Method and system for non-destructive testing of radioisotope purity based on online probing

Abstract

The application discloses an online detection-based radioisotope purity nondestructive detection method and system, and belongs to the technical field of radioisotope detection, and comprises the following steps: step 1, constructing an excitation light source composed of central excitation light and peripheral loss light, and obtaining a compressed detection area as a nanoscale luminescent probe; and step 2, introducing a resonance energy transfer probe into the nanoscale luminescent probe, wherein the resonance energy transfer probe has specific response to the chemical state of a nuclide, and converts the chemical state difference of the nuclide into the energy transfer efficiency difference of the resonance energy transfer probe. Through the introduction of an inert reference array, a dummy probe and an environment-light field transfer function, a double environment disturbance compensation mechanism can be constructed, the light field distortion and signal distortion caused by environmental changes can be stripped in real time, the signal drift can be effectively offset through dynamic fine adjustment of a simulation comparator threshold group, the accuracy of nuclide chemical state determination is improved, and detection errors caused by environmental interference and system loss are avoided.

Description

Technical Field

[0001] This invention relates to the field of radioactive isotope detection technology, and more specifically, to a non-destructive testing method and system for the purity of radioactive isotopes based on online detection. Background Technology

[0002] Currently, online detection of radioactive isotopes mainly relies on gamma cameras and single-photon emission computed tomography (SPECT). These technologies passively receive and analyze signals based on the energy-space two-dimensional information of the characteristic energy photons of radioactive nuclides. They can only obtain the spatial distribution and signal intensity data of radioactive nuclides, but cannot correlate the molecular state information of the nuclides.

[0003] In complex biological environments or matrix interference environments composed of solid-phase carriers, pH fluctuations, changes in ionic strength, and the action of metabolic enzymes in complex biological environments can easily cause the desorption of radionuclides labeled on biological macromolecules, nanoparticles, or drug molecules. For implantable medical devices carrying radionuclides, the matrix shielding effect can further make it difficult for external online detection to distinguish between free radioactive impurities and bound drug molecules. For example, in the development of Ac-225-labeled macrocyclic ligand-peptide mimics, due to the lack of direct characterization data of Ac complex molecular structures, conventional online detection cannot distinguish between intact drug molecules and radionuclide recoil effects and drug fragments generated by in vivo metabolism, directly leading to misjudgments of drug stability in vivo.

[0004] In complex matrix environments, detection signals are prone to severe attenuation or interference, and it is impossible to accurately distinguish whether the radioactive signal originates from an intact targeted drug, a detached free nuclide, or drug fragments. This leads to distortions in the results of drug stability assessment and implant radiopharmaceutical status monitoring. The underlying technical root of this defect is that traditional online detection can only obtain the characteristic energy and spatial distribution information of nuclides, and cannot obtain information on the microscopic chemical environment in which the nuclide is located, including the coordination state of the nuclide and the conformation of the labeled molecule. Under matrix interference, the chemical state of the signal source cannot be clearly identified, and it is difficult to accurately determine the purity of radiolabeled drugs. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a non-destructive testing method and system for the purity of radioactive isotopes based on online detection. This method can construct a dual environmental disturbance compensation mechanism by introducing an inert reference array, a dumb probe, and an ambient-optical field transfer function. This mechanism can isolate optical field distortion and signal distortion caused by environmental changes in real time. At the same time, by dynamically fine-tuning the threshold group of the analog comparator, it can effectively offset signal drift, improve the accuracy of nuclide chemical state determination, and avoid detection errors caused by environmental interference and system losses.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] Firstly, a non-destructive testing method for the purity of radioactive isotopes based on online detection, the method comprising:

[0008] Step 1: Construct an excitation source consisting of a central excitation light and a peripheral loss light to obtain a compressed detection region as a nanoscale luminescent probe;

[0009] Step 2: Introduce a resonant energy transfer probe into the nanoscale luminescent probe. The resonant energy transfer probe has a specific response to the chemical state of the nuclide, and converts the difference in the chemical state of the nuclide into the difference in the energy transfer efficiency of the resonant energy transfer probe.

[0010] Step 3: Excitation light is emitted in the form of picosecond pulses, and the emission signals of the nuclide are collected at different time windows after excitation to obtain the initial signal intensity corresponding to different chemical states;

[0011] Step 4: Introduce an inert reference object fixed to the matrix of the test object, monitor the signal of the inert reference object in real time to establish an environmental disturbance function, and use the environmental disturbance function to correct the initial signal intensity.

[0012] Step 5: Calculate the ratio of the corrected initial signal intensity and compare the ratio with the preset threshold range to determine the chemical state of the nuclide at the current nanoscale luminescent probe position;

[0013] Step 6: Move the nanoscale luminescent probe to perform spatial scanning on the surface of the analyte, and repeat steps 2 to 5 at each scanning position to reconstruct the chemical state distribution map of the analyte surface.

[0014] Further, step 1 includes:

[0015] Step 11: Emit a probe light pulse to the target area, receive the distorted echo signal reflected by the object under test, analyze the wavefront distortion function based on the distorted echo signal, and pre-distort the wavefronts of the excitation light and the loss light according to the analyzed wavefront distortion function to obtain the wavefront-predistorted excitation light and loss light.

[0016] Step 12: Apply a frequency shift to the obtained wavefront pre-distorted loss light, so that the frequency-shifted loss light interferes with the unshifted loss light in the focal region of step 11, forming a dynamically modulated loss light field.

[0017] Step 13: Under the action of the dynamically modulated lossy optical field, an intensity modulation of known amplitude is superimposed on the excitation light, the third harmonic component corresponding to the intensity modulation frequency in the nuclide emission signal is detected, and the existence of the third harmonic component is used as the basis for defining the effective detection signal.

[0018] Further, step 2 includes:

[0019] Step 21: Distribute two probe precursors, including a trapping group precursor and a quantum dot precursor, in the test area. Use the loss light corresponding to the effective detection signal defined by the third harmonic component in step 13 to irradiate and photolyze the trapping group precursor, so that the photolyzed trapping group precursor and the quantum dot precursor undergo a click chemical reaction, and a resonant energy transfer probe is formed in situ assembled in the nanoscale luminescent probe.

[0020] Step 22: The trapping group in the resonant energy transfer probe assembled in step 21 is bound to the nuclide. The energy transfer efficiency of the energy relay station is changed by the trapped group after binding, so that the energy transfer ratio of the energy relay station to the quantum dot array changes with the chemical state of the nuclide, and a multicolor signal with characteristic ratio determined by nuclides in different chemical states is obtained.

[0021] Step 23: Using the excitation light that has undergone wavefront pre-distortion in Step 1, the fluorescence lifetime of each color channel in the multicolor signal is measured through a two-photon absorption excitation energy relay station to obtain the nuclide chemical state information characterized by both color and lifetime.

[0022] Furthermore, step 3 includes:

[0023] Step 31: Apply controllable chirping to the excitation light that has undergone wavefront pre-distortion in step 1 to form a chirped pulse excitation light. Use the chirped pulse excitation light to excite the multicolor fluorescence signal output in step 23 to obtain a composite time decay waveform containing spectral and lifetime information.

[0024] Step 32: Inject the composite time decay waveform obtained in step 31 into the circular delay line for cyclic time broadening, and amplify the signal during the cyclic broadening process to obtain a broadened and amplified composite electrical signal.

[0025] Step 33: Using the chirped encoding rules of the chirped pulse excitation light in step 31, the broadened and amplified composite electrical signal obtained in step 32 is back-mapped into attenuation curves of different wavelength channels. The attenuation curves are then cross-correlated with the characteristic attenuation templates pre-calibrated and stored in step 23 to obtain the proportion data of each chemical state in the current nanoscale luminescent probe.

[0026] Furthermore, step 3 also includes:

[0027] Step 34: Collect the output signal of the single-photon detector that has not been processed in step 32, record the absolute arrival time of each photon and calculate the time interval between adjacent photons, construct a real-time time interval histogram based on the time interval, and check the consistency between the histogram and the theoretical time interval distribution corresponding to the characteristic attenuation template. Use the check result as the confidence label of the proportion data of each chemical state obtained in step 33.

[0028] Step 35: Monitor the confidence level tag obtained in step 34. When the confidence level is lower than a predetermined threshold, adjust the peak power or pulse repetition frequency of the chirped pulse excitation light in subsequent step 31 according to the confidence level tag, or trigger step 21 to perform in-situ assembly of the resonant energy transfer probe again in the nanoscale luminescent probe.

[0029] Furthermore, step 4 includes:

[0030] Step 41: In the test matrix region where the nanoscale luminescent probe is located, as confirmed in step 13, a set of inert reference arrays with orthogonal responses to a single environmental parameter are implanted. The emission spectra of each reference in the reference array do not overlap with each other and do not overlap with the emission spectrum of the probe in step 2, thereby obtaining an optical signal source that can report different single environmental parameters.

[0031] Step 42: Using the excitation light that has undergone wavefront pre-distortion in Step 1, the reference array implanted in Step 41 is sequentially excited in a time-division multiplexing manner, and the signals of each reference are sequentially acquired according to the time window synchronized with the excitation to obtain a multi-dimensional environmental parameter vector synchronized with the detection process.

[0032] Step 43: Input the multidimensional environmental parameter vector obtained in step 42 into the pre-stored environmental-light field transfer function, calculate in real time the compensating light field distortion required to maintain the nanoscale luminescent probe in step 1, and adjust the wavefronts of the excitation light and loss light in step 11 and the frequency shift of the loss light in step 12 according to the compensating light field distortion.

