Integrated free electron laser on-line collimation and visible indication laser system and method

Abstract

The invention discloses an integrated free electron laser on-line collimation and visible indication laser system and method, and the system employs a theoretical center line representing a magnetic axis of an undulator as a reference, and a collimation system completes the coincidence collimation of an electron beam axis and an optical axis with the theoretical center line; the visible light indication system provides a reference visible light beam for downstream beam line commissioning, where the reference visible light beam coincides with the theoretical centerline, and the system can be independently commissioned out of vacuum. The collimation system and the visible light indication system are mutually independent, are coupled through the upstream reflector and the downstream reflector, do not influence each other, and can be permanently used on line.

Description

Technical Field

[0001] This invention relates to the field of oscillator-type free-electron laser technology, specifically to an integrated free-electron laser online collimation and visible indicator laser system and method. Background Technology

[0002] The main components of an oscillator-type free-electron laser are an optical resonant cavity and a undulator. Infrared laser light is generated, amplified, stored, and output within the optical resonant cavity of the oscillator. The optical resonant cavity consists of upstream and downstream optical mirrors (including mirror housings), electron beam input and output channels, optical waveguides, and vacuum connection channels. The relativistic electron beam generated from the accelerator passes through the periodic magnetic field produced by the undulator within the resonant cavity, generating laser radiation. The laser oscillates between the upstream and downstream mirrors and interacts with subsequent electron beams in the undulator's magnetic field region, amplifying them multiple times until saturation, at which point it is output in a specific manner. The condition for continuous enhancement of laser oscillation is that the central axis of the electron beam trajectory, the central axis of the undulator's magnetic field, and the optical axis formed by the upstream and downstream mirrors are all within a very small tolerance range. Calculations show that the linearity error does not exceed 50 μm and the angular error does not exceed 0.5 mrad.

[0003] The main purpose of collimation is to implement engineering schemes to achieve triaxial alignment and meet the required accuracy for beam output. Simultaneously, to facilitate downstream beamline adjustment, a guiding laser beam aligned with the resonant cavity's optical axis is needed. Existing common collimation methods primarily use visible lasers, employing instruments including helium-neon lasers, laser trackers, autocollimators, collimating telescopes, apertures, and various optical mirrors. Due to workspace limitations, the instruments used may need to be moved or even disassembled, making the process quite complex.

[0004] In the existing technology, the free electron laser device disclosed by Wang Wei et al. at the National Synchrotron Radiation Laboratory of the University of Science and Technology of China in their paper "Collimation and Installation of Infrared Free Electron Laser Resonator" initially used the three instruments mentioned above (laser tracker, autocollimator, and autocollimating telescope) to complete the collimation of the entire device. However, due to space constraints, all instruments were dismantled and could not be reused. Subsequently, a helium-neon laser system was used to complete the repeated collimation and indicating laser functions.

[0005] The invention patent with patent application publication number CN117311009A, entitled "A Collimation System and Method for Optical Resonators of Free-Electron Lasers," solves the problems of numerous collimation devices, high costs, and complex operations in existing collimation methods when applied to optical resonators of oscillating free-electron lasers. However, the beam splitter is placed inside the resonator. A similar design concept is also mentioned in the paper "Collimation Installation of Infrared Free-Electron Laser Resonators," which describes an optical resonator and laser for oscillating free-electron lasers. A beam splitter is placed inside the resonator to calibrate the optical axis of the helium-neon laser. After aligning the helium-neon laser optical axis with the resonator's optical axis, a thin-film beam splitter and a CCD camera are used to calibrate the position of the helium-neon laser optical axis. Later, the helium-neon laser is introduced into the collimated resonator by switching mirrors within the resonator and serves as the indicator laser for the downstream beamline.

[0006] This method, which places the mirror assembly within the resonant cavity (in a high-vacuum environment), easily increases the gas load of the ultra-high vacuum. Although this method uses fewer instruments, it actually requires more than four platforms to house the relevant components, occupying a significant amount of space. Furthermore, the accuracy of collimating the resonant cavity using a helium-neon laser is not lower than that of the method using the aforementioned instruments. Summary of the Invention

[0007] The technical problem to be solved by this invention is: how to calibrate the angle and position of the resonant cavity mirror to form the optical axis and coincide with the theoretical center line during the initial installation, how to make the center line of the electron beam coincide with the theoretical center line, how to keep the collimation system and the indicator laser system permanently online and calibrate the collimation and indicator laser system when needed, and how to implement a visible indicator laser beam that coincides with the theoretical center line of the resonant cavity to provide a reference for downstream beamline debugging, while avoiding contamination of the high vacuum environment by the indicator laser system.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] An integrated free-electron laser online collimation and visible light indicator laser system includes a theoretical centerline 1 representing the undulator magnetic axis, and an independent, online collimation system 2 and a visible light indicator system 3. The collimation system 2 ensures that the optical axis and the electron beam axis coincide with the theoretical centerline 1. The visible light indicator system 3 provides a reference visible beam for downstream beamline tuning, and the optical axis of the reference visible beam coincides with the theoretical centerline 1. The visible light indicator system 3, except for the thin-film beam splitter 361, is located outside of a high vacuum.

[0010] In this embodiment, the collimation system 2 includes a digital internal focusing collimating telescope 21 with a bright crosshair, a target ball assembly 22, a target ball assembly 23, an upstream endoscope assembly 24, a downstream endoscope assembly 25, and three electronic position diagnostic systems 27.

[0011] The digital internal focusing collimating telescope 21 is located outside the vacuum environment at the upstream end of the oscillator 00; the target ball assembly 22 is located outside the vacuum environment, between the upstream cavity mirror group 24 and the digital internal focusing collimating telescope 21; the target ball assembly 23 is located inside the vacuum environment, downstream of the downstream cavity mirror group 25; the downstream cavity mirror group 25 is located inside the vacuum; the electronic position diagnostic system 27A and the electronic position diagnostic system 27C are located upstream and downstream of the waveguide 01 of the oscillator 00, respectively; the electronic position diagnostic system 27B is located in the middle of the waveguide 01.

[0012] In this embodiment, the visible light indication system 3 includes a helium-neon visible laser 31 located outside the vacuum environment, a beam expander 32, multiple planar mirrors, multiple identical CCD area array camera assemblies and a reflective target assembly 35, and also includes a thin film beam splitter 361 located inside the vacuum environment.

[0013] The helium-neon visible laser 31 emits visible laser P, which is expanded by the beam expander 32 to change the spot diameter. After being adjusted by multiple plane mirrors and reflected to the center of the thin film beam splitter 361, the beam is split into a laser reflection component P1 that is incident upstream of the oscillator 00 and a laser transmission component P2 that is incident in the direction of the reflective target assembly 35.

