Integrated calibration device and calibration method for Thomson scattering system

Abstract

The invention relates to the technical field of controlled nuclear fusion, in particular to an integrated calibration device and calibration method for a Thomson scattering system, and the device comprises a multi-degree-of-freedom mechanical arm module, a target plate calibration module, an integrating sphere transmittance calibration module and a control system. The interface structure is used for realizing in-situ exchange of the target plate calibration module and the integrating sphere transmittance calibration module; space microspur scanning is executed through an electric control displacement structure, a light outlet of an integrating sphere module is configured to be capable of accurately reproducing space coordinates locked by a target plate, and time sequence synchronization of mechanical movement and photoelectric signal collection is achieved in cooperation with a control system. Through the combination of the mechanical arm automatic platform, the radial fine adjustment mechanism and the in-situ module replacement design, the long-standing technical problems of difficulty in in-situ calibration, insufficient spatial positioning precision, geometric-optical data splitting and the like in a Thomson scattering diagnosis system are solved.

Description

Technical Field

[0001] This invention relates to the field of controlled nuclear fusion technology, specifically to an integrated calibration device and calibration method for a Thomson scattering system. Background Technology

[0002] Thomson scattering (TS) diagnostic systems are core diagnostic tools used in magnetic confinement fusion devices such as tokamaks to measure the electron temperature and density profiles of plasma. This system uses a high-energy laser to incident on the plasma and detects the spectral intensity distribution of the scattered light, thereby calculating the distribution of plasma electron temperature and density. A typical TS system consists of an emitting laser, a collecting optics system, a polychromator, a detector, and data acquisition devices. Its measurement accuracy is highly dependent on the system's spatial geometric consistency and the transmittance stability of the optical link. To ensure the accuracy and reliability of the measurement data, precise spatial coordinates of the scattering points (spatial geometric parameters) and the absolute spectral response of the entire optical link (system transmittance parameters) must be obtained.

[0003] In existing technologies, the calibration of Thomson scattering systems is usually carried out in two separate stages: spatial calibration and transmittance calibration.

[0004] For spatial calibration, the TS system spatial calibration of mainstream tokamak devices (such as JET, DIII-D, EAST, HL-2A, etc.) mostly adopts the following methods:

[0005] Artificial target plate method: When the device is stopped, a target plate is installed at the diagnostic window, and the position of the light spot is observed by external laser pointer or fiber optic light output to determine the spatial line of sight of each collection channel.

[0006] Fixed fixture calibration: Set a fixed collimation target or reference point on the optical channel, and determine the optical path geometry by manual ranging or laser rangefinder.

[0007] Theoretical geometric inverse calculation method: Based on the CAD model or EFIT magnetic surface data, the coordinates of the spatial point of the scatterer are calculated, and the RZ position is determined by virtual calibration.

[0008] While these methods can perform basic geometric calibration, they generally suffer from the following problems:

[0009] The operation relies on manual labor, and the calibration process is cumbersome and has poor repeatability;

[0010] The target plate installation position cannot be automatically adjusted, making it difficult to accurately match the center of the optical path.

[0011] Due to limited visibility, especially in the confined space and limited number of windows of a tokamak, some channel calibrations cannot be implemented;

[0012] The lack of a real-time attitude calibration mechanism means that target tilt and optical path angle deviation will lead to scattering point positioning errors, with typical deviations reaching several millimeters to several centimeters.

[0013] The inability to re-verify the minute displacements or jitters of the collecting optical fiber during the device's operating cycle leads to the gradual accumulation of spatial point errors over long-term operation.

[0014] For system transmittance calibration, the transmittance calibration of the front-end TS system is mostly carried out by offline light source calibration or partial link testing:

[0015] Using an external white light or standard light source, the optical path units (lens, polychromator, detector) are calibrated step by step;

[0016] Static comparison of the probe link was performed using a neutral density filter and a power meter;

[0017] Some experimental setups utilize an external integrating sphere to calibrate the response curve of the multicolor instrument.

[0018] However, these methods typically do not have optical path conditions consistent with actual scattering geometry, and have the following shortcomings:

[0019] Non-in-situ measurement, the calibration light source is inconsistent with the actual scattering path, which means that the transmittance cannot truly reflect the end-to-end performance of the system;

[0020] The cumulative calibration error at each stage cannot eliminate the coupling loss effect of the intermediate optical interface;

[0021] It is impossible to synchronize the responses of each spatial point; only the overall response of the channel can be obtained, which affects the quantitative evaluation of system performance.

[0022] The calibration results rely on manual comparison and table correction, lacking automation and repeatability.

[0023] Meanwhile, because the spatial calibration and transmittance calibration of the TS system are independent under the current technological system, and both are performed statically and offline, the lack of a unified coordinate and optical reference system between the two leads to:

[0024] The combined effect of spatial coordinate errors and transmittance errors affects the accuracy of temperature and density inversion.

[0025] The calibration data is difficult to reuse during different experimental periods, resulting in high system maintenance costs;

[0026] The calibration process is time-consuming and requires a lot of manual intervention, making it difficult to meet the rapid calibration needs of future high-frequency experiments. Summary of the Invention

[0027] To address the aforementioned technical problems, this invention provides an integrated calibration device and method for a Thomson scattering system. This device integrates spatial geometric calibration and optical transmittance measurement in the same coordinate system, obtaining highly consistent end-to-end system response data and improving the measurement accuracy of the Thomson scattering diagnostic system.