[0033] Furthermore, step 4 also includes:

[0034] Step 44: While assembling the resonant energy transfer probe in step 21, a dumb probe with the same structure as the resonant energy transfer probe but unable to bind nuclides is introduced into the same nanoscale luminescent probe. The multicolor signal of the dumb probe is monitored in real time. The multicolor signal of the dumb probe is compared with the chemical state ratio data obtained in step 35 by performing nonlinear difference operation to remove the nonlinear signal distortion caused by the environment and obtain the corrected chemical state signal.

[0035] Step 45: Perform correlation analysis on the historical multidimensional environmental parameter vector accumulated in step 42 and the corrected chemical state signal output in step 44 to identify the correlation between environmental change patterns and precursors of signal distortion. When a precursor correlation is detected again, trigger steps 43 and 44 to perform compensation operations in advance.

[0036] Furthermore, step 5 includes:

[0037] Step 51: Input the chemical state percentage data output in step 33, the confidence label output in step 34, the multidimensional environmental parameter vector output in step 42, and the corrected chemical state signal output in step 44 into the hardware lock-in amplifier network in parallel. Use the modulation frequency of the chirped pulse in step 31 and the modulation frequency of time division multiplexing in step 42 as reference signals to perform hardware coherent demodulation and obtain a set of analog characteristic voltages.

[0038] Step 52: Input a set of simulated characteristic voltages obtained in step 51 into a chemical state space mapping network composed of an array of simulated comparators in parallel. Each comparator in the array of simulated comparators corresponds to a preset chemical state and has a set of simulated comparator thresholds corresponding to the chemical state. By combining the logic levels output in parallel by all comparators, the chemical state determination result of the nuclide at the current nanoscale luminescent probe position is obtained.

[0039] Step 53: Continuously acquire the chemical state determination result output in step 52 and the corresponding analog characteristic voltage output in step 51. For multiple analog characteristic voltages corresponding to the same chemical state determination result, calculate the mean and broadening of the characteristic voltage cluster. When the deviation of the mean relative to the initial calibration point exceeds a preset threshold, generate a threshold fine-tuning signal based on the mean. The threshold fine-tuning signal is used to update the analog comparator threshold group of the analog comparator corresponding to the chemical state in step 52.

[0040] Furthermore, step 6 includes:

[0041] Step 61: During the spatial scanning process, the intensity of the effective detection signal defined by the third harmonic component in step 13 is monitored in real time. Based on the change in the intensity of the effective detection signal, a displacement compensation signal perpendicular to the surface of the object under test is generated in real time. The relative axial position of the nanoscale luminescent probe and the surface of the object under test is adjusted according to the displacement compensation signal.

[0042] Step 62: After completing the dynamic adjustment of the axial position in step 61, obtain the chemical state determination result output in step 52 at the current scanning position. Based on the chemical state determination result and the chemical state determination result of its neighboring position, adjust the scanning step size and scanning direction in real time to generate a non-uniform adaptive scanning path. After executing steps 2 to 5 at each scanning position, reconstruct the chemical state distribution map of the surface of the test object based on the chemical state determination results and coordinates collected at all scanning positions.

[0043] Secondly, the present invention also provides a non-destructive testing system for the purity of radioactive isotopes based on online detection, comprising:

[0044] The probe construction module is used to construct an excitation source consisting of a central excitation light and an outer loss light, and to obtain a compressed detection region as a nanoscale luminescent probe.

[0045] The probe response module is used to introduce a resonant energy transfer probe into a nanoscale luminescent probe. The resonant energy transfer probe has a specific response to the chemical state of the nuclide, converting the difference in the chemical state of the nuclide into the difference in the energy transfer efficiency of the resonant energy transfer probe.

[0046] The signal acquisition module is used to emit excitation light in the form of picosecond pulses and acquire the nuclide emission signals at different time windows after excitation to obtain the initial signal intensity corresponding to different chemical states;

[0047] The signal correction module is used to introduce an inert reference fixed to the matrix of the test object, monitor the signal of the inert reference in real time to establish an environmental disturbance function, and use the environmental disturbance function to correct the initial signal intensity.

[0048] The chemical state determination module is used to calculate the ratio of the corrected initial signal intensity and compare the ratio with a preset threshold range to determine the chemical state of the nuclide at the current nanoscale luminescent probe position.

[0049] The distribution reconstruction module is used to move the nanoscale luminescent probe to perform spatial scanning on the surface of the analyte, and repeatedly execute the probe response module, signal acquisition module, signal correction module and chemical state determination module at each scanning position to reconstruct the chemical state distribution map of the analyte surface.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] (1) This scheme introduces an inert reference array, a dumb probe and an environment-light field transfer function to construct a dual environmental disturbance compensation mechanism, which can strip away the light field distortion and signal distortion caused by environmental changes in real time. At the same time, by dynamically fine-tuning the threshold group of the analog comparator, it can effectively offset the signal drift, improve the accuracy of nuclide chemical state determination, and avoid detection errors caused by environmental interference and system loss.

[0052] (2) This scheme adopts a non-uniform adaptive scanning path. Based on the chemical state change gradient between the current scanning position and the neighboring position, the scanning step size and scanning direction are adjusted in real time. In areas with uniform chemical state distribution, the step size is increased to improve efficiency, while in areas with drastic changes, the step size is decreased to ensure accuracy. This scheme takes into account the comprehensiveness, efficiency and accuracy of detection, and avoids invalid scanning and omission of key information.

[0053] (3) This scheme uses in-situ assembly of resonant energy transfer probes, combined with chirped pulse excitation, hardware coherent demodulation and multi-dimensional signal fusion analysis, to convert the differences in the chemical state of nuclides into quantifiable multicolor signals and simulated characteristic voltages, thereby achieving rapid and accurate determination of the chemical state of nuclides without the need for destructive treatment of the test material, thus truly realizing non-destructive detection of the purity of radioactive isotopes.

[0054] (4) This scheme collects the chemical state determination results and corresponding coordinates of all locations through spatial scanning, and reconstructs the chemical state distribution map of the surface of the test object by combining spatial interpolation algorithm. It can intuitively present the distribution pattern of the chemical state of the nuclide on the surface of the test object, clearly distinguish the distribution area of ​​nuclides with different chemical states, and provide intuitive and reliable technical basis for the comprehensive and accurate assessment of the purity of radioactive isotopes, which is convenient for subsequent purity analysis and quality control. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0056] Figure 1 This is a flowchart of the non-destructive testing method for the purity of radioactive isotopes based on online detection according to the present invention;

[0057] Figure 2 This is a data flow diagram between various modules in the non-destructive testing system for the purity of radioactive isotopes based on online detection, as described in this invention. Detailed Implementation

[0058] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0059] Example 1

[0060] Please see Figure 1 A non-destructive testing method for the purity of radioactive isotopes based on online detection, the method comprising the following steps:

[0061] Step 1: Construct an excitation source consisting of a central excitation light and peripheral loss light to obtain a compressed detection region as a nanoscale luminescent probe. The specific operations are as follows:

[0062] By combining a central excitation light with a peripheral loss light to form a composite excitation source, and using optical field manipulation technology to compress the detection area, a nanoscale luminescent probe is ultimately obtained. The central excitation light provides energy to excite the nuclides in the target area and the subsequently introduced probe, enabling them to generate detectable optical signals. The peripheral loss light is used to suppress non-target signals outside the detection area. Through the interaction of the optical fields, the spatial compression of the detection area is achieved, limiting the detection range to the nanoscale. This design can effectively overcome the limitation of insufficient spatial resolution in traditional online detection, ensuring that the subsequent detection process only analyzes the nuclides in the tiny target area and avoids interference from signals in non-target areas.

[0063] Step 1 also includes the following steps:

[0064] Step 11: Emit a probe light pulse towards the target area, receive the distorted echo signal reflected by the object under test, analyze the wavefront distortion function based on the distorted echo signal, and pre-distort the wavefronts of the excitation light and loss light according to the analyzed wavefront distortion function to obtain the wavefront-predistorted excitation light and loss light. The specific operation is as follows:

[0065] First, a probe light pulse is emitted towards the target area of ​​the test object. This probe light pulse is a continuous, wavelength-stable laser pulse, whose wavelength is consistent with the wavelength of the subsequent excitation light to ensure consistent wavefront characteristics. When the probe light pulse interacts with the matrix of the test object, wavefront distortion occurs due to the inhomogeneity of the refractive index within the matrix, differences in surface micro-roughness, and scattering effects of the matrix components. After reflection, a distorted echo signal is formed. This echo signal carries all the characteristic information of the wavefront distortion caused by the matrix of the test object and must be completely received by a high-sensitivity photodetector to ensure no signal loss. Due to the inhomogeneity of the refractive index and surface roughness of the matrix of the test object, the probe light pulse will undergo wavefront distortion during reflection. This distortion will cause the subsequent excitation light and loss light to be unable to be accurately focused, thus affecting the detection accuracy. Based on the received distorted echo signal, the conventional Shack-Hartmann wavefront sensing algorithm is used to analyze the optical field and extract the wavefront distortion characteristic parameters. The specific operation process is as follows:

[0066] The received distorted echo signal is fed into a Shack-Hartmann wavefront sensor. The microlens array within this sensor divides the distorted echo signal into several independent sub-spots, each corresponding to a tiny region on the wavefront of the probed light pulse. A charge-coupled device (CCD) precisely captures the actual imaging position of each sub-spot, while simultaneously recording the ideal imaging position corresponding to each microlens—the theoretical position of the sub-spot without wavefront distortion. The offset between the actual and ideal imaging positions of each sub-spot is calculated; this offset is the core characteristic parameter of wavefront distortion. Additionally, two auxiliary characteristic parameters—the uniformity of light intensity distribution and the offset direction—are extracted for each sub-spot. These three parameters together constitute a complete set of wavefront distortion characteristic parameters. The offset directly reflects the amplitude of the wavefront distortion, the offset direction reflects the orientation of the wavefront distortion, and the uniformity of light intensity distribution reflects the uniformity of the distortion. The wavefront distortion function is constructed based on the extracted characteristic parameter set using the Zernike polynomial fitting method. The specific construction process is as follows:

[0067] Using the wavefront coordinates of the probe light pulse as the independent variable and the extracted sub-spot offset as the dependent variable, low-order terms of the Zernike polynomial, such as Z0 to Z9, are selected to describe the overall distortion of the wavefront, including tilt, defocus, and astigmatism. High-order terms, such as Z10 to Z20, are selected to describe local subtle distortions of the wavefront, such as local distortions caused by minor matrix defects. The least squares method is used to fit the feature parameter set, ensuring that the deviation between the fitted wavefront function and the actual distorted echo signal is controlled within a preset threshold, i.e., the deviation value is no greater than 1 / 100 of the probe light wavelength. Finally, a wavefront function that accurately describes the distortion pattern is obtained. A wavefront distortion function is used to precisely quantify the degree and direction of distortion at each point on the wavefront. Subsequently, based on the analytically obtained wavefront distortion function, the wavefronts of the excitation and loss light used to construct the nanoscale luminescent probe are pre-distorted. A pre-distortion signal with the same amplitude but opposite direction as the wavefront distortion function is loaded through a wavefront modulator, so that the direction of the pre-distortion is opposite to the direction of the wavefront distortion caused by the matrix of the test object and the amplitude is matched. After the pre-distortion processing, the wavefront distortion of the excitation and loss light is canceled by the distortion effect of the matrix of the test object when passing through it, and finally it can be precisely focused on the target area.

[0068] Step 12: Apply a frequency shift to the obtained wavefront-predistorted loss light, causing the frequency-shifted loss light to interfere with the unshifted loss light in the focal region of Step 11, forming a dynamically modulated loss light field. The specific operation is as follows:

[0069] After obtaining the pre-distorted loss light in step 11, a specific frequency shift is applied to the loss light, causing the frequency of part of the loss light to change, forming frequency-shifted loss light, while the other part of the loss light retains its original frequency, i.e., unshifted loss light. The frequency-shifted loss light and the unshifted loss light are simultaneously guided to the focal region determined in step 11. Due to the frequency difference between the two types of loss light, interference occurs in the focal region. This interference forms a loss light field whose spatial distribution changes dynamically over time, i.e., a dynamically modulated loss light field. This dynamically modulated loss light field can dynamically suppress the optical signal outside the focal region, further compressing the spatial range of the detection area, while enhancing the intensity stability of the optical field within the focal region, making the detection range of the nanoscale luminescent probe more accurate and the signal intensity more stable.

[0070] Step 13: Under the influence of the dynamically modulated lossy optical field, an intensity modulation of known amplitude is superimposed on the excitation light. The third harmonic component corresponding to the intensity modulation frequency in the nuclide emission signal is detected, and the presence of the third harmonic component is used as the basis for defining the effective detection signal. The specific operation is as follows:

[0071] Under the influence of the dynamic modulation loss optical field formed in step 12, an intensity modulation of known amplitude is superimposed on the wavefront pre-distortion excitation light obtained in step 11, causing the intensity of the excitation light to change periodically according to a specific frequency. This intensity modulation frequency serves as an identifier of the effective signal. When the intensity-modulated excitation light acts on the nuclide in the target area, the nuclide is excited and emits a corresponding optical signal. This emitted signal contains harmonic components corresponding to the intensity modulation frequency of the excitation light. The third harmonic component has strong anti-interference ability and high specificity, and is not easily interfered with by environmental noise or signals from non-target areas. The nuclide emission signal is analyzed by a dedicated detection device to detect whether there is a third harmonic component corresponding to the intensity modulation frequency of the excitation light. If the third harmonic component is detected, it indicates that the emitted signal comes from the target area covered by the nanoscale luminescent probe and is a valid detection signal. If the third harmonic component is not detected, it indicates that the signal is a non-target area signal or an environmental interference signal and needs to be excluded. In this way, the valid detection signal can be accurately defined, avoiding interference from invalid signals on the detection results.

[0072] In a preferred embodiment of the present invention, step 2 is further included: introducing a resonant energy transfer probe into the nanoscale luminescent probe. The resonant energy transfer probe has a specific response to the chemical state of the nuclide, converting the difference in the chemical state of the nuclide into a difference in the energy transfer efficiency of the resonant energy transfer probe. The specific operation is as follows:

[0073] The nanoscale luminescent probe has been constructed in step 1. It possesses precise spatial positioning capabilities and can focus on a tiny area of ​​the target region. A resonant energy transfer probe is introduced inside this nanoscale luminescent probe. This probe is specifically designed to produce a specific response to different chemical states of nuclides. This specificity stems from the selective interaction between the probe's own structure and the nuclide's chemical state. That is, nuclides in different chemical states will interact with the resonant energy transfer probe with different intensities and types of interactions. When nuclides are in different chemical states, their coordination states, electron cloud distributions, and other microscopic characteristics differ. These differences directly affect the energy transfer process inside the resonant energy transfer probe, leading to regular changes in the probe's energy transfer efficiency. In this way, the abstract differences in the nuclide's chemical state are converted into specific differences in the energy transfer efficiency of the resonant energy transfer probe. The differences in energy transfer efficiency can be quantified through subsequent signal acquisition and analysis, thereby achieving indirect detection of the nuclide's chemical state and overcoming the technical deficiency of traditional online detection methods that cannot obtain information on the microscopic chemical environment of nuclides.

[0074] Step 2 also includes the following steps:

[0075] Step 21: Distribute two probe precursors, one containing a trapping group precursor and the other a quantum dot precursor, in the test area. Use the loss light corresponding to the effective detection signal defined by the third harmonic component in step 13 to irradiate and photolyze the trapping group precursor. This causes a click chemical reaction between the photolyzed trapping group precursor and the quantum dot precursor, resulting in in-situ assembly of a resonant energy transfer probe within the nanoscale luminescent probe. The specific operation is as follows:

[0076] First, two probe precursors are uniformly distributed in the test area. One probe precursor contains a trapping group precursor, and the other contains a quantum dot precursor. The concentrations of the two precursors are controlled within a preset range to ensure uniform dispersion in the test area and coverage of the target area focused by the nanoscale luminescent probe. At the same time, excessive precursor concentration is avoided to prevent aggregation, which would affect the subsequent assembly effect. The trapping group precursor has photolytic properties and can undergo photolysis under light irradiation of specific wavelengths and intensities to generate active trapping groups. The quantum dot precursor has functional groups that specifically react with the trapping groups after photolysis, providing a basis for subsequent click chemistry reactions. Subsequently, the loss light corresponding to the effective detection signal defined by the third harmonic component in step 13 is extracted. This loss light has been confirmed to originate from the target area covered by the nanoscale luminescent probe and has stable light intensity and wavelength characteristics, which can be used as a trigger light source for the photolysis reaction.

[0077] The loss light is guided to the test area and irradiates the trapping group precursors distributed in the area, causing the trapping group precursors to undergo a photolysis reaction to generate highly reactive trapping groups. During the photolysis process, the irradiation intensity and irradiation time of the loss light are strictly controlled to ensure that the trapping group precursors are fully photolyzed, while avoiding damage to the quantum dot precursors due to excessive light intensity. The photolyzed trapping groups immediately undergo a click chemistry reaction with the surrounding quantum dot precursors. This reaction is characterized by fast reaction speed, high specificity, and few side reactions. It can occur in situ within the spatial range defined by the nanoscale luminescent probe, and finally assemble into a complete resonant energy transfer probe.

[0078] Step 22 involves binding the trapping group in the resonant energy transfer probe assembled in step 21 to the nuclide. Utilizing the altered energy transfer efficiency of the energy relay station by the binding trapping group, the energy transfer ratio from the energy relay station to the quantum dot array changes with the nuclide's chemical state, resulting in a multicolor signal with characteristic proportions determined by nuclides in different chemical states. The specific operation is as follows:

[0079] In the in-situ assembled resonance energy transfer probe of step 21, the trapping group has the ability to specifically bind to nuclides. Its binding site can form stable coordinate bonds or non-covalent interactions with the nuclide, and this binding varies depending on the nuclide's chemical state. When the nuclide is in different chemical states, its ionic valence state, coordination environment, electron cloud density, and other microscopic characteristics differ, leading to changes in the binding strength and mode with the trapping group. This, in turn, causes a regular change in the spatial conformation of the trapping group. The resonance energy transfer probe contains an energy relay station and a quantum dot array. The core function of the energy relay station is to receive excitation energy and transfer it to the quantum dot array, while the spatial conformational changes of the trapping group directly affect its binding strength and mode. The energy transfer efficiency of the energy relay station to the quantum dot array is directly affected. When the trapping group combines with nuclides of different chemical states, the degree of conformational change is different, and the effect on energy transfer efficiency is also different. This leads to a change in the energy transfer ratio of different colored quantum dots in the quantum dot array. The quantum dot array is composed of quantum dots with different emission wavelengths. Each quantum dot corresponds to a specific color channel. The change in the energy transfer ratio will cause the luminescence intensity of different color channels to change accordingly. Finally, a multicolor signal with a characteristic ratio is formed, which is determined by nuclides of different chemical states. Nuclides of different chemical states correspond to a unique multicolor signal ratio. This characteristic ratio can be used as an important basis for distinguishing the chemical states of nuclides.

