Metastable-state lithium and lithium-like pulsed ion beam preparation device and preparation method

Abstract

The invention discloses a metastable-state lithium and lithium-like pulsed ion beam preparation device which comprises an ion trap, an electron gun, a sputtering laser, an elemental metal target, an ion lens, a superconducting magnetic field coil and a voltage-stabilized source, and further discloses a metastable-state lithium and lithium-like pulsed ion beam preparation method. According to the invention, the electron gun and the ion trap are adopted to realize generation and continuous ionization excitation of target ions, so that the yield of metastable state lithium and lithium-like ions is improved and can be improved to more than 50%; according to the invention, pulse-type extraction of metastable-state lithium ions or metastable-state-like lithium ions is realized by adopting a pulse time sequence extraction mode, and the metastable-state lithium ions or metastable-state-like lithium ions are gathered in the pulse, so that the unit number density of the ion beam is improved; according to the method, required equipment is simpler, the complexity of equipment in the prior art can be effectively broken through, the problems of low ion yield and low ion beam density are solved, and the signal-to-noise ratio is remarkably improved in lithium and lithium-like ion spectrum research, so that the measurement precision is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metastable ion beam preparation, and specifically relates to a device for preparing metastable lithium and lithium-like pulse ion beams, and also relates to a method for preparing metastable lithium and lithium-like pulse ion beams. Background Art

[0002] As a system of few-electron ions, the spectra of lithium and lithium-like ions can be accurately calculated theoretically and can also be accurately measured experimentally. By comparing the results of theoretical calculations with those of nuclear experiments, we can obtain information on the nuclear structure and the precise value of the fine structure constant.

[0003] In the spectrum of lithium and lithium-like ions, the spectrum from the metastable state 2s to the excited state 2p is in the visible light band and is one of the most suitable transitions for spectral measurement. At present, the spectral measurement of lithium and lithium-like ions first requires the generation of metastable lithium and lithium-like ions. The traditional method is to use electron cyclotron resonance or electron bombardment ion source to prepare them. The problem with electron cyclotron resonance is that the equipment is large and complex, and the yield of metastable ions is about 10%. The electron bombardment ion source produces an unstable ion beam with a yield of only about 1%. In addition, the ions they induce are usually continuous ion beams with low unit density of ions. These have seriously affected the signal-to-noise ratio and accuracy of the spectral measurement of lithium and lithium-like ions. Summary of the invention

[0004] The purpose of the present invention is to provide a device for preparing metastable lithium and lithium-like pulsed ion beams, and also to provide a method for preparing metastable lithium and lithium-like pulsed ion beams in order to address the above-mentioned problems existing in the prior art.

[0005] The above-mentioned purpose of the present invention is achieved by the following technical means:

[0006] A device for preparing a metastable lithium and lithium-like pulsed ion beam comprises an ion trap, an electron gun, a sputtering laser, a single metal target, an ion lens, a superconducting magnetic field coil, a voltage-stabilized power supply, a data processing module, and an ion detector. The electron gun and the ion lens are respectively located below and above the ion trap. The voltage-stabilized power supply provides voltage for the ion trap and the ion lens. The ion detector detects the pulsed ion beam of metastable target ions and outputs information of the pulsed ion beam to the data processing module. The data processing module adjusts and optimizes the voltage value and voltage sequence of the ion trap and the ion lens according to the information of the pulsed ion beam. The superconducting magnetic field coil is arranged outside the ion trap. The superconducting magnetic field coil, the ion trap, and the ion lens share a central axis. The exit port of the electron gun is aligned with the central axis of the ion trap. The sputtering laser and the single metal target are respectively located on both sides of the ion trap. The laser exit port of the sputtering laser is aligned with the single metal target.

[0007] As described above, the ion trap includes a first electrode, a second electrode, and a third electrode, the first electrode and the third electrode are both horizontally arranged, the third electrode is located above the first electrode, the second electrode is arranged between the first electrode and the third electrode, the centers of the first electrode and the third electrode are both provided with central through holes, the second electrode includes two pairs of vertically placed electrode rods, the two pairs of electrode rods are arranged opposite to each other and spaced a set distance in between; the first electrode, the second electrode, and the third electrode, the superconducting magnetic field coil, and the ion lens share a common central axis, the electron gun is located directly below the first electrode, the electron gun outlet is aligned with the central through holes of the first electrode and the third electrode, the single-element metal target is arranged on one side of the second electrode, the vertical height of the center of the single-element metal target is consistent with the center height of the second electrode, and the sputtering laser is arranged on the other side of the second electrode.

[0008] As described above, the ion lens includes a fourth electrode, a fifth electrode, and a sixth electrode. The fourth electrode, the fifth electrode, and the sixth electrode are all placed vertically. The fourth electrode is located above the third electrode, the fifth electrode is located above the fourth electrode, the sixth electrode is in the shape of an inverted cone, and the sixth electrode is located above the fifth electrode. Vertical ion channels are provided on the fourth electrode, the fifth electrode, and the sixth electrode. The fourth electrode, the fifth electrode, and the sixth electrode share a central axis with the ion trap, and the bottom diameter of the ion channel of the sixth electrode is smaller than the diameters of the ion channels of the fourth electrode and the fifth electrode.

