Liquid sheet sample injection system and method for x-ray free electron laser experiments

Abstract

The application relates to a liquid sheet injection system and method for X-ray free electron laser experiments, which comprises a pneumatic nozzle device, a flow control device, a signal acquisition device and a vacuum device; the pneumatic nozzle device and the signal acquisition device are respectively arranged in the vacuum device, the pneumatic nozzle device comprises a tube assembly, a gas capillary and a liquid capillary are respectively arranged in the tube assembly, and the gas capillary and the liquid capillary are connected with the flow control device; the end of the liquid capillary comprises two symmetrically arranged flow guide inclined surfaces, two symmetrically arranged abutting inclined surfaces and a bottom surface, the flow guide inclined surfaces and the abutting inclined surfaces are alternately distributed around the bottom surface, and a first outlet is arranged on the bottom surface; a gas micro-flow channel is formed between the end inner wall of the tube assembly and the flow guide inclined surface, and a second outlet is arranged at the end of the tube assembly. The application utilizes the compression and shearing effect of high-speed gas on liquid to generate a free-flowing liquid sheet with a sub-micron thickness under vacuum.

Description

Technical Field

[0001] This application relates to the field of liquid thin-film injection equipment technology, and in particular to a liquid thin-film injection system and method for X-ray free electron laser experiments. Background Technology

[0002] Most chemical reactions and almost all biochemical reactions occur in aqueous solutions. Studying the kinetics and reaction pathways in solution systems is crucial for understanding the nature of reactions and life processes. The advent of X-ray free-electron lasers has facilitated leaps in the development of chemistry and biology at the atomic and molecular scales, providing a new tool for studying liquid-phase systems. However, traditional sample introduction methods such as fixed targets and solution sample cells cannot meet the new requirements in X-ray free-electron laser experiments. This is because high-energy X-ray pulses can disrupt traditional sample introduction systems and generate strong stray signals, and it is difficult to introduce sample solutions into the vacuum chamber without compromising vacuum levels. In particular, soft X-rays can only penetrate a few micrometers of solution, and the liquid layer in traditional sample introduction methods is too thick, limiting the transmission of X-rays and electrons.

[0003] Currently, the primary method for liquid sample introduction in X-ray free electron lasers (XPELs) is liquid flake technology. This technology can generate continuously flowing liquid flakes with a thickness of micrometers in a vacuum, at which photons can be easily transported. Devices used to generate liquid flakes mainly include slit nozzles, impact nozzles, and microfluidic chip pneumatic nozzles. Slit nozzles and impact nozzles produce relatively thick liquid flakes (typically between one and several hundred micrometers), and are prone to icing and clogging due to liquid evaporation in a vacuum, making them unsuitable for the sample introduction requirements of XPEL experiments. Microfluidic chip pneumatic nozzles utilize borosilicate chips fabricated using photolithography to generate submicrometer-thick liquid flakes using pneumatic principles, requiring a relatively high sample solution flow rate (approximately 150-250 μL / min). When microfluidic chip pneumatic nozzles are used in XPEL experimental chambers, additional mechanical devices and tubing are required, resulting in poor compatibility with other sample introduction technologies and hindering the design of multifunctional experimental stations.

[0004] This invention is proposed to solve the above-mentioned problems. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a liquid thin-film injection system and method for X-ray free electron laser experiments, which solves the problems of large sample thickness, high sample consumption and poor compatibility between different injection methods when injecting sample solutions in X-ray free electron laser experiments.

[0006] To achieve the above and other related objectives, this application provides a liquid thin-film sample introduction system for X-ray free electron laser experiments, comprising a pneumatic nozzle device, a flow control device, a signal acquisition device, and a vacuum device; the pneumatic nozzle device and the signal acquisition device are respectively disposed within the vacuum device; the pneumatic nozzle device includes a tube assembly, in which a gas capillary and a liquid capillary are respectively disposed, and the gas capillary and the liquid capillary are respectively connected to the flow control device; the end of the liquid capillary includes two symmetrically arranged guiding slopes, two symmetrically arranged contact slopes, and a bottom surface, the guiding slopes and the contact slopes being alternately distributed around the bottom surface, and a first outlet being provided on the bottom surface; a gas microchannel is formed between the inner wall of the end of the tube assembly and the guiding slopes, and a second outlet is provided at the end of the tube assembly.