[0028] This invention is achieved through the following technical solution:

[0029] An integrated calibration device for a Thomson scattering system includes:

[0030] A multi-degree-of-freedom robotic arm module for extending to the diagnostic window area of ​​a tokamak device, wherein the end of the multi-degree-of-freedom robotic arm module is provided with an interface structure;

[0031] The target calibration module is installed at the end of the multi-degree-of-freedom robotic arm module through the interface structure. The target calibration module includes an electrically controlled displacement structure, which is used to perform micro-scanning after determining the initial position to lock the calibration coordinates of the scattering space point.

[0032] An integrating sphere transmittance calibration module is replaceably mounted at the end of the multi-degree-of-freedom robotic arm module via the interface structure and positioned at the calibration coordinates to provide a simulated diffuse light source for system transmittance measurement.

[0033] The control system is connected to the multi-degree-of-freedom robotic arm module, the target calibration module, and the integrating sphere transmittance calibration module, respectively. It is used to control the robotic arm path planning, the fine-tuning of the target calibration module, and the synchronous acquisition of data, and to establish the correspondence between the calibration coordinates and the system optical transmittance data.

[0034] Optionally, the multi-degree-of-freedom robotic arm module includes:

[0035] A fixed base, which is installed outside the diagnostic window of the tokamak device;

[0036] A rotary drive unit, which is mounted on the fixed base, is used to drive the robotic arm to perform horizontal scanning motion around the vertical axis;

[0037] A telescopic drive unit, connected to the rotary drive unit, is used to drive the robotic arm to telescopically move along the R direction, and the end of the telescopic drive unit forms the interface structure.

[0038] The sensor assembly, integrated into the multi-degree-of-freedom robotic arm module, includes a displacement encoder for feedback of position information and a tilt sensor for monitoring the end effector's attitude.

[0039] Optionally, the target calibration module further includes:

[0040] A target plate, used to reflect incident light, is mounted on the moving end of the electrically controlled displacement structure;

[0041] The collimation structure, which is set on the target plate calibration module, includes collimation holes distributed vertically and an embedded light-transmitting medium, used to assist in establishing the incident reference optical axis;

[0042] The electrically controlled displacement structure drives the target plate to reciprocate linearly along the R direction relative to the end of the multi-degree-of-freedom robotic arm module.

[0043] Optionally, the integrating sphere transmittance calibration module includes:

[0044] The integrating sphere body is provided with a light outlet and a monitoring port, the aperture of which is adapted to the scattering spatial point size of the Thomson scattering system;

[0045] A standard light source, coupled to the integrating sphere body, is used to generate uniform diffuse light with a known spectral distribution;

[0046] When the integrating sphere transmittance calibration module is installed through the interface structure, the geometric center of the light outlet coincides spatially with the center position of the target plate when the target plate calibration module locks the calibration coordinates.

[0047] Optionally, the control system includes:

[0048] The motion control unit is connected in communication with the electrically controlled displacement structure of the multi-degree-of-freedom robotic arm module and the target calibration module, and is used to issue position commands and read the real-time coordinates fed back by the encoder.

[0049] The data processing unit is used to receive the detection signal from the Thomson scattering system and the power monitoring signal from the integrating sphere transmittance calibration module, and to achieve time synchronization of multi-source data.

[0050] The data processing unit is equipped with a focusing criterion algorithm, which is used to analyze the spot image or signal characteristics acquired during the macro scanning motion, and determine the optimal focusing position and mark it as calibration coordinates based on the minimum diameter of the spot or the clearest shape of the image.

[0051] A calibration method for a Thomson scattering system, based on the integrated calibration device, the calibration method comprising:

[0052] S1. Establish collimated optical axis: Turn on the collimating laser, control the multi-degree-of-freedom robotic arm module loaded with the target plate calibration module to enter the calibration area, adjust the target plate attitude so that the collimating laser passes through the collimating structure on the target plate, and record the position of the robotic arm at this time as the zero position of the incident axis.

[0053] S2, Reverse light output positioning: Turn off the collimating laser, connect the standard light source to the fiber optic polychromator end of the Thomson scattering system, and let the light shine back onto the target calibration module through the collection optical path.

[0054] S3. Spatial Fine-tuning and Coordinate Locking: Control the electrically controlled displacement structure of the multi-degree-of-freedom robotic arm module or the target calibration module to perform scanning movements in the Z and R directions near the zero position of the incident axis, find the optimal focusing position of the light spot on the target plate, and determine this position as the calibration coordinate of the scattering space point. ;

[0055] S4. In-situ module replacement: Keeping the robotic arm base stationary, replace the target plate calibration module with the integrating sphere transmittance calibration module through the interface structure.

[0056] S5. Integrating sphere positioning and spectral response measurement: Control the robotic arm to move the light outlet of the integrating sphere transmittance calibration module to the calibration coordinates. The system transmittance is calculated by scanning wavelengths at a certain location and collecting data on the response of the Thomson scattering system to different wavelengths of light signals.

[0057] Optionally, establishing the collimated optical axis specifically includes:

[0058] The control multi-degree-of-freedom robotic arm module sends the target calibration module to the preset position and uses the tilt sensor integrated on the target calibration module to monitor the horizontal and vertical angles of the target.

[0059] Fine-tune the posture of the robotic arm's end effector until the collimated laser beam passes through the upper and lower collimation holes on the target calibration module in sequence and coincides at the designated position within the holes, and the tilt sensor reading error is less than the preset threshold, thus determining the zero position of the incident axis.