[0009] As described above, the superconducting magnetic field coil includes an upper magnetic field coil and a lower magnetic field coil having a common central axis, and the upper magnetic field coil and the lower magnetic field coil are spaced apart by a set distance.

[0010] As described above, ceramic gaskets are arranged between the electron gun and the first electrode, the first electrode and the second electrode, the second electrode and the third electrode, the third electrode and the fourth electrode, the fourth electrode and the fifth electrode, the fifth electrode and the sixth electrode, and the elemental metal target and the two electrode plates of the second electrode, and they are all fixedly connected by ceramic screws.

[0011] A method for preparing a metastable lithium and lithium-like pulsed ion beam, using the above-mentioned device for preparing a metastable lithium and lithium-like pulsed ion beam, comprises the following steps:

[0012] Step 1: The sputtering laser generates a laser beam and outputs it to a single metal target after strong focusing. The single metal target generates target atoms and enters the second electrode;

[0013] Step 2: The electron beam generated by the electron gun is focused under the magnetic field generated by the superconducting magnetic field coil and then enters the second electrode to collide with the target atoms to generate target ions;

[0014] Step 3: applying voltage to the ion trap, using the ion trap to trap the target ions, and keeping the electron gun turned on all the time, so that the electron beam generated by the electron gun continuously bombards and excites the target ions to a metastable state;

[0015] Step 4: Apply a voltage to the ion lens and use an ion extraction timing sequence to extract a pulsed ion beam of metastable target ions in cooperation with the ion lens.

[0016] Applying a voltage to the ion trap in Step 3 as described above includes the following process: applying voltages U1, U2, and U3 to the first electrode, the second electrode, and the third electrode respectively, and U1≥U3>U2;

[0017] Step 4 specifically includes the following process: applying voltages U4, U5, and U6 to the fourth electrode, the fifth electrode, and the sixth electrode respectively, then performing a pulse modulation with a period of T on the voltage U2 applied to the second electrode. During each period, the voltage value of the second electrode is increased to U2+ΔU within a duration of Δt, and the voltage value of the second electrode is maintained at U2 at other times of each period, where U3<U2+ΔU. After the metastable target ions overflow the ion trap, the voltage U4 applied to the fourth electrode is much smaller than U2+ΔU, and the metastable target ions that overflow the ion trap are accelerated and extracted by the ion lens to form a pulsed ion beam of metastable target ions.

[0018] The following steps are also included to optimize voltages U1 to U6 and the duration Δt:

[0019] Step 5: Use an ion detector to detect information about the pulsed ion beam and transmit it to a data processing module. The data processing module optimizes the voltage values and voltage timing sequences of voltages U1 to U6 based on the obtained information about the pulsed ion beam, and obtains a pulsed ion beam of metastable target ions with a stable state after optimization.

[0020] Step 5 as described above specifically includes the following steps:

[0021] Step 5.1: Use an ion detector to detect the energy of the pulsed ion beam, the arrival time, and the kinetic energy of the metastable target ions in real time and transmit them to the data processing module. The data processing module outputs an ion pulse signal showing the variation of the pulse intensity with time in real time. The ion pulse signal includes multiple pulse peaks that vary with time. Locate the pulse peak of the metastable target ions based on the kinetic energy and arrival time of the metastable target ions, and obtain the intensity of the pulse peak of the metastable target ions.

[0022] Step 5.2, setting the expected pulse peak intensity A and the change step of voltage U1, voltage U2, and voltage U3, the data processing module obtains a first error signal according to the acquired pulse peak intensity and the expected pulse peak intensity A and outputs the first error signal to the voltage-stabilized power supply, the voltage-stabilized power supply simultaneously changes voltage U1, voltage U2, and voltage U3 according to the first error signal, so that the acquired pulse peak intensity is greater than the expected pulse peak intensity A or the pulse peak intensity of the metastable target ion is the largest, and the optimal voltage U1, the optimal voltage U2, and the optimal voltage U3 are obtained;

[0023] Step 5.3, setting the step size of the expected pulse peak intensity B and the duration Δt, the data processing module obtains a second error signal according to the acquired pulse peak intensity and the expected pulse peak intensity B and outputs the second error signal to the regulated power supply, the regulated power supply changes the duration Δt of the voltage U2+ΔU according to the second error signal, so that the acquired pulse peak intensity is greater than the expected pulse peak intensity B or the pulse peak intensity of the metastable target ion is the largest, and the optimal duration Δt is obtained;