[0080] Step 23: Using the excitation light pre-distorted by the wavefront in Step 1, the fluorescence lifetime of each color channel in the multicolor signal is measured through a two-photon absorption excitation energy relay station to obtain the nuclide chemical state information characterized by both color and lifetime. The specific operation is as follows:

[0081] The excitation light pre-distorted in step 1 has had its interference from the analyte matrix eliminated through wavefront correction, possessing precise focusing capability and stable optical field characteristics, and can be used as the excitation source for this step. This excitation light is guided into the nanoscale luminescent probe, and the energy relay station in the resonant energy transfer probe is excited via two-photon absorption. Two-photon absorption has advantages such as longer excitation wavelength, deeper penetration depth, and less damage to the probe and analyte, effectively avoiding background interference caused by single-photon excitation and ensuring precise excitation of the energy relay station. After the energy relay station is excited, it transfers the absorbed energy to the quantum dot array according to the characteristic ratio formed in step 22, causing the quantum dots in different color channels to emit fluorescence, forming a multicolor signal. Subsequently, time-correlated single-photon counting is used to measure the multicolor signals. This method measures the fluorescence lifetime of each color channel in a quantum dot signal. It can accurately capture the time it takes for the fluorescence signal to decay from the excited state to the ground state, exhibiting extremely high temporal resolution. Fluorescence lifetime is an inherent characteristic of quantum dots, but it is also affected by their surrounding chemical environment. Differences in the chemical state of nuclides can indirectly affect the surrounding environment of quantum dots through conformational changes in the trapping groups, leading to significant differences in the fluorescence lifetime of the same color channel corresponding to nuclides with different chemical states. By measuring the fluorescence lifetime of each color channel separately, lifetime characteristics related to the nuclide's chemical state can be obtained. Combined with the luminescence intensity ratio of that color channel, information on the nuclide's chemical state is formed by both color and lifetime. This dual characterization method can effectively eliminate misjudgments caused by single signal characteristics, further improving the accuracy of nuclide chemical state determination.

[0082] In a preferred embodiment of the present invention, step 3 is further included: emitting excitation light in the form of picosecond pulses, and collecting the nuclide emission signals at different time windows after excitation to obtain the initial signal intensity corresponding to different chemical states. The specific operation is as follows:

[0083] After step 2, the resonant energy transfer probe has transformed the differences in the chemical states of nuclides into multicolor signal features, and these multicolor signals carry key information about the chemical states of nuclides. This step uses picosecond pulses to emit excitation light. Picosecond pulses have extremely short pulse widths and high temporal resolution, which can accurately match the attenuation characteristics of the nuclide emission signals and avoid the superposition and indistinguishability of emission signals from nuclides of different chemical states due to excessively long pulse widths. After the excitation light is emitted in picosecond pulse form and excites the nuclide and the resonant energy transfer probe, the emission signals corresponding to nuclides of different chemical states will exhibit different attenuation patterns in different time windows. That is, the intensity of the emission signals of nuclides of different chemical states varies significantly in different time periods after excitation. By collecting the nuclide emission signals in different time windows after excitation, the signals corresponding to nuclides of different chemical states can be separated, and the signal intensity in each time window can be extracted. These signal intensities are the initial signal intensities corresponding to different chemical states.

[0084] Step 3 also includes the following steps:

[0085] Step 31: Apply controllable chirping to the excitation light that has undergone wavefront pre-distortion in Step 1 to form a chirped pulse excitation light. Use the chirped pulse excitation light to excite the multicolor fluorescence signal output in Step 23 to obtain a composite time-decay waveform containing spectral and lifetime information. The specific operation is as follows:

[0086] The excitation light pre-distorted in step 1 has completed wavefront correction, possessing stable optical field characteristics and precise focusing capabilities. It can be directly used as the basic excitation source for this step. A chirped modulator applies controllable chirping to this excitation light. The modulation parameters of the controllable chirping can be adjusted according to the type of nuclide to be tested and the detection requirements, so that the frequency of the excitation light changes linearly or nonlinearly with time, ultimately forming a chirped pulse excitation light. The advantage of this chirped pulse excitation light is that it can simultaneously cover different wavelength ranges of multicolor fluorescence signals, and wavelength information can be correlated with time information through chirped encoding to achieve time-domain differentiation of different wavelength signals. The chirped pulse excitation light is guided into the nanoscale luminescent probe to excite the multicolor fluorescence signal output in step 23. The multicolor fluorescence signal is composed of fluorescence from different color channels corresponding to different chemical states of nuclides, and each color channel has a unique lifetime characteristic. When the chirped pulse excitation light excites the multicolor fluorescence signal, fluorescence signals of different wavelengths and lifetimes will superimpose to form a composite signal. The decay process of this composite signal over time is the composite time decay waveform. The waveform contains not only the spectral information of the multicolor fluorescence signal, i.e. the signal components corresponding to different wavelengths, but also the lifetime information of each spectral component, i.e. the rate at which the signal intensity decays over time.

[0087] Step 32: Inject the composite time-decayed waveform obtained in step 31 into the circular delay line for cyclic time broadening, and amplify the signal during the cyclic broadening process to obtain a broadened and amplified composite electrical signal. The specific operation is as follows:

[0088] The composite time-decayed waveform obtained in step 31 has a short time scale and weak signal strength. Direct analysis of it is easily affected by noise and it is difficult to accurately extract the attenuation characteristics of different wavelength channels. Therefore, it is necessary to use a circular delay line to perform cyclic time broadening and synchronously amplify the signal. The circular delay line consists of multiple mirrors and optical amplifiers. After the composite time-decayed waveform is injected into the circular delay line, the signal will circulate and transmit within the circular structure. Each cycle increases the transmission time of the signal by a fixed duration. By controlling the number of cycles, the composite time-decayed waveform with a short time scale can be controllably broadened, so that the signal components at different time points can be fully separated, thereby improving the time resolution of the signal. During the cyclic time-width expansion process, the signal is simultaneously amplified by an optical amplifier. The gain parameters of the optical amplifier must be strictly controlled to ensure that no additional signal distortion is introduced while amplifying the signal, and that the signal attenuation law and spectral characteristics are not changed. The amplifier only compensates for the intensity loss of the signal during transmission and cyclic processing. After the cyclic time-width expansion and signal amplification, the originally weak and short composite time-width decay waveform is transformed into a broadened and amplified composite electrical signal. This electrical signal retains all the spectral and lifetime information in the original composite time-width decay waveform, and has higher signal strength and better time resolution.

[0089] Step 33: Using the chirp encoding rule of the chirped pulse excitation light in Step 31, the broadened and amplified composite electrical signal obtained in Step 32 is back-mapped into attenuation curves for different wavelength channels. The attenuation curves are then cross-correlated with the characteristic attenuation template pre-calibrated and stored in Step 23 using hardware to obtain the proportion data of each chemical state within the current nanoscale luminescent probe. The specific operations are as follows:

[0090] The controllable chirp applied in step 31 has a clear chirp coding rule. This rule pre-defines the correspondence between excitation light frequency and time and wavelength, that is, the determination of the excitation light frequency corresponding to different time points. Different excitation light frequencies correspond to different wavelength channels in the multicolor fluorescence signal. Therefore, the chirp coding rule can be used to achieve the reverse mapping of the time domain signal to the wavelength domain signal. The broadened and amplified composite electrical signal obtained in step 32 is imported into the signal analysis module. According to the preset chirp coding rule, the signal components at different time points in the composite electrical signal are reverse mapped to the corresponding wavelength channel signals. Then, the decay process of each wavelength channel signal over time is extracted to form the decay curves of different wavelength channels. The attenuation curve of each wavelength channel corresponds to the fluorescence attenuation characteristics of a specific chemical state nuclide. In step 23, the fluorescence attenuation characteristics corresponding to different chemical state nuclides have been pre-calibrated, and corresponding characteristic attenuation templates have been formed and stored. Each characteristic attenuation template corresponds one-to-one with a specific chemical state nuclide, including the wavelength channel and attenuation rule corresponding to that chemical state nuclide. The attenuation curves of each wavelength channel obtained by reverse mapping are cross-correlated with the pre-stored characteristic attenuation templates using hardware. Hardware cross-correlation can quickly quantify the similarity between the two curves. The higher the similarity, the better the signal component corresponding to the current attenuation curve matches the signal characteristics of the chemical state nuclide corresponding to the characteristic attenuation template.

[0091] The formula for hardware cross-correlation calculation is: ;

[0092] The derivation of this formula is based on the quantification requirement of signal similarity. By translating and superimposing the attenuation curve f(t) and the characteristic attenuation template g(t) and integrating, the maximum value of the integration result R(τ) corresponds to the translation amount τ, which can reflect the similarity between the two curves. This allows for the quantification of the contribution ratio of the corresponding chemical nuclide in the current signal. In the formula, f(t) represents the attenuation curve of a certain wavelength channel obtained by reverse mapping, and t is the time variable; g(t-τ) represents the characteristic attenuation template after translation τ, and τ is the translation variable; R(τ) represents the result of the cross-correlation operation, and its value is positively correlated with the similarity between the two curves. By performing this cross-correlation operation on the attenuation curves of all wavelength channels and the corresponding characteristic attenuation templates, and combining the signal intensity ratio of each wavelength channel, the proportion of each chemical nuclide at the current nanoscale luminescent probe position can be calculated. This data directly reflects the relative content of different chemical nuclides at the current detection position.

