Multi-channel plasma visible bremsstrahlung distribution measurement system and method for EAST Tokamak device

Abstract

The invention discloses a multi-channel plasma visible bremsstrahlung distribution measuring system and method for an EAST Tokamak device. The front-end optical structure comprises two arrays and 22 channels, each channel comprises a front-end collimating lens, a long-distance transmission optical fiber, a lens, an optical filter and a photomultiplier, and the rear-end electronic equipment comprises a current amplifier, a high-voltage power supply, a data collector and an upper computer calculation program. Wherein the front-end collimating lenses of the 22 arrays are arranged in a fan-shaped manner, receive radiation signals on a path emitted by plasma, transmit the radiation signals to the correction lens through the optical fiber to be adjusted into parallel light, screen out radiation signals to be measured through the optical filter, converge the radiation signals through the focusing lens, and measure the optical radiation of the radiation signals through the calibrated photomultiplier. And the photon energy is converted and output into a current signal, the current signal is amplified by a current amplifier and then is collected by a data collector, and final visible bremsstrahlung radiation polar distribution data is obtained through processing.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of plasma diagnosis, and particularly relates to a system and method for measuring the distribution of visible bremsstrahlung of multi-channel plasma of EAST Tokamak device. BACKGROUND

[0002] EAST is an important international magnetic confinement plasma experimental device, and the existence of impurities not only affects the purity of the plasma, but also causes the loss of plasma radiation energy through bremsstrahlung and line radiation, affects the spatial distribution of plasma parameters and the confinement performance of the plasma, and reduces the reaction power density of fusion. The effective charge number (Z eff ) of the plasma reflects the overall average level of impurity ions in the plasma, and the analysis and research on Z eff and impurity behavior help to understand the mechanism of impurity generation and transport, so as to find an effective method to control the impurity level of the plasma and improve the quality of the plasma. Therefore, the effective charge number (Z eff ) of the plasma obtained by measuring the bremsstrahlung distribution is a key parameter for studying the performance of the plasma and the behavior of the impurities.

[0003] Z eff can be measured by various methods, such as plasma conductivity, charge exchange recombination spectroscopy, X-ray measurement, etc., but these methods have limited scope, such as the plasma conductivity can only be measured under ohmic discharge conditions, the charge exchange recombination spectroscopy can only be measured when the neutral particle beam is injected, and these diagnostic system devices are complex, have higher establishment and maintenance costs, and have larger calculation errors, which are difficult to meet the needs of EAST device effective charge number measurement. Visible bremsstrahlung is a continuous spectrum generated by the collision of electrons and ions in the plasma, and its intensity is closely related to the effective charge number. By establishing a visible bremsstrahlung distribution measurement system on the EAST device, the spatial distribution of visible bremsstrahlung can be measured, the Z eff distribution of the plasma can be indirectly deduced, and the method has universality, can be measured under various discharge conditions of the EAST device, has lower establishment and maintenance costs, and has smaller errors. SUMMARY

[0004] In order to measure the effective charge number of the plasma in the EAST device, the application provides a system and method for measuring the distribution of visible bremsstrahlung of multi-channel plasma of EAST Tokamak device, which has good effects in terms of spatial resolution, signal transmission rate and real-time data processing. The system can realize high-precision and high-resolution visible bremsstrahlung distribution measurement through protection and optimization of front-end optical design, signal transmission and processing process, and provides important support for the operation optimization and physical analysis of the EAST device.