[0024] Step 5.4, set the expected pulse peak intensity C, the change step size of the voltage U4, the change step size of the voltage U5, and the change step size of the voltage U6. The data processing module obtains a third error signal according to the acquired pulse peak intensity and the expected pulse peak intensity C and outputs the third error signal to the voltage-stabilized power supply. The voltage-stabilized power supply changes the voltage U4, the voltage U5, and the voltage U6 in turn according to the third error signal. Each time the optimization is performed, the acquired pulse peak intensity is made greater than the expected pulse peak intensity C or the pulse peak intensity of the metastable target ion is maximized, and then the expected pulse peak intensity is reset and the next voltage is optimized, so that the acquired pulse peak intensity is greater than the expected pulse peak intensity or the pulse peak intensity of the metastable target ion is maximized, and the optimal voltage U4, the optimal voltage U5, and the optimal voltage U6 are obtained in turn.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention uses an electron gun and an ion trap to achieve the generation and continuous ionization excitation of target ions, so as to increase the yield of metastable lithium and lithium-like ions to more than 50%.

[0027] (2) The present invention adopts a pulse timing extraction method to realize the pulse extraction of metastable lithium ions or metastable lithium-like ions, which gathers the metastable lithium ions or metastable lithium-like ions in the pulse, increases the unit number density of the ion beam, and can greatly improve the signal-to-noise ratio and accuracy in spectral measurement.

[0028] (3) The equipment required for the method of the present invention is simpler, which can effectively break through the complexity of existing technical equipment, solve the problems of low ion yield and low ion beam density, and significantly improve the signal-to-noise ratio in lithium and lithium-like ion spectral research, thereby improving measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of the method of the present invention;

[0030] Figure 2 is a schematic diagram of the circuit structure of the device of embodiment 1 of the present invention;

[0031] Figure 3 is a schematic structural diagram of a device according to Embodiment 1 of the present invention;

[0032] Figure 4 is a front view of the device of Example 1 of the present invention;

[0033] Figure 5 is a timing diagram of applying voltage to the first electrode, the second electrode, and the third electrode in Example 2 of the present invention;

[0034] Reference numerals and corresponding component names:

[0035] 1—electron gun; 201—superconducting magnetic field coil; 202—first electrode; 203—second electrode; 204—third electrode; 301—elemental metal target; 303—sputtering laser; 402—fourth electrode; 403—fifth electrode; 404—sixth electrode; 405—ceramic screw; 5—ion detector; 6—data processing module; 7—voltage-stabilized power supply. DETAILED DESCRIPTION

[0036] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below in conjunction with embodiments. The embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0037] Embodiment 1:

[0038] A device for preparing a metastable lithium and lithium-like pulsed ion beam, comprising an ion trap, an electron gun 1, a sputtering laser 303, a single metal target 301 (the present embodiment uses a single metal target 301), an ion lens, a superconducting magnetic field coil 201, a voltage regulator 7, a data processing module 6 (a computer is used in the present embodiment), and an ion detector 5, wherein the electron gun 1 and the ion lens are respectively located below and above the ion trap, the voltage regulator 7 provides voltage for the ion trap and the ion lens, and the ion detector 5 detects the pulsed ion beam of metastable lithium ions and outputs information of the pulsed ion beam to the ion detector 5. The electron beam is output to the data processing module 6, which adjusts and optimizes the voltage value and voltage timing of the ion trap and the ion lens according to the information of the pulsed ion beam. The superconducting magnetic field coil 201 is arranged outside the ion trap. The superconducting magnetic field coil 201, the ion trap, and the ion lens share a central axis. The exit port of the electron gun 1 is aligned with the central axis of the ion trap, so that the electron beam emitted by the electron gun 1 is emitted along the central axis of the ion trap. The sputtering laser 303 and the elemental metal target 301 are respectively located on both sides of the ion trap, and the laser exit port of the sputtering laser 303 is aligned with the elemental metal target 301.

[0039] The ion trap includes a first electrode 202, a second electrode 203, and a third electrode 204. The first electrode 202 and the third electrode 204 are both horizontally arranged, the third electrode 204 is located above the first electrode 202, the second electrode 203 is arranged between the first electrode 202 and the third electrode 204, and the centers of the first electrode 202 and the third electrode 204 are both provided with a central through hole. The second electrode 203 includes two pairs of vertically placed electrode rods, the two pairs of electrode rods are arranged oppositely and spaced apart by a set distance, and each pair of electrode rods includes two electrode rods arranged side by side. The first electrode 202, the second electrode 203, and the third electrode 204 are arranged horizontally, the third electrode 204 is located above the first electrode 202, the second electrode 203, and the third electrode 204 are arranged between the first electrode 202 and the third electrode 204. The third electrode 204, the superconducting magnetic field coil 201, and the ion lens share a central axis, the electron gun 1 is located directly below the first electrode 202, and the outlet of the electron gun 1 is aligned with the central through holes of the first electrode 202 and the third electrode 204; the single-element metal target 301 is arranged on one side of the second electrode 203, and the vertical height of the center of the single-element metal target 301 is consistent with the center height of the second electrode 203, and the sputtering laser 303 is arranged on the other side of the second electrode 203, and the pulsed sputtering laser emitted by the sputtering laser 303 passes through the gap between the electrode rods of the second electrode 203 and hits the single-element metal target 301.