[0093] Step 34: Acquire the output signal of the single-photon detector before the processing in step 32, record the absolute arrival time of each photon and calculate the time interval between adjacent photons, construct a real-time time interval histogram based on the time intervals, and check the consistency between the histogram and the theoretical time interval distribution corresponding to the characteristic attenuation template. Use the check result as the confidence label for the proportion data of each chemical state obtained in step 33. The specific operation is as follows:

[0094] Single-photon detectors can accurately capture individual photon signals emitted by nuclides without undergoing the cyclic broadening and amplification process in step 32, thus preserving the original temporal characteristics of the photon signal. Therefore, the output signal of this single-photon detector is collected for confidence testing. During the acquisition process, the absolute arrival time of each photon is recorded synchronously, i.e., the specific moment when each photon is captured by the detector. Then, the difference in the absolute arrival times of two adjacent photons is calculated to obtain the time interval between adjacent photons. Based on the data of all adjacent photon time intervals, a real-time time interval histogram is constructed. The horizontal axis of this histogram represents the time interval between adjacent photons, and the vertical axis represents the number of photon pairs in the corresponding time interval. This histogram can intuitively reflect the temporal distribution characteristics of the photon signal. The temporal distribution characteristics of the photon signal are directly related to the fluorescence lifetime of the nuclide, and there are clear differences in the distribution of photon time intervals corresponding to different chemical states of nuclides. The pre-calibrated characteristic attenuation template in step 23 not only contains the fluorescence attenuation law but also corresponds to the theoretical time interval distribution of the photon signal of the chemical state nuclide. This theoretical distribution is derived based on the fluorescence lifetime of the characteristic attenuation template and can accurately reflect the temporal distribution characteristics of the photon signal of the chemical state nuclide. The real-time time interval histogram constructed is compared with the theoretical time interval distribution corresponding to the characteristic attenuation template to check the degree of agreement. The chi-square test method is used to check the degree of agreement by calculating the deviation between the actual distribution and the theoretical distribution of the histogram. The higher the degree of agreement, the more reliable the proportion data obtained in step 33 is. The lower the degree of agreement, the more likely there is an error in the proportion data, which needs to be further verified. The result of the degree of agreement test is converted into a confidence label, which is presented in the form of a quantitative value and directly corresponds to the reliability of the proportion data.

[0095] Step 35: Monitor the confidence level tag obtained in step 34. When the confidence level is lower than a predetermined threshold, adjust the peak power or pulse repetition frequency of the chirped pulse excitation light in subsequent step 31 according to the confidence level tag, or trigger step 21 to perform in-situ assembly of the resonant energy transfer probe again within the nanoscale luminescent probe. The specific operation is as follows:

[0096] A predetermined confidence threshold is set in advance based on the required detection accuracy. This threshold, determined in conjunction with the detection scenario and nuclide type, serves as a critical standard for judging the reliability of the proportion data. During the detection process, the confidence label obtained in step 34 is continuously monitored, and its relationship with the predetermined threshold is compared in real time. When the confidence label is higher than the predetermined threshold, it indicates that the proportion data obtained in step 33 is reliable, and subsequent detection steps can continue. When the confidence label is lower than the predetermined threshold, it indicates that the current proportion data has a large error, and adjustment measures need to be taken promptly to eliminate the source of error. The sources of error are mainly divided into two categories: one is that unreasonable excitation light parameters lead to inaccurate signal acquisition, and the other is that the resonant energy transfer probe fails or is assembled inaccurately, leading to abnormal signal conversion. For the first type of error, based on the confidence label... In the subsequent step 31, the peak power or pulse repetition frequency of the chirped pulse excitation light is adjusted. If the low confidence level is due to insufficient signal strength, the peak power of the chirped pulse excitation light is appropriately increased to enhance the excitation signal strength and improve photon collection efficiency. If the low confidence level is due to a mismatch between the pulse repetition frequency and the photon decay rate, the pulse repetition frequency is adjusted to synchronize the excitation pulse with the photon emission rhythm and reduce signal superposition interference. For the second type of error, that is, when the confidence level still cannot reach the predetermined threshold after adjusting the excitation light parameters, it indicates that the resonant energy transfer probe may have problems such as failure or inaccurate assembly. At this time, step 21 is triggered to re-execute the in-situ assembly of the resonant energy transfer probe in the nanoscale luminescent probe and reconstruct a probe system that can accurately respond to the chemical state of the nuclide.

[0097] In a preferred embodiment of the present invention, step 4 is further included: introducing an inert reference object fixed to the substrate of the test object, monitoring the signal of the inert reference object in real time to establish an environmental perturbation function, and using the environmental perturbation function to correct the initial signal intensity. The specific operation is as follows:

[0098] During online detection of radioactive isotopes, the environment surrounding the analyte matrix undergoes dynamic changes. These environmental changes lead to distortion of the detection light field and signal attenuation, resulting in initial signal intensity distortion and affecting the accuracy of nuclide chemical state determination. By introducing an inert reference material fixed to the analyte matrix, which does not interact with the analyte, nuclide, or resonance energy transfer probe, but only specifically responds to environmental changes, its signal changes can accurately reflect the degree and pattern of environmental disturbances. The environmental disturbance function is established using a combination of experimental calibration and data fitting. The specific process is as follows:

[0099] First, before detection begins, all possible environmental changes in the matrix of the analyte are simulated. Individual environmental parameters, such as pH, ionic strength, and temperature, are changed one by one, and the signal intensity changes of the inert reference under each environmental parameter gradient are recorded. Simultaneously, the distortion level of the nuclide emission signal under the corresponding environmental parameter is also recorded. Then, using the change in environmental parameters as the independent variable and the degree of nuclide emission signal distortion as the dependent variable, multiple sets of data obtained from calibration are imported into the data fitting module. Linear or nonlinear fitting is performed using the least squares method. Outlier data points are removed during the fitting process to ensure that the fitting error is controlled within a preset range, with a goodness of fit R² not less than 0.98. Finally, an environmental disturbance function is obtained that can quantify the impact of environmental disturbances on the detection signal. This function can accurately describe the degree of signal distortion corresponding to changes in different environmental parameters. The initial signal intensity obtained in step 3 is corrected using this environmental disturbance function to remove signal distortion caused by environmental disturbances, restore the true intensity of the nuclide emission signal, and solve the technical defects of signal attenuation and interference leading to distorted detection results in complex matrix environments.

[0100] Step 4 also includes the following steps:

[0101] Step 41: Within the analyte matrix region where the nanoscale luminescent probe, confirmed in step 13, is located, an array of inert reference materials with orthogonal responses to a single environmental parameter is implanted. The emission spectra of each reference material in the array do not overlap with each other and do not overlap with the emission spectrum of the probe in step 2, thus obtaining an optical signal source capable of reporting different single environmental parameters. The specific operation is as follows:

[0102] First, the implantation area is determined to be the analyte matrix region where the nanoscale luminescent probe identified in step 13 is located. This region is consistent with the nuclide detection region, ensuring that the environment monitored by the reference material is completely synchronized with the environment of the nuclide detection, avoiding monitoring errors caused by environmental differences. A set of inert reference materials is implanted to form a reference material array. Each reference material in the array is specifically designed to respond to only a single environmental parameter, and the responses of different reference materials to different environmental parameters are orthogonal. That is, the signal change of each reference material is caused by the change of only one environmental parameter and is not affected by other environmental parameters. This orthogonal response characteristic enables independent and accurate monitoring of multiple environmental parameters. The selection of the reference material array must meet the requirement that the emission spectra do not overlap. At the same time, the emission spectra of each reference material must not overlap with the emission spectrum of the resonant energy transfer probe in step 2. This avoids spectral interference between the reference material signal and the nuclide emission signal and probe signal, ensuring that the various types of signals can be accurately distinguished during subsequent signal acquisition, and that there is no signal superposition or confusion. By implanting this inert reference material array, an optical signal source that can report different single environmental parameters can be obtained.

[0103] Step 42: Using the excitation light pre-distorted by the wavefront in Step 1, the reference array implanted in Step 41 is sequentially excited in a time-division multiplexing manner. The signals of each reference are acquired sequentially according to the time window synchronized with the excitation, and a multi-dimensional environmental parameter vector synchronized with the detection process is obtained. The specific operation is as follows:

[0104] The excitation light pre-distorted in step 1 has undergone wavefront correction, possessing stable optical field characteristics and precise focusing capabilities. It can be directly used as the light source for exciting the reference array in this step, ensuring that the excitation light can accurately act on each inert reference and that the excitation conditions are consistent with those for nuclide detection. This avoids signal errors caused by differences in excitation light. A time-division multiplexing method is used to sequentially excite each reference in the reference array. The time-division multiplexing method divides the action time of the excitation light into multiple independent time windows by setting a fixed time sequence. Each time window corresponds to one reference in the array, and only the corresponding reference is excited within each time window, while other references remain unexcited. This excitation method can effectively avoid signal superposition caused by the simultaneous excitation of multiple references, ensuring that the signal of each reference can be acquired individually and accurately. During the excitation process, signals from each reference object are sequentially acquired according to the time window synchronized with the excitation. That is, when each reference object is excited, the signal acquisition device is activated to acquire the optical signal emitted by it. The acquired signal intensity has a linear or preset correspondence with the change of the corresponding environmental parameter. The signal acquired by each reference object is converted into the corresponding environmental parameter quantization value. The environmental parameter quantization values ​​corresponding to all reference objects are combined to form a multi-dimensional environmental parameter vector. This vector is generated synchronously with the nuclide detection process and can reflect the dynamic changes of environmental parameters in real time during the detection process.