[0007] In some embodiments of the present invention, the included angle between the two guide slopes is 30°-70°.

[0008] In some embodiments of the present invention, the included angle between the two mating inclined surfaces is 40°-100°.

[0009] In some embodiments of the present invention, the gas capillary has an inner diameter of 20-75 μm, an outer diameter of 300-430 μm, and a length of 500-1000 mm.

[0010] In some embodiments of the present invention, the gas capillary is a fused silica capillary.

[0011] In some embodiments of the present invention, the liquid capillary has an inner diameter of 20-80 μm, an outer diameter of 300-450 μm, and a length of 800-1000 mm.

[0012] In some embodiments of the present invention, the liquid capillary is a fused silica capillary.

[0013] In some embodiments of the present invention, the tube assembly includes a connected stainless steel extension tube and an outer glass tube, the gas capillary is disposed inside the stainless steel extension tube, and the liquid capillary extends from the stainless steel extension tube into the end of the outer glass tube.

[0014] In some embodiments of the present invention, the stainless steel extension tube and the outer glass tube are sealed and fixed by a first sealant.

[0015] In some embodiments of the present invention, the stainless steel extension tube has an inner diameter of 1000-1200 μm and an outer diameter of 1400-1800 μm.

[0016] In some embodiments of the present invention, the inner diameter of the outer glass tube is 500-850 μm and the outer diameter is 1000-1200 μm.

[0017] In some embodiments of the present invention, the second outlet is located at the end of the outer glass tube, and the diameter of the second outlet is 30-80 μm.

[0018] In some embodiments of the present invention, the outer glass tube and the liquid capillary are connected by a central positioning ring.

[0019] In some embodiments of the present invention, the gas capillary, the liquid capillary, and the stainless steel extension tube are sealed and fixed by a second sealant.

[0020] In some embodiments of the present invention, the tube assembly is fitted with a fastening joint, and the pneumatic nozzle device further includes a movable vacuum interface for moving the tube assembly, gas capillary, and liquid capillary as a whole. The movable vacuum interface includes a connected three-axis manipulator and an internal pipe.

[0021] In some embodiments of the present invention, the flow control device includes a nitrogen cylinder, a nitrogen electronic pressure regulator, a sample cell, and a liquid mass flow meter connected in sequence; the liquid mass flow meter is connected to the liquid capillary.

[0022] In some embodiments of the present invention, the flow control device further includes a helium cylinder, a helium electronic pressure regulator, and a gas mass flow meter connected in sequence; the gas mass flow meter is connected to the gas capillary tube.

[0023] In some embodiments of the present invention, the signal acquisition device includes an X-ray free electron laser source and a sensor. The laser pulse generated by the X-ray free electron laser source comes into contact with the sample. The sensor is located inside the vacuum device and is used to collect the signal generated after the X-ray free electron laser pulse interacts with the sample solution.

[0024] In some embodiments of the present invention, the vacuum device includes a trapping unit, a first molecular pump assembly, and a vacuum chamber. The trapping unit and the first molecular pump assembly are respectively connected to the vacuum chamber. The pneumatic nozzle device and the signal acquisition device are respectively disposed in the vacuum chamber. The trapping unit is disposed below the tube assembly.

[0025] Another aspect of the present invention provides a method for using a liquid thin-film sample introduction system for X-ray free-electron laser experiments as described in the first aspect of the present invention, comprising the following steps:

[0026] 1) Fill the sample cell with sample liquid and place it vertically. Reduce the pressure of the nitrogen cylinder to 500-1000 psi using a nitrogen electronic pressure regulator. Apply the pressure to the upper surface of the sample liquid in the sample cell.

[0027] 2) Reduce the pressure of the helium cylinder to 500-1000 psi using an electronic helium pressure regulator; adjust the helium flow rate to 30-260 SCCM using a gas mass flow meter and input it into the gas capillary tube;

[0028] 3) Adjust the liquid flow rate of the liquid mass flow meter to 40-200ul / min, input the liquid into the liquid capillary, and under the pneumatic action of helium, the sample liquid will generate multiple orthogonally arranged spindle-shaped liquid flakes at the outlet of the outer glass tube.

