Secondary radiation excitation device and analysis and detection instrument

Abstract

The invention relates to the technical field of electron optics, provides a secondary radiation excitation device and an analysis and detection instrument, and is used for solving the problem that the reliability of an electron gun and other accessories is influenced by metal steam and cations generated when a high-energy electron beam bombards a metal target material. The secondary radiation excitation device comprises an excitation source and a metal target material, the excitation source is used for emitting electron beams, and the metal target material is arranged on an advancing path of the electron beams, receives bombardment of the electron beams and generates secondary radiation; at least one conductive film layer is arranged on the bombarded working surface of the metal target material and / or at least one conductive film layer is arranged on the traveling path of the electron beam, and the conductive film layer is used for preventing metal atoms and metal cations generated when the metal target material is bombarded from passing through, so that the electron beam and secondary radiation can pass through the conductive film layer under the condition of not influencing the electron beam and secondary radiation to pass through the conductive film layer; and metal cation reverse detonation can be prevented, and metal steam is prevented from polluting devices such as insulating parts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electron optics, in particular to a secondary radiation excitation device and an analytical detection instrument. BACKGROUND

[0002] The open-tube excitation source device emits a high-energy electron beam through a cathode emission unit to bombard a metal target, thereby generating X-rays or secondary electrons; it is widely used in precise analytical detection instruments such as X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy, computed tomography, and scanning electron microscopy.

[0003] When the high-energy electron beam collides with the metal target, the kinetic energy of the electrons is instantaneously converted into heat energy, and the metal vapor generated by the rapid melting and evaporation of the surface of the metal target will freely diffuse to other components, such as ceramic insulating parts, in an ultra-high vacuum environment, and condense on the surface of the ceramic insulating parts, forming a continuous, conductive metal film, which destroys the electrical insulation of the ceramic insulating parts. At the same time, part of the positive ions generated when the high-energy electron beam collides with the metal target will also back-bombard the cathode emission unit, causing damage to the cathode emission unit and affecting the life cycle and reliability of the equipment. SUMMARY

[0004] The present application discloses a secondary radiation excitation device and an analytical detection instrument, which solves the problem of metal vapor and positive ions generated when a high-energy electron beam bombards a metal target affecting other key components.

[0005] In a first aspect, the present application provides a secondary radiation excitation device, comprising: an excitation source configured to emit an electron beam; a metal target disposed in the travel path of the electron beam, which receives bombardment of the electron beam and generates secondary radiation; the working surface of the metal target receiving bombardment is provided with at least one conductive film layer and / or the travel path of the electron beam is provided with at least one conductive film layer, which is configured to block metal atoms and metal positive ions generated when the metal target receives bombardment.

[0006] By adopting the above technical solution, a conductive film layer is provided on the working surface of the metal target receiving electron bombardment and / or the travel path of the electron beam, and the conductive film layer can block metal atoms and metal positive ions generated when the metal target receives high-energy electron bombardment, thereby preventing metal positive ions from back-bombarding, avoiding metal vapor from polluting ceramic insulating parts and other devices, and prolonging the life cycle of the equipment; at the same time, the conductive film layer can also neutralize the charge accumulated when the electron beam passes through, avoiding the subsequent vertically falling electron beam from being deviated due to charge accumulation.

[0007] In a possible implementation, the conductive film layer is a conductive diamond film or a conductive silicon nitride film. The diamond film and the silicon nitride film have excellent electron transmittance and thermal conductivity, and X-rays and secondary electrons have high transmittance when passing through the diamond film and the silicon nitride film. However, due to the large atomic nucleus size of metal atoms and metal cations, the metal atoms and the metal cations cannot penetrate the diamond film and the silicon nitride film, thereby achieving the isolation function of the metal atoms and the metal cations. Meanwhile, the conductive diamond film and the conductive silicon nitride film can retain their own characteristics while being conductive. The conductivity of the conductive diamond film and the conductive silicon nitride film provides a fast conductive path for accumulated charges, thereby timely discharging the charges to avoid the accumulation of the charges to form an electric field.

[0008] In a possible implementation, the conductive silicon nitride film is formed by doping yttrium, lanthanum, cerium, or aluminum in silicon nitride; the conductive diamond film is formed by doping boron, nitrogen, or phosphorus in diamond; or the conductive diamond film is a hydrogen-terminated diamond film with a surface conductive layer.

[0009] In a possible implementation, the thickness of the conductive film layer is 1 nm to 500 nm. The thickness of the conductive film layer is controlled to be within 500 nm to prevent the conductive film layer from being too thick to affect the passage of the electron beam.

[0010] In a possible implementation, on the path of the electron beam, the back surface of the metal target opposite to the working surface is provided with a heat conduction assembly, and the heat conduction assembly includes stacked diamond and heat conduction copper base, and the diamond is close to the back surface. The heat conduction copper base can quickly spread the high heat flow generated by the metal target to the entire copper base, ensuring the heat dissipation of the metal target. The heat conduction copper base can also serve as a base to support the metal target, ensuring the stability of the metal target. The heat conduction copper base also serves as part of the circuit to ensure that the electrons after hitting the metal target can be led out to prevent the accumulation of charges. The diamond has excellent heat conduction performance, and its heat conduction capacity is much greater than that of copper. Therefore, the diamond layer arranged between the metal target and the heat conduction copper base can greatly improve the heat dissipation efficiency.

