode plate 23. The temperature control module regulates the temperature of the first pyroelectric crystal 31 in the vacuum chamber 1, so that the first pyroelectric crystal 31 discharges into the ion trap while the temperature changes, so as to provide the electrons required for ionizing the gas. The electrons entering the ion trap ionize the gas, causing air molecules to be collided and ionized into air ions, which are then neutralized and adsorbed by the first electrode plate 22.

[0034] During temperature regulation, the pulsed laser 34 provides periodic heating to the first pyroelectric crystal 31, causing it to discharge into the ion trap. The heat sink allows the first pyroelectric crystal 31 to cool down faster during heat dissipation, providing a larger discharge current. The first thermocouple 33 monitors the temperature of the first pyroelectric crystal 31 to achieve the optimal temperature variation range.

[0035] During the ionization of the gas, the radio frequency power supply 24 provides voltage to the first electrode 22 through the electric feed 21 and the adsorption layer 25, forming a radio frequency electric field in the ion trap, causing electrons to oscillate between the first electrode 22 and the second electrode 23, extending the electron movement trajectory and increasing the electron density.

[0036] During the neutralization and adsorption of ions, the radio frequency power supply 24 is turned off, and the pulsed laser 34 is turned on to heat the first pyroelectric crystal 31, thereby providing a high voltage to the second electrode 23. This causes the ions in the ion trap to accelerate and drift towards the first electrode 22 and the adsorption layer 25. Some ions are sputtered onto the surface of the first electrode 22, while others can also be sputtered onto the adsorption layer 25 through the micro-holes on the first electrode 22. The ions gain electrons and become neutral molecules the instant they collide with the first electrode 22 and the adsorption layer 25, and are then buried on the surface of the first electrode 22 and the adsorption layer 25.

[0037] Furthermore, such as Figure 2 As shown, the radio frequency ion trap module 2 also includes a mounting plate 26 disposed above the adsorption layer 25 and fasteners 27 uniformly distributed circumferentially along the upper side of the mounting plate 26. The fasteners 27 are fixedly installed on the top of the vacuum chamber 1 and are fixed together with the mounting plate 26, the adsorption layer 25, the first electrode plate 22 and the second electrode plate 23, so that the distance between the first pyroelectric crystal 31 and the adsorption layer 25, the first electrode plate 22 and the second electrode plate 23 is fixed. The electric feedthrough 21 is fixed to the top wall of the vacuum chamber 1 by bolts. The top of the fastener 27 is fixed to the bottom of the bolt that passes through the electric feedthrough 21, so that the fastener 27 and the vacuum chamber 1 are fixed to each other. The fastener 27 is fixed to the mounting plate 26, the adsorption layer 25, the first electrode plate 22 and the second electrode plate 23 by bolts and nuts. The pins of the electric feedthrough 21 pass through the fasteners 27 and the mounting plate 26, and the pins of the electric feedthrough 21 are reinforced by the fasteners 27 and the mounting plate 26.

[0038] Both the first electrode plate 22 and the second electrode plate 23 have uniformly distributed micro-through holes. Electrons generated by the first pyroelectric crystal 31 are emitted into the ion trap through the second electrode plate 23. By opening micro-through holes in the second electrode plate 23, the discharge effect of the second electrode plate 23 is improved. Ions generated after ionization in the ion trap can be sputtered onto the surface of the first electrode plate 22, and some ions can also be sputtered onto the adsorption layer 25 through the first electrode plate 22.

[0039] Specifically, the first electrode 22 and the second electrode 23 are both made of titanium, and the adsorption layer 25 is made of tantalum. Tantalum has a relatively high atomic mass, which can increase the adsorption and burial of inert gas ions.

