Photoelectron spectrometer

Abstract

The utility model relates to a photoelectron spectrometer, which comprises a main cavity and a gas injection device, an inner cavity is limited by the main cavity, and the gas injection device is positioned outside the inner cavity, is communicated with the inner cavity and is used for injecting inert gas into the inner cavity; a vacuumizing hole is formed in the main cavity and is used for communicating the vacuumizing device with the inner cavity, so that the inner cavity is vacuumized through the vacuumizing device; eight electronic time-of-flight spectrometers are arranged in the inner cavity, and the electronic time-of-flight spectrometers are located on the same plane and arranged around a center shaft extending in the Y direction; the main cavity is provided with an incident port, and the incident port is used for enabling light to be incident into the inner cavity and transmitting the light along the central axis. To-be-detected light interacts with inert gas in the inner cavity to generate photoelectrons, and each electron time-of-flight spectrometer is used for collecting and detecting the photoelectrons; and an electronics system is arranged outside the inner cavity, is electrically connected with the electronic time-of-flight spectrometers, and is used for determining the photoelectron kinetic energy according to the detection results of the electronic time-of-flight spectrometers.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of optoelectronic energy detection, more particularly to a photoelectron spectrometer. BACKGROUND

[0002] Currently, the free electron laser (XFEL) devices in operation and under construction in the world mainly include self-amplified spontaneous emission (SASE) (for details, see document 1 and document 2) and high-gain high-harmonic amplification (HGHG) (for details, see document 3 and document 4) types. The radiation characteristics of the XFEL beamline operated in the SASE mode fluctuate from pulse to pulse due to the random SASE process. This random characteristic makes the energy spectrum distribution of each XFEL pulse have a non-negligible fluctuation and random jitter. Typically, the pulse-to-pulse energy spectrum fluctuation can randomly vary within the range of 0.1% to 5% of the relative bandwidth (for details, see document 5). Therefore, the real-time and high-precision measurement of the XFEL energy spectrum has become a problem to be solved in the scientific research field. This not only plays a crucial role in beam control, beam transmission control and experimental station debugging, but also is an indispensable basic beam information for scientific users to analyze experimental data.

[0003] wherein document 1 is: Kondratenko, A. M.; Saldin, E. L. Generating of coherent radiation by a relativistic electron beam in an ondulator. Part. Accel. 1980, 10, 207-216; document 2 is: Bonifacio, R.; Pellegrini, C.; Narducci, L. M. Collective instabilities and high-gain regime in a free electron laser. Opt. Commun. 1984, 50, 373-378; document 3 is: Yu, L.-H. Generation of intense uv radiation by subharmonically seeded single-pass free-electron lasers. Phys. Rev. A 1991, 44, 5178; document 4 is: Yu, L.-H.; Babzien, M. High-gain harmonic-generation free-electron laser. Science 2000, 289, 932-935; and document 5 is: Bermúdez Macías IJ, Düsterer S, Ivanov R, et al. Study of temporal, spectral, arrival time and energy fluctuations of SASE FEL pulses. Optics Express. 2021 Mar; 29(7): 10491-10508. Content of the utility model

[0004] The utility model aims at providing a photoelectron spectrometer, which can measure photoelectron kinetic energy in real time and high precision, so as to determine the energy spectrum information of light through photoelectron kinetic energy.

[0005] In order to achieve the above object, the utility model provides a kind of photoelectron spectrometer, including main cavity and gas injection device, the main cavity defines a inner cavity, the gas injection device is located the inner cavity outside and with the inner cavity communication, for injecting inert gas into the inner cavity;Vacuumizing hole is equipped on the main cavity, the vacuumizing hole is used to make vacuumizing device with the inner cavity communication, to carry out vacuumizing to the inner cavity by the vacuumizing device;Eight electron time-of-flight spectrometers are equipped in the inner cavity, each electron time-of-flight spectrometer is located the same plane and is arranged around the center axis extending along Y direction;Incident port is equipped on the main cavity, the incident port is used for the light to be measured to be incident into the inner cavity and transmit along the center axis;The light to be measured interacts with the inert gas in the inner cavity and generates photoelectron, each electron time-of-flight spectrometer is used to collect and detect the photoelectron;Electronic system is equipped outside the inner cavity, the electronic system is electrically connected with each electron time-of-flight spectrometer, for determining photoelectron kinetic energy according to the detection result of each electron time-of-flight spectrometer.

[0006] Further, each electron time-of-flight spectrometer is divided into four groups, two electron time-of-flight spectrometers of each group are symmetrically arranged relative to the center axis and coaxial, two electron time-of-flight spectrometers of the first group are arranged in Z direction, two electron time-of-flight spectrometers of the second group are arranged in X direction, the third group and the fourth group intersect each other, and the angle between the axis of two electron time-of-flight spectrometers of the third group and X direction and the angle between the axis of two electron time-of-flight spectrometers of the fourth group and X direction are both 54.7°.