[0011] In a possible implementation, the secondary radiation excitation device further includes an electrostatic lens assembly. The electrostatic lens assembly is arranged on the path of the electron beam and close to the excitation source. The electrostatic lens assembly includes a first electrode, a second electrode, and a third electrode arranged between the first electrode and the second electrode. The first electrode and / or the second electrode is grounded, and the third electrode is configured with a negative high voltage potential to form an electric field. The electric field is used to generate a radial electrostatic focusing force on the electron beam passing therethrough, so as to converge the electron beam to the axis, thereby converging the divergent electron beam into a more concentrated and denser beam spot.

[0012] In a possible implementation, the secondary radiation excitation device further comprises an electromagnetic lens assembly; the electromagnetic lens assembly is arranged on the path of the electron beam and is close to the metal target; the electromagnetic lens assembly comprises a magnetic yoke with a central through hole and an annular focusing coil arranged in the magnetic yoke, the central axis of the central through hole coincides with the path of the electron beam, and the annular focusing coil is used for focusing the electron beam passing therethrough. The magnetic yoke is connected to the ground potential of the secondary radiation excitation device. The electromagnetic lens assembly adopts a composite structure, so that the high-energy electrons spiral in the axisymmetric non-uniform magnetic field, and the electrons are converged to a point on the axis by the Lorentz force, so as to constrain and tighten the divergent distributed electron beam to form a focused beam spot with significantly improved energy density, ensuring that the electron beam can bombard the metal target with a very small spot.

[0013] In a possible implementation, the conductive film layer arranged on the path of the electron beam is fixedly connected to the magnetic yoke, the first electrode or the second electrode. Since the magnetic yoke is connected to the ground potential of the whole device, the first electrode is grounded, and the second electrode is grounded, the conductive film layer can prevent metal cation back bombardment, avoid metal vapor pollution of ceramic insulating parts and other devices, and at the same time provide a fast conductive path for the accumulated charge to the ground, so as to timely discharge the charge and avoid the accumulation of the charge to form an electric field.

[0014] In a possible implementation, the secondary radiation excitation device further comprises an annular connecting piece; the outer ring of the annular connecting piece is fixedly connected to the magnetic yoke, the first electrode or the second electrode, and the conductive film layer is fixedly connected to the inner ring of the annular connecting piece. The above connection mode is simple in structure and easy to implement.

[0015] In a second aspect, the present application provides an analytical detection instrument comprising the secondary radiation excitation device described above. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figure 1 Structure diagram of the secondary radiation excitation device in the related art Figure One ;

[0018] Figure 2 Structure diagram of the secondary radiation excitation device in the related art Figure Two;

[0019] Figure 3 Structure diagram of a secondary radiation excitation device in the related art Figure Three ;

[0020] Figure 4 Structure diagram of a secondary radiation excitation device in the related art Figure Four ;

[0021] Figure 5 Structure diagram of a secondary radiation excitation device in the related art Figure Five ;

[0022] Figure 6 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure One ;

[0023] Figure 7 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure Two ;

[0024] Figure 8 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure Three ;

[0025] Figure 9 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure Four ;

[0026] Figure 10 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure Five ;

[0027] Figure 11 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure Six ;

[0028] Figure 12 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure Seven ;

[0029] Figure 13 Structure diagram of a secondary radiation excitation device provided by an embodiment of the present application Figure Eight ;

[0030] Figure 14 Front view structural diagram of a secondary radiation excitation device provided by an embodiment of the present application, in which a conductive film layer is fixedly connected to a ring-shaped connecting member

[0031] Figure 15 Side view structural diagram of a secondary radiation excitation device provided by an embodiment of the present application, in which a conductive film layer is fixedly connected to a ring-shaped connecting member

[0032] Reference Signs List:

[0033] 100 - cathode emission unit

[0034] 101 - optical axis; 102 - deflection coil

[0035] 200 - grid

[0036] 300 - metal target

[0037] 401 - first electrode; 402 - second electrode; 403 - third electrode

[0038] 500 - conductive film layer

[0039] 601 - diamond; 602 - heat-conductive copper base

[0040] 701 - magnetic yoke; 702 - annular focusing coil DETAILED DESCRIPTION

[0041] Reference Figure 1 In the related art, the excitation source of the secondary radiation excitation device includes a cathode emission unit 100 and a grid 200. The cathode emission unit 100 is a filament, and the current heats the filament to emit hot electrons. The grid 200 is used to control the emission of electrons. After the electrons are emitted from the cathode emission unit 100, they are accelerated by the negative high voltage of the cathode to form an electron beam.

[0042] The metal target 300 of the secondary radiation excitation device is arranged on the path of the electron beam. When the electron beam bombards the metal target 300, the kinetic energy of the electron beam is converted into heat energy. At the same time, the atoms of the target material are excited to release X-rays or secondary electrons. The X-rays and secondary electrons are collectively referred to as secondary radiation. The secondary electrons diffuse in the vacuum chamber and contact grounded components such as aluminum or stainless steel cavities, which are annihilated. The generated X-rays are collected, screened, or focused to the measurement point by specific optical elements.

