Chirped pulse Fourier transform microwave spectrometer and detection method
The chirped pulse Fourier transform microwave spectrometer, which integrates pulsed sample introduction and in-situ reactant generation systems, solves the problems of frequency band coverage and sample introduction adaptability, and realizes continuous broadband and high-sensitivity detection in the 18-40 GHz frequency band, which is suitable for research in atmospheric chemistry, astrochemistry and other fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUDAN UNIVERSITY
- Filing Date
- 2026-02-25
- Publication Date
- 2026-05-12
AI Technical Summary
Existing CP-FTMW spectrometers have limited frequency coverage in the 18-40 GHz band, which cannot meet the detection requirements of high-intensity rotational transition signals of small and medium-sized molecules and key transient species. At the same time, the sample introduction system has poor adaptability and cannot realize the in-situ generation and direct detection of highly reactive, short-lived transient intermediates.
A chirped pulse Fourier transform microwave spectrometer was designed, integrating a pulsed sample introduction and in-situ reactant generation system, combined with a segmented chirped pulse generation and radiation system, a signal detection and high-speed acquisition system, and a synchronous timing control system, to achieve continuous broadband and high-sensitivity detection in the 18-40 GHz frequency band, and to generate broadband microwave spectra through signal processing and automated acquisition components.
It achieves continuous broadband and high-sensitivity detection in the 18-40 GHz frequency band, has in-situ sample introduction capability, and can efficiently detect highly reactive intermediates and their molecular clusters, improving research efficiency and detection accuracy.
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Figure CN122016734A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of microwave spectroscopy, and in particular to a chirped pulse Fourier transform microwave spectrometer and its detection method. Background Technology
[0002] Microwave spectroscopy, as a core technology for molecular structure analysis and species identification, can achieve high-precision determination of molecular parameters such as bond length, bond angle, and dipole moment by capturing pure rotational transition signals of molecules. It plays an irreplaceable role in fields such as chemistry, astronomy, and materials science, and is the cornerstone of molecular structure analysis, astrochemical detection, and research on transient reaction intermediates.
[0003] Chirped pulsed Fourier transform microwave (CP-FTMW) spectroscopy, as a core branch of microwave spectroscopy, achieves broadband excitation of molecules by generating frequency chirped pulses. It is then combined with a high-speed digital acquisition module to capture the free induction decay signal, and the microwave spectrum is obtained after Fourier transform processing. Compared with traditional microwave spectroscopy, it significantly improves the spectral acquisition speed, detection sensitivity and frequency band coverage, and has become the mainstream technical solution for modern microwave spectral analysis.
[0004] However, existing CP-FTMW spectrometers have significant technical shortcomings in frequency band coverage and sample introduction adaptability, making it difficult to meet the needs of cutting-edge scientific research. Firstly, frequency coverage is limited. Due to the performance constraints of key electronic components such as traveling wave tube amplifiers, the operating frequency bands of commercial and laboratory CP-FTMW spectrometers are mostly limited to below 18 GHz. Broadband, high-sensitivity CP-FTMW spectrometers in the 18-40 GHz band have long been a technological gap. However, the 18-40 GHz band precisely covers a large number of small and medium-sized molecules, especially the high-intensity rotational transition signals of key transient species in atmospheric and interstellar chemistry. The lack of instruments in this band severely restricts in-depth research on transient species and reaction kinetic mechanisms in related fields. Secondly, the sample introduction system has poor adaptability. The analyte sample introduction system and the spectral detection unit of existing spectrometers are mostly designed separately, which cannot realize the in-situ generation and direct detection of highly reactive, short-lived transient intermediates. As a result, such species are prone to attenuation and decomposition during transmission, which greatly reduces the accuracy and effectiveness of detection and makes it difficult to meet the scientific research needs related to transient species.
[0005] In summary, developing a CP-FTMW spectrometer that operates in the 18-40 GHz frequency band, possesses high-sensitivity broadband detection capabilities, and integrates in-situ sample introduction functionality will overcome existing technological bottlenecks and is of great significance for promoting research progress in fields such as reaction kinetics, atmospheric chemistry, and astrochemistry. Summary of the Invention
[0006] The purpose of this invention is to provide a chirped pulse Fourier transform microwave spectrometer and detection method, which can achieve continuous, broadband, and high-sensitivity operation in the 18-40 GHz frequency band, and integrates a pulsed discharge sample introduction system, which can generate and directly detect highly reactive intermediates and their molecular clusters in situ.