[0029] 4) After the generated liquid sheet stabilizes, the incident X-ray laser pulse from the X-ray free electron laser source is made perpendicular to the plane of the primary liquid sheet. The X-ray laser pulse acts on the thinnest part of the primary liquid sheet, and the generated high signal-to-noise ratio signal is received by the sensor and stored and analyzed by the computer.

[0030] 5) The gas and liquid continuously ejected by the pneumatic nozzle device are collected by the collection unit and discharged from the vacuum chamber through the collection unit;

[0031] 6) The liquid sheet injection system can operate stably under vacuum for several hours. After the test is completed, in order to avoid the residual liquid freezing in the vacuum chamber, first turn off the liquid mass flow meter, and after the liquid in the liquid capillary is emptied, turn off the gas mass flow meter.

[0032] Compared with the prior art, the beneficial effects of this application are as follows:

[0033] 1. This invention is compatible with gas dynamic virtual nozzle injection systems and does not require additional auxiliary devices such as flow control devices, movable vacuum interfaces and traps, which is beneficial for the design and functional integration of multifunctional experimental chambers.

[0034] 2. The small size of the gas and liquid channels requires a small liquid sample flow rate, which helps to save sample and reduce the damage of water vapor to the vacuum of the chamber.

[0035] 3. At the nozzle outlet, the cross-sectional area of ​​the liquid sheet is much smaller than the nozzle outlet area, making it less prone to freezing and clogging, and enabling stable operation for a long time. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the liquid thin-film sample introduction system used in X-ray free electron laser experiments according to this application.

[0037] Figure 2 This is a schematic diagram of the structure of the liquid capillary end of this application.

[0038] Figure 3 This is a schematic diagram of the structure of the central positioning ring in this application.

[0039] Figure 4An optical microscope image of a liquid thin film obtained by the liquid thin film injection system of this application.

[0040] Figure 5 This is an optical microscope image of GDVN.

[0041] Component designation explanation

[0042] 1. Pneumatic nozzle device

[0043] 101 Gas Capillary

[0044] 102 Liquid capillary

[0045] 103 Stainless Steel Extension Tube

[0046] 104 Outer Glass Tube

[0047] 1041 Second Exit

[0048] 105 Center Positioning Ring

[0049] 106 First sealant

[0050] 107 Fastening Connector

[0051] 108 Second sealant

[0052] 109 Removable Vacuum Interface

[0053] 1091 Three-axis manipulator

[0054] 1092 Internal Pipeline

[0055] 1093 Three-dimensional displacement stage

[0056] 1094 Corrugated Pipe

[0057] 110 tube assembly

[0058] 2. Flow control device

[0059] 201 Nitrogen Cylinder

[0060] 202 Helium Cylinder

[0061] 203 Nitrogen Electronic Pressure Regulator

[0062] 204 Helium Electronic Pressure Regulator

[0063] 205 Gas Mass Flow Meter

[0064] 206 Sample Cells

[0065] 207 Liquid Mass Flow Meter

[0066] 3. Signal Acquisition Device

[0067] 301 X-ray Free Electron Laser Source

[0068] 302 sensor

[0069] 4. Vacuum device

[0070] 401 Capture Unit

[0071] 4011 trap

[0072] 4012 Second Molecular Pump Set

[0073] 402 First Molecular Pump Unit

[0074] 403 Vacuum Chamber

[0075] 501 Guide Surface

[0076] 502 Adhesive Bevel

[0077] 503 Bottom

[0078] 504 First Exit Detailed Implementation

[0079] In the description of this application, it should be noted that the devices, proportions, sizes, etc., illustrated in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modification to the device, change in proportion, or adjustment of size, without affecting the effects and purposes that this application can achieve, should still fall within the scope of the technical content disclosed in this application. Furthermore, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0080] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0081] Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0082] like Figure 1 This application provides a liquid sheet injection system for X-ray free electron laser experiments, including a pneumatic nozzle device 1, a flow control device 2, a signal acquisition device 3, and a vacuum device 4. The pneumatic nozzle device 1 is installed within the vacuum device 4 and is used to generate liquid sheets with submicron thickness (e.g., ...). Figure 4 The flow control device 2 is connected to the pneumatic nozzle device 1 to provide sample solution and helium gas; the signal acquisition device 3 is installed inside the vacuum device 4 to emit X-ray free electron laser pulses and collect signals; the vacuum device 4 is used to provide a low vacuum environment for X-ray free electron laser experiments. Therefore, this invention utilizes the compression and shearing effect of high-speed gas on liquid to generate free-flowing, submicron-thick liquid sheets under vacuum.