[0043] In an embodiment of the related art, a metal with a high melting point is selected to make the metal target 300, such as aluminum, copper, gold, molybdenum, tungsten, or tantalum, to prevent the surface of the metal target 300 from rapidly melting and evaporating to generate metal vapor.

[0044] However, the above solution cannot solve the problem of part of the cations back-hitting the cathode emission unit 100. At the same time, when a high-power electron beam bombards, a small amount of metal vapor will still be generated on the surface of the metal target 300. Therefore, the above solution cannot weaken or completely avoid the pollution of metal vapor to the ceramic insulating part.

[0045] Reference Figure 2In another embodiment of the related art, the cathode emission unit 100 is offset from the optical axis 101 of the secondary radiation excitation device, which is a central symmetry axis running through the entire secondary radiation excitation device, and all components in the secondary radiation excitation device, such as electromagnetic lenses, diaphragms, etc., are designed and aligned with the axis as the center; the off-axis of the cathode emission unit 100 can weaken the back bombardment of part of the positive ions and avoid filament damage.

[0046] However, the off-axis electron beam is inclined and asymmetric when it enters the electromagnetic lens, which introduces aberration and makes it difficult to focus the electron beam into a perfect circle at the metal target, making the design and implementation of the electromagnetic lens that matches the result more difficult. At the same time, this scheme cannot avoid the pollution of metal vapor to the ceramic insulating part.

[0047] Reference Figure 3 In a third embodiment of the related art, a deflection coil 102 is added to the path of the electron beam, so that the electron beam is offset from the optical axis of the secondary radiation excitation device, and the back bombardment of part of the positive ions is weakened to avoid filament damage.

[0048] However, the addition of the deflection coil 102 increases the complexity and cost of the device, and also causes distortion of the electron beam spot; at the same time, this scheme cannot avoid the pollution of metal vapor to the ceramic insulating part.

[0049] Reference Figure 4 In a fourth embodiment of the related art, the metal target 300 is deflected so that the electron beam is inclined to hit the metal target 300, thereby weakening the back bombardment of part of the positive ions and avoiding filament damage. However, this scheme cannot avoid the pollution of metal vapor to the ceramic insulating part.

[0050] Reference Figure 5 In a fifth embodiment of the related art, the secondary radiation excitation device further includes an ion trap assembly.

[0051] The ion trap assembly is composed of a first electrode 401, a second electrode 402, and a third electrode 403 disposed between the first electrode 401 and the second electrode 402; wherein the first electrode 401 has a positive voltage, the second electrode 402 is grounded, and the third electrode 403 has a very high negative voltage. Through the above symmetrical structure, an electrostatic potential barrier or well is formed inside the secondary radiation excitation device. When part of the positive ions tries to fly towards the cathode emission unit 100 against the direction of the electron beam, the kinetic energy of the positive ions is not enough to overcome the electrostatic potential barrier or well, and it will be pushed away from the optical axis or bound in a certain area, unable to reach the cathode emission unit 100, thereby achieving the purpose of weakening the back bombardment of part of the positive ions.

[0052] However, the ion trap assembly described above cannot inhibit the bombardment of cations along the electron beam light path to the cathode emission unit 100, cannot avoid the pollution of metal vapor to the ceramic insulating part, and increases the complexity of the device.

[0053] To solve the above problems, the embodiment of the present application provides a secondary radiation excitation device. A conductive film layer is arranged on the working surface of the metal target material receiving bombardment and / or the travel path of the electron beam. The conductive film layer allows the electron beam and the secondary radiation to pass through, and can prevent the metal atoms and metal cations generated when the metal target material receives bombardment from passing through, thereby preventing the back bombardment of metal cations, avoiding the pollution of metal vapor to the ceramic insulating part and other devices, and prolonging the service life of the equipment. At the same time, the conductive film layer can also neutralize the charge accumulated when the electron beam passes through, thereby avoiding the deviation of the subsequent emitted electron beam caused by the accumulation of charge.

[0054] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0055] Reference Figure 6 The secondary radiation excitation device provided by the embodiment of the present application comprises an excitation source and a metal target material 300.

[0056] The excitation source is used for emitting an electron beam. The excitation source comprises a cathode emission unit 100 and a grid 200. The cathode emission unit 100 is used for emitting hot electrons. The grid 200 is used for controlling the emission of hot electrons. After the hot electrons are emitted from the cathode emission unit 100, the hot electrons are accelerated by the negative high voltage of the cathode to form an electron beam.

[0057] In the present application, the travel path of the electron beam refers to the motion trajectory of the electron beam. The travel path of the electron beam coincides with the optical axis 101 of the secondary radiation excitation device. The optical axis 101 is the central symmetry axis of the entire secondary radiation excitation device. The key components in the device, such as the cathode emission unit 100, the grid 200 and the metal target material 300, are arranged in rotational symmetry around the optical axis 101. The center points of these key components all accurately fall on the optical axis 101.

[0058] The metal target material 300 is arranged on the travel path of the electron beam. The electron beam will fly along the optical axis 101 from the cathode to the anode, that is, the metal target material 300. The metal target material 300 receives the bombardment of the electron beam and generates secondary radiation. When the electron beam bombards the metal target material 300, the kinetic energy of the electron beam is converted into heat energy. The target atoms are excited and release X-rays or secondary electrons. In the present application, the X-rays and the secondary electrons are collectively referred to as secondary radiation.