[0105] Step 43: Input the multidimensional environmental parameter vector obtained in step 42 into the pre-stored environment-light field transfer function, and calculate in real time the compensating light field distortion required to maintain the nanoscale luminescent probe in step 1. Adjust the wavefronts of the excitation light and loss light in step 11 and the frequency shift of the loss light in step 12 according to the compensating light field distortion. The specific operation is as follows:

[0106] Based on real-time changes in environmental parameters, compensatory optical field distortion is calculated and optical field parameters are adjusted to maintain the stability and detection accuracy of the nanoscale luminescent probe. The construction of the environment-optical field transfer function requires prior system calibration. The specific construction process is as follows: First, determine the required range of environmental parameters and optical field parameter indices for constructing the function. The environmental parameter range covers all possible variations in the matrix of the analyte, and the optical field parameter indices include the wavefront distortion values ​​of the excitation and loss light, and the frequency shift of the loss light. Subsequently, in the calibration experiment, different multidimensional environmental parameter vectors are set one by one; each vector contains all monitored environmental parameter values. In the environment corresponding to each parameter vector, a wavefront sensor is used to detect the actual wavefront distortion of the excitation and loss light after passing through the matrix of the test object, and a frequency shift detector is used to detect the actual frequency shift change of the loss light. The correlation data between each set of environmental parameter vectors and corresponding optical field parameters, such as wavefront distortion and frequency shift, are recorded. Then, using the multidimensional environmental parameter vector as input variables and the optical field parameters as output variables, a multivariate nonlinear regression method is used to fit the data and construct the environment-optical field transfer function. Considering the nonlinear influence of environmental parameters on optical field parameters and the interaction between various environmental parameters, the specific expression obtained by fitting the calibration data is as follows:

[0107] ;

[0108] The derivation of this formula is based on the influence mechanism of environmental parameters on light field propagation. Changes in environmental parameters, such as pH value, ionic strength, and temperature, will alter the propagation path and phase of the light field. Different environmental parameters have different and interactive effects on various light field parameters, such as excitation wavefront distortion, loss wavefront distortion, and loss frequency shift. By performing multivariate nonlinear regression fitting on a large amount of calibration data, the coefficients of each environmental parameter and the coefficients of the interaction terms are determined, and the quantitative correlation between environmental parameters and light field parameters is abstracted, enabling the function of outputting the corresponding light field parameters by inputting the environmental parameter vector; in the formula, Represents a multidimensional environment parameter vector, where This is a quantified value for pH. This is a quantified value of ionic strength. The temperature is quantified, and the vector dimension and parameter meaning can be adjusted according to the actual type of environmental parameter being monitored. This represents the output light field parameter vector, where To excite the wavefront distortion value, This represents the loss wavefront distortion value. This is the amount of optical frequency shift due to loss; to , to , to , to , and , to All of these are constant coefficients obtained by fitting the calibration data in the early stage. Their specific values ​​are determined by the calibration experimental data. During the fitting process, the goodness of fit R² is ensured to be no less than 0.98 to guarantee the fitting accuracy of the function.

[0109] The specific function expression is pre-stored in the detection system. During the detection process, the real-time multidimensional environmental parameter vector obtained in step 42 is input into the pre-stored function. The optical field distortion parameters caused by the environment are calculated in real time through function operation, thereby obtaining the compensatory optical field distortion required to maintain the nanoscale luminescent probe constructed in step 1. The amplitude of the compensatory optical field distortion is equal to the amplitude of the optical field distortion caused by the environment and opposite in direction, which can accurately cancel the interference of environmental changes on the optical field. According to the calculated compensatory optical field distortion, the wavefronts of the excitation light and the loss light in step 11 are adjusted in real time. The compensatory wavefront distortion signal is loaded through the wavefront modulator to correct the wavefront deviation caused by the environment. At the same time, the frequency shift parameter of the loss light in step 12 is adjusted so that the frequency shift of the loss light matches the compensatory optical field distortion, ensuring that the dynamically modulated loss light field can continuously and stably compress the detection area, maintaining the spatial resolution and optical field stability of the nanoscale luminescent probe. Through this real-time compensation adjustment, the interference of environmental changes on the optical field can be effectively canceled, ensuring that the nanoscale luminescent probe is always in a stable working state.

[0110] Regarding the range of values ​​for each constant coefficient under normal circumstances, the details are as follows:

[0111] Firstly, a conventional environment, such as a common solid or liquid matrix for the analyte, with a pH of 4.0 to 9.0, an ionic strength of 0.1 to 1.0 mol / L, a temperature of 20 to 30°C, no significant turbulence, and a humidity of 50% to 70%. This environment is the most commonly used detection scenario, and the values ​​of the coefficients are as follows: Among the linear term coefficients, , The corresponding pH value effect ranges from 0.01 to 0.08 rad / pH, with the upper limit of 0.05 to 0.08 rad / pH for acidic environments (pH 4.0 to 6.0), the lower limit of 0.01 to 0.04 rad / pH for alkaline environments (pH 7.0 to 9.0), and the lower limit of 0.03 to 0.05 rad / pH for neutral environments (pH 6.0 to 7.0). , The value ranges from 0.05 to 0.2 rad / (mol / L) depending on the ionic strength, with the higher the ionic strength, the closer the value is to the upper limit. , The corresponding temperature effect ranges from 0.002 to 0.01 rad / ℃. The further the temperature deviates from the 25℃ reference temperature, the closer the value is to the upper limit, and temperature compensation requirements must be met. This is the coefficient of the quadratic term of pH, which affects the frequency shift of the loss light, and its value ranges from 0.0005 to 0.002 rad / pH². This is the coefficient of the linear term of ion intensity, which affects the frequency shift of loss light, and its value ranges from 0.02 to 0.08 rad / (mol / L). The coefficient for the linear temperature term affects the frequency shift of the lossy optical signal, and its value ranges from 0.001 to 0.005 rad / ℃; among the coefficients for the nonlinear and interaction terms, , , , , Because the impact is relatively weak, the value range is uniformly set between 0.001 and 0.01. The unit is rad / (mol / L)². The units are rad / (pH·mol / L·℃). The units of the coefficients of the remaining interaction terms are consistent with the units of the products of the coefficients of the corresponding linear terms, and the coefficients of the interaction terms tend to be higher in acidic and high ionic strength environments; in the constant term, , The baseline value of wavefront distortion under no environmental disturbance ranges from 0.005 to 0.03 rad, with the value for solid matrix being closer to the lower limit (0.005 to 0.015 rad) and the value for liquid matrix being closer to the upper limit (0.015 to 0.03 rad). This is the baseline value for optical frequency shift loss under no environmental disturbance, and its range is [value missing]. The baseline value must be consistent with the initial parameters of the light field calibrated in step 1, and must match the baseline calibration value after temperature compensation.

[0112] Second, a high ionic strength environment, i.e., ionic strength > 1.0 mol / L, is commonly found in high-concentration electrolyte matrices. The coefficients are adjusted as follows: , The value range is increased to 0.2 to 0.3 rad / (mol / L). The value range is increased to 0.08 to 0.15 rad / (mol / L); interaction term coefficient , The value related to ion strength is increased to 0.008 to 0.015; the other coefficients remain unchanged in the normal environmental range. When fitting, calibration data in the high ion strength range needs to be added to ensure that the goodness of fit is not less than 0.98.

[0113] Thirdly, in highly turbulent environments, commonly found in flowing matrices and outdoor detection scenarios, where environmental disturbances are severe, the coefficients are adjusted as follows: Temperature correlation coefficient , The value range has been increased to 0.01 to 0.02 rad / ℃. The value range is increased to 0.005 to 0.01 rad / ℃; interaction term coefficient , Temperature-dependent, with values ​​increasing to 0.008 to 0.015; constant term , The value range was adjusted to 0.01 to 0.04 rad to match the baseline shift caused by turbulence; the remaining coefficients remained within the normal environmental range. During the calibration process, turbulent disturbances needed to be simulated to ensure that the function could adapt to dynamic environmental changes.

[0114] Fourth, high humidity environments, i.e., humidity > 70%, are commonly found in damp substrates and enclosed high-humidity detection scenarios. The coefficients are adjusted as follows. , The value range is fine-tuned to 0.02 to 0.09 rad / pH. The higher the humidity, the closer the value is to the upper limit. Since high humidity will affect the accuracy of pH detection, the pH calibration frequency needs to be increased and recalibrated every 4 to 8 hours. , The value range is adjusted to 0.01 to 0.035 rad. The range of values ​​was fine-tuned to The remaining coefficients should remain within the normal environmental range. During the calibration process, the humidity gradient should be controlled and the effect of humidity on the light field baseline should be recorded.

[0115] Step 44: While assembling the resonant energy transfer probe in step 21, a dumb probe with the same structure as the resonant energy transfer probe but unable to bind nuclides is introduced into the same nanoscale luminescent probe. The multicolor signal of the dumb probe is monitored in real time. The multicolor signal of the dumb probe is then subjected to nonlinear difference operation with the chemical state ratio data obtained in step 35 to remove the nonlinear signal distortion caused by the environment and obtain the corrected chemical state signal. The specific operation is as follows:

[0116] Simultaneously with the assembly of the resonant energy transfer probe in step 21, a dumb probe is introduced into the same nanoscale luminescent probe. The dumb probe has a completely identical structure to the resonant energy transfer probe, possessing the same optical properties and spatial distribution characteristics. However, due to structural modification, binding sites capable of binding nuclides have been removed, thus preventing binding interactions with nuclides. Because the dumb probe and the resonant energy transfer probe have highly identical structures, their susceptibility to environmental changes is exactly the same as that of the resonant energy transfer probe. That is, the multicolor signal changes of the dumb probe are only caused by environmental disturbances and do not contain any information related to the chemical state of the nuclide. It can serve as a reference for environmental disturbance signals. During nuclide detection... The multicolor signal of the dumb probe is monitored in real time, and the changes in its characteristic parameters such as signal intensity and fluorescence lifetime are recorded. These changes are nonlinear signal distortions caused by environmental disturbances. The monitored multicolor signal of the dumb probe is compared with the chemical state proportion data obtained in step 35 by performing a nonlinear difference operation. During the operation, the nonlinear signal distortion component caused by environmental disturbances in the chemical state proportion data is removed based on the signal change of the dumb probe, and the signal component determined only by the chemical state of the nuclide is retained. Through this nonlinear difference operation, the influence of environmental disturbances on the nuclide signal can be effectively eliminated, and the corrected chemical state signal can be obtained. This signal can truly reflect the characteristics of the nuclide chemical state.