[0083] In the liquid sheet injection system provided by this invention, such as Figure 1 The pneumatic nozzle device 1 includes a gas capillary 101, a liquid capillary 102, a tube assembly 110 (the tube assembly 110 includes a stainless steel extension tube 103 and an outer glass tube 104), a central positioning ring 105, a first sealant 106, a fastening joint 107, a second sealant 108, and a movable vacuum interface 109.

[0084] Preferably, the gas capillary 101 has an inner diameter of 20-75 μm, an outer diameter of 300-430 μm (e.g., 360 μm), and a length of 500-1000 mm. The gas capillary 101 can be, for example, a fused silica capillary. The gas capillary 101 is used to transport helium. In a specific embodiment, the end of the gas capillary 101 is inserted 10 mm into the front end of the stainless steel extension tube 103. Helium passes sequentially through the gas capillary 101, the stainless steel extension tube 103, and the outer glass tube 104.

[0085] Preferably, the liquid capillary 102 has an inner diameter of 20-80 μm, an outer diameter of 300-450 μm, and a length of 800-1000 mm. The liquid capillary 102 can be, for example, a fused silica capillary. The liquid capillary 102 passes sequentially through the interior of the movable vacuum interface 109, the stainless steel extension tube, and the outer glass tube 104 for transporting liquid samples. The end of the liquid capillary 102 has four special bevels. Specifically, the end of the liquid capillary 102 has two symmetrically positioned guide bevels 501, and on either side of the guide bevels 501 are two symmetrically positioned contact bevels 502. The guide bevels 501 and contact bevels 502 are alternately distributed around the outlet of the end of the liquid capillary 102. In a specific embodiment, the included angle between the two guide bevels 501 can be, for example, 30°-70°, 30°-50°, or 50°-70°. The included angle between the two mating inclined surfaces 502 can be, for example, 40°-100°, 40°-60°, 60°-80°, or 80°-100°. The mating inclined surface 502 contacts the inner wall of the end of the outer glass tube 104, and the flow guiding inclined surface 501 and the inner wall of the end of the outer glass tube 104 together form a gas channel converging towards the center.

[0086] Preferably, the outer glass tube 104 is a borosilicate glass tube with an inner diameter of 500-850 μm and an outer diameter of 1000-1200 μm, and a length of 50 mm. The end of the outer glass tube 104 gradually tapers to form a second outlet 1041, which can be, for example, a circular outlet with a diameter of 30-80 μm, 30-50 μm, or 50-80 μm. In a specific embodiment, the front end of the outer glass tube 104 is inserted 10 mm into the end of the stainless steel extension tube 103. Furthermore, the connection between the stainless steel extension tube 103 and the outer glass tube 104 is fixed and sealed by the first sealant 106. The first sealant 106 is, for example, epoxy resin. The converging inner wall at the end of the outer glass tube 104 and the guide slope 501 at the end of the liquid capillary 102 together form a gas microchannel. Helium flows in the gas microchannel and acts on the sample solution sprayed from the outlet of the liquid capillary 102, forming a liquid sheet at the outlet of the outer glass tube 104.

[0087] Preferably, the outer glass tube 104 and the liquid capillary tube 102 are connected by a central positioning ring 105. In a specific embodiment, such as... Figure 3The central positioning ring 105 is a polyimide sheet composed of a circular ring and three support legs spaced 120° apart outside the circular ring. The inner diameter of the circular ring is the same as the outer diameter of the liquid capillary 102, and the total length of a single support leg and the outer diameter of the circular ring is the same as the inner diameter of the outer glass tube 104. Furthermore, the central positioning ring 105 is fitted 400-600 μm before the first outlet 504 of the liquid capillary 102, and the three support legs contact the outer glass tube 104 for coaxial fixation between the liquid capillary 102 and the outer glass tube 104.