[0014] The laser reflection component P1 is reflected back by the upstream mirror 241 located upstream of the resonant cavity, and is split again by the thin film beam splitter 361. The transmitted component forms the transmitted beam P′1, which shines downstream of the resonant cavity.

[0015] The laser transmission component P2 is reflected back by the reflective target assembly 35 and then split again by the thin-film beam splitter 361. The reflected component forms a reflected beam P′2 in the direction downstream of the resonant cavity.

[0016] In this embodiment, the digital internal focusing collimating telescope 21 has both collimating lens and telescope functions. The collimating lens function can be used to adjust the angle of the reflector, and the telescope function can be used to adjust the position of the reflector.

[0017] The cross beam emitted from the digital internal focusing collimating telescope 21 is reflected by the mirror and returns to the eyepiece of the digital internal focusing collimating telescope 21. If the reflected cross beam does not coincide with the cross line on the eyepiece, it means that the mirror is not perpendicular to the optical axis of the digital internal focusing collimating telescope 21. Adjust the angle of the mirror until the reflected cross beam on the eyepiece coincides with the cross line on the eyepiece of the digital internal focusing collimating telescope 21.

[0018] When using the telescope function, adjust the focus of the digital internal focusing collimating telescope 21 to the object being measured, and adjust the position of the key point of the object being measured until the position of the key point is adjusted to the center of the crosshairs on the eyepiece of the digital internal focusing collimating telescope 21, that is, the key point of the object being measured is adjusted to the optical axis of the digital internal focusing collimating telescope 21.

[0019] In this embodiment, the target ball assembly 22 includes a target ball 221, a target ball seat 222, a YZ adjustment platform 223, and a pad 224 arranged sequentially from top to bottom. The target ball 221 is a precision sphere with three mutually perpendicular reflective surfaces, and the center position of the target ball can be precisely measured using a laser tracker. The upper part of the target ball seat 222 is a conical surface that matches the outer spherical surface of the target ball 221. No matter how the target ball 221 is rotated or reset, the center of the target ball on the target ball seat 222 remains unchanged. The YZ adjustment platform 223 is used to adjust the vertical and lateral positions of the target ball 221. The pad 224 is used to set the initial height of the target ball 221.

[0020] Target ball assembly 23 includes a precision adjustment platform 231, a five-port vacuum cross device 232, a target ball 233, and a target ball seat 234;

[0021] The precision adjustment platform 231 is used to adjust the vertical direction and lateral position of the target ball 233. When the target ball 233 needs to work, the precision adjustment platform 231 can adjust the center of the target ball 233 to the theoretical center line 1. After the alignment is completed, the precision adjustment platform 231 can drive the target ball 233 back into the branch of the five-port vacuum cross device 232 to make way for the visible infrared laser beam path.

[0022] The upper end of the target ball holder 234 is fixed to the bottom end of the drive rod of the precision adjustment platform 231, and the lower end is provided with a conical surface that matches the target ball 233. The center of the target ball remains unchanged no matter how the target ball 233 is rotated.

[0023] In this embodiment, the upstream endoscope assembly 24 includes an upstream reflector 241 and an upstream endoscope mount 242;

[0024] The reflecting surface of the upstream reflector 241 is a spherical surface, and the back surface of the upstream reflector 241 is parallel to the pole tangent of the reflecting surface. A small hole and a cross line are opened on the back surface of the upstream reflector 241, which are defined as upstream back hole 2411 and upstream cross line 2412, respectively. The center line of the upstream back hole 2411 passes through the pole of the reflecting surface of the upstream reflector 241, and the center of the upstream back hole 2411 coincides with the fork of the upstream cross line 2412. The upstream reflector 241 is mounted on the upstream mirror frame 242.

[0025] In this embodiment, the downstream endoscope assembly 25 includes a downstream reflector 251 and a downstream endoscope frame 252;

[0026] The reflecting surface of the downstream reflector 251 is a spherical surface. A through conical hole is opened in the center of the downstream reflector 251. The center line of the conical hole coincides with the normal of the pole of the reflecting surface. The hole formed by the conical hole of the downstream reflector 251 on the reflecting surface is defined as the downstream front center hole 2511. Small holes and cross lines are processed on the back of the downstream reflector 251, which are defined as the downstream center hole 2512 and the downstream cross line 2513, respectively. The intersection point of the downstream cross line 2513 coincides with the center of the downstream back center hole 2512.

[0027] The downstream reflector 251 is mounted on the downstream mirror frame 252.

[0028] In this embodiment, each electronic position diagnostic system includes a precision linear actuator 271, a YAG plate 272, a six-port vacuum cross device 273, a support arm 274, a reflector frame 275, a reflector 276, a camera lens 277, and a CCD area array camera 278.

[0029] YAG plate 272 is mounted on the bottom of precision linear actuator 271; the position of YAG plate 272 is finely adjusted by precision linear actuator 271, and after the electron beam collimation is completed, YAG plate 272 is removed from theoretical center line 1; support arm 274 is fixed on six-port vacuum cross device 273 to support reflector frame 275; reflector 276 is mounted on reflector frame 275.

[0030] This invention provides a method for using an integrated free-electron laser online collimation and visible indicator laser system, including a method for using the collimation system 2:

[0031] S10, adjust the positions of target ball assembly 1 22 and target ball assembly 23 so that the centers of target ball 1 221 of target ball assembly 1 and target ball 233 of target ball assembly 23 fall on the theoretical center line 1;

[0032] S20, adjust the position and angle of the digital internal focusing collimating telescope 21, and use the telescope function of the digital internal focusing collimating telescope 21 to aim at target ball 1 221 and target ball 233 respectively; when aiming at target ball 233, move target ball 221 away; when the center of target ball 1 221 and target ball 233 is not on the intersection of the crosshairs of the eyepiece of the digital internal focusing collimating telescope 21, repeatedly adjust the position and angle of the digital internal focusing collimating telescope 21 until the crosshairs and the center of target ball 1 221 and target ball 233 are seen to coincide within the allowable error range through the eyepiece of the digital internal focusing collimating telescope 21; after adjustment, remove target ball assembly 1 22 and target ball assembly 23.

[0033] S30, using the telescope function of the digital internal focusing collimating telescope 21, focus on the downstream mirror 251 of the downstream cavity mirror group 25. The downstream front center hole 2511 of the downstream mirror 251 is imaged on the eyepiece of the digital internal focusing collimating telescope 21. Adjust the position of the downstream frame 252 in the downstream cavity mirror group 25 until the center of the downstream front center hole 2511 of the downstream mirror 251 coincides with the intersection of the crosshairs of the digital internal focusing collimating telescope 21.