[0059] Reference Figure 6 The working surface of the metal target material 300 receiving bombardment is provided with at least one conductive film layer 500.

[0060] Alternatively, referring to Figures 7-10 , the travel path of the electron beam is provided with at least one conductive film layer 500.

[0061] Alternatively, referring to Figure 11 , Figure 12 and Figure 13 , the working surface of the metal target 300 receiving bombardment and the travel path of the electron beam are respectively provided with at least one conductive film layer 500.

[0062] The conductive film layer 500 is configured to block the passage of metal atoms and metal cations generated when the metal target 300 is bombarded by the electron beam. Thus, without affecting the passage of the electron beam and secondary radiation through the conductive film layer 500, the metal cation back bombardment can be prevented, the metal vapor pollution of the ceramic insulating parts and other devices can be avoided, and the service life of the equipment can be prolonged.

[0063] Since the conductive film layer 500 has conductivity and the ability to block the passage of the above-mentioned metal atoms and metal cations, the conductive film layer 500 provided by the present application can simultaneously realize high transmission of the electron beam and secondary radiation, high blocking of the metal atoms and metal cations generated when the metal target 300 is bombarded, and neutralization of the charges carried by the electron beam.

[0064] In one example, high transmission is that the transmittance of the conductive film layer 500 to the electron beam and the secondary radiation excited thereby in the working energy range is higher than 99%, ensuring that the electron beam can pass through the conductive film layer 500 and bombard the working surface of the metal target 300, and the secondary radiation excited when bombarded can also pass through the conductive film layer 500 and be collected, screened or focused by a specific optical element to a measurement point.

[0065] High blocking is that the conductive film layer 500 has a very high blocking rate to the metal atoms and metal cations escaping from the metal target 300 under bombardment of the electron beam, and the blocking rate is higher than 99%, thereby preventing the passage of metal atoms and metal cations, preventing the back bombardment of the metal atoms and metal cations to the cathode emission unit 100, avoiding the pollution of metal vapor to the ceramic insulating parts and other devices, and prolonging the service life of the equipment.

[0066] It should be noted that the metal atoms and metal cations generated when the metal target 300 is bombarded have a semicircular distribution in their motion trajectory when leaving the metal target 300, and the metal atoms and metal cations escaping along the travel path of the electron beam are easy to enter the interior of the electron gun, so that the insulation of the ceramic insulating parts is destroyed. Therefore, by providing the conductive film layer 500 in the travel path of the electron beam, the pollution of metal vapor to the ceramic insulating parts and other devices can also be effectively prevented.

[0067] As the electron beam passes through the conductive film layer 500, negative charges are accumulated, which form an electrostatic field that repels the subsequent electron beam; the conductivity of the conductive film layer 500 neutralizes the charges accumulated when the electron beam passes through, avoiding the formation of an electric field due to the accumulation of charges.

[0068] The scheme of arranging the conductive film layer 500 directly on the working surface of the metal target 300 subjected to bombardment can be understood as arranging the conductive film layer 500 at the end of the electron beam, without occupying the internal space of the original excitation device and without affecting the internal structure of the original excitation device.

[0069] The scheme of arranging the conductive film layer 500 on the path of the electron beam can be understood as arranging the conductive film layer 500 in the middle of the electron beam, which is easy to implement. In the scheme of arranging the conductive film layer 500 on both the working surface of the metal target 300 subjected to bombardment and the path of the electron beam, the target surface film layer reduces the amount of metal vapor and cations generated from the source, and the film layer in the path ensures that even if a small amount of contaminants enter, it will not affect the function of the key components (especially the insulating components), which provides double protection and effectively prolongs the service life of the secondary radiation excitation device.

[0070] In the scheme, a connecting piece can be arranged on the path of the electron beam, and the connecting piece is also arranged rotationally symmetrically around the optical axis 101, and the conductive film layer 500 is arranged on the connecting piece, so that the conductive film layer 500 is arranged on the path of the electron beam.

[0071] In an embodiment of the present application, the conductive film layer 500 is a conductive diamond thin film or a conductive silicon nitride thin film.

[0072] The diamond thin film is a layer of polycrystalline or single-crystal diamond material artificially synthesized on a non-diamond substrate by chemical vapor deposition or other methods, which has extremely high carrier mobility and breakdown field strength and is suitable for making high-temperature, high-frequency, and high-power electronic devices; the silicon nitride thin film is an inorganic ceramic thin film composed of silicon and nitrogen.

[0073] The diamond thin film and the silicon nitride thin film have excellent electron transmittance and thermal conductivity, and X-rays and secondary electrons have high transmittance when passing through the diamond thin film and the silicon nitride thin film, but the atomic nucleus size of metal atoms and metal cations is large and cannot penetrate the diamond thin film and the silicon nitride thin film, thereby realizing the isolation function of metal atoms and metal cations.

[0074] The conductive diamond thin film and the conductive silicon nitride thin film can conduct electricity while retaining their own characteristics, and the conductivity of the conductive diamond thin film and the conductive silicon nitride thin film provides a rapid conduction path for the accumulated charges, thereby timely discharging the charges and avoiding the accumulation of charges to form an electric field.

[0075] For example, the conductive silicon nitride film is formed by doping, such as yttrium, lanthanum, cerium or aluminum, in silicon nitride.