[0117] Step 45: Perform correlation analysis on the historical multidimensional environmental parameter vector accumulated in Step 42 and the corrected chemical state signal output in Step 44 to identify the correlation between environmental change patterns and precursors of signal distortion. When a precursor correlation is detected again, trigger the compensation operation in Steps 43 and 44 in advance. The specific operation is as follows:

[0118] During the detection process, the historical multidimensional environmental parameter vector obtained in step 42 and the corrected chemical state signal output in step 44 are continuously accumulated to form a large number of historical data samples. These samples contain the correlation information between different environmental change patterns and corresponding signal distortions. The correlation analysis adopts a hierarchical analysis strategy. First, the historical data samples are preprocessed by removing signal noise through low-pass filtering. Then, the environmental parameter vector and the corrected chemical state signal are normalized to ensure that all data are on the same order of magnitude, avoiding analysis errors caused by differences in parameter magnitudes. For linear correlations, the Pearson correlation coefficient method is used for quantitative analysis to calculate the correlation coefficient between each environmental parameter in the multidimensional environmental parameter vector and the distortion value of the corrected chemical state signal. The closer the absolute value of the correlation coefficient is to 1, the stronger the linear correlation between the two. For nonlinear correlations, the mutual information method is used for quantitative analysis to calculate the mutual information value between environmental parameter changes and signal distortion. The larger the mutual information value, the stronger the nonlinear correlation between the two.

[0119] During the analysis, correlation thresholds were pre-set: a linear correlation coefficient threshold of 0.8 and a mutual information value threshold of 0.7. Environmental parameters with correlations exceeding these thresholds were selected to correlate with signal distortion. Time series analysis was then used to extract patterns where environmental parameter changes precede signal distortion, identifying precursory correlations between environmental change patterns and signal distortion. Specifically, when a specific environmental parameter change pattern occurs, such as a parameter continuously rising within a preset time period at a rate exceeding a preset value, a corresponding signal distortion will inevitably follow. This correlation pattern is termed a precursory correlation. The identified precursory correlations were then analyzed using feature parameter groups. The combined form is pre-stored in the detection system. During subsequent real-time detection, the changes in multi-dimensional environmental parameter vectors are continuously monitored. By comparing through a sliding window, it is determined in real time whether the current environmental change pattern is consistent with the pre-stored precursors. When a consistent environmental change pattern is detected, the compensation operation in steps 43 and 44 is triggered in advance without waiting for the actual occurrence of signal distortion. The compensation operation in advance can promptly offset the interference of environmental changes on the light field and signal, avoid detection errors caused by the accumulation of signal distortion, ensure that the corrected chemical state signal always maintains high accuracy, and further improve the stability and reliability of the entire detection method.

[0120] In a preferred embodiment of the present invention, step 5 is further included: calculating the ratio of the corrected initial signal intensity and comparing the ratio with a preset threshold range to determine the chemical state of the nuclide at the current nanoscale luminescent probe position. The specific operation is as follows:

[0121] After signal correction in step 4, signal distortion caused by environmental disturbances has been eliminated, and a corrected initial signal intensity that truly reflects the characteristics of the nuclide's chemical state has been obtained. This signal intensity has a clear correspondence with the nuclide's chemical state. The corrected initial signal intensity varies for nuclides with different chemical states. By calculating the ratio between different corrected initial signal intensities, this difference can be further amplified, improving the discriminative power of chemical state determination and avoiding misjudgments caused by small fluctuations in a single signal intensity. The preset threshold range is determined based on previous calibration experiments. For each preset nuclide chemical state, there is a unique signal ratio threshold range. This range is obtained through statistical analysis of a large amount of calibration data and can cover the normal fluctuation range of the nuclide signal ratio for that chemical state. The calculated signal ratio is compared with the preset threshold range one by one. When the signal ratio falls into a certain preset threshold range, the nuclide at the current nanoscale luminescent probe position can be determined to be the chemical state corresponding to that threshold range, thus completing the nuclide chemical state determination at a single detection position.

[0122] Step 5 also includes the following steps:

[0123] Step 51: Input the chemical state percentage data output from Step 33, the confidence labels output from Step 34, the multidimensional environmental parameter vector output from Step 42, and the corrected chemical state signal output from Step 44 into a hardware lock-in amplifier network in parallel. Use the modulation frequency of the chirped pulse in Step 31 and the modulation frequency of the time-division multiplexing in Step 42 as reference signals to perform hardware coherent demodulation to obtain a set of analog characteristic voltages. The specific operation is as follows:

[0124] The chemical state percentage data output in step 33, the confidence labels output in step 34, the multidimensional environmental parameter vector output in step 42, and the corrected chemical state signal output in step 44 all carry information related to the nuclide's chemical state. These four sets of data are interconnected and complementary. Parallel inputting them into a hardware lock-in amplifier network enables synchronous processing of multidimensional information, improving the accuracy of signal feature extraction. The hardware lock-in amplifier network consists of multiple lock-in amplifiers and employs a parallel processing architecture, capable of simultaneously demodulating the four sets of input data, avoiding signal distortion caused by data processing delays. During demodulation, the chirped pulse from step 31 is selected. The modulation frequency and the time-division multiplexing modulation frequency in step 42 are used as reference signals. These two modulation frequencies are the characteristic frequencies of the excitation light and the reference array, respectively. They have a clear synchronous relationship with the nuclide signal and the reference signal. Using them as reference signals can accurately lock the effective signal related to the chemical state of the nuclide and filter out irrelevant noise signals. Through hardware coherent demodulation operation, the signal components that are synchronized with the reference signal in the four sets of input data are extracted and converted into a set of standardized analog characteristic voltages. The amplitude and phase of the analog characteristic voltages have a strict correspondence with the chemical state of the nuclide. Different chemical states of nuclides correspond to different combinations of analog characteristic voltages.

[0125] Step 52: Input the set of simulated characteristic voltages obtained in step 51 into a chemical state space mapping network composed of an array of simulated comparators in parallel. Each comparator in the array corresponds to a preset chemical state and has a set of simulated comparator thresholds corresponding to that chemical state pre-stored. By combining the logic levels output in parallel by all comparators, the chemical state determination result of the nuclide at the current nanoscale luminescent probe position is obtained. The specific operation is as follows:

[0126] The analog comparator array consists of multiple analog comparators, each pre-defined to correspond to a specific nuclide chemical state. Each comparator also internally stores a set of analog comparator thresholds for that chemical state. These thresholds, obtained from previous calibration experiments, include the upper and lower limits of the analog characteristic voltage corresponding to that chemical state, accurately covering the normal fluctuation range of the analog characteristic voltage for that chemical state. Furthermore, the threshold sets for different chemical states do not overlap, avoiding ambiguity in judgment. The set of analog characteristic voltages obtained in step 51 is input in parallel into the chemical state spatial mapping network. Each analog comparator simultaneously receives its corresponding analog characteristic voltage and... The voltage is compared with its own pre-stored threshold group. When the input analog characteristic voltage falls within the threshold group range of the analog comparator, the analog comparator outputs a high level; when the input analog characteristic voltage exceeds the threshold group range, the analog comparator outputs a low level. Since each analog comparator corresponds to a chemical state, the combination of logic levels output by all analog comparators in parallel is unique. Each logic level combination corresponds to only one nuclide chemical state. By identifying this logic level combination, the chemical state determination result of the nuclide at the current nanoscale luminescent probe position can be directly obtained. This determination process is fast and accurate, and can meet the real-time requirements of online detection.

[0127] Step 53: Continuously acquire the chemical state determination results output in Step 52 and the corresponding simulated characteristic voltages output in Step 51. For multiple simulated characteristic voltages corresponding to the same chemical state determination result, calculate the mean and broadening of their characteristic voltage clusters. When the deviation of the mean relative to the initial calibration point exceeds a preset threshold, generate a threshold fine-tuning signal based on the mean. The threshold fine-tuning signal is used to update the analog comparator threshold group corresponding to the simulated comparator in Step 52. The specific operation is as follows:

[0128] During the detection process, the chemical state determination result output in step 52 and the corresponding simulated characteristic voltage output in step 51 are continuously collected, forming a continuous detection data sequence. For multiple simulated characteristic voltages corresponding to the same chemical state determination result, the mean and broadening of the characteristic voltage cluster need to be calculated. The mean reflects the baseline level of the simulated characteristic voltage for that chemical state, and the broadening reflects the dispersion of the voltage data set. The mean of the characteristic voltage cluster is calculated using the arithmetic mean method, and the formula is as follows:

[0129] ;

[0130] The derivation of this formula is based on the statistical regularity of multiple measurement data. By summing and averaging n simulated characteristic voltages corresponding to the same chemical state, fluctuations caused by random noise can be offset, thus obtaining the true reference value of the simulated characteristic voltage for that chemical state. In the formula, The mean of the characteristic voltage cluster is represented by n; n represents the number of simulated characteristic voltage acquisitions corresponding to the same chemical state determination result. This represents the simulated characteristic voltage value acquired in the i-th acquisition. The broadening of the characteristic voltage cluster is obtained by calculating the standard deviation of the voltage data set, which is used to measure the dispersion of the voltage data and ensure the reliability of the mean. A preset threshold for mean deviation is set in advance during the detection process. This threshold is determined based on the detection accuracy requirements and is used to determine whether the mean has a significant drift. When the deviation of the calculated characteristic voltage cluster mean relative to the initial calibration point exceeds the preset threshold, it indicates that due to factors such as slow environmental changes and slight probe wear during long-term detection, the simulated characteristic voltage has experienced a systematic drift. If the threshold group is not adjusted, it will lead to errors in subsequent chemical state determination. At this time, a threshold fine-tuning signal is generated based on the calculated mean. The amplitude of the fine-tuning signal is proportional to the mean deviation and is used to dynamically update the threshold group of the analog comparator corresponding to the chemical state in step 52. The upper and lower limits of the threshold group are synchronously adjusted to the range that matches the current mean, ensuring that the comparison of subsequent simulated characteristic voltages can still accurately correspond to the nuclide chemical state and maintain the accuracy and stability of the chemical state determination results.