[0034] S40, the collimation function of the digital internal focusing collimating telescope 21 is used to collimate the downstream reflector 251. When the crosshair reflected by the downstream reflector 251 does not coincide with the crosshair on the collimating eyepiece in the digital internal focusing collimating telescope 21, the angle of the downstream frame 252 is adjusted until the reflected crosshair coincides with the downstream frame 252 on the eyepiece. At this time, the downstream reflector 251 is adjusted so that the reflecting surface is perpendicular to the theoretical center line 1.

[0035] S50, using the telescope function of the digital internal focusing collimating telescope 21, adjust the electronic position diagnostic system 27A, and adjust the focus of the digital internal focusing collimating telescope 21 to the YAG plate 272 of the electronic position diagnostic system 27A. The crosshairs on the YAG plate 272 will be imaged onto the eyepiece of the digital internal focusing collimating telescope 21. Adjust the precision linear actuator 271 in the electronic position diagnostic system 27A to make the crosshair image coincide with the crosshairs. At this time, the crosshair intersection point of the YAG plate 272 falls on the theoretical center line 1. Similarly, use the same method to adjust the crosshair center of the YAG plate 272 of the electronic position diagnostic system 27B and the electronic position diagnostic system 27C to the theoretical center line 1.

[0036] S60, using the telescope function of the digital internal focusing collimating telescope 21, guides the adjustment of the center of the small hole 2411 on the back of the upstream cavity mirror group 24 to the theoretical center line 1; using the collimation function of the digital internal focusing collimating telescope 21, guides the adjustment of the back of the upstream reflector 241 to be perpendicular to the theoretical center line 1. At this time, the pole of the upstream reflector 241 is adjusted to be on the theoretical center line 1, and the reflecting surface is adjusted to be perpendicular to the theoretical center line 1.

[0037] In this embodiment, the usage method includes the usage method of the visible light indicator system 3:

[0038] After the collimation system 2 completes collimation, the helium-neon visible laser 31 emits visible laser P, which is reflected by multiple plane mirrors in sequence and illuminates the center of the thin-film beam splitter 361. The thin-film beam splitter 361 splits the laser into a laser reflection component P1 that is incident upstream of the oscillator 00 and a laser transmission component P2 that is incident in the direction of the reflective target assembly 35.

[0039] The laser reflection component P1 is reflected back by the upstream reflector 241 located upstream of the resonant cavity, and is split again by the thin-film beam splitter 361. The transmitted beam P′1 shines downstream of the resonant cavity.

[0040] The laser transmission component P2 is reflected back by the reflective target assembly 35 and then split by the thin film beam splitter 361. The reflected component forms a reflected beam P′2 in the direction downstream of the resonant cavity.

[0041] At the thin-film beam splitter 361, the transmitted beam P′1 and the reflected beam P′2 are combined and used as the visible indicator laser for adjusting the downstream beamline of the resonant cavity mirror.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] The collimation system 2 uses a digital internal focusing collimating telescope 21, which replaces the traditional collimating lens and telescope. It occupies less space, makes it possible for the collimation system to be permanently online, and eliminates the need for repeated installation and removal of the collimating lens and telescope. This greatly shortens the collimation system debugging time and improves collimation accuracy.

[0044] The digital internal focusing collimating telescope 21 and the target ball assembly 22 are placed outside the vacuum upstream of the resonant cavity, thus not occupying the working space of the resonant cavity and allowing for long-term placement. The target ball assembly 23 is precisely positioned and removed from the vacuum using the vacuum external precision adjustment platform 231. This allows the collimation system 2 to be permanently online, enabling continuous verification of the optical axis of the digital internal focusing collimating telescope 21 and the upstream and downstream reflectors and YAG plates of each optical component of the recollimating resonant cavity. This greatly facilitates the replacement and adjustment of mirrors in the free electron laser resonant cavity and its future operation and maintenance.

[0045] Since the collimation system 2 is online for extended periods, the indicator laser system does not need to perform its collimation function later on. This simplifies the indicator laser system.

[0046] The visible light indicator system 3 outside the vacuum is dedicated to downstream beamline calibration. This system has few components inside the vacuum. Only one thin-film beam splitter 361 and beam splitter mount 362 are inside the vacuum in the thin-film beam splitter assembly 36, while the rest are outside the vacuum. This has little impact on the vacuum. Only the three or more planar mirrors outside the vacuum need to be adjusted to make the helium-neon laser optical axis coincide with the theoretical center line 1 of the resonant cavity. The calibration process is simple and convenient.

[0047] During the operation of the free electron laser, the visible light indicator system 3, like other optical systems, will experience directional drift. The permanent online status of the collimation system 2 ensures that the visible light indicator system 3 is calibrated before it can be used.

[0048] The collimation system 2 and the visible light indication system 3 are independent of each other and are coupled through upstream and downstream reflectors, so they do not affect each other. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of an integrated free-electron laser online collimation and visible indicator laser system according to an embodiment of the present invention.

[0050] Figure 2 This is a system schematic diagram according to an embodiment of the present invention.

[0051] Figure 3 This is a schematic diagram of the collimation system layout according to an embodiment of the present invention.

[0052] Figure 4 This is a schematic diagram of a target ball assembly according to an embodiment of the present invention.

[0053] Figure 5 This is a schematic diagram of the second target ball assembly according to an embodiment of the present invention.

[0054] Figure 6 This is a schematic diagram of the upstream endoscope assembly in an embodiment of the present invention.

[0055] Figure 7 This is a schematic diagram of the downstream endoscope assembly in an embodiment of the present invention.

[0056] Figure 8 This is a schematic diagram of an electronic position diagnostic system according to an embodiment of the present invention.

[0057] Figure 9 This is a layout diagram of the optical elements of a visible light indicator system according to an embodiment of the present invention.

[0058] Figure 10 This is a schematic diagram of a thin-film beam splitter assembly according to an embodiment of the present invention.

[0059] Figure 11 This is a schematic diagram of a CCD area array camera assembly according to an embodiment of the present invention.

[0060] Figure 12 This is a schematic diagram of a visible laser calibration target assembly according to an embodiment of the present invention. Detailed Implementation

[0061] To facilitate understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will now be further described in conjunction with the accompanying drawings.

[0062] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0063] Please see Figure 1 and Figure 2 As shown, this invention provides an integrated free-electron laser online collimation and visible light indication laser system, including a theoretical centerline 1 representing the undulator magnetic axis, and an independent, online collimation system 2 and a visible light indication system 3. The collimation system 2 and the visible light indication system 3 provide a reference visible beam for downstream beamline tuning, and the reference visible beam coincides with the theoretical centerline 1. Furthermore, the visible light indication system 3 is located outside a high vacuum.

[0064] Please see Figure 2 and Figure 3 As shown, in one embodiment of the present invention, the collimation system 2 includes a digital internal focusing collimating telescope 21 with a bright crosshair, a target ball assembly 22, a target ball assembly 23, an upstream endoscope assembly 24 and a downstream endoscope assembly 25, and three electronic position diagnostic systems 27.