[0060] Optionally, spatial fine-tuning and coordinate locking specifically include:

[0061] Coarse scan: Maintaining the target calibration module's orientation, control the robotic arm to scan the Z-axis position along the R-axis reference baseline, finding the initial position where the reverse-emitting light spot falls on the center of the target plate. );

[0062] Fine scanning: Near the initial position, the electrically controlled displacement structure of the target calibration module is controlled to perform micro-scanning along the R direction in millimeter-level steps;

[0063] Coordinate locking: Observe the shape of the light spot on the target plate. When the light spot diameter is smallest or the shape is clearest, record the current position of the robotic arm and the adjustment amount of the electronically controlled displacement structure as calibration coordinates. ).

[0064] Optionally, the transmittance of the wavelength scanning and calculation system specifically includes:

[0065] Connect the calibration light source to the integrating sphere transmittance calibration module, and connect the power meter to the monitoring port of the integrating sphere;

[0066] Control the calibration light source to perform wavelength scanning within a preset wavelength range according to a set step value;

[0067] For each wavelength point, the response value of the multicolor meter channel and the monitoring value of the power meter are collected simultaneously;

[0068] The system transmittance at that spatial point is calculated based on the ratio of the polychromator response value to the power meter monitoring value, combined with the light output efficiency of the integrating sphere.

[0069] Optionally, the calibration employs a multi-channel cyclic calibration strategy:

[0070] After completing the spatial calibration of one fiber optic line-of-sight channel, repeat step S3 until the spatial point coordinates of all fiber optic line-of-sight channels are calibrated to form a spatial coordinate set.

[0071] Then, step S4 is executed to replace the module, and step S5 is executed cyclically according to the spatial coordinate set to complete the system transmittance calibration of all corresponding spatial points and generate a correspondence table between spatial coordinates and wavelength transmittance.

[0072] Compared with the prior art, the present invention has the following features and beneficial effects:

[0073] This invention employs a multi-degree-of-freedom robotic arm extending into the diagnostic window area of ​​the tokamak as an automation carrier. It utilizes an interface structure to enable in-situ interchange between the target plate calibration module and the integrating sphere transmittance calibration module. Spatial micro-scanning is performed through an electrically controlled displacement structure. The light output port of the integrating sphere module is configured to accurately reproduce the spatial coordinates locked by the target plate. The control system is used to achieve time synchronization between mechanical motion and photoelectric signal acquisition.

[0074] This invention solves the long-standing technical problems in Thomson scattering diagnostic systems, such as difficulties in in-situ calibration, insufficient spatial positioning accuracy, and separation of geometric and optical data, by combining an automated robotic arm platform, a radial fine-tuning mechanism, and an in-situ module replacement design. This improves the overall measurement accuracy and data reliability of the plasma diagnostic system for nuclear fusion devices. Attached Figure Description

[0075] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, but do not constitute a limitation on the embodiments of the present invention.

[0076] Figure 1 This is a schematic diagram of an integrated calibration device for a Thomson scattering system according to the present invention.

[0077] Figure 2 This is a schematic flowchart of a calibration method for a Thomson scattering system according to the present invention.

[0078] Reference numerals: 1-Platform, 2-Target calibration module, 3-Integrating sphere transmittance calibration module, 4-Multi-degree-of-freedom robotic arm module, 5-Standard light source, 10-Tokamak device. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0080] It should also be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0081] Where there is no conflict, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0082] Example 1

[0083] like Figure 1 Therefore, this embodiment provides an integrated calibration device for a Thomson scattering system, which uses a highly flexible automated mechanical device to solve the problem of separation between spatial alignment and optical measurement in traditional calibration. The overall operation process can be summarized as follows: using a robotic arm as a unified motion carrier, it successively carries a position calibration tool (target plate) and an optical measurement tool (integrating sphere). Through unified scheduling by the control system, the spatial coordinates are first accurately locked, and then the coordinates are reproduced in situ for optical parameter measurement.

[0084] This embodiment will be described in detail with reference to its specific structure:

[0085] A multi-degree-of-freedom robotic arm module 4 is mounted on platform 1 and extends to the diagnostic window area of ​​the tokamak device 10. The end of the multi-degree-of-freedom robotic arm module 4 is equipped with an interface structure. "Multi-degree-of-freedom" indicates that the robotic arm can flexibly adjust its position and orientation in three-dimensional space, thereby adapting to the complex external structure and limited window space of the tokamak device 10. Furthermore, under normal circumstances, a suitable robotic arm structure can be selected based on the situation. The interface structure allows for the rapid installation / switching of target plates or integrating spheres.

[0086] The target calibration module 2 is installed at the end of the multi-degree-of-freedom robotic arm module 4 through the interface structure. The target calibration module 2 includes an electrically controlled displacement structure, which is used to perform micro-scanning after determining the initial position to lock the calibration coordinates of the scattering space point. After the robotic arm sends the target plate to the approximate initial position, the electrically controlled displacement structure intervenes to perform micro-scanning, capture the best feedback point of the light signal, and thus lock the calibration coordinates of the "scattering space point".

[0087] Micro-scanning refers to high-precision reciprocating movement within an extremely small area. Electrically controlled displacement refers to linear motion or position adjustment mechanisms achieved through electric drive.