[0088] Preferably, the stainless steel extension tube 103 is a stainless steel tube with an inner diameter of 1000-1200 μm and an outer diameter of 1400-1800 μm, and a length of 50 mm, used to provide rigid structural support. The front end of the stainless steel extension tube 103 includes a connecting portion that connects the gas capillary tube 101, the liquid capillary tube 102, and the stainless steel extension tube 103. The connecting portion is fixed and sealed by the second sealant 108. The second sealant 108 is, for example, epoxy resin.

[0089] Preferably, the fastening joint 107 is fitted onto the stainless steel extension tube 103 and connected to the movable vacuum interface 109 via an external thread, for fixing and sealing the stainless steel extension tube 103. The movable vacuum interface 109 includes a connected three-axis manipulator 1091 and an internal pipe 1092, the internal pipe 1092 being threadedly connected to the fastening joint 107. Specifically, the three-axis manipulator 1091 includes a three-dimensional displacement stage 1093 and a bellows 1094, wherein the three-dimensional displacement stage 1093 is connected to the vacuum chamber 403, the internal pipe 1092 is connected to the three-dimensional displacement stage 1093, and the three-dimensional displacement stage 1093 and the vacuum chamber 403 are flexibly connected via the bellows 1094, the three-dimensional displacement stage 1093 allowing the internal pipe 1092 to move horizontally and vertically relative to the vacuum chamber 403. The built-in pipe 1092 of the movable vacuum interface 109 is connected to the fastening joint 107 via an internal thread, introducing the liquid capillary 102 and the gas capillary 101 from the outside into the vacuum chamber 403, and adjusting the relative position of the X-ray free electron laser and the liquid sheet generated at the end of the outer glass tube 104. This invention can employ a universal three-axis manipulator 1091. In a specific embodiment, the manufacturer of the three-axis manipulator 1091 may be, for example, a custom three-axis vacuum chamber manipulator from Pfaff Vacuum.

[0090] In the liquid thin-film injection system provided by this invention, the flow control device 2 includes a nitrogen cylinder 201, a helium cylinder 202, a nitrogen electronic pressure regulator 203, a helium electronic pressure regulator 204, a gas mass flow meter 205, a sample cell 206, and a liquid mass flow meter 207, connected in sequence. Specifically, the flow control device 2 includes the nitrogen cylinder 201, the nitrogen electronic pressure regulator 203, the sample cell 206, and the liquid mass flow meter 207, which are connected in sequence; the liquid mass flow meter 207 is connected to the liquid capillary tube 102. The flow control device 2 also includes the helium cylinder 202, the helium electronic pressure regulator 204, and the gas mass flow meter 205, which are connected in sequence; the gas mass flow meter 205 is connected to the gas capillary tube 101.

[0091] Preferably, the nitrogen cylinder 201 is used to provide high-pressure nitrogen with a purity of 99.999%, and is connected to the nitrogen electronic pressure regulator 203 via a pipeline; the nitrogen electronic pressure regulator 203 is used to regulate the pressure output of nitrogen, and is connected to the top inlet of the sample cell 206 via a pipeline; the sample cell 206 is a 20-50ml double-opening cylinder, placed vertically, used to store sample solutions, and the sample solution in the sample cell 206 enters the liquid mass flow meter 207 through the bottom outlet under the drive of nitrogen pressure; the liquid mass flow meter 207 is used to quantitatively regulate the flow rate of the sample solution, and is connected to the liquid capillary 102 via a pipeline.

[0092] Preferably, the helium cylinder 202 is used to provide high-pressure helium with a purity of 99.999%, and is connected to the electronic helium pressure regulator 204 via a pipeline; the electronic helium pressure regulator 204 is used to regulate the pressure output of the helium, and is connected to the gas mass flow meter 205 via a pipeline; the gas mass flow meter 205 is used to quantitatively regulate the flow rate of the helium, and is connected to the gas capillary tube 101 via a pipeline.