[0040] The ion lens includes a fourth electrode 402, a fifth electrode 403, and a sixth electrode 404. The fourth electrode 402, the fifth electrode 403, and the sixth electrode 404 are all placed vertically. The fourth electrode 402 is located above the third electrode 204, the fifth electrode 403 is located above the fourth electrode 402, the sixth electrode 404 is in the shape of an inverted cone, and the sixth electrode 404 is located above the fifth electrode 403. The fourth electrode 402, the fifth electrode 403, and the sixth electrode 404 are all provided with vertical ion channels. The fourth electrode 402, the fifth electrode 403, and the sixth electrode 404 share a central axis with the ion trap.

[0041] The bottom diameter of the ion channel of the inverted cone-shaped sixth electrode 404 is smaller than the diameters of the ion channels of the fourth electrode 402 and the fifth electrode 403, so that the sixth electrode 404 can not only allow the generated lithium ions to pass smoothly, but also slow down and diverge the electron beam, so that it hits the sixth electrode and is blocked and collected, reducing or eliminating the electron beam that may exist in the pulsed ion beam.

[0042] The superconducting magnetic field coil 201 includes an upper magnetic field coil and a lower magnetic field coil with a common central axis. The upper magnetic field coil and the lower magnetic field coil are separated by a set distance (such as 17 mm). The superconducting magnetic field coil 201 is used to focus the electron beam emitted by the electron gun 1.

[0043] Ceramic gaskets are arranged between the electron gun 1 and the first electrode 202, the first electrode 202 and the second electrode 203, the second electrode 203 and the third electrode 204, the third electrode 204 and the fourth electrode 402, the fourth electrode 402 and the fifth electrode 403, the fifth electrode 403 and the sixth electrode 404, and the elemental metal target 301 and the two electrode plates of the second electrode 203, and they are all fixedly connected by ceramic screws 405.

[0044] By applying voltage U1, voltage U2, and voltage U3 to the first electrode 202, the second electrode 203, and the third electrode 204 of the ion trap respectively, and U1≥U3>U2, the electric potential of the second electrode 203 is the lowest in the axial direction (vertical direction in this embodiment), forming an ion trap region. In the radial direction, since the electron beam passes through the center of the ion trap, the electron beam is focused by the magnetic field generated by the superconducting magnetic field coil 201, and the density of the electron beam presents a Gaussian distribution in the radial direction, that is, the density is the highest in the center of the electron beam, and the density gradually decreases to the edge of the electron beam. Due to the charge accumulation effect and the negative charge of electrons, the electric potential in the center of the electron beam is the lowest, which is a negative potential, and the electric potential at the edge gradually increases to zero potential. Therefore, due to the existence of the electron beam in the radial direction, there will also be a potential well region; then a pulsed sputtering laser is generated by the sputtering laser 303 and focused on the single metal target of lithium. 301, thereby sputtering lithium atoms, and the sputtered lithium atoms scatter in all directions, and some lithium atoms will enter the second electrode 203 along the middle interval of the second electrode. The lithium atoms entering the second electrode 203 will produce target lithium ions under the bombardment of the electron beam generated by the electron gun 1. The produced lithium ions are trapped in the ion trap region in the axial direction and in the center of the electron beam in the radial direction, so that the trapped lithium ions will be bombarded by a continuous stream of electron beams, thereby being continuously excited to a metastable state, thereby increasing the yield of metastable lithium ions.

[0045] Embodiment 2:

[0046] A method for preparing a metastable lithium and lithium-like pulsed ion beam, using a metastable lithium and lithium-like pulsed ion beam preparation device described in the above embodiment 1, comprises the following steps:

[0047] Step 1, turn on the continuous light mode of the sputtering laser 303, the sputtering laser 303 generates a laser beam and outputs it to the lithium metal target 301 after strong focusing, and the short-term pulse energy of the strongly focused laser beam heats the surface of the lithium metal target 301, so that the lithium metal target 301 produces a large number of lithium atoms and enters the second electrode 203.

[0048] As an implementation method, the laser power of the sputtering laser 303 is greater than 1 W, and the beam waist of the focused light spot is less than 50 μm.

[0049] Step 2, turning on the electron gun 1, the electron gun 1 generates an electron beam which is focused under the magnetic field generated by the superconducting magnetic field coil 201 and passes through the central through hole of the first electrode 202, and then collides with the lithium atoms entering the second electrode 203, thereby generating lithium ions;

[0050] As an implementable embodiment, the electron gun 1 generates an electron beam current of >4mA, the energy of the electron beam current is adjustable between 50eV and 500eV, the superconducting magnetic field coil 201 generates a vertical uniform magnetic field of >0.15 Tesla (T) in the ion trap region, the diameter of the electron beam current after being focused by the superconducting magnetic field coil 201 is <0.5mm, the superconducting magnetic field coil 201 uses high-temperature superconducting material, and the total power of the superconducting magnetic field coil 201 is <10W.