[0076] The silicon nitride is an excellent insulator with a wide band gap, and by introducing a metal organic or inorganic precursor containing yttrium (Y), lanthanum (La), cerium (Ce) or aluminum (Al) in the process of preparing the silicon nitride film by a chemical vapor deposition (CVD) or physical vapor deposition (PVD) technique, uniform doping of the elements can be achieved, thereby obtaining a conductive silicon nitride film.

[0077] For example, the conductive diamond film is formed by doping boron, nitrogen or phosphorus in diamond.

[0078] By introducing a gas containing a doping element in the process of growing the diamond film by a chemical vapor deposition (CVD) technique, wherein borane is used as a boron source gas, nitrogen or ammonia is used as a nitrogen source, and phosphine is used as a phosphorus source, impurity atoms are introduced into the diamond lattice, thereby providing additional free electrons (n-type) or holes (p-type) to achieve conductivity.

[0079] For example, the conductive diamond film is a hydrogen-terminated diamond film with a surface conductive layer.

[0080] By a chemical vapor deposition (CVD) technique, a high-quality intrinsic insulating diamond film is prepared, and then a hydrogen-terminated treatment process is performed on the diamond film to obtain a surface conductive layer. Without bulk doping, the conductivity of the diamond film can be achieved, and the diamond lattice is perfect.

[0081] In the embodiment of the present application, the thickness of the conductive film layer 500 is in the range of 1 nm to 500 nm.

[0082] If the thickness of the conductive film layer 500 is less than 1 nm, the conductive film layer 500 will grow in an island mode to form individual discontinuous islands instead of a uniform film, resulting in extremely high resistance of the conductive film layer 500 and failing to effectively neutralize the electric charge. If the thickness of the conductive film layer 500 is greater than 500 nm, the secondary radiation generated by the bombardment of the metal target 300 will be largely absorbed and attenuated when passing through the film layer, which will significantly reduce the output efficiency.

[0083] Therefore, the thickness of the conductive film layer 500 is controlled within 1 nm to 500 nm to ensure that the conductive film layer 500 can form a continuous, stable and reliable conductive path in any area thereof, thereby completing its charge neutralization function; at the same time, the conductive film layer 500 is prevented from being too thick to affect the passage of the electron beam.

[0084] With reference to the foregoing Figure 6 In the embodiment, the back surface of the metal target 300 is opposite to the working surface in the travel path of the electron beam, and the back surface is provided with a heat conduction assembly including a stacked diamond 601 and a heat conduction copper base 602, and the diamond 601 is close to the back surface.

[0085] When the metal target 300 is bombarded by the electron beam, most of the kinetic energy is instantaneously converted into heat energy, and the heat generated is very concentrated. If the heat cannot be taken away in time, the target surface will be melted, evaporated or even burned through. The heat conduction copper base 602 has good heat conduction performance. By tightly combining the heat conduction copper base 602 with the metal target 300, the high heat flow generated by the metal target 300 can be quickly diffused to the entire copper base, ensuring the heat dissipation of the metal target 300.

[0086] Meanwhile, the heat conduction copper base 602 can also serve as a base for supporting the metal target 300, ensuring the stability of the metal target 300.

[0087] Further, the heat conduction copper base 602 also serves as part of the circuit, ensuring that the electrons after bombarding the metal target 300 can be guided out, preventing the accumulation of electric charge.

[0088] Diamond has excellent heat conduction performance, and its heat conduction capacity is much greater than that of copper. By arranging a layer of diamond 601 between the metal target 300 and the heat conduction copper base 602, the heat dissipation efficiency can be greatly improved.

[0089] With reference to the foregoing Figure 6 In the embodiment, the secondary radiation excitation device further includes an electrostatic lens assembly.

[0090] The electrostatic lens assembly is arranged in the travel path of the electron beam and close to the excitation source.

[0091] The electrostatic lens assembly includes a first electrode 401, a second electrode 402, and a third electrode 403 arranged between the first electrode 401 and the second electrode 402.

[0092] In one embodiment, the first electrode 401 and the second electrode 402 are grounded, the potential of the first electrode 401 and the second electrode 402 is 0V, and the third electrode 403 is configured with a negative high voltage potential to form an electric field; in another embodiment, the first electrode 401 is configured with a positive high voltage potential, the second electrode 402 is grounded, and the third electrode 403 is configured with a negative high voltage potential to form an electric field; in another embodiment, the first electrode 401 is grounded, the second electrode 402 is configured with a positive high voltage potential, and the third electrode 403 is configured with a negative high voltage potential to form an electric field.

[0093] The electric field is used to generate a radial electrostatic focusing force on the electron beam passing therethrough, so as to converge the electron beam to the axis.

[0094] The electrostatic lens assembly can effectively counteract the electrostatic repulsion force between the electrons, so as to converge the divergent electron beam into a more concentrated and finer beam spot.

[0095] It should be noted that the electrostatic lens assembly is also rotationally symmetrically arranged around the optical axis 101, and the center point of the electrostatic lens assembly is accurately located on the optical axis 101.

[0096] With reference back to Figure 6 In an embodiment, the secondary radiation excitation device further comprises an electromagnetic lens assembly.

[0097] The electromagnetic lens assembly is arranged in the path of the electron beam and is close to the metal target 300.