[0065] The digital internal focusing collimating telescope 21 is located outside the vacuum environment at the upstream end of the oscillator 00. Target sphere assembly 1 22 is located outside the vacuum environment, between the upstream cavity mirror group 24 and the digital internal focusing collimating telescope 21. Target sphere assembly 23 is located inside the vacuum environment, downstream of the downstream cavity mirror group 25. The downstream cavity mirror group 25 is located in the vacuum environment. Electronic position diagnostic systems 1 and 3 are located upstream and downstream of the oscillator waveguide 01, respectively. Electronic position diagnostic system 2 27B is located in the middle of the waveguide 01. The three electronic position diagnostic systems have the same structure, differing only in their specific placement. Please refer to the appendix. Figure 2 As shown, the block diagram labeled 02 represents the vacuum boundary.

[0066] Please see Figure 3 As shown, in this embodiment, the digital internal focusing collimating telescope 21 functions as both a collimating lens and a telescope. The collimating lens function can be used to adjust the angle of the reflecting mirror, and the telescope function can be used to adjust the position of the reflecting mirror. The collimating system 2, which includes the upstream endoscope group 24, the downstream endoscope group 25, and three sets of electronic position diagnostic systems, all have the function of reflecting mirrors.

[0067] When using the collimation function, the crosshair emitted from the digital internal focusing collimating telescope 21 is reflected by the mirror and returns to the eyepiece of the digital internal focusing collimating telescope 21. If the reflected crosshair spot does not coincide with the crosshairs on the eyepiece, it indicates that the mirror is not perpendicular to the optical axis of the digital internal focusing collimating telescope. Adjust the angle of the mirror until the reflected crosshair spot on the eyepiece coincides with the crosshairs on the eyepiece, indicating that the mirror has been adjusted to be completely perpendicular to the optical axis of the digital internal focusing collimating telescope. When using the telescope function, adjust the focus of the digital internal focusing collimating telescope 21 to the object being measured, such as the mirror or YAG plate, and the object will be clearly imaged on the telescope eyepiece. Adjusting the position of the object being measured can adjust key points on the object, such as the center point of the aperture or the intersection of the crosshairs, to be aligned with the optical axis of the digital internal focusing collimating telescope 21.

[0068] Please see Figure 4 As shown, in one embodiment of the present invention, the target ball assembly 22 includes a target ball 221, a target ball seat 222, a YZ adjustment platform 223, and a pad 224 arranged sequentially from top to bottom. The target ball 221 is a precision sphere with three mutually perpendicular reflective surfaces, allowing for precise measurement of the target ball's center position using a laser tracker. The upper part of the target ball seat 222 is a conical surface that matches the outer spherical surface of the target ball 221. Due to the fit between the spherical and conical surfaces and the weight of the target ball, even if the target ball 221 is rotated or reset, its center on the target ball seat 222 remains unchanged. The YZ adjustment platform 223 adjusts the vertical and lateral positions of the target ball 221. The pad 224 is used to set the initial height of the target ball 221.

[0069] Please see Figure 5 As shown, in one embodiment of the present invention, the target ball assembly 23 includes a precision adjustment platform 231, a five-port vacuum cross device 232, a target ball 233, and a target ball seat 234.

[0070] The precision adjustment platform 231 is used to adjust the vertical and lateral positions of the target ball 233, and the adjustment stroke of the precision adjustment platform 231 in the vertical direction is greater than 100mm. When the target ball 233 needs to work, the precision adjustment platform 231 can adjust the center of the target ball 233 to the theoretical center line 1. After collimation, the precision adjustment platform 231 can drive the target ball 233 back into the branch of the five-port vacuum cross device 232 to clear the visible infrared laser path. In future use of the resonant cavity, if it is necessary to recalibrate the theoretical center line 1, the precision adjustment platform 231 can send the target ball 233 back to the theoretical center line 1.

[0071] The upper end of the C-shaped target ball holder 234 is fixed to the bottom end of the drive rod of the precision adjustment platform 231, and the lower end is provided with a conical surface that matches the target ball 233. Due to the fit between the spherical surface and the conical surface and the gravity of the target ball, the center of the target ball 233 remains unchanged even if the target ball 233 is rotated arbitrarily.

[0072] Please see Figure 6 As shown, in one embodiment of the present invention, the upstream endoscope assembly 24 includes an upstream reflecting mirror 241 and an upstream endoscope mount 242. The reflecting surface of the upstream reflecting mirror 241 is a sphere, and the back surface of the upstream reflecting mirror 241 is parallel to the pole tangent of the reflecting surface. The center point of the sphere is called the pole, and the number of upstream reflecting mirrors 241 can be multiple; in this embodiment, two are used.

[0073] A small hole and a crosshair are formed on the back of the upstream reflector 241, defined as upstream back hole 2411 and upstream crosshair 2412, respectively. The centerline of the upstream back hole 2411 passes through the pole of the reflecting surface of the upstream reflector 241, and the center of the upstream back hole 2411 coincides with the fork of the upstream crosshair 2412. The upstream reflector 241 is mounted on the upstream mirror mount 242, and the upstream mirror mount 242 has a center hole 2421 at its center.

[0074] Therefore, as long as the back of the upstream reflector 241 is adjusted to be perpendicular to the optical axis of the digital internal focusing collimating telescope 21, and the center of the back hole 2411 on the upstream back is on the optical axis of the digital internal focusing collimating telescope 21, it indicates that the reflecting surface of the upstream reflector 241 is perpendicular to the optical axis of the digital internal focusing collimating telescope 21, and the pole is on the optical axis of the digital internal focusing collimating telescope 21.

[0075] Please see Figure 7 As shown, in one embodiment of the present invention, the downstream endoscope assembly 25 includes a downstream reflector 251 and a downstream mirror mount 252. The number of downstream reflectors 251 can be multiple; in this embodiment, there are two. The reflecting surface of the downstream reflector 251 is a sphere, and the center point of the sphere is called the pole. A through-conical hole is opened at the center of the front side of the downstream reflector 251. The center line of the conical hole coincides with the normal to the pole of the reflecting surface. The hole formed by the hole in the reflecting surface of the downstream reflector 251 is defined as the downstream front center hole 2511. The center line of the downstream front center hole 2511 passes through the pole of the reflecting surface of the downstream reflector 251, and the downstream front center hole 2511 is used for the output of infrared free electron laser. A center hole and a crosshair are machined on the back side of the downstream reflector 251, defined as the downstream back center hole 2512 and the downstream crosshair 2513, respectively. The intersection point of the downstream crosshair 2513 coincides with the center of the downstream back center hole 2512 and the downstream front center hole 2511. The downstream reflector 251 is mounted on the downstream mirror frame 252, and the downstream mirror frame 252 has a downstream mirror frame center hole 2521 at its center.