[0088] The integrating sphere transmittance calibration module 3 is replaceably installed at the end of the multi-degree-of-freedom robotic arm module 4 through the interface structure and positioned at the calibration coordinates to provide a simulated scattering light source for measuring the system transmittance; the integrating sphere provides a simulated scattering light source (a uniformly distributed standard light source 5) to simulate real plasma scattering light, thereby measuring the overall transmittance (light energy transmission efficiency) of the Thomson scattering system.

[0089] The control system is connected to the multi-degree-of-freedom robotic arm module 4, the target calibration module 2, and the integrating sphere transmittance calibration module 3, respectively. It is used to control the robotic arm path planning (directing the robotic arm to avoid obstacles and reach the diagnostic window), the fine-tuning of the target calibration module 2 (the electronic control structure performs small scanning actions), and the synchronous acquisition of data (synchronously recording position data and optical detection data), and to establish the correspondence between the calibration coordinates and the system optical transmittance data.

[0090] The working principle and operation steps are summarized as follows: First, the multi-degree-of-freedom robotic arm module 4 is driven by the control system to send the target plate calibration module 2 into the diagnostic area; then, the electronically controlled displacement structure inside the target plate module is used to perform a fine micro-scan near the initial position, thereby accurately locking the calibration coordinates of the scattering spatial point; subsequently, the target plate module is replaced with the integrating sphere transmittance calibration module 3 through the interface structure, and the robotic arm is controlled to accurately position it to the above-locked calibration coordinates, so that the simulated light source emitted by it coincides with the real scattering position; finally, under the synchronous management of the control system, the transmittance of the system is measured, thereby achieving precise correspondence and integrated calibration of spatial geometric position and optical performance parameters.

[0091] Example 2

[0092] This embodiment provides a detailed description of the modules in Embodiment 1.

[0093] I. The multi-degree-of-freedom robotic arm module 4 includes: a fixed base, a rotation drive unit, a telescopic drive unit, and a sensor assembly.

[0094] The mounting base is installed outside the diagnostic window of the tokamak device 10;

[0095] A rotary drive unit is mounted on the fixed base and is used to drive the robotic arm to perform horizontal scanning motion around the vertical axis;

[0096] The telescopic drive unit is connected to the rotary drive unit and is used to drive the robotic arm to telescopically move along the R direction. The end of the telescopic drive unit forms the interface structure.

[0097] The sensor components are integrated into the multi-degree-of-freedom robotic arm module 4, including a displacement encoder for feedback of position information and a tilt sensor for monitoring the end effector attitude.

[0098] The robotic arm has at least three rotational degrees of freedom and two linear telescopic degrees of freedom. It achieves horizontal scanning around the vertical axis through a rotational drive unit and telescopic movement along the R direction (large radius direction) through a telescopic drive unit, thereby enabling multi-dimensional adjustment of the R direction, Z direction and tilt angle outside the tokamak diagnostic window.

[0099] To ensure accurate positioning, the system is equipped with a high-precision displacement encoder and tilt sensor, with a positioning accuracy of ≤ ±0.5mm and an attitude accuracy of ≤ 0.2°. It can automatically record and reproduce the pose of each calibrated spatial point.

[0100] II. The target calibration module 2 includes: a target plate (main plate), a support frame, and a collimation structure.

[0101] The target plate is used to reflect incident light, and the target plate is installed on the moving end of the electrically controlled displacement structure;

[0102] A collimation structure is installed on the target calibration module 2, comprising vertically distributed collimation holes and an embedded light-transmitting medium to assist in establishing the incident reference optical axis. To establish the reference optical axis during initial installation, the module is equipped with vertically distributed collimation hole cover plates. Planar glass is embedded within each of the upper and lower collimation holes. In the initial calibration phase, the operator can visually observe the overlap of the light spots as the collimated laser beam passes through these two layers of glass to assist in correcting the initial attitude.

[0103] The electrically controlled displacement structure drives the target plate to reciprocate linearly along the R direction relative to the end of the multi-degree-of-freedom robotic arm module 4. The main body plate has left and right sliding grooves and matching electrically controlled drive mechanisms on both sides, capable of driving the target plate to reciprocate linearly along the R direction relative to the end of the robotic arm. The control step size of this motion is set to ≤1mm.

[0104] This structure is used to determine the location of spatial points and to make fine adjustments to the focal point of the light spot, in order to eliminate geometric errors or assess spatial offset caused by fiber jitter.

[0105] III. The integrating sphere transmittance calibration module 3 includes: the integrating sphere body, the standard light source 5, and the matching interface.

[0106] The inner wall of the integrating sphere is coated with a high-reflectivity diffuse reflection coating with a reflectivity of ≥95% and the uniformity of light output is controlled within ≤±3%, ensuring the ideal diffuse characteristics of the output light field.

[0107] The integrating sphere has a light-emitting port and a monitoring port, and the aperture of the light-emitting port is adapted to the scattering spatial point size of the Thomson scattering system.

[0108] The light outlet is designed as a rectangle with dimensions of 1cm × 0.5cm (or adjustable according to actual needs), and its shape is equivalent to the scattering volume of an actual Thomson scatterer. When the module is installed in place, and the integrating sphere transmittance calibration module 3 is installed through the interface structure, the geometric center of the light outlet coincides spatially with the center position of the target plate when the target plate calibration module 2 locks the calibration coordinates.

[0109] The monitoring port is equipped with a power meter monitoring port and a light shield. By connecting the power meter's optical fiber, the light energy input to the integrating sphere is measured in real time and synchronously.