[0007] To achieve the above objectives, the present invention provides a chirped pulse Fourier transform microwave spectrometer, comprising: A pulsed injection and reactant in-situ generation system includes a pulse valve and a pulsed discharge electrode integrated at the nozzle of the pulse valve, for generating a cryogenic molecular beam containing transient reaction intermediates; A segmented chirped pulse generation and radiation system, comprising an arbitrary waveform generator, a frequency multiplier, a microwave power amplifier, and a transmitting horn antenna connected in sequence, is used to generate and radiate a series of microwave excitation pulses covering the 18-40 GHz frequency band; The signal detection and high-speed acquisition system includes a receiving horn antenna, a limiter, a single-pole double-throw switch, a low-noise amplifier, and an oscilloscope connected in sequence. It is used to receive and digitize the free-induction decay signal of molecular radiation and protect subsequent circuits from strong excitation pulses. Finally, the signal is digitized at a sampling rate of 80 GS / s.
[0008] The synchronous timing control system includes a digital delay generator and a signal transmission line, which is electrically connected to the above-mentioned systems through the signal transmission line to coordinate the operation timing of the above-mentioned systems. The signal processing and automated acquisition component includes a data processing terminal and automated acquisition software stored in the terminal. The data processing terminal is electrically connected to an oscilloscope and a synchronous timing control system. The automated acquisition software calls hardware resources to control the overall operation of the instrument and performs Fourier transform processing on the digitized free induction attenuation signal to generate a broadband microwave spectrum.
[0009] Preferably, the pulse discharge electrode is integrated with the pulse valve base, and the pulse discharge electrode includes a ceramic insulating spacer and a brass electrode, which are spaced apart.
[0010] Preferably, the pulsed discharge electrode is connected to a high-voltage discharge circuit controlled by the synchronous timing control system, which is used to inject sample molecules in a carrier gas (such as neon or argon) into a vacuum cavity, and generate free radicals, ions and metastable intermediates in situ through synchronous electrical discharge, and then cool them to 2-5 K through ultrasonic expansion.
[0011] Preferably, the arbitrary waveform generator generates a series of microsecond-level chirped pulses with increasing center frequency and a bandwidth of 4.4 GHz. After being amplified by a frequency multiplier and a microwave power amplifier, the pulses are radiated into the vacuum cavity by a transmitting horn antenna to cover a continuous frequency band of 18-40 GHz.
[0012] Preferably, the chirped pulse sequence generated by the arbitrary waveform generator is: within a single trigger cycle, it contains several repeating subsequences, each subsequence consisting of multiple chirped pulses with sequentially increasing center frequencies.
[0013] Preferably, the limiter is used to isolate the receiving horn antenna from the low-noise amplifier during microwave excitation pulse radiation, and the oscilloscope has a sampling rate of not less than 80 GS / s.
[0014] Preferably, the synchronous timing control system is based on a digital delay generator, which provides a precise trigger signal with adjustable delay for the pulse injection and reactant in-situ generation system, the segmented chirped pulse generation and radiation system, and the signal detection and high-speed acquisition system. This signal is used to precisely synchronize the triggering timing of the pulse valve, pulse discharge, arbitrary waveform generator, and high-speed oscilloscope, ensuring that the sample pulse, discharge plasma, and microwave excitation pulse are precisely coincident in time and space.
[0015] Preferably, the signal processing and automated acquisition software runs on a data processing terminal and executes the following steps by calling the hardware resources of the oscilloscope and the synchronous timing control system: S101, Control each hardware module to work collaboratively according to the set timing sequence; S102. Acquire the free induction attenuation signal in the time domain from the oscilloscope; S103. Perform piecewise Fourier transform on the free induction attenuation signal segments corresponding to different excitation frequency bands; S104. The transformed sub-spectrums are spliced together to form a complete 18-40 GHz broadband spectrum; S105. A segmented cumulative averaging strategy is adopted to perform long-term stable averaging of the signal to improve the signal-to-noise ratio, achieving a value exceeding 10. 7 The signal is averaged continuously and with high stability.