[0098] The electromagnetic lens assembly comprises a magnetic yoke 701 having a central through hole and an annular focusing coil 702 arranged in the magnetic yoke 701, the magnetic yoke 701 is used to guide and concentrate the magnetic field, the central axis of the central through hole coincides with the path of the electron beam, and the annular focusing coil 702 is used to focus the electron beam passing therethrough; wherein the magnetic yoke 701 is connected to the ground potential of the secondary radiation excitation device.

[0099] The electromagnetic lens assembly adopts a composite structure, so that the high-energy electrons spiral in the axisymmetric non-uniform magnetic field, and the electrons are converged to a point on the axis by the Lorentz force, so as to constrain and tighten the divergent distributed electron beam to form a focused beam spot with significantly improved energy density, thereby ensuring that the electron beam can bombard the metal target 300 with a very small spot.

[0100] It should be noted that the electromagnetic lens assembly is also rotationally symmetrically arranged around the optical axis 101, and the center point of the electromagnetic lens assembly is accurately located on the optical axis 101.

[0101] With reference back to Figure 7 In the embodiment of the present application, the conductive film layer 500 arranged in the path of the electron beam is fixedly connected to the magnetic yoke 701.

[0102] Alternatively, with reference back to Figure 8 The conductive film layer 500 arranged in the path of the electron beam is fixedly connected to the second electrode 402.

[0103] Alternatively, with reference back to Figure 9 The conductive film layer 500 arranged in the path of the electron beam is fixedly connected to the first electrode 401.

[0104] The edge of the conductive film layer 500 can be directly bonded to the magnetic yoke 701, the first electrode 401 or the second electrode 402; or a connecting piece is arranged on the magnetic yoke 701, the first electrode 401 or the second electrode 402, and the conductive film layer 500 can be bonded to the connecting piece, or the edge of the conductive film layer 500 can be embedded in a connecting groove of the connecting piece.

[0105] Since the magnetic yoke 701 is connected to the ground potential of the whole device, the first electrode 401 is grounded, and the second electrode 402 is grounded, the conductive film layer 500 can prevent metal cation back bombardment, avoid metal vapor pollution of ceramic insulating parts and other devices, and also provide a fast conductive path to the ground for accumulated charges, thereby timely discharging the charges and avoiding the accumulation of electric charges to form an electric field.

[0106] It should be noted that in the actual installation process of the conductive film layer 500, since the structure at the positions of the first electrode 401 and the second electrode 402 is relatively compact, it is relatively easy to operate to fix the conductive film layer 500 to the magnetic yoke 701 compared to fixing the conductive film layer 500 to the first electrode 401 or the second electrode 402. Those skilled in the art can selectively fix the conductive film layer 500 to the magnetic yoke 701, the first electrode 401 or the second electrode 402 according to the actual situation.

[0107] Reference Figure 14 and Figure 15 The connecting piece can be a ring-shaped connecting piece 800.

[0108] In the embodiment of the application, the secondary radiation excitation device further comprises a ring-shaped connecting piece 800, and the conductive film layer 500 is fixedly connected to the magnetic yoke 701, the first electrode 401 or the second electrode 402 through the ring-shaped connecting piece 800.

[0109] The outer ring of the ring-shaped connecting piece 800 is fixedly connected to the magnetic yoke 701, the first electrode 401 or the second electrode 402 by bonding, threaded connection or clamping groove connection, and the conductive film layer 500 is fixedly connected to the inner ring of the ring-shaped connecting piece 800.

[0110] The edge of the conductive film layer 500 can be bonded to the inner ring of the ring-shaped connecting piece 800; or the inner ring of the ring-shaped connecting piece 800 can be provided with a connecting groove 801, and the edge of the conductive film layer 500 is embedded in the connecting groove 801.

[0111] The ring-shaped connecting piece 800 is a rotary body part, which has simple structure, is easy to machine and has low cost; and the conductive film layer 500 and the ring-shaped connecting piece 800 can be pre-assembled outside the equipment as a whole module for installation or replacement, which only needs to be aligned and installed, avoids direct operation of the conductive film layer 500 in a narrow space, and is convenient to disassemble and assemble, has high reliability and is not easy to damage the film layer.

[0112] The secondary radiation excitation device will be described in detail below according to the accompanying drawings and specific embodiments:

[0113] With reference to Figure 6 The secondary radiation excitation device provided in the present application comprises an excitation source, a metal target 300, an electrostatic lens assembly and an electromagnetic lens assembly.

[0114] The excitation source comprises a cathode emission unit 100 and a grid 200, the cathode emission unit 100 emits hot electrons, and the grid 200 controls the emission of hot electrons. After the hot electrons are emitted from the cathode emission unit 100, they are accelerated by the negative high voltage of the cathode to form an electron beam.

[0115] The electrostatic lens assembly, the electromagnetic lens assembly and the metal target 300 are sequentially arranged on the path of the electron beam. The electron beam will fly straight from the cathode to the metal target 300 along the optical axis 101. The metal target 300 is bombarded by the electron beam and generates secondary radiation, which is X-ray or secondary electron.

[0116] The electrostatic lens assembly comprises a first electrode 401, a second electrode 402 and a third electrode 403 arranged between the first electrode 401 and the second electrode 402. The first electrode 401 and the second electrode 402 are grounded, and the third electrode 403 is configured with a negative high voltage potential to form an electric field. The electric field generates a radial electrostatic focusing force on the electron beam passing therethrough, so as to converge the electron beam to the axis, and converges the divergent electron beam into a more concentrated beam spot.