[0076] Please see Figure 8 As shown, in one embodiment of the present invention, each electronic position diagnostic system includes a precision linear actuator 271, a YAG plate 272, a six-port vacuum cross device 273, a support arm 274, a reflector frame 275, a reflector 276, a camera lens 277, and a CCD area array camera 278.

[0077] YAG plate 272 is mounted on the bottom of precision linear actuator 271. The position of YAG plate 272 is finely adjusted by precision linear actuator 271, and after the electron beam collimation is completed, YAG plate 272 is removed from theoretical center line 1. Support arm 274 is fixed on six-port vacuum cross device 273, supporting mirror frame 275, and mirror 276 is mounted on mirror frame 275.

[0078] During operation, when the electron beam strikes the YAG film 272, a visible light spot is generated within the diameter of the electron beam. A reflector 276 outside the vacuum chamber reflects this visible light spot onto a camera lens 277. The camera lens 277 focuses the visible light spot onto the photosensitive plate of a CCD area array camera 278. The CCD area array camera 278 converts the light spot on the photosensitive plate into a digital signal and transmits it to a computing terminal for position analysis.

[0079] The YAG plate 272 is engraved with crosshairs for easy aiming by the digitally focused collimating telescope 21. The precision linear actuator 271 is used to fine-tune the up, down, left, and right positions of the YAG plate 272. The support arm 274 is clamped to the vacuum cross window flange. By properly adjusting the two adjusting screws on the mirror mount 275, the light spot on the YAG plate 272 can be adjusted to the center position of the camera lens 277.

[0080] Please see Figure 2 , Figure 9 As shown, in one embodiment of the present invention, the visible light indication system 3 includes a helium-neon visible laser 31 located outside a vacuum environment, a beam expander 32, multiple planar mirrors, multiple identical CCD area array camera assemblies and a reflective target assembly 35, and also includes a thin film beam splitter assembly 36 and a visible laser calibration target assembly 37 located in a low vacuum environment.

[0081] Please see Figure 10As shown, in this embodiment, the thin-film beam splitter assembly 36 includes a thin-film beam splitter 361, a beam splitter mount 362, a beam splitting vacuum chamber 363, and a one-dimensional precision actuator 364. The thin-film beam splitter 361 is mounted on the beam splitter mount 362 and located within the beam splitting vacuum chamber 363. The beam splitter mount 362 is connected to the one-dimensional precision actuator 364, which drives the thin-film beam splitter 361 to move longitudinally. The thin-film beam splitter 361 has a 50% reflection and 50% transmission ratio and a thickness of approximately 10 micrometers. After light passes through the thin-film beam splitter 361, the parallel offset is less than 1 micrometer, which is far less than the allowable collimation error range. Therefore, the transmitted light from the thin-film beam splitter 361 can be considered coaxial with the incident light.

[0082] In this embodiment, three identical plane mirrors are provided, specifically defined as plane mirror 33A, plane mirror 33B, and plane mirror 33C. By adjusting the frame corresponding to each plane mirror, the visible laser P emitted by the helium-neon visible laser 31 can be directed at a 45° angle to the center of the thin-film beam splitter 361. The thin-film beam splitter 361 reflects 50% of the incident visible laser P upstream of the waveguide 01 as the laser reflection component P1, and transmits 50% along the direction of the visible laser P as the laser transmission component P2. By using the frame of the plane mirrors outside the vacuum and jointly adjusting the angles of multiple plane mirrors, the direction and position of the laser reflection component P1 can be adjusted.

[0083] Please see Figure 9 As shown, in this embodiment, four CCD area array camera assemblies are set up, respectively defined as CCD area array camera assembly one 34A, CCD area array camera assembly two 34B, CCD area array camera assembly three 34C, and CCD area array camera assembly four 34D. Among them, CCD area array camera assembly one 34A is used to observe the light spot of the laser reflection component P1 illuminating the back of the downstream reflector 251 and the downstream back center hole 2512. The visible light spot of the laser reflection component P1, the downstream back center hole 2512, and the downstream crosshair 2513 imaged by CCD area array camera assembly one 34A are input into the computer terminal, and the degree of coincidence between the center of the light spot and the downstream back center hole 2512 can be analyzed and determined. CCD area array camera assembly 2 34B is used to observe the position of the laser reflection component P1 illuminating the front of the upstream reflector 241. CCD area array camera assembly 3 34C is used to image the light spot of the laser reflection component P1 reflected back by the upstream reflector 241 and illuminating the front of the downstream reflector 251, as well as the downstream front center hole 2511 of the downstream reflector 251. The imaged light spot and the downstream front center hole 2511 are input into the computer to analyze and determine the degree of coincidence between the center of the light spot and the downstream front center hole 2511.

[0084] Please see Figure 11As shown, in this embodiment, each CCD area array camera assembly includes a clamp 341, a camera support plate 342, a second photographic lens 343, and a second CCD area array camera 344. The clamp 341 is used to fix the entire CCD area array camera assembly on the outer circle of the observation window of the vacuum chamber. The camera support plate 342 is connected to the clamp 341, and the second CCD area array camera 344 is mounted on the camera support plate 342.

[0085] Please see Figure 9 As shown in this embodiment, the reflected component P1 of the laser P after being split by the thin-film beam splitter 361 will illuminate the front of the upstream mirror 241 through the downstream back center hole 2512 on the downstream mirror 251. After being reflected back by the upstream mirror 241, the laser reflected component P1 will be reflected back to the thin-film beam splitter 361 through the downstream front center hole 2511 of the downstream mirror 251. The thin-film beam splitter 361 will split the laser reflected component P1 again, of which 50% of the reflected beam is useless and 50% of the transmitted beam P′1 illuminates the downstream of the resonant cavity. With the upstream reflector 241 and downstream reflector 251 calibrated by collimation system 2, the positional relationship between the laser reflection component P1 and the pinhole image on the front and back sides of the downstream reflector 251 is analyzed using CCD area array camera 344 in CCD area array camera assembly 34A and CCD area array camera assembly 34B. When the center of the laser reflection component P1 does not coincide with the center of the pinhole image, the angles of the three planar reflectors outside the vacuum are adjusted to adjust the laser reflection component P1 until the laser reflection component P1 and the pinhole on both sides of the downstream reflector 251 are aligned. At this point, the laser reflection component P1 and the transmitted beam P′1 coincide with the theoretical center line 1. It is important to note that when adjusting the direction and position of the laser reflection component P1, the beam expander 32 must be adjusted to enlarge the laser reflection component P1 to a size larger than the diameter of the center hole 2512 on the downstream back side of the downstream reflector 251 in order to analyze the positional relationship. After the direction and position are adjusted, when the laser reflection component P1 illuminates the downstream beamline, the beam expander 32 must be adjusted to minimize the beam diameter and reduce beam loss.