[0110] A standard light source 5 is coupled to the integrating sphere body to generate uniform diffuse light with a known spectral distribution.

[0111] IV. The control system includes a motion control unit and a data processing unit, typically implemented as integrated host computer software. The host computer software integrates functions such as path planning, coordinate positioning, automatic alignment, and wavelength stepping control. It can send position commands to the robotic arm and target plate's electronic control structure and read encoder feedback.

[0112] The motion control unit is connected to the electrically controlled displacement structure of the multi-degree-of-freedom robotic arm module 4 and the target calibration module 2, and is used to issue position commands and read the real-time coordinates fed back by the encoder.

[0113] The data processing unit is used to receive the detection signal from the Thomson scattering system and the power monitoring signal from the integrating sphere transmittance calibration module 3, and to achieve time synchronization of multi-source data;

[0114] The data processing unit is equipped with a focusing criterion algorithm, which is used to analyze the spot image or signal characteristics acquired during the macro scanning motion, and determine the optimal focusing position and mark it as calibration coordinates based on the minimum diameter of the spot or the clearest shape of the image.

[0115] It supports synchronization with the trigger signal of the Thomson scattering (TS) system, enabling fully automated linkage from spatial movement to data acquisition. It also automatically archives calibration data (coordinates, light intensity, power ratio) and establishes a unified space-optical mapping table.

[0116] The calibration device and method of this embodiment are not only applicable to tokamak Thomson scattering systems, but can also be extended to other laser scattering diagnostic systems, such as laser interferometer systems, laser-induced fluorescence (LIF) measurement systems, Raman scattering systems, or multi-band spectral measurement systems.

[0117] In different device environments: the robotic arm can be replaced with a linear guide rail + rotary table structure; the tilt sensor can be replaced with a laser rangefinder or a visual recognition system to achieve attitude calibration; the integrating sphere can be replaced with a diffuse surface light source or an LED array module, as long as the requirements for light output uniformity and spectral width are met; the electronically controlled fine-tuning structure can be achieved through a stepper motor, a piezoelectric displacement stage, or a magnetic levitation drive. As long as the functional logic of "in-situ spatial point fine calibration" and "in-situ quantization of transmittance" is achieved, it still falls within the equivalent protection scope of this embodiment.

[0118] The product signals and main parameters are provided for reference:

[0119] Robotic arm: FANUC M-10iD / 12 (6 axes).

[0120] Tilt sensor: AmphenolTSDA-J-IR025-HM-C.

[0121] Interface module for the robotic arm control system: SferaLabsIMMS13X I / O.

[0122] Fiber optic power meter: -70~+10dBm / Fiber light meter.

[0123] Integrating ball: 819C-SL-3.3-CAL2.

[0124] Electric displacement stage: X-LSM150B-E03.

[0125] Example 3

[0126] like Figure 2 As shown, this embodiment provides a calibration method for a Thomson scattering system based on the integrated calibration device, the calibration method comprising:

[0127] S1. Establish collimated optical axis: Turn on the collimating laser, control the multi-degree-of-freedom robotic arm module loaded with the target calibration module to enter the calibration area, adjust the target attitude so that the collimating laser passes through the collimation structure on the target, and record the position of the robotic arm at this time as the zero position of the incident axis.

[0128] S2, Reverse Light Output Positioning: Turn off the collimating laser, connect the standard light source to the fiber optic polychromator end of the Thomson scattering system, and let the light shine back onto the target calibration module through the collection optical path; at this time, the position of the light spot on the target plate represents the current actual observation field of the Thomson scattering collection system.

[0129] S3. Spatial Fine-tuning and Coordinate Locking: Control the electrically controlled displacement structure of the multi-degree-of-freedom robotic arm module or the target calibration module to perform scanning motions in the Z-axis (vertical direction) and R-axis (radial / large radius direction) near the zero position of the incident axis to find the optimal focusing position of the light spot on the target plate (usually referring to the state where the light spot diameter is the smallest or the edge is the clearest), and determine this position as the calibration coordinate of the scattering space point. , which is the center coordinate of the actual scattering point in space.

[0130] S4. In-situ module replacement: Keeping the robotic arm base stationary, replace the target plate calibration module with the integrating sphere transmittance calibration module through the interface structure.

[0131] S5. Integrating sphere positioning and spectral response measurement: Control the robotic arm to move the light outlet of the integrating sphere transmittance calibration module to the calibration coordinates. At point ), the integrating sphere light source is turned on, and wavelength scanning is performed (changing the wavelength of the output light). The response data of the Thomson scattering system to different wavelength light signals are collected, and the system transmittance is calculated.

[0132] Example 4

[0133] This embodiment provides a detailed description of Embodiment 3.

[0134] (1) Establish the collimated optical axis.

[0135] The control multi-degree-of-freedom robotic arm module sends the target calibration module to the preset position and uses the tilt sensor integrated on the target calibration module to monitor the horizontal and vertical angles of the target.

[0136] Turn on the external collimating laser (main laser off), fine-tune the posture of the robotic arm end until the collimating laser beam passes through the upper and lower collimating holes on the target calibration module in sequence and forms an overlapping spot in the center of the glass inside the hole.

[0137] When the light spots are observed to overlap and the reading error of the tilt sensor is less than a preset threshold (e.g., ≤0.2°), the system determines that the optical axis has been established and determines the zero position of the incident axis.

[0138] (2) Lock the scattering space axis.