[0093] In the liquid thin-film sample introduction system provided by this invention, the signal acquisition device 3 includes an X-ray free-electron laser source 301 and a sensor 302. The X-ray free-electron laser source 301 is generated by an X-ray free-electron laser and introduced into the vacuum cavity 403, and the spot size of the X-ray free-electron laser at the point of interaction with the sample is approximately 3*3 μm. The sensor 302 is located inside the vacuum cavity 403 and is used to collect the signal generated after the X-ray free-electron laser pulse interacts with the sample solution.

[0094] In the liquid sheet injection system provided by the present invention, the vacuum device 4 includes a collection unit 401, a first molecular pump group 402, and a vacuum chamber 403.

[0095] Preferably, the trapping unit 401 is located downstream of the outer glass tube 104 and consists of a trapping device 4011 (e.g., a stainless steel container with a conical opening) and a second molecular pump assembly 4012. It is used to remove waste gas and liquid after the X-ray free electron laser pulse interacts with the sample solution, preventing damage to the vacuum level of the vacuum device 4. The first molecular pump assembly 402 is connected to the vacuum chamber 403 to maintain the vacuum level of the vacuum chamber 403. The vacuum chamber 403 provides a low vacuum environment, for example, a vacuum level of 1*10⁻⁶. -5 -1*10 -6 mbar. In a specific embodiment, the first molecular pump assembly 402 and the second molecular pump assembly 4012 may be, for example, an nEXT TIC cart XL pump truck manufactured by Edwards Vacuum.

[0096] The liquid thin-film sample introduction system of this invention includes the flow control device 2, the vacuum device 4, and the movable vacuum interface 109, which are compatible with the Gas Dynamic Virtual Nozzle (GDVN) sample introduction system. The two sample introduction systems are highly compatible and can be quickly switched, which is beneficial for the design and functional integration of multifunctional experimental chambers. The Gas Dynamic Virtual Nozzle sample introduction system is a technique that uses gas to focus liquid into a micrometer-sized cylindrical jet, commonly used for the introduction of microcrystalline samples in X-ray serial crystallography.

[0097] Working principle of the invention:

[0098] The liquid capillary 102 and the outer glass tube 104 together form a converging gas microchannel. Under the influence of a pressure difference, the helium gas within the microchannel generates a radial momentum component pointing towards the axis and an axial momentum component pointing downstream. The liquid ejected from the end of the liquid capillary 102 interacts with the helium on both sides: the radial momentum of the gas jet compresses the liquid into a thin sheet, thinner at the center and thicker at the edges. The axial momentum of the gas jet shears and accelerates the liquid, causing the liquid sheet to gradually thin further away from the nozzle in the longitudinal direction. During the flow of the first liquid sheet, the surface tension of the liquid gradually overcomes its radial momentum, causing the thicker edges of the liquid sheet to converge again, thus generating smaller secondary liquid sheets in the orthogonal direction. This process repeats continuously, forming multiple orthogonally arranged spindle-shaped liquid sheets until the momentum gained by the liquid from the gas decays due to viscous dissipation, ultimately forming droplets. Among them, the primary liquid sheet has the largest area and the smallest thickness near its geometric center downstream, making it an ideal region for the interaction between X-ray free electron laser and liquid sample, and can be used for liquid sample introduction in X-ray free electron laser experiments.

[0099] The present invention also provides a method for using a liquid thin-film sample introduction system for X-ray free electron laser experiments, comprising the following steps:

[0100] Step 1: The sample cell 206 is filled with sample liquid and placed vertically. The nitrogen cylinder 201 is depressurized to 500-1000 psi by the nitrogen electronic pressure regulator 203. The pressure acts on the upper surface of the sample liquid in the sample cell 206.

[0101] Step 2: The helium cylinder 202 is depressurized to 500-1000 psi by the helium electronic pressure regulator 204. The helium is then regulated to 30-260 SCCM by the gas mass flow meter 205 and introduced into the gas capillary tube 101.

[0102] Step 3: The liquid mass flow meter 207 adjusts the liquid flow rate to 40-200 μL / min and inputs it into the liquid capillary 102. Under the pneumatic action of helium gas, the sample liquid generates multiple orthogonally arranged spindle-shaped liquid flakes at the outlet of the outer glass tube 104.