[0086] In this embodiment, the reflective target assembly 35 is the same as the target ball assembly 22. By adjusting the YZ adjustment platform at the bottom of the reflective target assembly 35, the center of the target is moved to the center line of the laser transmission component P2. The laser transmission component P2 will be reflected back to the thin-film beam splitter 361 by the reflective target. The laser transmission component P2 will be split again by the thin-film beam splitter 361, and the reflected beam P′2 will be directed downstream of the resonant cavity.

[0087] Please see Figure 12As shown, in this embodiment, the visible laser calibration target assembly 37 includes a laser calibration target plate 371 located in a low vacuum environment and a linear actuator 372 located outside the vacuum environment. The linear actuator 372 is mounted on the flange of the downstream beamline mirror box. When calibration is required, the linear actuator 372 is manually driven to bring the center of the laser calibration target plate 371 to the position of the theoretical centerline 1. The CCD area array camera assembly 34D can image the transmitted beam P′1 and the reflected beam P′2. The spot of the reflected beam P′2 on the laser calibration target plate 371 is analyzed for overlap. When the spot of the reflected beam P′2 does not overlap with the spot of the transmitted beam P′1, the YZ adjustment platform under the reflective target assembly 35 is adjusted until the two spots are displayed on the screen of the CCD area array camera assembly 34D and overlap within the allowable error range. It can be considered that the transmitted beam P′1 and the reflected beam P′2 are collinear, resulting in a superimposed visible laser beam for auxiliary installation of the downstream beamline components. After calibration, manually drive the linear driver 372 to move the laser calibration target plate 371 out of the optical path. The operation can be repeated if recalibration is required.

[0088] Without considering beam loss, due to the two passes through the thin-film beam splitter 361, the intensity of the transmitted beam P′1 and the reflected beam P′2 is 25% of the original intensity of the visible laser P. After considering transmission loss, the intensity of the transmitted beam P′1 may only be 10% of that of the visible laser P. If the brightness of the transmitted beam P′1 is insufficient downstream, the position of the reflective target assembly 35 can be adjusted to adjust the direction of the reflected beam P′2 until it coincides with the transmitted beam P′1. After the transmitted beam P′1 and the reflected beam P′2 are combined, the brightness is enhanced.

[0089] Please see Figures 1 to 12 As shown, the present invention also provides a method of using an integrated free-electron laser online collimation and visible indicator laser system, including a method of using the collimation system 2:

[0090] S10, adjust the positions of target ball assembly 1 22 and target ball assembly 23 so that the center of the target ball of both falls on the theoretical center line 1.

[0091] In this embodiment, the positions of target ball 1 221 and target ball 233 are measured and adjusted using a laser tracker so that the centers of target ball 1 221 and target ball 233 fall on the theoretical center line 1. At this time, the line connecting the centers of target ball 1 221 and target ball 233 represents the theoretical center line 1.

[0092] S20, adjust the position and angle of the digital internal focusing collimating telescope 21, and use its telescope function to aim at target sphere 1 221 and target sphere 233 respectively. While aiming at target sphere 233, move target sphere 1 221 away. When the centers of target sphere 1 221 and target sphere 233 are no longer at the intersection of the crosshairs on the eyepiece of the digital internal focusing collimating telescope 21, repeatedly adjust the position and angle of the digital internal focusing collimating telescope 21 until the crosshairs on the eyepiece of the digital internal focusing collimating telescope 21 coincide with the centers of target sphere 1 221 and target sphere 233 within the allowable error range. At this point, the optical axis of the digital internal focusing collimating telescope 21 is aligned with the theoretical center line 1, and the position and angle of the optical axis of the digital internal focusing collimating telescope 21 will not be adjusted in the following steps. Remove target sphere 1 221 and move target sphere 233 into the branch tube of the five-port vacuum cross-connector 232. If it is necessary to check whether the optical axis of the internal focusing digital collimating telescope 21 coincides with the theoretical center line 1 later, the target sphere 1 221 and the target sphere 233 can be reset. If there is a deviation, repeat step S20.

[0093] S30. Using the telescope function of the digital internal focusing collimating telescope 21, focus is applied to the downstream mirror 251 of the downstream cavity mirror group 25. The downstream front center hole 2511 of the downstream mirror 251 is imaged on the eyepiece of the digital internal focusing collimating telescope 21. Adjust the up, down, left, and right positions of the downstream frame 252 in the downstream cavity mirror group 25 until the center of the downstream front center hole 2511 of the downstream frame 252 coincides with the intersection of the crosshairs of the digital internal focusing collimating telescope 21, indicating that the pole of the downstream mirror 251 has been adjusted to the theoretical center line 1.

[0094] S40, the collimation function of the digital internal focusing collimating telescope 21 is used to collimate the downstream reflector 251. When the reflected light spot of the downstream reflector 251 does not coincide with the crosshairs on the collimating eyepiece in the digital internal focusing collimating telescope 21, the angle of the downstream frame 252 is adjusted until the reflected crosshairs coincide with the downstream frame 252 on the eyepiece. At this time, the downstream reflector 251 is adjusted so that the reflecting surface is perpendicular to the theoretical center line 1.

[0095] S50, using the telescope function of the digital internal focusing collimating telescope 21, adjust the focus of the electronic position diagnostic system 27A to the YAG plate 272 of the electronic position diagnostic system 27A. The crosshairs on the YAG plate 272 will be imaged onto the eyepiece of the digital internal focusing collimating telescope 21. When the crosshairs on the eyepiece do not coincide with the crosshairs, adjust the precision linear actuator 271 until the crosshairs coincide with the crosshairs. At this time, the crosshair intersection point of the YAG plate 272 falls on the theoretical center line 1. Remember the position of the YAG plate 272 on the precision linear actuator 271, and then remove the YAG plate 272 from the theoretical center line 1. During subsequent electronic diagnostics, the precision linear actuator 271 can accurately reset the YAG plate 272 to the theoretical center line 1. Similarly, use the same method to adjust the crosshair center of the YAG plate 272 of the electronic position diagnostic systems 27B and 27C to the theoretical center line 1 and remember the position for easy removal and precise reset. When the electron beam is introduced into the oscillator, the center of the electron spot on the YAG plate 272 is observed to coincide with the intersection of the cross lines on the YAG plate 272 from the CCD area array camera 278 screen of the three electronic position diagnostic systems.