[0139] Keeping the target plate in place, turn off the collimating light. The robotic arm automatically measures the horizontal distance from the center of the target plate to the diagnostic window. Combined with the known distance from the center of the device to the window Calculate the spatial coordinates of the scattering axis: This The axis is defined as the reference baseline for subsequent optical spatial point searches.

[0140] (3) Reverse light output positioning.

[0141] Connect the fiber optic polychromator to the collimated white light output device so that the light is emitted in reverse through the collection optical path and shines on the target plate through the window.

[0142] Keeping the target calibration module in the same orientation, control the robotic arm to move along the above-mentioned path. The Z-axis scan position is used to locate the initial position where the reverse-emitting light spot falls on the center of the target plate. ).

[0143] (4) Focus on fine-tuning and spatial fine-tuning.

[0144] Near the initial position, the electrically controlled displacement structure of the target calibration module performs micro-scanning along the R direction in millimeter-level (e.g., 1 mm) steps;

[0145] As needed, using current conventional principles, components such as cameras / spot imaging / photosensitive arrays can be installed at the required locations to acquire spot images. These images are then transmitted to the control system. The spot shape on the target plate is observed through image recognition or light intensity detection. When the spot diameter is smallest or the shape is clearest, the current position of the robotic arm and the amount of adjustment of the electronically controlled displacement structure are recorded as calibration coordinates. This represents the actual scattering point of the fiber optic channel. Simultaneously, the system records the adjustment amount of the target plate in the R direction at this time, used to calculate the micro-jitter or angular error of the fiber optic line of sight.

[0146] (5) Multi-channel spatial calibration cycle.

[0147] To improve efficiency, the geometric calibration of all spatial points is completed first. Steps (3) and (4) are repeated to complete the spatial point calibration of all fiber optic lines of sight for each channel, ultimately forming a spatial coordinate set containing the precise positions of all channels: At this point, the spatial calibration phase is complete.

[0148] (6) Module replacement.

[0149] Keeping the robotic arm base and upper arm in the same position, the target plate calibration module is disassembled through the interface structure and replaced with the integrating sphere transmittance calibration module.

[0150] Connect the integrating sphere input port to the TS calibration light source system, connect the monitoring port to the power meter, and place the output port in the light shielding frame to prevent stray light.

[0151] (7) Preparation for transmittance calibration.

[0152] Connect the calibration light source to the integrating sphere transmittance calibration module, and connect the power meter to the monitoring port of the integrating sphere.

[0153] Connect the integrating sphere input port to the TS calibration light source system, connect the monitoring port to the power meter, and place the output port in a light-shielding frame to prevent stray light. Then, the system calls the calibration coordinates saved in step (5). The automated robotic arm precisely moves the light outlet of the integrating sphere to that position.

[0154] (8) Wavelength scanning and transmittance calculation.

[0155] Start the calibration light source and confirm that there is a light signal response in the corresponding polychromator channel.

[0156] Control the calibration light source to perform wavelength scanning within a preset wavelength range at set step values; control it to perform wavelength scanning within a preset wavelength range (e.g., 600–1100 nm) at set step values ​​(e.g., 2–5 nm).

[0157] For each wavelength point, the response values ​​of the multicolor meter channel and the monitoring values ​​of the power meter are simultaneously acquired; for each wavelength point The system simultaneously acquires two sets of data: the response values ​​of the Thomson scattering polychromator channels. The power meter response value at the integrating sphere monitoring port .

[0158] The system transmittance at that spatial point is calculated based on the ratio of the polychromator response value to the power meter reading, combined with the integrating sphere's light extraction efficiency. The calculation formula is: Calculate the system transmittance at that wavelength based on the collected data. The calculation formula is: .

[0159] (9) Calibration of the entire channel is completed.

[0160] After completing the spatial calibration of one fiber optic line-of-sight channel, repeat step S3 until the spatial point coordinates of all fiber optic line-of-sight channels are calibrated to form a spatial coordinate set.

[0161] Then, step (6) is executed to replace the module, and steps (7) and (8) are executed cyclically according to the spatial coordinate set to complete the system transmittance calibration of all corresponding spatial points and generate a correspondence table between spatial coordinates and wavelength transmittance.

[0162] Compared with existing technologies, this embodiment integrates a spatial calibration module and a system transmittance calibration module on the same mechanical platform, and combines a multi-degree-of-freedom robotic arm, an electrically controlled displacement target plate, and an in-situ integrating sphere light source to achieve synchronous calibration and precise calibration of spatial coordinates and optical links, thereby obtaining the following specific technical effects:

[0163] 1. Achieve in-situ automated calibration within the confined space of a tokamak.

[0164] This embodiment employs a multi-degree-of-freedom telescopic rotary robotic arm structure. The robotic arm can be adjusted omnidirectionally along the R-axis, Z-axis, and tilt angle outside the tokamak vacuum chamber window. Automatic loading and unloading of the target plate or integrating sphere is achieved through upper computer control. This structure eliminates the need for manual entry into the device during calibration, allowing target plate positioning, attitude adjustment, and calibration to be completed in situ within the device.

[0165] Technical effects: Under complex and constrained diagnostic window geometry, the calibration position error is ≤ ±0.5mm and the attitude error is ≤0.2°, which greatly improves the repeatability and safety of calibration and realizes the in-situ automated geometric axis finding function that cannot be achieved by traditional manual methods.