[0007] Further, the spacing between two electron time-of-flight spectrometers of each group is 50mm.

[0008] Further, each electron time-of-flight spectrometer includes a shell, the shell is provided with electrostatic lens, field-free drift tube and detector arranged in sequence, one end of the shell is formed into a receiving portion, the receiving portion is used for the photoelectron to enter the shell, the photoelectron reaches the detector after passing through the electrostatic lens and the field-free drift tube in sequence, and the detector is used for detecting the number of photoelectrons reaching the detector at different times.

[0009] Further, the electronic system is used for determining photoelectron kinetic energy according to the number of photoelectrons reaching the detector at different times detected by the detector of each electron time-of-flight spectrometer.

[0010] Further, the electrostatic lens includes a plurality of non-magnetic ring electrodes arranged in sequence with intervals, and a voltage is applied to each ring electrode.

[0011] Further, the spacing of any two adjacent ring electrodes is the same, and a hollow insulating column is arranged between any two adjacent ring electrodes and between the field-free drift tube and the adjacent ring electrode.

[0012] Further, the field-free drift tube is a field-free drift tube made of non-magnetic metal.

[0013] Further, the gas injection device comprises a gas storage bottle, a gas pipe and a capillary gas injection rod, the gas storage bottle is connected with one end of the gas pipe, the other end of the gas pipe is connected with one end of the capillary gas injection rod, the other end of the capillary gas injection rod extends into the inner cavity, and a micro leakage valve is arranged on the gas pipe.

[0014] Further, the inner wall of the main cavity and the inner wall of the outer shell are both embedded with permalloy. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the photoelectron spectrometer according to the embodiment of the utility model;

[0016] Figure 2 It is a structural schematic diagram of the electron time-of-flight spectrometer of the photoelectron spectrometer according to the embodiment of the utility model;

[0017] Figure 3 It is a structural schematic diagram of the gas injection device of the photoelectron spectrometer according to the embodiment of the utility model;

[0018] Figure 4 It is a flight trajectory schematic diagram of photoelectrons in the Simion simulation according to the embodiment of the utility model;

[0019] Figure 5 It is a time-of-flight spectrum schematic diagram of photoelectrons according to the embodiment of the utility model. DETAILED DESCRIPTION

[0020] The preferred embodiments of the utility model are described in detail below with reference to the drawings.

[0021] As Figure 1As shown, the utility model embodiment provides a kind of photoelectron spectrometer, including main cavity 100 and injection device 200, main cavity 100 limits one inner cavity 110, injection device 200 is located inner cavity 110 outside and is communicated with inner cavity 110, for injecting inert gas into inner cavity 110;Vacuum hole 120 is equipped on main cavity 100, and vacuum hole 120 is used to make vacuumizing device (for example molecular pump) and inner cavity 110 communicate, to carry out vacuumizing to inner cavity 110 by vacuumizing device, so that inner cavity 110 is in vacuum environment that vacuum degree meets experimental requirement;Eight electron time-of-flight spectrometer 300 are equipped in inner cavity 110, eight electron time-of-flight spectrometer 300 are located same plane (for example XZ plane) and surround center axis O and are arranged, wherein center axis O extends along Y direction, and Y direction is the direction perpendicular to XZ plane (i.e. the direction perpendicular to paper surface);Incident port (not shown in the drawing) is equipped on main cavity 100, and incident port is used to supply the light (for example X ray) to be measured to be incident to inner cavity 110 and transmit along center axis O;After the light to be measured enters inner cavity 110, it will interact with inert gas, and gas atom absorbs high-energy light to be measured and is ionized, and generates photoelectron;Each electron time-of-flight spectrometer 300 is used to collect photoelectron, and the photoelectron collected is detected;Electronic system 400 is equipped outside inner cavity 110, and electronic system 400 is connected (for example electrically connected) with each electron time-of-flight spectrometer 300, for determining photoelectron kinetic energy according to the detection result of each electron time-of-flight spectrometer 300.

[0022] In some embodiments, the inert gas can be argon, krypton, xenon, nitrogen, etc.

[0023] In some embodiments, eight electron time-of-flight spectrometers 300 are divided into four groups, each group includes two electron time-of-flight spectrometers 300, and the two electron time-of-flight spectrometers 300 of each group are symmetrically arranged relative to the center axis O and coaxial (the axis of the two passes through O point), the two electron time-of-flight spectrometers 300 of the first group are arranged in Z direction, the two electron time-of-flight spectrometers 300 of the second group are arranged in X direction, the third group and the fourth group intersect each other, and the angle α between the axis of the two electron time-of-flight spectrometers 300 of the third group and X direction is 54.7°, and the angle β between the axis of the two electron time-of-flight spectrometers 300 of the fourth group and X direction is also 54.7°.