[0117] The electromagnetic lens assembly comprises a magnetic yoke 701 and an annular focusing coil 702 arranged in the magnetic yoke 701. The magnetic yoke 701 is used to guide and concentrate the magnetic field, and the annular focusing coil 702 is used to focus the electron beam passing therethrough. The magnetic yoke 701 is connected to the ground potential of the secondary radiation excitation device. The electromagnetic lens assembly restrains and tightens the divergent distributed electron beam to form a focused beam spot, so that the electron beam bombards the metal target 300 with a very small spot.

[0118] The working surface of the metal target 300 subjected to bombardment is provided with a conductive film layer 500. The thickness of the conductive film layer 500 is 100 nm. The conductive film layer 500 is a conductive diamond film. The conductive film layer 500 can simultaneously realize high transmission of the electron beam and the secondary radiation, high blocking of metal atoms and metal cations generated when the metal target 300 is subjected to bombardment, and neutralization of the charges carried by the electron beam, prevent metal cation back bombardment, avoid metal vapor pollution of ceramic insulating parts and other devices, and prolong the service life of the equipment. At the same time, the conductive film layer can also neutralize the charge accumulated when the electron beam passes through, to avoid the subsequent emitted electron beam from being deviated due to the accumulation of charge.

[0119] The back surface of the metal target 300 is opposite to the working surface, and the back surface is further provided with a heat conduction assembly, the heat conduction assembly comprises a laminated diamond 601 and a heat conduction copper base 602, and the diamond 601 is close to the back surface; the heat conduction assembly is used for rapidly diffusing the high heat flow generated by the metal target 300 into the entire copper base, and ensuring heat dissipation of the metal target 300.

[0120] Reference Figure 7 , Figure 14 and Figure 15 In one embodiment, a conductive film layer 500 is arranged in the path of the electron beam in the secondary radiation excitation device, such as the conductive silicon nitride film.

[0121] In one example, the secondary radiation excitation device further comprises a ring-shaped connecting piece 800, the outer ring of the ring-shaped connecting piece 800 is fixedly connected to the magnetic yoke 701, the inner ring of the ring-shaped connecting piece 800 is provided with a connecting groove 801, and the edge of the conductive film layer 500 is embedded in the connecting groove 801, so that the conductive film layer 500 is arranged in the path of the electron beam.

[0122] The edge of the conductive film layer 500 can be directly bonded in the connecting groove 801.

[0123] The mounting mode of the conductive film layer 500 through the ring-shaped connecting piece 800 is simple in structure and easy to implement.

[0124] Reference Figure 8 In one embodiment, the outer ring of the ring-shaped connecting piece 800 is fixedly connected to the second electrode 402.

[0125] Reference Figure 9 In one embodiment, the outer ring of the ring-shaped connecting piece 800 is fixedly connected to the first electrode 401.

[0126] Reference Figure 10 In one embodiment, three conductive film layers 500 are arranged in the path of the electron beam.

[0127] In one example, as shown in Figure 10 The secondary radiation excitation device further comprises three ring-shaped connecting pieces 800, and the outer rings of the three ring-shaped connecting pieces 800 are fixedly connected to the magnetic yoke 701, the first electrode 401 and the second electrode 402 respectively.

[0128] The triple protection in the path prevents the back bombardment of metal cations and avoids the pollution of metal vapor to devices such as ceramic insulating parts.

[0129] Reference Figure 11 In one embodiment, the working surface of the metal target 300 in the secondary radiation excitation device is provided with a conductive film layer 500, and the path of the electron beam is further provided with a conductive film layer 500.

[0130] In one example, such as Figure 11 As shown, the secondary radiation excitation device also includes an annular connector 800. The outer ring of the annular connector 800 is fixedly connected to the magnetic yoke 701, and the inner ring of the annular connector 800 is provided with a connecting groove 801. The edge of the conductive film layer 500 is fitted into the connecting groove 801.

[0131] The target film layer reduces the generation of metal vapor and cations at the source, and the film layer in the path ensures at the end that even if a small amount of contaminants enter, it will not affect the function of critical components (especially insulation components).

[0132] refer to Figure 12 In one embodiment, a conductive film layer 500 is provided on the working surface of the metal target 300 in the secondary radiation excitation device that receives the bombardment, and two conductive film layers 500 are also provided in the travel path of the electron beam.

[0133] In one example, such as Figure 12 As shown, the secondary radiation excitation device also includes two annular connectors 800, the outer rings of which are fixedly connected to the magnetic yoke 701 and the first electrode 401, respectively.

[0134] The dual safeguards along the path further ensure that even if a small amount of contaminants enters, it will not affect the function of critical components, especially insulation.

[0135] refer to Figure 13 In one embodiment, a conductive film layer 500 is provided on the working surface of the metal target 300 in the secondary radiation excitation device that receives the bombardment, and three conductive film layers 500 are also provided in the path of the electron beam.

[0136] In one example, such as Figure 13 As shown, the secondary radiation excitation device also includes three annular connectors 800, the outer rings of which are fixedly connected to the magnetic yoke 701, the first electrode 401, and the second electrode 402, respectively.