[0096] S60, using the telescope function of the digital internal focusing collimating telescope 21, guides the adjustment of the center of the upstream back aperture 2411 of the upstream cavity mirror group 24 to the theoretical center line 1. Using the collimation function of the digital internal focusing collimating telescope 21, guides the adjustment of the back of the upstream reflector 241 to be perpendicular to the theoretical center line 1. At this time, the pole of the upstream reflector 241 is adjusted to be on the theoretical center line 1, and the reflecting surface is adjusted to be perpendicular to the theoretical center line 1.

[0097] This completes the collimation of one set of mirrors and the electron beam. Remember the position of this set of mirrors; the collimation of the second set of mirrors can be completed using the same method.

[0098] Please see Figures 1 to 12 As shown, the present invention also provides a method of using the visible light indicator system 3:

[0099] After the collimation system 2 completes collimation, the helium-neon visible laser 31 emits visible laser P, which is reflected by multiple plane mirrors in sequence and illuminates the center of the thin-film beam splitter 361. The thin-film beam splitter 361 splits the laser into a laser reflection component P1 that is incident upstream of the oscillator and a laser transmission component P2 that is incident in the direction of the reflective target assembly 35.

[0100] The laser reflection component P1 is reflected back by the upstream reflector 241 located upstream of the resonant cavity, and the component transmitted light formed by the thin film beam splitter 361 is reflected back by the reflective target assembly 35, and is split again by the thin film beam splitter 361, forming a transmitted beam P′1 that shines downstream of the resonant cavity.

[0101] The laser transmission component P2 is reflected back by the reflective target assembly 35 and then split again by the thin film beam splitter 361 to form a reflected beam P′2 toward the downstream direction of the resonant cavity.

[0102] At the thin-film beam splitter 361, the transmitted beam P′1 and the reflected beam P′2 are combined and used as the visible indicator laser for adjusting the downstream beamline of the resonant cavity mirror.

[0103] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0104] The above embodiments are merely examples of implementation methods of the invention. The scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A laser system integrating free-electron laser online collimation and visible indicator, characterized in that, It includes a theoretical centerline (1) representing the magnetic axis of the undulator, and a collimation system (2) and a visible light indicator system (3) that operate independently and online; the collimation system (2) ensures that the optical axis and the electron beam axis coincide with the theoretical centerline (1); the visible light indicator system (3) provides a reference visible beam for downstream beamline tuning, and the reference visible beam coincides with the theoretical centerline (1); and the visible light indicator system (3) is located outside the high vacuum.

2. The integrated free-electron laser online collimation and visible indicator laser system according to claim 1, characterized in that, The collimation system (2) includes a digital internal focusing collimating telescope with a bright crosshair (21), a target ball assembly one (22), a target ball assembly two (23), an upstream endoscope assembly (24), a downstream endoscope assembly (25), and three electronic position diagnostic systems (27); The digital internal focusing collimating telescope (21) is located outside the vacuum environment at the upstream end of the oscillator (00); the target ball assembly one (22) is located outside the vacuum environment, between the upstream cavity mirror group (24) and the digital internal focusing collimating telescope (21); the target ball assembly two (23) is located in the low vacuum environment, downstream of the downstream cavity mirror group (25); the downstream cavity mirror group (25) is located in the low vacuum environment; the electronic position diagnostic system one (27A) and the electronic position diagnostic system three (27C) are located in the low vacuum environment, upstream and downstream of the waveguide (01) of the oscillator (00); the electronic position diagnostic system two (27B) is located in the middle of the high vacuum waveguide (01).

3. The integrated free-electron laser online collimation and visible indicator laser system according to claim 2, characterized in that, The visible light indication system (3) includes a helium-neon visible laser (31) located outside the vacuum environment, multiple planar mirrors, multiple identical CCD area array camera components and reflective target components (35), and also includes a thin film beam splitter (361) located inside the vacuum environment; The helium-neon visible laser (31) emits visible laser P, which is adjusted and reflected by multiple plane mirrors and then split at the center of the thin film beam splitter (361) to form a laser reflection component P1 that is incident upstream of the oscillator and a laser transmission component P2 that is incident in the direction of the reflective target assembly (35). The laser reflection component P1 is reflected back by the upstream mirror (241) located upstream of the resonant cavity, and is split again by the thin film beam splitter (361), forming a transmitted beam P′1 that shines downstream of the resonant cavity. The laser transmission component P2 is reflected back by the reflective target assembly (35) and then split again by the thin-film beam splitter (361) to form a reflected beam P′2 directed downstream of the resonant cavity.

4. The integrated free-electron laser online collimation and visible indicator laser system according to claim 2, characterized in that, The digital internal focusing collimating telescope (21) combines the functions of a collimating lens and a telescope. The collimating lens function can be used to adjust the angle of the reflector, and the telescope function can be used to adjust the position of the reflector. The cross beam emitted from the digital internal focusing collimating telescope (21) is reflected by the mirror and returns to the eyepiece of the digital internal focusing collimating telescope (21). If the reflected cross beam does not coincide with the cross line on the eyepiece, it means that the mirror is not perpendicular to the optical axis of the digital internal focusing collimating telescope (21). Adjust the angle of the mirror until the reflected cross beam on the eyepiece coincides with the cross line on the eyepiece of the digital internal focusing collimating telescope (21). When using the telescope function, adjust the focus of the digital internal focusing collimating telescope (21) to the object being measured, and adjust the key points of the object's position until they are on the optical axis of the digital internal focusing collimating telescope (21).

5. The integrated free-electron laser online collimation and visible indicator laser system according to claim 2, characterized in that, The target ball assembly (22) includes a target ball (221), a target ball seat (222), a YZ adjustment platform (223), and a pad (224) arranged sequentially from top to bottom. The target ball (221) is a precision sphere with three mutually perpendicular reflective surfaces, and the center position of the target ball can be precisely measured using a laser tracker. The upper part of the target ball seat (222) is a conical surface that matches the outer spherical surface of the target ball (221). No matter how the target ball (221) is rotated or reset, the center of the target ball on the target ball seat (222) remains unchanged. The YZ adjustment platform (223) is used to adjust the vertical and horizontal positions of the target ball (221). The second target ball assembly (23) includes a precision adjustment platform (231), a five-port vacuum cross device (232), a second target ball (233), and a second target ball seat (234); The precision adjustment platform (231) is used to adjust the vertical direction and lateral position of the target ball (233). When the target ball (233) needs to work, the precision adjustment platform (231) can adjust the center of the target ball (233) to the theoretical center line (1). After the alignment is completed, the precision adjustment platform (231) can drive the target ball (233) back to the branch pipe of the five-port vacuum cross device (232) to make way for the visible infrared laser beam path. The upper end of the target ball seat (234) is fixed to the bottom end of the drive rod of the precision adjustment platform (231), and the lower end is provided with a conical surface that matches the target ball (233). The center of the target ball remains unchanged no matter how the target ball (233) is rotated.