[0005] To achieve the above objectives, this invention proposes a measurement system for the visible bremsstrahlung distribution of multichannel plasma in the EAST tokamak device. This system comprises the following modules: a front-end collimating lens array, a long-distance transmission fiber, a corrective lens, a filter, a focusing lens, a photomultiplier tube, a high-voltage power supply, a current amplifier, a data acquisition unit, and a host computer program for inverting the visible bremsstrahlung distribution; wherein,

[0006] The front-end collimating lens array has a protective design, specifically consisting of a guide rail body and components mounted outside the diagnostic window for mounting the 22-channel front-end array, a fixing block for mounting the front-end collimating lens, and a sealing plate for protecting the front-end collimating lens and eliminating external optical signal interference. The front-end collimating lens array is used to receive optical signals on the plasma path;

[0007] The long-distance transmission optical fiber is used to transmit optical signals to the back end;

[0008] The corrective lens is used to adjust the transmitted signal into parallel light;

[0009] The filter is used to filter out the signal to be measured in parallel light;

[0010] The focusing lens is used to converge the signal to be measured filtered out by the filter;

[0011] The photomultiplier tube is used to measure the signal to be measured converged by the focusing lens and convert the optical signal into a weak current signal;

[0012] The high-voltage power supply is used to provide operating power for the photomultiplier tube;

[0013] The current amplifier is used to amplify weak current signals;

[0014] The data acquisition device is used to acquire the amplified signal and upload it to the server database;

[0015] The host computer's visible bremsstrahlung inversion program is used to process the data and obtain the visible bremsstrahlung poloidal distribution.

[0016] A measurement method for a multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device, the method comprising the following steps:

[0017] Step S1, signal reception, includes: the front-end collimating lens array receiving radiation signals emitted along the plasma path;

[0018] Step S2, signal transmission, includes: long-distance transmission optical fiber for transmitting radiated signals;

[0019] Step S3, optical processing, includes: a corrective lens, a focusing lens, and a filter; the corrective lens is used to adjust the transmitted light signal into parallel light; the filter is used to filter out the light signal to be measured; the focusing lens converges the light signal filtered out by the filter and converges it again onto the photomultiplier tube;

[0020] Step S4, photoelectric conversion, includes: the photomultiplier tube converts the signal into a current signal;

[0021] Step S5, signal amplification, including: current amplifier amplifying the current signal;

[0022] Step S6, Data Acquisition, includes: the data acquisition device collects and uploads data;

[0023] Step S7, data processing, includes: the host computer inversion program uses the uploaded data to calculate the visible bremsstrahlung distribution.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention proposes a multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device, capable of autonomously measuring plasma visible bremsstrahlung data during each discharge experiment of the magnetically confined plasma device. The system employs a modular design, with seamless integration between the front-end optical design and the back-end electronic equipment, facilitating maintenance and upgrades, and resulting in more accurate, reliable, and efficient results. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the multichannel plasma visible bremsstrahlung distribution measurement system of the EAST tokamak device;

[0027] Figure 2 This is a schematic diagram illustrating the working principle of the multichannel plasma visible bremsstrahlung distribution measurement system of the EAST tokamak device.

[0028] Figure 3 This is a schematic diagram of the process for measuring the distribution of visible bremsstrahlung radiation in multichannel plasma at the EAST tokamak device. Detailed Implementation

[0029] like Figure 1 As shown, this invention proposes a multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device, comprising two parts: a front-end optical structure and a back-end electronic device. The front-end optical structure includes two arrays with a total of 22 channels. Each channel includes a front-end collimating lens array, a long-distance transmission fiber, a corrective lens, a filter, a focusing lens, and a photomultiplier tube. The back-end electronic device includes a current amplifier, a precision high-voltage power supply, a data acquisition unit, and a host computer program for inverting visible bremsstrahlung distribution.

[0030] like Figure 2 As shown, each channel of the front-end optical structure includes:

[0031] Front-end collimating lens: 22 channels are arranged in a fan shape to receive optical radiation signals along the plasma path in EAST. The lens of each channel is optimized for the specific poloidal space of the plasma to ensure high spatial resolution;

[0032] Long-distance optical fiber: transmits the radiated signals received at the front end to the back end;

[0033] Corrective lens: Adjusts the transmitted light radiation signal into parallel light, improving the accuracy of subsequent filtering and measurement;

[0034] Filters: to filter out visible bremsstrahlung light signals of specific wavelengths and eliminate stray light interference;