[0051] Step 3, applying voltage U1, voltage U2, and voltage U3 to the first electrode 202, the second electrode 203, and the third electrode 204 of the ion trap respectively, and U1≥U3>U2, so that the potential at the second electrode is the lowest, forming an ion trap that can trap ions, and trapping the lithium ions generated in step 2 by the ion trap, and keeping the electron gun 1 turned on all the time, and generating an electron beam through the electron gun 1 to continuously bombard and excite lithium to a metastable state;

[0052] Step 4: applying voltages to the fourth electrode 402, the fifth electrode 403, and the sixth electrode 404 of the ion lens respectively and using an ion extraction timing to cooperate with the ion lens to extract a pulsed ion beam of metastable lithium ions, specifically including the following processes:

[0053] The fourth electrode 402, the fifth electrode 403, and the sixth electrode 404 are respectively applied with voltages U4, U5, and U6, and U3>U4>U5>U6, and then the voltage U2 applied to the second electrode 203 is pulse modulated with a period of T, and the voltage value of the second electrode 203 is increased to U2+ΔU within a duration of Δt in each period, and the voltage value of the second electrode 203 is maintained at U2 for the rest of each period, wherein (U2+ΔU)>U3. During the Δt time, since the voltage U2+ΔU applied to the second electrode 203 is greater than the voltage U3 of the third electrode 204, the lithium ions overflow the ion trap, and the voltage U4 applied to the fourth electrode 402 is much smaller than U2+ΔU, and the metastable lithium ions overflowing the ion trap are accelerated and extracted by the ion lens to form a pulsed ion beam of metastable lithium ions.

[0054] Step 5: Detect the information of the pulsed ion beam using the ion detector 5 and transmit it to the data processing module 6. The data processing module 6 optimizes the voltage values ​​and voltage timing of the voltages U1 to U6 according to the information of the pulsed ion beam obtained, and optimizes to obtain a metastable lithium ion pulsed ion beam with a stable state, which specifically includes the following steps:

[0055] Step 5.1, using the ion detector 5 to detect the energy of the pulsed ion beam and the arrival time and kinetic energy of the metastable lithium ions in real time and transmit them to the data processing module 6, the data processing module 6 outputs in real time an ion pulse signal whose pulse intensity varies with time, the ion pulse signal includes the appearance of multiple pulse peaks that vary with time, corresponding to ions of different mass-to-charge ratios, the pulse peak of the metastable lithium ions is found according to the kinetic energy and arrival time of the metastable lithium ions, and the pulse peak intensity of the metastable lithium ions is obtained through the data processing module 6;

[0056] Step 5.2, setting the expected pulse peak intensity A and the change step of the voltage U1, the voltage U2, and the voltage U3, the data processing module 6 obtains a first error signal according to the acquired pulse peak intensity and the expected pulse peak intensity A and outputs the first error signal to the voltage-stabilized power supply 7, the voltage-stabilized power supply 7 simultaneously changes (increases or decreases) the voltage U1, the voltage U2, and the voltage U3 according to the first error signal, thereby optimizing the voltage U1, the voltage U2, and the voltage U3, so that the acquired pulse peak intensity is greater than the expected pulse peak intensity A or the pulse peak intensity of the lithium ion is the largest, and the optimal voltage U1, the optimal voltage U2, and the optimal voltage U3 are obtained, which specifically includes the following steps:

[0057] Step 5.2.1, set the expected pulse intensity A and the change step of voltage U1, voltage U2, and voltage U3 to 1V, the data processing module 6 obtains the first error signal (A-A0) according to the obtained pulse peak intensity A0 and the expected pulse intensity A and outputs the first error signal to the voltage-stabilized power supply 7, the voltage-stabilized power supply 7 randomly selects an optimization direction (in this embodiment, the voltage U1, voltage U2, and voltage U3 are increased at the same time), and then repeats step 5.1 to obtain a new pulse peak intensity A1;

[0058] Step 5.2.2, obtain a new first error signal according to the expected pulse intensity A of the new pulse peak intensity A1. If A>A1>A0, then the new first error signal A-A1<the previous first error signal A-A0, then continue to increase the voltage U1, the voltage U2, and the voltage U3 at the same time; if A>A0>A1, then the new first error signal A-A1>the previous first error signal A-A0, then reduce the voltage U1, the voltage U2, and the voltage U3 at the same time; until An>A0 after the nth optimization, Or during the n+1th optimization, no matter the voltage U1, voltage U2, and voltage U3 are increased or decreased at the same time, An+1 is less than An, then the optimization of voltage U1, voltage U2, and voltage U3 is completed, and the voltage values ​​after the Anth optimization are the optimal voltage U1, voltage U2, and voltage U3. The voltage U1, voltage U2, and voltage U3 are set to the optimal voltage U1, voltage U2, and voltage U3, at which time the pulse peak intensity of metastable lithium ions is the largest.