[0166] 2. Possesses spatial precision calibration capability for R-axis electronically controlled fine adjustment.

[0167] The main body of the target plate assembly achieves micro-displacement adjustment along the R-axis via left and right sliding grooves and an electronically controlled drive mechanism. After the Z-position is determined, the system can scan in 1mm steps along the R-axis, automatically locking the scattering spatial point based on the smallest spot diameter or the clearest image shape. Through this R-axis fine-tuning mechanism, spatial deviations can be precisely corrected within a millimeter range, and the adjustment amount can be recorded to infer fiber optic line-of-sight jitter.

[0168] Technical effects: It enables precise calibration and position error compensation of scattering spatial points, reducing the spatial point error of each channel to within 2mm. It also has a system geometric stability diagnostic function, which can assess the geometric error caused by micro-jitter or deformation of the fiber end.

[0169] 3. Integration of spatial calibration and transmittance calibration.

[0170] This embodiment employs a modular design: the same robotic arm interface allows for quick replacement of the target plate module and the integrating sphere module; the former is used for spatial positioning, and the latter for optical transmittance calibration. After the spatial coordinates are determined, the integrating sphere automatically moves to the corresponding position, achieving light source illumination consistent with the actual scattering geometry.

[0171] Technical effects: It realizes a unified coordinate system and a unified control platform for spatial calibration and transmittance calibration, ensuring that the transmittance measurement of each channel strictly corresponds to the actual scattering spatial point, eliminating the geometric mismatch error of traditional step-by-step calibration, and effectively improving the end-to-end response consistency of the Thomson scattering system.

[0172] 4. Achieve in-situ quantification of system transmittance and evaluation of optical consistency.

[0173] In this embodiment, the integrating sphere calibration module realizes light source illumination at the same coordinate point, covering a spectral range of 600–1100nm with a step of 2–5nm. The system synchronously acquires the output of the multicolor meter and the monitoring of the power meter, and calculates the end-to-end transmittance.

[0174] Technical benefits: Obtain the true transmittance curve for each channel under actual geometry, enabling quantitative analysis of the impact of system optical path aging, fiber loss, or multicolorist drift on measurement accuracy.

[0175] It provides the Thomson scattering system with absolute optical calibration capability under real optical path conditions.

[0176] 5. Establish a unified spatial-optical database to improve the traceability of calibration data.

[0177] Through the control and integration software system, the spatial coordinates, power response and transmittance data during the calibration process are automatically stored, forming a mapping table between spatial points and transmittance.

[0178] Technical benefits: Enables long-term archiving and traceability of calibration data, supports rapid reuse of multi-cycle experiments, provides highly reliable input parameters for the inversion of electron temperature and density in Thomson scattering, and significantly improves the system's maintenance efficiency and physical measurement accuracy.

[0179] 6. Overall effects at the engineering and application levels.

[0180] The calibration device in this embodiment has a compact structure and a high degree of modularity. It is compatible with Thomson scattering systems with different window specifications and different numbers of channels, and can complete the entire calibration process without disassembling the main optical system.

[0181] Overall technical benefits: Achieve high-precision in-situ calibration in confined spaces; establish a unified link between spatial fine calibration and transmittance calibration; improve system geometric consistency and measurement accuracy; provide a repeatable and traceable fully automated calibration solution.

[0182] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0183] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above invention, and these changes or modifications still fall within the scope of the present invention.

Claims

1. An integrated calibration device for a Thomson scattering system, characterized in that, include: A multi-degree-of-freedom robotic arm module (4) is used to extend to the diagnostic window area of ​​the tokamak device (10), and the end of the multi-degree-of-freedom robotic arm module (4) is provided with an interface structure; The target calibration module (2) is installed at the end of the multi-degree-of-freedom robotic arm module (4) through the interface structure. The target calibration module (2) includes an electrically controlled displacement structure, which is used to perform micro-scanning after determining the initial position to lock the calibration coordinates of the scattering space point. The integrating sphere transmittance calibration module (3) is replaceably installed at the end of the multi-degree-of-freedom robotic arm module (4) through the interface structure and positioned at the calibration coordinates to provide a simulated scattering light source for system transmittance measurement; The control system is connected to the multi-degree-of-freedom robotic arm module (4), the target calibration module (2) and the integrating sphere transmittance calibration module (3) respectively. It is used to control the robotic arm path planning, the fine-tuning of the target calibration module (2) and the synchronous acquisition of data, and to establish the correspondence between the calibration coordinates and the system optical transmittance data.

2. The integrated calibration device for the Thomson scattering system according to claim 1, characterized in that, The multi-degree-of-freedom robotic arm module (4) includes: A fixed base is mounted on the outside of the diagnostic window of the tokamak device (10); A rotary drive unit, which is mounted on the fixed base, is used to drive the robotic arm to perform horizontal scanning motion around the vertical axis; A telescopic drive unit, connected to the rotary drive unit, is used to drive the robotic arm to telescopically move along the R direction, and the end of the telescopic drive unit forms the interface structure. The sensor assembly, which is integrated into the multi-degree-of-freedom robotic arm module (4), includes a displacement encoder for feedback of position information and an tilt sensor for monitoring the end-effector attitude.

3. The integrated calibration device for the Thomson scattering system according to claim 1, characterized in that, The target calibration module (2) also includes: A target plate, used to reflect incident light, is mounted on the moving end of the electrically controlled displacement structure; The collimation structure is set on the target plate calibration module (2) and includes collimation holes distributed vertically and an embedded light-transmitting medium, which is used to assist in establishing the incident reference optical axis. The electrically controlled displacement structure drives the target plate to reciprocate linearly along the R direction relative to the end of the multi-degree-of-freedom robotic arm module (4).