[0035] Focusing lens: focuses the bremsstrahlung signal that has passed through the filter onto the photocathode window of the photomultiplier tube;

[0036] Photomultiplier tube: A calibrated high-sensitivity photomultiplier tube is used to measure the filtered light radiation and convert photon energy into a weak current signal;

[0037] High-voltage power supply: Provides a stable high-voltage operating power supply for the photomultiplier tube to ensure its normal operation;

[0038] Current amplifier: amplifies the weak current signal output by the photomultiplier tube, increasing the signal strength;

[0039] Data acquisition unit: Acquires amplified current signals and uploads them to the server database;

[0040] Upper computer visible bremsstrahlung distribution inversion program: Run the visible bremsstrahlung distribution inversion program, process the collected data, and generate plasma visible bremsstrahlung poloidal distribution data.

[0041] The EAST tokamak device multichannel plasma visible bremsstrahlung distribution measurement system of the present invention also includes a protection design, which includes: a guide rail body and components installed outside the diagnostic window for mounting the front-end 22 optical channel array; a fixing block for mounting the front-end collimating lens; and a sealing plate for protecting the front-end collimating lens and eliminating external optical signal interference.

[0042] Furthermore, the measurement of visible bremsstrahlung needs to be performed at a specific wavelength; the wavelength range of the visible bremsstrahlung measurement system is 523.0 nm. 0.5 nm; the sampling rate of the visible bremsstrahlung signal is 50 kHz.

[0043] Furthermore, after the long-distance transmission optical fiber transmits the radiation signal to the back end, the corrective lens adjusts the signal into parallel light, the filter selects the light signal to be measured at a specific wavelength, and finally the focusing lens converges it onto the photocathode window of the photomultiplier tube.

[0044] Furthermore, the specific method for using a photomultiplier tube to measure light radiation and convert photon energy into a weak current signal is as follows: a calibrated photomultiplier tube is used to perform photoelectric conversion on the light signal filtered by the filter, and outputs the corresponding weak current.

[0045] like Figure 3 As shown, the method for measuring the visible bremsstrahlung distribution of multichannel plasma in the EAST tokamak device proposed in this invention includes the following steps:

[0046] Step S1, Signal Reception: The front-end collimating lens array (two arrays with a total of 22 channels, arranged in a fan shape) receives the visible bremsstrahlung signal emitted by the plasma. The lens of each channel is aligned with a different radial position of the plasma to achieve high-resolution spatial coverage.

[0047] Step S2, Signal Transmission: Long-distance transmission optical fiber efficiently transmits the received radiation signal to the back-end optical components, reducing signal loss.

[0048] Step S3, Optical Processing: The corrective lens adjusts the transmitted signal into parallel light, then the filter selects the radiation signal to be measured at a specific wavelength, eliminates interference from other wavelengths, and then the focusing lens converges it onto the photomultiplier tube.

[0049] Step S4, photoelectric conversion: The calibrated photomultiplier tube measures the filtered light radiation signal and converts the photon energy into a weak current signal to ensure high sensitivity and low noise.

[0050] Step S5: The high-voltage power supply provides a stable high-voltage power supply to the photomultiplier tube to ensure its operational stability.

[0051] Step S6, Signal Amplification: The current amplifier amplifies the weak current signal output by the photomultiplier tube to improve the signal strength.

[0052] Step S7, Data Acquisition: The data acquisition device acquires the amplified electrical signal at a high sampling rate and uploads the data to the server database.

[0053] Step S8, Data Processing: The visible bremsstrahlung distribution inversion program in the host computer analyzes the collected data, calculates the poloidal distribution of visible bremsstrahlung in the plasma based on the visible bremsstrahlung intensity, and generates the final result.