[0059] Step 5.3, setting the step size of the expected pulse peak intensity B and the duration Δt change, the data processing module 6 obtains a second error signal according to the acquired pulse peak intensity and the expected pulse peak intensity B and outputs the second error signal to the stabilized power supply 7, the stabilized power supply 7 changes (increases or decreases) the duration Δt of the voltage (U2+ΔU) according to the second error signal, thereby optimizing the duration Δt of the voltage (U2+ΔU), so that the acquired pulse peak intensity is greater than the expected pulse peak intensity B or the pulse peak intensity of the metastable lithium ions is the largest, and the optimal duration Δt is obtained, which specifically includes the following steps:

[0060] Step 5.3.1, set the step size of the expected pulse peak intensity B and the duration Δt to 0.1 μs, the data processing module 6 obtains the second error signal (B-B0) according to the obtained pulse peak intensity B0 and the expected pulse intensity B and outputs the second error signal to the voltage-stabilized power supply 7, the voltage-stabilized power supply 7 randomly selects an optimization direction (in this embodiment, the duration Δt of the voltage (U2+ΔU) is increased), and then repeats step 5.1 to obtain a new pulse peak intensity B1;

[0061] Step 5.3.2, obtain a new second error signal according to the expected pulse intensity B of the new pulse peak intensity B1. If B>B1>B0, the new second error signal B-B1<the previous second error signal B-B0, and continue to increase the duration Δt of the voltage (U2+ΔU); if B>B0>B1, the new second error signal B-B1>the previous second error signal B-B0, and reduce the duration Δt of the voltage (U2+ΔU); until Bn>B0 after the nth optimization, or during the n+1th optimization, regardless of increasing or decreasing the duration Δt of the voltage (U2+ΔU), Bn+1 is less than Bn, then the optimization of the duration Δt of the voltage (U2+ΔU) is completed, and the duration Δt after the Bnth optimization is the optimal duration Δt. The duration Δt of the voltage (U2+ΔU) is set to the optimal duration Δt, at which time the pulse peak intensity of the metastable lithium ions is the largest.

[0062] Step 5.4, setting the expected pulse peak intensity C, the change step size of the voltage U4, the change step size of the voltage U5, and the change step size of the voltage U6, the data processing module 6 obtains a third error signal according to the acquired pulse peak intensity and the expected pulse peak intensity C and outputs the third error signal to the voltage-stabilized power supply 7, the voltage-stabilized power supply 7 sequentially changes (increases or decreases) the voltage U4, the voltage U5, and the voltage U6 according to the third error signal, thereby optimizing the voltage U4, the voltage U5, and the voltage U6, each time the optimization is performed, the acquired pulse peak intensity is made greater than the expected pulse peak intensity C or the pulse peak intensity of the metastable lithium ions is maximized, and then the expected pulse peak intensity is reset and the next voltage is optimized, so that the acquired pulse peak intensity is greater than the expected pulse peak intensity or the pulse peak intensity of the metastable lithium ions is maximized, and the optimal voltage U4, the optimal voltage U5, and the optimal voltage U6 are obtained in turn, which specifically includes the following steps:

[0063] Step 5.4.1, setting the change step of the expected pulse intensity A and the voltage U4 to 5V, the data processing module 6 obtains the third error signal (C-C0) according to the obtained pulse peak intensity C0 and the expected pulse intensity C and outputs the third error signal to the voltage stabilized power supply 7, the voltage stabilized power supply 7 randomly selects an optimization direction (in this embodiment, increasing the voltage U4), and then repeats step 5.1 to obtain a new pulse peak intensity C1;

[0064] Step 5.4.2, obtain a new third error signal according to the expected pulse intensity C of the new pulse peak intensity C1. If C>C1>C0, then the new third error signal C-C1<the previous third error signal C-C0, and the voltage U4 continues to increase; if C>C0>C1, then the new third error signal C-C1>the previous third error signal C-C0, and the voltage U4 is reduced; until Cn>C0 after the nth optimization, or during the n+1th optimization, no matter whether the voltage U4 is increased or decreased, Cn+1 is less than Cn, then the optimization of the voltage U4 is completed, and the voltage value after the Cnth optimization is the optimal voltage U4. The voltage U4 is set to the optimal voltage U4, at which time the pulse peak intensity of the metastable lithium ions is the largest.

[0065] Step 5.4.3: Repeat steps 5.4.1 and 5.4.2 to optimize voltage U5 and voltage U6 in turn to obtain the optimal voltage U5 and voltage U6.

[0066] After the optimization is completed, the ion detector 5 can be removed, and the ions can be led out to other related equipment and instruments farther away for spectral measurement. The ions led out are pulsed ion beams of lithium ions with a period of T and a pulse width ≤Δt.