[0016] This invention also provides a method for molecular rotational spectroscopy detection using a chirped pulse Fourier transform microwave spectrometer, comprising the following steps: S201. A gaseous mixture containing precursors is injected into a vacuum chamber through the pulse injection and reactant in-situ generation system, and synchronous pulse discharge is triggered by the pulse discharge electrode integrated into the pulse valve to generate free radicals, ions or metastable molecules in situ. S202. The segmented chirped pulse generation and radiation system radiates microwave pulses covering 18-40 GHz to excite molecules in the vacuum cavity; S203. Acquire the time-domain signal of molecular radiation using the aforementioned signal detection and high-speed acquisition system; S204. The time-domain signal is processed using the signal processing and automated acquisition software to obtain a broadband molecular rotation spectrum in the range of 18-40 GHz.
[0017] Preferably, the gaseous mixture comprises haloalkanes, oxygen, and water vapor, and generates Criegee intermediates and related products through pulsed discharge; step S204 includes performing piecewise Fourier transform and spectral splicing on the time-domain signal, and employing more than 10 7 The signals are accumulated and averaged.
[0018] Therefore, the present invention employs the above-mentioned chirped pulse Fourier transform microwave spectrometer and detection method, and the technical effects are as follows: Filling a technological gap: For the first time, continuous broadband and high-sensitivity CP-FTMW spectral measurements were achieved in the 18-40 GHz band, solving the long-standing problem of the lack of effective broadband detection methods in this key frequency band.
[0019] Functional integration innovation: The pulsed discharge sample introduction system and the broadband microwave detection system are creatively integrated in situ and synchronously, realizing the integration of "generation-cooling-detection", and providing a general platform for the structural study of highly reactive transient species.
[0020] High performance: The instrument has a spectral resolution of approximately 20 kHz and a bandwidth of approximately 10 kHz in the 18–40 GHz range. 10 The detection sensitivity is measured in molecules per cubic centimeter. By discharging a CH2I2 / O2 / H2O mixed gas, the Criegee intermediate CH2OO, its precursor complex CH2OO-H2O with water, and the oxidation product HMHP can be generated efficiently. The vibrational excited state and cluster signal can be observed simultaneously, verifying its excellent comprehensive performance.
[0021] High throughput and automation: By adopting segmented chirped excitation and a fully automated data acquisition and processing workflow, an acquisition rate of up to 10 complete broadband spectra per second and long-term stable unattended operation were achieved, which greatly improved research efficiency.
[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of a chirped pulse Fourier transform microwave spectrometer according to a first embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the discharge electrode in one embodiment of a chirped pulse Fourier transform microwave spectrometer according to the present invention; Figure 3 This is a time-voltage diagram of a segmented chirped pulse sequence output by an arbitrary waveform generator in Embodiment 1 of the chirped pulse Fourier transform microwave spectrometer of the present invention. Figure 4 This is a time-frequency spectrum of a segmented chirped pulse sequence from an embodiment of a chirped pulse Fourier transform microwave spectrometer of the present invention; Figure 5 This is a time-frequency domain spectrum of a chirped pulse Fourier transform microwave spectrometer according to a first embodiment of the present invention; Figure 5 (a) in the figure is a typical time-domain plot recorded by an oscilloscope, containing leakage chirp pulses and free induction decay signals; Figure 5 (b) in the figure is the frequency domain spectrum obtained after performing a Fourier transform on the free induction attenuation signal segment in the time domain diagram; Figure 6 In Example 2, the present invention was used to measure a 0.1% OCS / Ne mixture, after 10... 5 Broadband spectrum of the transition region obtained after multiple averaging; Figure 7 This is a comparison of broadband spectra of the CH2I2 / O2 / H2O mixture measured in Example 3 under pulse discharge on and off states.