[0024] In some embodiments, the spacing between the two electron time-of-flight spectrometers 300 of each group is 50mm.

[0025] As Figure 2As shown, in some embodiments, the electron time-of-flight spectrometer 300 comprises a housing 310, inside which are arranged an electrostatic lens 320, a field-free drift tube 330 and a detector 340, one end of the housing 310 is formed into a receiving portion 311, the receiving portion 311, the electrostatic lens 320, the field-free drift tube 330 and the detector 340 are arranged in sequence, photoelectrons can enter the housing 310 from the receiving portion 311 and pass through the electrostatic lens 320 and the field-free drift tube 330 in sequence, and then reach the detector 340, the detector 340 can detect the number of photoelectrons reaching the detector 340 at different times.

[0026] An electronic system is connected to the detector 340 of each electron time-of-flight spectrometer 300, for obtaining the number of photoelectrons reaching the detector 340 at different times detected by the detector 340 and determining the kinetic energy of the photoelectrons according to them. Specifically, the electronic system can determine the photoelectron generation time according to the trigger device arranged in the inner cavity 110 in advance, and then subtract the time of arrival of photoelectrons reaching the detector 300 at each time from the photoelectron generation time, to obtain the time of flight of photoelectrons at that time, according to the time of flight of photoelectrons at different times and the number of photoelectrons, the time-of-flight spectrum of photoelectrons can be obtained, the time of flight of photoelectrons is related to the energy of photoelectrons, and the kinetic energy of photoelectrons can be obtained according to the time of flight. The kinetic energy of photoelectrons is the difference between the photon energy and the electron binding energy, the electron binding energy can be obtained in advance according to the type of inert gas, thereby the photon energy can be obtained, and the energy spectrum information of light can be obtained according to the photon energy and the number of photoelectrons (the number of photoelectrons is proportional to the light intensity).

[0027] In some embodiments, the electrostatic lens 320 comprises a plurality of non-magnetic metal ring electrodes 321 arranged in sequence with intervals, a voltage is applied to the ring electrodes 321 to generate an electrostatic field, and the electrostatic field generated by each ring electrode 321 can focus photoelectrons.

[0028] In some embodiments, the distance between any two adjacent ring electrodes 321 can be set to be the same. A hollow insulating column is arranged between any two adjacent ring electrodes 321 and between the field-free drift tube 330 and the ring electrode 321 adjacent thereto for isolation, the hollow insulating column can be multiple (for example, three), each ring electrode 321 is fixed by a screw rod passing through the center hole of the insulating column, and a pin hole for fixing a lead wire is arranged on the outer diameter edge of each ring electrode 321.

[0029] In some embodiments, the number of ring electrodes 321 is 13.

[0030] In some embodiments, the field-free drift tube 330 is a non-magnetic metal cylindrical barrel structure. The length of the field-free drift tube is 550 mm.

[0031] In some embodiments, the receiving part 311 is formed in a conical shape, and its receiving angle is ±3° (i.e., α = β = 3°).

[0032] In some embodiments, the inner wall of the main cavity 100 and the inner wall of the outer shell 310 are both nested with permalloy as a magnetic shielding structure to reduce or eliminate the interference of external magnetic fields on electron movement.

[0033] like Figure 3 As shown, in some embodiments, the gas injection device 200 may include a gas storage cylinder 210, a gas tube 220, and a capillary injection rod 230. The gas storage cylinder 210 is used to store inert gas. One end of the gas storage cylinder 210 is connected to the gas tube 220, and the other end of the gas tube 220 is connected to one end of the capillary injection rod 230. The other end of the capillary injection rod 230 extends into the inner cavity 110 to inject the inert gas from the gas storage cylinder 210 into the inner cavity 110. A micro-leakage valve 240 may be provided on the gas tube 220, through which the gas flow and flow rate can be controlled.

[0034] The space enclosed by each electronic time-of-flight spectrometer 300 can be called the target area. The capillary gas injection tube 230 can extend into the target area to inject inert gas into the target area.

[0035] The gas injection direction is located in the horizontal plane and forms a 45° angle with the optical path.

[0036] In some embodiments, the outer diameter of the capillary injection rod 230 is 1 mm, and the inner diameter of the capillary injection rod 230 is 0.3 mm.