[0137] The triple safeguards along the path further ensure that a small amount of contaminants do not affect the insulation components.

[0138] This application also provides an analytical detection instrument, which includes the secondary radiation excitation device described above.

[0139] In summary, the embodiment provides a secondary radiation excitation device and an analysis and detection instrument. The secondary radiation excitation device comprises an excitation source and a metal target 300. The excitation source is configured to emit an electron beam. The metal target 300 is arranged on a path of the electron beam. The metal target 300 is bombarded by the electron beam and generates secondary radiation, which comprises X-rays or secondary electrons. The working surface of the metal target 300 that is bombarded is provided with at least one conductive film layer 500, and / or the path of the electron beam is provided with at least one conductive film layer 500. The conductive film layer 500 can block metal atoms and metal cations generated when the metal target 300 is bombarded.

[0140] According to the above technical solution, the conductive film layer 500 is arranged on the working surface of the metal target 300 that is bombarded by the electron beam and / or the path of the electron beam. The conductive film layer 500 can block metal atoms and metal cations generated when the metal target 300 is bombarded by high-energy electrons. Therefore, without affecting the passing of the electron beam and the secondary radiation through the conductive film layer 500, the metal cation back bombardment can be prevented, the metal vapor can be prevented from polluting the ceramic insulating part and other devices, and the service life of the equipment can be prolonged.

[0141] Meanwhile, the conductive film layer 500 can also neutralize the electric charge accumulated when the electron beam passes through, so as to avoid the subsequent vertically falling electron beam from being deviated due to the accumulation of the electric charge.

[0142] Further, the scheme of directly arranging the conductive film layer 500 on the working surface of the metal target 300 that is bombarded by the electron beam and / or the path of the electron beam is simple in structure, easy to implement, and will not affect the internal structure of the original excitation device, thereby maintaining the stability of the device.

[0143] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0144] It should be understood that the term "and / or" used herein is merely a description of the same field of associated objects, which means that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0145] It should be understood that "first", "second", and the like used in the present application are only for the purpose of distinguishing description, and cannot be understood as indicating or implying relative importance, nor indicating or implying sequence.

[0146] As used herein, "in the range of" includes the two end values of the range, unless otherwise indicated, for example, in the range of 1 to 5, includes the two values of 1 and 5.

[0147] It should be noted that the described embodiments are merely a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

Claims

1. A secondary radiation excitation device, characterized in that, include: An excitation source, configured to emit an electron beam; A metal target is disposed in the path of the electron beam, and the metal target receives the bombardment of the electron beam and generates secondary radiation. The working surface of the metal target receiving the bombardment is provided with at least one conductive film layer and / or the travel path of the electron beam is provided with at least one conductive film layer, the conductive film layer being configured to block the passage of metal atoms and metal cations generated when the metal target receives the bombardment.

2. The secondary radiation excitation device according to claim 1, characterized in that, The conductive film is a conductive diamond film or a conductive silicon nitride film.

3. The secondary radiation excitation device according to claim 2, characterized in that, The conductive silicon nitride film is a conductive silicon nitride film formed by doping silicon nitride with yttrium, lanthanum, cerium or aluminum; The conductive diamond film is a conductive diamond film formed by doping diamond with boron, nitrogen, or phosphorus; or... The conductive diamond film is a hydrogen-terminated diamond film with a surface conductive layer.

4. The secondary radiation excitation device according to any one of claims 1-3, characterized in that, The thickness of the conductive film is in the range of 1 nm to 500 nm.

5. The secondary radiation excitation device according to any one of claims 1-4, characterized in that, Along the path of the electron beam, the back side of the metal target faces the working surface. A heat-conducting component is provided on the back side, which includes stacked diamond and a heat-conducting copper base, with the diamond close to the back side.

6. The secondary radiation excitation device according to any one of claims 1-5, characterized in that, It also includes electrostatic lens assemblies; The electrostatic lens assembly is disposed in the path of the electron beam and close to the excitation source; The electrostatic lens assembly includes a first electrode, a second electrode, and a third electrode disposed between the first electrode and the second electrode. The first electrode and / or the second electrode are grounded, and the third electrode is configured with a negative high voltage potential to form an electric field.

7. The secondary radiation excitation device according to any one of claims 1-6, characterized in that, It also includes electromagnetic lens assemblies; The electromagnetic lens assembly is disposed in the path of the electron beam and close to the metal target. The electromagnetic lens assembly includes: a magnetic yoke with a central through hole and an annular focusing coil disposed within the magnetic yoke, wherein the central axis of the central through hole coincides with the travel path of the electron beam, and the annular focusing coil is used to focus the electron beam passing through it. The magnetic yoke is connected to the ground potential of the secondary radiation excitation device.

8. The secondary radiation excitation device according to claim 6, characterized in that, The conductive film layer disposed on the travel path of the electron beam is fixedly connected to the magnetic yoke, the first electrode, or the second electrode.

9. The secondary radiation excitation device according to claim 8, characterized in that, It also includes ring connectors; The outer ring of the annular connector is fixedly connected to the magnetic yoke, the first electrode, or the second electrode, and the conductive film layer is fixedly connected to the inner ring of the annular connector.

10. An analytical testing instrument, characterized in that, Includes the secondary radiation excitation device as described in any one of claims 1-9.

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