[0103] Step 4: After the generated liquid sheet has stabilized, the incident X-ray laser pulse from the X-ray free electron laser source 301 is made perpendicular to the plane of the primary liquid sheet. The X-ray laser pulse acts on the thinnest part of the primary liquid sheet, and the generated high signal-to-noise ratio signal is received by the sensor 302 and stored and analyzed by the computer.

[0104] Step 5: The gas and liquid continuously ejected by the pneumatic nozzle device 1 are collected by the capture unit 401 and discharged from the vacuum chamber 403 via the collector 4011 and the second molecular pump group 4012.

[0105] Step Six: The liquid sheet injection system disclosed in this embodiment can operate stably under vacuum for several hours. After the test is completed, in order to prevent the residual liquid from freezing in the vacuum chamber 403, the liquid mass flow meter 207 should be turned off first. After the liquid in the liquid capillary 102 is drained, the gas mass flow meter 205 should be turned off.

[0106] The following specific examples further illustrate this point:

[0107] Example 1

[0108] Step 1: The sample cell 206 is filled with sample liquid and placed vertically. The nitrogen cylinder 201 is depressurized to 600 psi by the nitrogen electronic pressure regulator 203. The pressure is applied to the upper surface of the sample liquid in the sample cell 206.

[0109] Step 2: The helium cylinder 202 is depressurized to 600 psi by the helium electronic pressure regulator 204. The helium is then regulated to 70 SCCM by the gas mass flow meter 205 and introduced into the gas capillary 101.

[0110] Step 3: The liquid mass flow meter 207 adjusts the liquid flow rate to 140 μL / min and inputs it into the liquid capillary 102. Under the pneumatic action of helium gas, the sample liquid generates multiple orthogonally arranged spindle-shaped liquid flakes at the outlet of the outer glass tube 104, such as... Figure 4 As shown in the figure, the thickness of the middle part of the primary liquid sheet is less than 1 μm.

[0111] Comparative Example 1

[0112] Replace the nozzle with GDVN. Figure 5 This is a cylindrical jet generated by GDVN, with a jet width of 3.8 μm. The jet appears bright in the middle and dark on both sides due to the refraction of light by the cylindrical jet.

[0113] In summary, this application effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0114] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A liquid sheet sample injection system for X-ray free electron laser experiments, characterized by, The system includes a pneumatic nozzle device (1), a flow control device (2), a signal acquisition device (3), and a vacuum device (4). The pneumatic nozzle device (1) and the signal acquisition device (3) are respectively housed within the vacuum device (4). The pneumatic nozzle device (1) includes a tube assembly (110), in which a gas capillary (101) and a liquid capillary (102) are respectively provided. The gas capillary (101) and the liquid capillary (102) are respectively connected to the flow control device (2). The end of the capillary (102) includes two symmetrically arranged guide slopes (501), two symmetrically arranged fitting slopes (502), and a bottom surface (503). The guide slopes (501) and fitting slopes (502) are alternately distributed around the bottom surface (503). A first outlet (504) is provided on the bottom surface (503). A gas microchannel is formed between the inner wall of the end of the tube assembly (110) and the guide slopes (501). A second outlet (1041) is provided at the end of the tube assembly (110). The tube assembly (110) includes a connected stainless steel extension tube (103) and an outer glass tube (104), the gas capillary (101) is disposed inside the stainless steel extension tube (103), and the liquid capillary (102) extends from the stainless steel extension tube (103) into the end of the outer glass tube (104). The tube assembly (110) is fitted with a fastening joint (107). The pneumatic nozzle device (1) also includes a movable vacuum interface (109) for moving the tube assembly (110), gas capillary (101), and liquid capillary (102) as a whole. The movable vacuum interface (109) includes a connected three-axis manipulator (1091) and an internal pipe (1092). The internal pipe (1092) is threadedly connected to the fastening joint (107). The flow control device (2) includes a nitrogen cylinder (201), a nitrogen electronic pressure regulator (203), a sample cell (206), and a liquid mass flow meter (207) connected in sequence; the liquid mass flow meter (207) is connected to the liquid capillary (102); The flow control device (2) also includes a helium cylinder (202), a helium electronic pressure regulator (204), and a gas mass flow meter (205) connected in sequence; the gas mass flow meter (205) is connected to the gas capillary (101).