[0037] The trajectory and time-of-flight spectrum of the electron time-of-flight spectrometer 300 were analyzed using Simion software. The results showed that under the conditions of a spot size of 3 mm and an initial electron kinetic energy of 120 electron volts, the electrons reached the detector 340 after deceleration, focusing and transmission by the electron time-of-flight spectrometer 300. The energy of the photoelectrons after deceleration was 10 eV. Figure 4 This is a diagram of the electron's flight trajectory in a Simion simulation. Figure 5 The time-of-flight spectra are for initial kinetic energies of 120 eV (right peak) and 120.03 eV (left peak). This electron time-of-flight spectrometer 300 achieves an energy resolution of 0.03 eV and an electron transport efficiency of up to 90%.

[0038] The photoelectron spectrometer of this invention can measure photoelectron kinetic energy in real time and with high precision, so as to determine the energy spectrum information of light (such as free electron laser) through photoelectron kinetic energy, thereby providing strong technical support for in-depth research in the fields of free electron laser device energy spectrum diagnosis, optoelectronics, materials science, and biomedicine.

[0039] The above merely describes preferred embodiments of the present application, and is not intended to limit the scope of the present application, and the above embodiments of the present application can be variously changed. That is, simple, equivalent changes and modifications made according to the content of the claims and the specification of the present application fall within the scope of the claims of the present application. The present application is not described in detail, and is conventional technical content.

Claims

1. A photoelectron spectrometer, characterized in that, The device includes a main cavity and a gas injection device. The main cavity defines an inner cavity, and the gas injection device is located outside the inner cavity and communicates with it to inject inert gas into the inner cavity. The main cavity has a vacuum port for communicating with the vacuum device to evacuate the inner cavity. Eight time-of-flight spectrometers (TOF-SFS) are located within the inner cavity, all positioned in the same plane and arranged around a central axis extending along the Y direction. An entrance port is provided on the main cavity for incident light to the inner cavity and propagate along the central axis. The light interacts with the inert gas within the inner cavity to generate photoelectrons, and each TOF-SFS collects and detects these photoelectrons. An electronics system is located outside the inner cavity and electrically connected to each TOF-SFS to determine the kinetic energy of the photoelectrons based on their detection results.

2. The photoelectron spectrometer according to claim 1, characterized in that, Each electronic time-of-flight spectrometer is divided into four groups. The two electronic time-of-flight spectrometers in each group are symmetrically arranged with respect to the central axis and are coaxial. The two electronic time-of-flight spectrometers in the first group are arranged in the Z-axis, the two electronic time-of-flight spectrometers in the second group are arranged in the X-axis, and the third and fourth groups intersect each other. The angle between the axis of the two electronic time-of-flight spectrometers in the third group and the X-axis and the axis of the two electronic time-of-flight spectrometers in the fourth group are both 54.7°.

3. The photoelectron spectrometer according to claim 2, characterized in that, The spacing between the two electronic time-of-flight spectrometers in each group is 50 mm.

4. The photoelectron spectrometer according to claim 1, characterized in that, Each electron time-of-flight spectrometer includes a housing containing an electrostatic lens, a field-free drift tube, and a detector arranged in sequence. One end of the housing is formed as a receiving section, which allows photoelectrons to enter the housing. The photoelectrons pass sequentially through the electrostatic lens and the field-free drift tube before reaching the detector, which is used to detect the number of photoelectrons arriving at the detector at different times.

5. The photoelectron spectrometer according to claim 4, characterized in that, The electronics system is used to determine the photoelectron kinetic energy based on the number of photoelectrons arriving at the detector at different times detected by the detectors of each electron time-of-flight spectrometer.

6. The photoelectron spectrometer according to claim 4, characterized in that, The electrostatic lens includes a plurality of non-magnetic ring electrodes arranged at intervals in sequence, and a voltage is applied to each ring electrode.

7. The photoelectron spectrometer according to claim 6, characterized in that, The spacing between any two adjacent annular electrodes is the same; a hollow insulating column is provided between any two adjacent annular electrodes and between the fieldless drift tube and its adjacent annular electrode.

8. The photoelectron spectrometer according to claim 4, characterized in that, The field-free drift tube is a non-magnetic metal cylindrical barrel; the length of the field-free drift tube is 550mm.

9. The photoelectron spectrometer according to claim 1, characterized in that, The gas injection device includes a gas storage bottle, a gas tube, and a capillary gas injection rod. The gas storage bottle is connected to one end of the gas tube, and the other end of the gas tube is connected to one end of the capillary gas injection rod. The other end of the capillary gas injection rod extends into the inner cavity. A micro-leakage valve is provided on the gas tube.

10. The photoelectron spectrometer according to claim 4, characterized in that, Both the inner wall of the main cavity and the inner wall of the outer shell are inlaid with permalloy.

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