[0024] Figure Labels 1. Pulse valve; 2. Microwave power amplifier; 3. Transmitting horn antenna; 4. Receiving horn antenna; 5. Limiter; 6. Single-pole double-throw switch; 7. Low-noise amplifier; 8. Oscilloscope; 9. Rubidium clock; 10. Arbitrary waveform generator; 11. Digital delay generator; 12. Frequency multiplier; 13. Pulse valve base; 14. Ceramic insulating spacer; 15. Brass electrode. Detailed Implementation
[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0026] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," and similar terms used in this invention, mean that the element or object preceding the term encompasses the elements or objects listed following the term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0027] Example 1: The spectrometer is constructed as follows: like Figure 1 As shown, the present invention provides a chirped pulse Fourier transform microwave spectrometer, comprising: The pulsed injection and reactant in-situ generation system includes a pulse valve 1 and a pulsed discharge electrode integrated at the nozzle of the pulse valve, for generating a cryogenic molecular beam containing transient reaction intermediates.
[0028] Pulse valve 1 operates at a repetition frequency of 10 Hz, mixing the sample with a Ne or Ar carrier gas at a back pressure of 4-8 bar before injecting it into the vacuum chamber. A nozzle of pulse valve 1 is integrated with... Figure 2 The stainless steel disc-shaped discharge electrode shown is supplied with 1-2kV voltage by a high-voltage power supply, gated by a fast high-voltage switch, and triggered by a digital delay generator 11. The pulse discharge electrode is integrated with the pulse valve base 13. The pulse discharge electrode includes a ceramic insulating spacer 14 and a brass electrode 15, which are spaced apart.
[0029] A high-capacity capacitor of approximately 0.1 µF is connected in parallel in the discharge circuit to accelerate the voltage rise time, and a high-value ballast resistor of approximately 10 kΩ is connected in series to limit the peak current, ensuring stable and controllable discharge.
[0030] The segmented chirped pulse generation and radiation system includes an arbitrary waveform generator 10, a frequency multiplier 12, a microwave power amplifier 2, and a transmitting horn antenna 3 connected in sequence, for generating and radiating a series of microwave excitation pulses covering the 18-40 GHz frequency band; The arbitrary waveform generator 10 generates microsecond-level chirped pulses at a rate of 50 GS / s, such as... Figure 3 and Figure 4As shown: Each sequence consists of five chirped pulses with a center frequency increasing by 4.4 GHz (lasting 2 µs), repeated five times to form a complete 18-40 GHz coverage. The pulse is up-converted by a frequency multiplier 12, amplified to approximately 50 W by a solid-state microwave power amplifier 2, and radiated into the vacuum cavity through a transmitting horn antenna 3.
[0031] The signal detection and high-speed acquisition system includes a receiving horn antenna 4, a limiter 5, a single-pole double-throw switch 6, a low-noise amplifier 7, and an oscilloscope 8 connected in sequence. It is used to receive and digitize the free induction decay signal of molecular radiation and protect subsequent circuits from strong excitation pulses. Finally, the signal is digitized at a sampling rate of 80 GS / s.
[0032] The receiving horn antenna 4 collects the free induction attenuation (FID) signal, which is protected by a limiter 5 and a single-pole double-throw switch 6. The signal is then amplified by a 40 dB low-noise amplifier 7 and digitized at a rate of 80 GS / s by a high-speed oscilloscope 8. All components are phase-locked by a 10 MHz rubidium clock 9 to ensure coherence.
[0033] The synchronous timing control system includes a digital delay generator 11 and a signal transmission line, which is electrically connected to the above-mentioned systems through the signal transmission line and is used to coordinate the operation timing of the above-mentioned systems. The signal processing and automated acquisition component includes a data processing terminal and automated acquisition software stored in the terminal. The data processing terminal is electrically connected to an oscilloscope and a synchronous timing control system. The automated acquisition software calls hardware resources to control the overall operation of the instrument and performs Fourier transform processing on the digitized free induction attenuation signal to generate a broadband microwave spectrum.
[0034] The signal processing software, developed using Python, automates data acquisition: after every 100,000 averages, it automatically transmits data, resets the averager, and processes the FID signal in segments (isolation with a 10 µs window, apodization using a Kaiser-Bessel window function α = 9.5, and Fourier transform followed by spectrum stitching). Figure 5 a and Figure 5 As shown in b.