6. The integrated free-electron laser online collimation and visible indicator laser system according to claim 2, characterized in that, The upstream endoscope assembly (24) includes an upstream mirror (241) and an upstream endoscope frame (242); The reflecting surface of the upstream reflector (241) is a spherical surface, and the back surface of the upstream reflector (241) is parallel to the pole tangent of the reflecting surface. A small hole and a cross line are opened on the back surface of the upstream reflector (241), which are defined as the upstream back hole (2411) and the upstream cross line (2412), respectively. The center line of the upstream back hole (2411) passes through the pole of the reflecting surface of the upstream reflector (241), and the center of the upstream back hole (2411) coincides with the fork of the upstream cross line (2412). The upstream reflector (241) is mounted on the upstream mirror frame (242).

7. The integrated free-electron laser online collimation and visible indicator laser system according to claim 2, characterized in that, The downstream endoscope assembly (25) includes a downstream mirror (251) and a downstream frame (252); The reflecting surface of the downstream reflector (251) is a spherical surface. A through conical hole is opened in the center of the downstream reflector (251). The center line of the conical hole coincides with the normal of the pole of the reflecting surface. The hole formed by the conical hole of the downstream reflector (251) on the reflecting surface is defined as the downstream front center hole (2511). Small holes and cross lines are processed on the back of the downstream reflector (251), which are defined as the downstream center hole (2512) and the downstream cross line (2513) respectively. The intersection point of the downstream cross line (2513) coincides with the center of the downstream back center hole (2512). The downstream reflector (251) is mounted on the downstream mirror frame (252).

8. The integrated free-electron laser online collimation and visible indicator laser system according to claim 2, characterized in that, Each electronic position diagnostic system includes a precision linear actuator (271), a YAG plate (272), a six-port vacuum cross device (273), a support arm (274), a reflector mount (275), a reflector (276), a camera lens (277), and a CCD area array camera (278). The YAG plate (272) is mounted on the bottom of the precision linear actuator (271); the position of the YAG plate (272) is finely adjusted by the precision linear actuator (271), and after the electron beam is collimated, the YAG plate (272) is removed from the theoretical center line (1); the support arm (274) is fixed on the six-port vacuum cross device (273) to support the reflector frame (275); the reflector one (276) is mounted on the reflector frame (275).

9. A method of using the integrated free-electron laser online collimation and visible indicator laser system according to any one of claims 3-8, comprising a method of using the collimation system (2): S10, adjust the positions of target ball assembly one (22) and target ball assembly two (23) so that the centers of target ball one (221) of target ball assembly one (22) and target ball two (233) of target ball assembly two (23) fall on the theoretical center line (1); S20, adjust the position and angle of the digital internal focusing collimating telescope (21), and use the telescope function of the digital internal focusing collimating telescope (21) to aim at target ball one (221) and target ball two (233) respectively; when the center of target ball one (221) and target ball two (233) is not on the intersection of the crosshairs of the eyepiece of the digital internal focusing collimating telescope (21), repeatedly adjust the position and angle of the digital internal focusing collimating telescope (21) until the crosshairs and the center of target ball one (221) and target ball two (233) are seen to coincide within the allowable error range through the eyepiece of the digital internal focusing collimating telescope (21); after the adjustment is completed, remove target ball assembly one (22) and target ball assembly two (23); S30, using the telescope function of the digital internal focusing collimating telescope (21), focus on the downstream mirror (251) of the downstream cavity mirror group (25). The downstream front center hole (2511) of the downstream mirror (251) is imaged on the eyepiece of the digital internal focusing collimating telescope (21). Adjust the position of the downstream frame (252) in the downstream cavity mirror group (25) until the center of the downstream front center hole (2511) of the downstream frame (252) coincides with the intersection of the crosshairs of the digital internal focusing collimating telescope (21). S40, using the collimation function of the digital internal focusing collimating telescope (21), collimate the downstream mirror (251). When the reflected crosshair of the downstream mirror (251) does not coincide with the crosshair on the collimating eyepiece in the digital internal focusing collimating telescope (21), adjust the angle of the downstream frame (252) until the reflected crosshair coincides with the downstream frame (252) on the eyepiece. At this time, the downstream mirror (251) is adjusted so that the reflecting surface is perpendicular to the theoretical center line (1). S50, using the telescope function of the digital internal focusing collimating telescope (21), adjust the electronic position diagnostic system one (27A), adjust the focus of the digital internal focusing collimating telescope (21) to the YAG plate (272) of the electronic position diagnostic system one (27A), the crosshairs on the YAG plate (272) will be imaged onto the eyepiece of the digital internal focusing collimating telescope (21), adjust the precision linear actuator (271) in the electronic position diagnostic system one (27A) to make the crosshair image coincide with the crosshairs, at this time the crosshair intersection point of the YAG plate (272) falls on the theoretical center line (1); after the adjustment is completed, remove the electronic position diagnostic system one (27A); similarly, use the same method to adjust the crosshair center of the YAG plate (272) of the electronic position diagnostic system two (27B) and the electronic position diagnostic system three (27C) to the theoretical center line (1) and then remove them; S60, using the telescope function of the digital internal focusing collimating telescope (21), guide the adjustment of the center of the back hole (2411) on the back of the upstream mirror (241) of the upstream cavity mirror group (24) to the theoretical center line (1); using the collimation function of the digital internal focusing collimating telescope (21), guide the adjustment of the back of the upstream mirror (241) to be perpendicular to the theoretical center line (1). At this time, the pole of the upstream mirror (241) is adjusted to be on the theoretical center line (1), and the reflecting surface is adjusted to be perpendicular to the theoretical center line (1).

10. The method of using the integrated free-electron laser online collimation and visible light indicating laser system according to claim 9, including the method of using the visible light indicating system (3): After the collimation system (2) completes collimation, the helium-neon visible laser (31) emits visible laser P, which is reflected by multiple plane mirrors in sequence and illuminates the center of the thin film beam splitter (361). The thin film beam splitter (361) splits the laser into a laser reflection component P1 that is incident upstream of the oscillator and a laser transmission component P2 that is incident in the direction of the reflective target assembly (35). The laser reflection component P1 is reflected back by the upstream mirror (241) located upstream of the resonant cavity, and is split again by the thin film beam splitter (361), forming a transmitted beam P′1 that shines downstream of the resonant cavity. The laser transmission component P2 is reflected back by the reflective target assembly (35) and then split again by the thin film beam splitter (361) to form a reflected beam P′2 toward the downstream direction of the resonant cavity. At the thin-film beam splitter (361), the transmitted beam P′1 and the reflected beam P′2 are combined and used as the visible indicator laser of the downstream beamline of the resonant cavity to adjust the reflector.

Images