[0040] Second Embodiment

[0041] like Figure 5 and Figure 6 As shown, the difference between this embodiment and the first embodiment is that the first electrode plate 22 and the second electrode plate 23 are horizontally arranged inside the vacuum chamber 1, forming a horizontally arranged ion trap inside the vacuum chamber 1. The radio frequency ion trap module 2 also includes a DC power supply 28 for energizing the heat dissipation component 32. During the neutralization and adsorption of ions, the DC power supply 28 provides voltage and current to the heat dissipation component 32 and the Pole element 36, causing the first pyroelectric crystal 31 to discharge into the ion trap while its temperature changes, so as to provide the electrons required for ionizing the gas, and causing the second pyroelectric crystal 37 to generate a temperature change, storing charge on the crystal surface to provide a high voltage for the first electrode plate 22 and the second electrode plate 23, so that the ions in the ion trap move towards the first electrode plate 22. The temperature control module of the pyroelectric electron source 3 also includes two symmetrical Pellets 36 fixed on the inner wall of the vacuum chamber 1 and a second pyroelectric crystal 37 fixed at one end of the two Pellets 36. The Pellets 36 are composed of Pellets and heat sinks. The Pellets and the second pyroelectric crystal 37 are fixed together. The Pellets are electrically connected to the power supply 21. The structure of the heat dissipation component 32 in this embodiment is the same as that of the Pellets 36, also composed of Pellets and heat sinks. By continuously changing the direction of the current in the Pellets, the heat dissipation component 32 and the Pellets 36 alternately heat and cool the first pyroelectric crystal 31 and the second pyroelectric crystal 37, respectively, to achieve the heating and cooling of the first pyroelectric crystal 31 and the second pyroelectric crystal 37. The periodic heating of the pyroelectric crystal 31 and the second pyroelectric crystal 37 is achieved by fixing the Peltier of the heat dissipation component 32 between the first pyroelectric crystal 31 and the heat sink. The heat sink of the heat dissipation component 32 is fixed on the bottom wall of the vacuum chamber 1. The Peltier element 36 and the Peltier of the heat dissipation component 32 are electrically connected to the electrical feed 21. The heat sink of the Peltier element 36 is fixed on the inner side wall of the vacuum chamber 1. The first electrode plate 22 and the second electrode plate 23 are respectively fixed to the two second pyroelectric crystals 37. A second thermocouple 38 is also installed through the vacuum chamber 1. The detection end of the second thermocouple 38 is fixed to the surface of the second pyroelectric crystal 37 and is used to detect the temperature change of the second pyroelectric crystal 37.

[0042] Electrons are emitted into the center of the ion trap by the first pyroelectric crystal 31. A second pyroelectric crystal 37 and a Pole element 36 are provided on the side of the first electrode 22 and the second electrode 23 that are far apart from each other. The pyroelectric crystal 37 is divided into a +Z surface and a -Z surface according to its electrical properties. The +Z surface of one second pyroelectric crystal 37 and the -Z surface of another second pyroelectric crystal 37 are respectively attached to the first electrode 22 and the second electrode 23, so that the two electrodes 22 and 23 can carry high voltages with different electrical properties, thereby improving the ionization efficiency.