[0035] This invention also provides a method for molecular rotational spectroscopy detection using a chirped pulse Fourier transform microwave spectrometer, comprising the following steps: S201. A gaseous mixture containing precursors is injected into a vacuum chamber through the pulse injection and reactant in-situ generation system, and synchronous pulse discharge is triggered by the pulse discharge electrode integrated into the pulse valve to generate free radicals, ions or metastable molecules in situ. The gaseous mixture contains haloalkanes, oxygen and water vapor, and generates Criegee intermediates and related products through pulsed discharge; S202. Using the segmented chirped pulse generation and radiation system, microwave pulses covering 18-40 GHz are generated to excite molecules in the cavity; S203. Acquire the time-domain signal of molecular radiation using the aforementioned signal detection and high-speed acquisition system; S204. Process the time-domain signal using the aforementioned signal processing and automated acquisition software, including performing piecewise Fourier transform and spectral splicing on the time-domain signal, and employing more than 10 7 By averaging the signals from multiple signals, a broadband molecular rotation spectrum in the range of 18-40 GHz was obtained.
[0036] Example 2: Instrument performance testing is as follows: The carrier gas was diluted with 0.1% OCS and injected into the vacuum chamber at 10 Hz through pulse valve 1, without discharge. The microwave excitation pulse was synchronized with the gas pulse, and after averaging 100,000 pulses (approximately 33 minutes), the desired result was obtained. Figure 6 The broadband spectrum of the transition region shown indicates the observation of 10 naturally abundant isotopes, including the least abundant one. 18 O 12 C 34 S (SNR≈8). Major isotopes 16 O 12 C 32 S has an SNR exceeding 150,000 and a detection limit of approximately 10. 10 Molecules / cubic centimeter. SNR varies with the mean number N. 0.5 The dependency relationship confirms that the noise is random.
[0037] Example 3: Discharge performance test is as follows: A CH2I2 / O2 / H2O mixture (CH2I2 diluted with Ne, with trace amounts of O2 and H2O vapor added) was injected into the vacuum chamber through pulse valve 1. Broadband spectra were compared between the discharge off and on states, such as... Figure 7 As shown. Numerous new spectral lines appeared after the discharge was initiated, including the Criegee intermediate CH2I2 (SNR>10). 3 The high yield and high SNR of these transient species, including their vibrational excited state, CH2OO-H2O precursor complex, and oxidation product HMHP (HOCH2OOH), demonstrate the effectiveness of the pulsed discharge system and the instrument's ability to detect reaction intermediates.
[0038] Through the above embodiments, the spectrometer described in this invention achieves continuous broadband coverage, high-sensitivity detection, and in-situ generation of transient species in the 18-40 GHz frequency band, making it suitable for atmospheric chemistry, combustion, and astrochemistry research.
[0039] Therefore, the present invention employs the above-mentioned chirped pulse Fourier transform microwave spectrometer and detection method to achieve continuous, broadband, and high-sensitivity operation in the 18-40 GHz frequency band, and integrates a pulsed discharge sample introduction system, which can generate and directly detect highly reactive intermediates and their molecular clusters in situ.
[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A chirped pulse Fourier transform microwave spectrometer, characterized in that, include: A pulsed injection and reactant in-situ generation system includes a pulse valve and a pulsed discharge electrode integrated at the nozzle of the pulse valve, for generating a cryogenic molecular beam containing transient reaction intermediates; A segmented chirped pulse generation and radiation system, comprising an arbitrary waveform generator, a frequency multiplier, a microwave power amplifier, and a transmitting horn antenna connected in sequence, is used to generate and radiate a series of microwave excitation pulses covering the 18-40 GHz frequency band; The signal detection and high-speed acquisition system includes a receiving horn antenna, a limiter, a single-pole double-throw switch, a low-noise amplifier, and an oscilloscope connected in sequence, used to receive and digitize the free induction attenuation signal of molecular radiation. The synchronous timing control system includes a digital delay generator and a signal transmission line, which is electrically connected to the above-mentioned systems through the signal transmission line to coordinate the operation timing of the above-mentioned systems. The signal processing and automated acquisition component includes a data processing terminal and automated acquisition software stored in the terminal. The data processing terminal is electrically connected to an oscilloscope and a synchronous timing control system. The automated acquisition software calls hardware resources to control the overall operation of the instrument and performs Fourier transform processing on the digitized free induction attenuation signal to generate a broadband microwave spectrum.