2. The liquid sheet feeding system for X-ray free electron laser experiments of claim 1, wherein, The included angle between the two guide slopes (501) is 30°-70°; And / or, the included angle between the two mating inclined surfaces (502) is 40°-100°.

3. The liquid thin-film sample introduction system for X-ray free-electron laser experiments as described in claim 1, characterized in that, The gas capillary (101) has an inner diameter of 20-75 μm, an outer diameter of 300-430 μm, and a length of 500-1000 mm. And / or, the gas capillary (101) is a fused silica capillary; And / or, the liquid capillary (102) has an inner diameter of 20-80 μm, an outer diameter of 300-450 μm, and a length of 800-1000 mm; And / or, the liquid capillary (102) is a fused silica capillary.

4. The liquid thin-film sample introduction system for X-ray free-electron laser experiments as described in claim 1, characterized in that, The stainless steel extension tube (103) and the outer glass tube (104) are sealed and fixed by the first sealant (106); And / or, the stainless steel extension tube (103) has an inner diameter of 1000-1200 μm and an outer diameter of 1400-1800 μm; And / or, the inner diameter of the outer glass tube (104) is 500-850 μm, and the outer diameter is 1000-1200 μm; And / or, the second outlet (1041) is located at the end of the outer glass tube (104), and the diameter of the second outlet (1041) is 30-80 μm; And / or, the outer glass tube (104) and the liquid capillary (102) are connected by a central positioning ring (105); And / or, the gas capillary (101), liquid capillary (102) and stainless steel extension tube (103) are sealed and fixed by a second sealant (108).

5. The liquid thin-film sample introduction system for X-ray free-electron laser experiments as described in claim 1, characterized in that, The signal acquisition device (3) includes an X-ray free electron laser source (301) and a sensor (302). The laser pulse generated by the X-ray free electron laser source (301) comes into contact with the sample. The sensor (302) is located in the vacuum device (4) and is used to collect the signal generated after the X-ray free electron laser pulse interacts with the sample solution.

6. The liquid thin-film sample introduction system for X-ray free-electron laser experiments as described in claim 1, characterized in that, The vacuum device (4) includes a trapping unit (401), a first molecular pump group (402), and a vacuum chamber (403). The trapping unit (401) and the first molecular pump group (402) are respectively connected to the vacuum chamber (403). The pneumatic nozzle device (1) and the signal acquisition device (3) are respectively located inside the vacuum chamber (403). The trapping unit (401) is located below the tube assembly (110).

7. A method of using the liquid sheet sample introduction system for X-ray free electron laser experiments according to any one of claims 1 to 6, characterized in that, Includes the following steps: 1) The sample cell (206) is filled with sample liquid and placed vertically. The nitrogen cylinder (201) is depressurized to 500-1000 psi through the nitrogen electronic pressure regulator (203). The gas pressure acts on the upper liquid surface of the sample liquid in the sample cell (206). 2) The helium cylinder (202) is depressurized to 500-1000 psi by the helium electronic pressure regulator (204); the helium is adjusted to 30-260 SCCM by the gas mass flow meter (205) and introduced into the gas capillary tube (101). 3) Adjust the liquid flow rate of the liquid mass flow meter (207) to 40-200 ul / min and input it into the liquid capillary (102). Under the action of helium gas, the sample liquid produces multiple orthogonally arranged spindle-shaped liquid flakes at the outlet of the outer glass tube (104). 4) After the generated liquid sheet stabilizes, the incident X-ray laser pulse from the X-ray free electron laser source (301) is made perpendicular to the plane of the primary liquid sheet. The X-ray laser pulse acts on the thinnest part of the primary liquid sheet, and the generated high signal-to-noise ratio signal is received by the sensor (302) and stored and analyzed by the computer. 5) The gas and liquid continuously ejected by the pneumatic nozzle device (1) are collected by the collection unit (401) and discharged from the vacuum chamber (403) through the collection unit (401). 6) The liquid sheet injection system can be stably operated under vacuum for several hours. After the test is completed, in order to avoid the residual liquid freezing in the vacuum chamber (403), the liquid mass flow meter (207) is turned off first. After the liquid in the liquid capillary (102) is drained, the gas mass flow meter (205) is turned off.

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