Claims

1. A system for measuring the distribution of visible bremsstrahlung radiation in multichannel plasma of the EAST tokamak device, characterized in that, The system includes a front-end optical structure comprising two arrays with a total of 22 channels. Each channel includes a front-end collimating lens, a long-distance transmission fiber, a corrective lens, a filter, a focusing lens, and a photomultiplier tube. The back-end electronic equipment includes a current amplifier, a high-voltage power supply, a data acquisition unit, and a host computer inversion program. The front collimating lens is used to receive radiation signals emitted by the plasma along its path; The long-distance transmission optical fiber is used to transmit the radiated signal to the back end. The corrective lens is used to adjust the transmitted radiation signal into parallel light. The filter is used to filter out the optical signal to be measured; The focusing lens converges the light signal filtered by the filter and then converges it back onto the photomultiplier tube; The photomultiplier tube is used to measure the radiation intensity of the light signal filtered by the filter and convert photon energy into a current signal; The high-voltage power supply is used to provide operating power for the photomultiplier tube; The current amplifier is used to amplify the current signal; The data acquisition device is used to acquire the amplified signal and upload it to the server database; The host computer's visible bremsstrahlung distribution inversion program is used to process the collected data and obtain the visible bremsstrahlung poloidal distribution.

2. The multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device according to claim 1, characterized in that, The front-end optical structure contains 22 channels arranged in a fan shape.

3. The system for measuring the distribution of visible bremsstrahlung radiation in multichannel plasma of the EAST tokamak device according to claim 1, characterized in that, It is evident that bremsstrahlung measurements are performed at a specific wavelength, within the range of 523.0 nm. 0.5 nm.

4. The system for measuring the distribution of visible bremsstrahlung radiation in multichannel plasma of the EAST tokamak device according to claim 1, characterized in that, The sampling rate of the data acquisition device is 50 kHz.

5. A multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device according to claim 1, characterized in that, After the long-distance transmission optical fiber transmits the radiation signal to the back end, the corrective lens adjusts the signal into parallel light, the filter selects the light signal to be measured at a specific wavelength, and finally the focusing lens converges it onto the photocathode window of the photomultiplier tube.

6. A multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device according to claim 1, characterized in that, The specific method for using a photomultiplier tube to measure light radiation and convert photon energy into a current signal is as follows: a calibrated photomultiplier tube is used to perform photoelectric conversion on the light signal filtered by the filter, and the corresponding current signal is output.

7. A multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device according to claim 1, characterized in that, The front-end optical structure has a protective design, including: a guide rail body and components mounted outside the diagnostic window for mounting the front-end 22 optical channel array, a fixing block for mounting the front-end collimating lens, and a sealing plate for protecting the front-end collimating lens and eliminating external light signal interference.

8. A measurement method for a multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device, as described in any one of claims 1-7, characterized in that, The method includes the following steps: Step S1, signal reception, includes: the front-end collimating lens array receiving radiation signals emitted along the plasma path; Step S2, signal transmission, includes: long-distance transmission optical fiber for transmitting radiated signals; Step S3, optical processing, includes: a corrective lens, a focusing lens, and a filter; the corrective lens is used to adjust the transmitted light signal into parallel light; the filter is used to filter out the light signal to be measured; the focusing lens converges the light signal filtered out by the filter and converges it again onto the photomultiplier tube; Step S4, photoelectric conversion, includes: the photomultiplier tube converts the signal into a current signal; Step S5, signal amplification, including: current amplifier amplifying the current signal; Step S6, Data Acquisition, includes: the data acquisition device collects and uploads data; Step S7, data processing, includes: the host computer inversion program uses the uploaded data to calculate the visible bremsstrahlung distribution.

9. A multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device according to claim 8, characterized in that, In step S2, the radiation signal emitted by the plasma in S1 along its path is transmitted through a long-distance transmission optical fiber.

10. A multichannel plasma visible bremsstrahlung distribution measurement system for the EAST tokamak device according to claim 8, characterized in that, In step S3, based on the result of step S2, a corrective lens is used to adjust the transmitted signal into parallel light, a filter is used to filter out the light signal to be measured from the parallel light, and then the light is transmitted to the focusing lens and focused again onto the photomultiplier tube.

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