[0043] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A micro ion pump based on the pyroelectric principle, comprising a vacuum chamber (1), characterized in that: The vacuum chamber (1) is provided with a radio frequency ion trap module (2) on one side and a pyroelectric electron source (3) on the other side. The pyroelectric electron source (3) is used to ionize the gas in the vacuum chamber (1), and the radio frequency ion trap module (2) is used to adsorb the ions formed by the ionized gas. The pyroelectric electron source (3) includes a first pyroelectric crystal (31) located at the bottom of the vacuum chamber (1) and a temperature control module for adjusting the temperature of the first pyroelectric crystal (31). The first pyroelectric crystal (31) can release electrons to the outside as the temperature changes. The radio frequency ion trap module (2) includes an electrical feed (21) that is sealed and fixed at the top of the vacuum chamber (1) and a first electrode plate (22) and a second electrode plate (23) that are disposed opposite to each other inside the vacuum chamber (1). An ion trap is formed between the first electrode plate (22) and the second electrode plate (23). The ion trap is used to capture electrons released by the first pyroelectric crystal (31) and ionize them by collision with air molecules inside the vacuum chamber (1). The temperature control module of the pyroelectric electron source (3) includes a heat dissipation component (32) fixed at the bottom of the first pyroelectric crystal (31) and a first thermocouple (33) for detecting the temperature of the first pyroelectric crystal (31). The radio frequency ion trap module (2) also includes a radio frequency power supply (24) electrically connected to the power supply (21) and an adsorption layer (25) fixed at the top of the first electrode plate (22). The temperature control module also includes a pulsed laser (34) located directly below the first pyroelectric crystal (31). During the temperature regulation process, the first pyroelectric crystal (31) is periodically heated by the pulsed laser (34) so ​​that the first pyroelectric crystal (31) discharges to the ion trap. The heat sink makes the first pyroelectric crystal (31) cool down faster during the heat dissipation period. The first thermocouple (33) monitors the temperature of the first pyroelectric crystal (31) to achieve the optimal temperature change range. During the ionization of the gas, the radio frequency power supply (24) provides voltage to the first electrode (22) through the electric feed (21) and the adsorption layer (25), forming a radio frequency electric field in the ion trap, causing electrons to oscillate between the first electrode (22) and the second electrode (23), extending the electron movement trajectory and increasing the electron density; During the neutralization and adsorption of ions, the radio frequency power supply (24) is turned off and the pulsed laser (34) is turned on to heat the first pyroelectric crystal (31), thereby providing a high voltage to the second electrode plate (23) through the first pyroelectric crystal (31), causing the ions in the ion trap to accelerate towards the first electrode plate (22) and the adsorption layer (25). Some ions are sputtered onto the surface of the first electrode plate (22), and other ions can also be sputtered onto the adsorption layer (25) through the micro-holes on the first electrode plate (22). The ions gain electrons and become neutral molecules the instant they collide with the first electrode plate (22) and the adsorption layer (25), and are buried on the surface of the first electrode plate (22) and the adsorption layer (25).

2. The micro ion pump according to claim 1, characterized in that: The first electrode plate (22) and the second electrode plate (23) are vertically disposed inside the vacuum chamber (1). The second electrode plate (23) is located directly below the first electrode plate (22). The first electrode plate (22) is the cathode and the second electrode plate (23) is the anode.

3. The micro ion pump according to claim 2, characterized in that: The radio frequency ion trap module (2) also includes a mounting plate (26) disposed above the adsorption layer (25) and a fixing member (27) evenly distributed along the upper circumference of the mounting plate (26). The fixing member (27) is fixedly installed on the top of the vacuum chamber (1) and fixed together with the mounting plate (26), the adsorption layer (25), the first electrode plate (22) and the second electrode plate (23).

4. The micro ion pump according to claim 3, characterized in that: Both the first electrode plate (22) and the second electrode plate (23) have uniformly distributed through holes.

5. The micro ion pump according to claim 3, characterized in that: The temperature control module of the pyroelectric electronic source (3) also includes an insulating pad (35) fixed between the heat dissipation component (32) and the bottom wall of the vacuum chamber (1), and the first pyroelectric crystal (31) is attached to the second electrode plate (23).

6. The micro ion pump according to claim 3, characterized in that: The first electrode plate (22) and the second electrode plate (23) are both made of titanium, and the adsorption layer (25) is made of tantalum.

7. The micro ion pump according to claim 1, characterized in that: The first electrode plate (22) and the second electrode plate (23) are horizontally disposed inside the vacuum chamber (1). The radio frequency ion trap module (2) also includes a DC power supply (28). The temperature control module of the pyroelectric electron source (3) also includes two mutually symmetrical Pell elements (36) fixed on the inner side wall of the vacuum chamber (1) and a second pyroelectric crystal (37) fixed at one end opposite to the two Pell elements (36). The first electrode plate (22) and the second electrode plate (23) are respectively fixed to the two second pyroelectric crystals (37).

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