[0067] As an implementation method, the period T is in the range of 10 ms-1 s, the duration Δt is in the range of 0.5 μs-5 μs, and the voltage ΔU is between 10-100 V. The lithium metal target 301 in this embodiment can also be replaced by a lithium-ion-like or other target metal metal target 301 .

[0068] It should be noted that the embodiments described in the present invention are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.

Claims

1. A device for preparing a metastable lithium and lithium-like pulsed ion beam, comprising an ion trap, characterized in that: The invention also comprises an electron gun (1), a sputtering laser (303), a simple metal target (301), an ion lens, a superconducting magnetic field coil (201), a voltage-stabilized power supply (7), a data processing module (6), and an ion detector (5). The electron gun (1) and the ion lens are respectively located below and above the ion trap. The voltage-stabilized power supply (7) provides voltage for the ion trap and the ion lens. The ion detector (5) detects the pulsed ion beam of the metastable target ions and outputs the information of the pulsed ion beam to the data processing module (6). The data processing module (6) adjusts and optimizes the voltage value and the voltage sequence of the ion trap and the ion lens according to the information of the pulsed ion beam. The superconducting magnetic field coil (201) is arranged outside the ion trap. The superconducting magnetic field coil (201), the ion trap, and the ion lens share a central axis. The exit port of the electron gun (1) is aligned with the central axis of the ion trap. The sputtering laser (303) and the simple metal target (301) are respectively located on both sides of the ion trap. The laser exit port of the sputtering laser (303) is aligned with the simple metal target (301).

2. A metastable lithium and lithium-like pulse ion beam preparation device according to claim 1, characterized in that: The ion trap comprises a first electrode (202), a second electrode (203), and a third electrode (204); the first electrode (202) and the third electrode (204) are both arranged horizontally; the third electrode (204) is located above the first electrode (202); the second electrode (203) is arranged between the first electrode (202) and the third electrode (204); a central through hole is arranged at the center of the first electrode (202) and the third electrode (204); the second electrode (203) comprises two pairs of vertically placed electrode rods; the two pairs of electrode rods are arranged opposite to each other and are spaced apart by a set distance; the first electrode (202) and the third electrode (204) are arranged horizontally; the third electrode (204) and the first electrode (202) are arranged horizontally; the third electrode (204) and the first electrode (202) are arranged horizontally; the third electrode (204) and the first electrode (203 ... The first electrode (202), the second electrode (203), and the third electrode (204), the superconducting magnetic field coil (201), and the ion lens share a central axis; the electron gun (1) is located directly below the first electrode (202); the electron gun (1) has an outlet aligned with the central through holes of the first electrode (202) and the third electrode (204); a single metal target (301) is arranged on one side of the second electrode (203); the vertical height of the center of the single metal target (301) is consistent with the center height of the second electrode (203); and a sputtering laser (303) is arranged on the other side of the second electrode (203).

3. The device for preparing metastable lithium and lithium-like pulsed ion beams according to claim 2, characterized in that: The ion lens comprises a fourth electrode (402), a fifth electrode (403), and a sixth electrode (404); the fourth electrode (402), the fifth electrode (403), and the sixth electrode (404) are all placed vertically; the fourth electrode (402) is located above the third electrode (204); the fifth electrode (403) is located above the fourth electrode (402); the sixth electrode (404) is in the shape of an inverted cone; the sixth electrode (404) is located above the fifth electrode (403); vertical ion channels are provided on the fourth electrode (402), the fifth electrode (403), and the sixth electrode (404); the fourth electrode (402), the fifth electrode (403), and the sixth electrode (404) share a central axis with the ion trap; and the bottom diameter of the ion channel of the sixth electrode (404) is smaller than the diameters of the ion channels of the fourth electrode (402) and the fifth electrode (403).

4. The device for preparing metastable lithium and lithium-like pulsed ion beams according to claim 3, characterized in that: The superconducting magnetic field coil (201) comprises an upper magnetic field coil and a lower magnetic field coil having a common central axis, and a set distance is spaced between the upper magnetic field coil and the lower magnetic field coil.

5. The device for preparing metastable lithium and lithium-like pulsed ion beams according to claim 4, characterized in that: Ceramic gaskets are provided between the electron gun (1) and the first electrode (202), the first electrode (202) and the second electrode (203), the second electrode (203) and the third electrode (204), the third electrode (204) and the fourth electrode (402), the fourth electrode (402) and the fifth electrode (403), the fifth electrode (403) and the sixth electrode (404), and the single metal target (301) and the two electrode plates of the second electrode (203), and are fixedly connected by ceramic screws (405).