4. The integrated calibration device for the Thomson scattering system according to claim 3, characterized in that, The integrating sphere transmittance calibration module (3) includes: The integrating sphere body is provided with a light outlet and a monitoring port, the aperture of which is adapted to the scattering spatial point size of the Thomson scattering system; A standard light source (5) is coupled to the integrating sphere body to generate uniform diffuse light with a known spectral distribution; When the integrating sphere transmittance calibration module (3) is installed through the interface structure, the geometric center of the light outlet coincides in space with the center position of the target plate when the target plate calibration module (2) locks the calibration coordinates.

5. The integrated calibration device for the Thomson scattering system according to claim 1, characterized in that, The control system includes: The motion control unit is connected in communication with the electrically controlled displacement structure of the multi-degree-of-freedom robotic arm module (4) and the target calibration module (2), and is used to issue position commands and read the real-time coordinates fed back by the encoder. The data processing unit is used to receive the detection signal of the Thomson scattering system and the power monitoring signal of the integrating sphere transmittance calibration module (3), and to realize the time synchronization of multi-source data; The data processing unit is equipped with a focusing criterion algorithm, which is used to analyze the spot image or signal characteristics acquired during the macro scanning motion, and determine the optimal focusing position and mark it as calibration coordinates based on the minimum diameter of the spot or the clearest shape of the image.

6. A calibration method for a Thomson scattering system, characterized in that, Based on the integrated calibration device as described in any one of claims 1-5, the calibration method includes: S1. Establish collimated optical axis: Turn on the collimating laser, control the multi-degree-of-freedom robotic arm module loaded with the target plate calibration module to enter the calibration area, adjust the target plate attitude so that the collimating laser passes through the collimating structure on the target plate, and record the position of the robotic arm at this time as the zero position of the incident axis. S2, Reverse light output positioning: Turn off the collimating laser, connect the standard light source to the fiber optic polychromator end of the Thomson scattering system, and let the light shine back onto the target calibration module through the collection optical path. S3. Spatial Fine-tuning and Coordinate Locking: Control the electrically controlled displacement structure of the multi-degree-of-freedom robotic arm module or the target calibration module to perform scanning movements in the Z and R directions near the zero position of the incident axis, find the optimal focusing position of the light spot on the target plate, and determine this position as the calibration coordinate of the scattering space point. ; S4. In-situ module replacement: Keeping the robotic arm base stationary, replace the target plate calibration module with the integrating sphere transmittance calibration module through the interface structure. S5. Integrating sphere positioning and spectral response measurement: Control the robotic arm to move the light outlet of the integrating sphere transmittance calibration module to the calibration coordinates. The system transmittance is calculated by scanning wavelengths at a certain location and collecting data on the response of the Thomson scattering system to different wavelengths of light signals.

7. The calibration method for a Thomson scattering system according to claim 6, characterized in that, Establishing the collimated optical axis specifically includes: The control multi-degree-of-freedom robotic arm module sends the target calibration module to the preset position and uses the tilt sensor integrated on the target calibration module to monitor the horizontal and vertical angles of the target. Fine-tune the posture of the robotic arm's end effector until the collimated laser beam passes through the upper and lower collimation holes on the target calibration module in sequence and coincides at the designated position within the holes, and the tilt sensor reading error is less than the preset threshold, thus determining the zero position of the incident axis.

8. The calibration method for a Thomson scattering system according to claim 6, characterized in that, Spatial calibration and coordinate locking specifically include: Coarse scan: Maintaining the target calibration module's orientation, control the robotic arm to scan the Z-axis position along the R-axis reference baseline, finding the initial position where the reverse-emitting light spot falls on the center of the target plate. ); Fine scanning: Near the initial position, the electrically controlled displacement structure of the target calibration module is controlled to perform micro-scanning along the R direction in millimeter-level steps; Coordinate locking: Observe the shape of the light spot on the target plate. When the light spot diameter is smallest or the shape is clearest, record the current position of the robotic arm and the adjustment amount of the electronically controlled displacement structure as calibration coordinates. ).

9. The calibration method for a Thomson scattering system according to claim 6, characterized in that, The transmittance of the wavelength scanning and calculation system specifically includes: Connect the calibration light source to the integrating sphere transmittance calibration module, and connect the power meter to the monitoring port of the integrating sphere; Control the calibration light source to perform wavelength scanning within a preset wavelength range according to a set step value; For each wavelength point, the response value of the multicolor meter channel and the monitoring value of the power meter are collected simultaneously; The system transmittance at that spatial point is calculated based on the ratio of the polychromator response value to the power meter monitoring value, combined with the light output efficiency of the integrating sphere.

10. A calibration method for a Thomson scattering system according to claim 6, characterized in that, The calibration method employs a multi-channel cyclic calibration strategy: After completing the spatial calibration of one fiber optic line-of-sight channel, repeat step S3 until the spatial point coordinates of all fiber optic line-of-sight channels are calibrated to form a spatial coordinate set. Then, step S4 is executed to replace the module, and step S5 is executed cyclically according to the spatial coordinate set to complete the system transmittance calibration of all corresponding spatial points and generate a correspondence table between spatial coordinates and wavelength transmittance.

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