2. The chirped pulse Fourier transform microwave spectrometer according to claim 1, characterized in that, The pulse discharge electrode is integrated with the pulse valve base. The pulse discharge electrode includes a ceramic insulating spacer and a brass electrode, which are spaced apart.
3. A chirped pulse Fourier transform microwave spectrometer according to claim 2, characterized in that, The pulsed discharge electrode is connected to a high-voltage discharge circuit controlled by the synchronous timing control system, and is used to generate synchronous pulsed discharge when the gas pulse passes through, thereby generating free radicals, ions or metastable molecules in situ in the supersonic expanding jet.
4. A chirped pulse Fourier transform microwave spectrometer according to claim 1, characterized in that, The arbitrary waveform generator is configured to generate 4-6 chirped pulse sequences with a bandwidth of 2-6 GHz and a center frequency interval of 5-8 GHz. After being amplified by a frequency multiplier and a microwave power amplifier, the frequency combination covers a continuous frequency band of 18-40 GHz.
5. A chirped pulse Fourier transform microwave spectrometer according to claim 4, characterized in that, The chirped pulse sequence generated by the arbitrary waveform generator is as follows: within a single trigger cycle, it contains several repeating subsequences, each subsequence consisting of multiple chirped pulses with sequentially increasing center frequencies.
6. A chirped pulse Fourier transform microwave spectrometer according to claim 1, characterized in that, The limiter is used to isolate the receiving horn antenna from the low-noise amplifier during microwave excitation pulse radiation, and the oscilloscope has a sampling rate of not less than 80 GS / s.
7. A chirped pulse Fourier transform microwave spectrometer according to claim 1, characterized in that, The synchronous timing control system, with a digital delay generator as its core, provides precise trigger signals with adjustable delays for the pulse injection and reactant in-situ generation system, the segmented chirped pulse generation and radiation system, and the signal detection and high-speed acquisition system.
8. A chirped pulse Fourier transform microwave spectrometer according to claim 7, characterized in that, The signal processing and automated acquisition software runs on the data processing terminal and executes the following steps by calling the hardware resources of the oscilloscope and the synchronous timing control system: S101, Control each hardware module to work collaboratively according to the set timing sequence; S102. Acquire the free induction attenuation signal in the time domain from the oscilloscope; S103. Perform piecewise Fourier transform on the free induction attenuation signal segments corresponding to different excitation frequency bands; S104. The transformed sub-spectrums are spliced together to form a complete 18-40 GHz broadband spectrum; S105. A segmented cumulative averaging strategy is adopted to perform long-term stable averaging of the signal in order to improve the signal-to-noise ratio.
9. A detection method for a chirped pulse Fourier transform microwave spectrometer according to any one of claims 1-8, characterized in that, Includes the following steps: S201. A gaseous mixture containing precursors is injected into a vacuum chamber through the pulse injection and reactant in-situ generation system, and synchronous pulse discharge is triggered by the pulse discharge electrode integrated into the pulse valve to generate free radicals, ions or metastable molecules in situ. S202. The segmented chirped pulse generation and radiation system radiates microwave pulses covering 18-40 GHz to excite molecules in the vacuum cavity; S203. Acquire the time-domain signal of molecular radiation using the aforementioned signal detection and high-speed acquisition system; S204. The time-domain signal is processed using the signal processing and automated acquisition software to obtain a broadband molecular rotation spectrum in the range of 18-40 GHz.
10. The detection method of a chirped pulse Fourier transform microwave spectrometer according to claim 9, characterized in that, The gaseous mixture contains halogenated hydrocarbons, oxygen, and water vapor, and generates a Criegee intermediate through pulsed discharge; step S204 includes performing piecewise Fourier transform and spectral splicing on the time-domain signal, and using more than 10 7 The signals are accumulated and averaged.