6. A method for preparing a metastable lithium and lithium-like pulsed ion beam, using the device for preparing a metastable lithium and lithium-like pulsed ion beam according to claim 5, characterized in that: The following steps are involved: Step 1: The sputtering laser (303) generates a laser beam and outputs it to the single-element metal target (301) after strong focusing, and the single-element metal target (301) generates target atoms and enters the interior of the second electrode (203); Step 2: The electron beam generated by the electron gun (1) is focused under the magnetic field generated by the superconducting magnetic field coil (201) and then enters the second electrode (203) to collide with the target atoms to generate target ions; Step 3, applying voltage to the ion trap, using the ion trap to trap the target ions, and keeping the electron gun (1) turned on all the time, so that the electron gun (1) generates an electron beam to continuously bombard and excite the target ions to a metastable state; Step 4: Apply voltage to the ion lens and use an ion extraction sequence in conjunction with the ion lens to extract a pulsed ion beam of metastable target ions.

7. A method for preparing metastable lithium and lithium-like pulsed ion beams according to claim 6, characterized in that: The step 3 of applying voltage to the ion trap includes the following process: applying voltage U1, voltage U2, and voltage U3 to the first electrode (202), the second electrode (203), and the third electrode (204), respectively, and U1≥U3>U2; Step 4 specifically includes the following process: Voltages U4, U5, and U6 are respectively applied to the fourth electrode (402), the fifth electrode (403), and the sixth electrode (404), and then the voltage U2 applied to the second electrode (203) is subjected to pulse modulation with a period of T. During a duration of Δt in each period, the voltage value of the second electrode (203) is increased to U2 + ΔU, and the voltage value of the second electrode (203) is maintained at U2 at other times in each period. Where U3 < U2 + ΔU, after the metastable target ions overflow from the ion trap, the voltage U4 applied to the fourth electrode (402) is much smaller than U2 + ΔU, and the metastable target ions overflowing from the ion trap are accelerated and extracted by the ion lens to form a pulsed ion beam of metastable target ions.

8. The method for preparing metastable lithium and lithium-like pulsed ion beams according to claim 7, characterized in that: The following steps are also included to optimize voltages U1 to U6 and the duration Δt: Step 5: Use an ion detector (5) to detect information about the pulsed ion beam and transmit it to the data processing module (6). The data processing module (6) optimizes the voltage values and voltage timings of voltages U1 to U6 according to the obtained information about the pulsed ion beam, and after optimization, a pulsed ion beam of metastable target ions with stable state is obtained.

9. The method for preparing metastable lithium and lithium-like pulsed ion beams according to claim 8, characterized in that: Step 5 specifically includes the following steps: Step 5.1: Use an ion detector (5) to detect the energy of the pulsed ion beam, the arrival time and kinetic energy of the metastable target ions in real time and transmit them to the data processing module (6). The data processing module (6) outputs an ion pulse signal of the pulse intensity varying with time in real time. The ion pulse signal includes multiple pulse peaks varying with time. The pulse peak of the metastable target ions is found according to the kinetic energy and arrival time of the metastable target ions, and the pulse peak intensity of the metastable target ions is obtained. Step 5.2: Set the expected pulse peak intensity A and the change step sizes of voltages U1, U2, and U3. The data processing module (6) obtains a first error signal according to the obtained pulse peak intensity and the expected pulse peak intensity A and outputs the first error signal to the voltage stabilizer (7). The voltage stabilizer (7) simultaneously changes voltages U1, U2, and U3 according to the first error signal, so that the obtained pulse peak intensity is greater than the expected pulse peak intensity A or the pulse peak intensity of the metastable target ions is the largest, and the optimal voltages U1, the optimal voltage U2, and the optimal voltage U3 are obtained. Step 5.3: Set the expected pulse peak intensity B and the change step size of the duration Δt. The data processing module (6) obtains a second error signal according to the obtained pulse peak intensity and the expected pulse peak intensity B and outputs the second error signal to the voltage stabilizer (7). The voltage stabilizer (7) changes the duration Δt of U2 + ΔU according to the second error signal, so that the obtained pulse peak intensity is greater than the expected pulse peak intensity B or the pulse peak intensity of the metastable target ions is the largest, and the optimal duration Δt is obtained. Step 5.4, setting the expected pulse peak intensity C, the change step size of the voltage U4, the change step size of the voltage U5, and the change step size of the voltage U6. The data processing module (6) obtains a third error signal according to the acquired pulse peak intensity and the expected pulse peak intensity C and outputs the third error signal to the voltage-stabilized power supply (7). The voltage-stabilized power supply (7) sequentially changes the voltage U4, the voltage U5, and the voltage U6 according to the third error signal. Each time the optimization is performed, the acquired pulse peak intensity is made greater than the expected pulse peak intensity C or the pulse peak intensity of the metastable target ion is maximized, and then the expected pulse peak intensity is reset and the next voltage is optimized, so that the acquired pulse peak intensity is greater than the expected pulse peak intensity or the pulse peak intensity of the metastable target ion is maximized, and the optimal voltage U4, the optimal voltage U5, and the optimal voltage U6 are obtained in turn.

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