[0131] In a preferred embodiment of the present invention, step 6 is further included: moving the nanoscale luminescent probe to perform spatial scanning on the surface of the analyte, and repeating steps 2 to 5 at each scanning position to reconstruct the chemical state distribution map of the analyte surface. The specific operation is as follows:

[0132] After step 5, the chemical state of a single nanoscale luminescent probe can be accurately determined. However, the detection result at a single location cannot reflect the overall distribution of the chemical state of the nuclide on the surface of the analyte, and cannot meet the comprehensive requirements of non-destructive testing of radioactive isotope purity. By moving the nanoscale luminescent probe, it is made to perform a systematic spatial scan on the surface of the analyte. During the scan, all operations from step 2 to step 5 are repeated at each scan location to ensure that an accurate determination result of the chemical state of the nuclide can be obtained at each location. At the same time, the spatial coordinate information corresponding to each scan location is recorded. The chemical state determination results of all scan locations are correlated with the corresponding coordinate information to form a complete set of detection data. Based on this set of data, the discrete detection point data is transformed into a continuous distribution map of the chemical state on the surface of the analyte through spatial interpolation and spectral reconstruction algorithms. This distribution map can intuitively present the distribution of the chemical state of the nuclide in different regions of the surface of the analyte, and clearly distinguish the regions where the complete targeted drug, the detached free nuclide, and the drug fragments are located.

[0133] Step 6 also includes the following steps:

[0134] Step 61: During the spatial scanning process, the intensity of the effective detection signal defined by the third harmonic component in step 13 is monitored in real time. Based on the change in the intensity of the effective detection signal, a displacement compensation signal perpendicular to the surface of the object under test is generated in real time. The relative axial position of the nanoscale luminescent probe and the surface of the object under test is adjusted according to the displacement compensation signal. The specific operation is as follows:

[0135] During spatial scanning, the surface of the analyte may have microscopic unevenness, and the probe may experience slight axial displacement during movement. These factors cause changes in the relative axial distance between the probe and the analyte surface, thus affecting the intensity of the effective detection signal. If the distance is too far, the signal intensity will attenuate; if the distance is too close, the signal will saturate and distort, both affecting the accuracy of chemical state determination. Therefore, during scanning, it is necessary to monitor the intensity of the effective detection signal defined by the third harmonic component in step 13 in real time. This effective detection signal directly reflects the rationality of the relative position between the probe and the analyte surface, and its intensity change has a clear correlation with the axial distance. Excessively high or low intensity indicates that the axial distance deviates from the optimal detection range. Based on the real-time monitored changes in the intensity of the effective detection signal, the system generates a vertical [detection signal] in real time. The displacement compensation signal on the surface of the analyte is proportional to the degree to which the intensity of the effective detection signal deviates from the preset reference value. The compensation direction is determined according to the intensity change trend. If the signal intensity is lower than the preset reference value, it indicates that the probe is too far from the surface of the analyte, and the displacement compensation signal controls the probe to move closer to the surface of the analyte. If the signal intensity is higher than the preset reference value, it indicates that the probe is too close to the surface of the analyte, and the displacement compensation signal controls the probe to move away from the surface of the analyte. Based on this displacement compensation signal, the relative axial position of the nanoscale luminescent probe and the surface of the analyte is adjusted in real time by the probe driving mechanism to ensure that the probe is always at the optimal detection distance throughout the scanning process, and the intensity of the effective detection signal is maintained within the preset stable range, providing a stable signal basis for the chemical state determination at each scanning position.

[0136] Step 62: After completing the dynamic adjustment of the axial position in Step 61, obtain the chemical state determination result output in Step 52 at the current scanning position. Based on the chemical state determination result and the chemical state determination results of its neighboring positions, adjust the scanning step size and scanning direction in real time to generate a non-uniform adaptive scanning path. After executing Steps 2 to 5 at each scanning position, reconstruct the chemical state distribution map of the surface of the analyte based on the chemical state determination results and coordinates collected at all scanning positions. The specific operations are as follows:

[0137] After completing the dynamic adjustment of the axial position in step 61, the probe is in the optimal detection state at the current scanning position. At this time, the system acquires the nuclide chemical state determination result output in step 52 at this scanning position, and simultaneously calls the chemical state determination results corresponding to the positions that have been scanned in the neighborhood of this position. The range of the neighborhood position is preset according to the detection accuracy requirements, usually a 3×3 scanning area around the current scanning position, to ensure that the chemical state distribution trend around the current position can be fully reflected. Based on the chemical state determination result of the current scanning position and the chemical state determination result of the neighborhood position, the change gradient of the chemical state is analyzed in real time. If the chemical state of the current position is consistent with or changes gently with the neighborhood position, it indicates that the nuclide chemical state distribution in this area is uniform, and dense scanning is not required. The scanning step size of the next step can be appropriately increased to improve scanning efficiency. If there is a significant difference or drastic change in the chemical state between the current position and the neighborhood position, it indicates that the nuclide chemical state distribution in this area is complex and there may be abrupt changes in the nuclide chemical state. The scanning step size of the next step needs to be reduced and the scanning density increased to ensure that the details of the chemical state change can be accurately captured and to avoid missing key detection information.

[0138] Simultaneously, the scanning direction is adjusted in real time according to the chemical state change trend, prioritizing the extension of the scan to areas with drastic chemical state changes, forming a non-uniform adaptive scanning path. This path maximizes scanning efficiency while ensuring detection accuracy, balancing comprehensiveness and high efficiency. Steps 2 to 5 are strictly executed at each scanning position to ensure accurate and reliable chemical state determination results at each position. The two-dimensional spatial coordinates (x, y) and corresponding chemical state determination results for each scanning position are recorded. The coordinates of all scanning positions and the chemical state determination results form a complete discrete detection dataset. After scanning, a spatial interpolation algorithm is used to complete the discrete data, smoothing the chemical state distribution between adjacent detection points. Corresponding feature labels are set according to different chemical states, and the chemical state determination result of each coordinate point is converted into a corresponding visual label. Finally, a complete and continuous chemical state distribution map of the analyte surface is reconstructed. This distribution map clearly and intuitively presents the distribution of nuclide chemical states in different regions of the analyte surface, providing an intuitive technical basis for the comprehensive and accurate assessment of radioactive isotope purity.

[0139] Example 2

[0140] Please see Figure 2 Based on Example 1, this embodiment provides a non-destructive testing system for the purity of radioactive isotopes based on online detection, including:

[0141] The probe construction module is used to construct an excitation source consisting of a central excitation light and an outer loss light, and to obtain a compressed detection region as a nanoscale luminescent probe.

[0142] The probe response module is used to introduce a resonant energy transfer probe into a nanoscale luminescent probe. The resonant energy transfer probe has a specific response to the chemical state of the nuclide, converting the difference in the chemical state of the nuclide into the difference in the energy transfer efficiency of the resonant energy transfer probe.

[0143] The signal acquisition module is used to emit excitation light in the form of picosecond pulses and acquire the nuclide emission signals at different time windows after excitation to obtain the initial signal intensity corresponding to different chemical states;

[0144] The signal correction module is used to introduce an inert reference fixed to the matrix of the test object, monitor the signal of the inert reference in real time to establish an environmental disturbance function, and use the environmental disturbance function to correct the initial signal intensity.

[0145] The chemical state determination module is used to calculate the ratio of the corrected initial signal intensity and compare the ratio with a preset threshold range to determine the chemical state of the nuclide at the current nanoscale luminescent probe position.

[0146] The distribution reconstruction module is used to move the nanoscale luminescent probe to perform spatial scanning on the surface of the analyte, and repeatedly execute the probe response module, signal acquisition module, signal correction module and chemical state determination module at each scanning position to reconstruct the chemical state distribution map of the analyte surface.

[0147] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A non-destructive testing method for the purity of radioactive isotopes based on online detection, characterized in that, include: Step 1 involves constructing an excitation source consisting of a central excitation light and peripheral loss light to obtain a compressed detection region as a nanoscale luminescent probe. This step also includes: Step 11: Emit a probe light pulse to the target area, receive the distorted echo signal reflected by the object under test, analyze the wavefront distortion function based on the distorted echo signal, and pre-distort the wavefronts of the excitation light and the loss light according to the analyzed wavefront distortion function to obtain the wavefront-predistorted excitation light and loss light. Step 12: Apply a frequency shift to the obtained wavefront pre-distorted loss light, so that the frequency-shifted loss light interferes with the unshifted loss light in the focal region of step 11, forming a dynamically modulated loss light field. Step 13: Under the action of the dynamically modulated lossy optical field, an intensity modulation of known amplitude is superimposed on the excitation light, the third harmonic component corresponding to the intensity modulation frequency in the nuclide emission signal is detected, and the existence of the third harmonic component is used as the basis for defining the effective detection signal. Step 2 involves introducing a resonant energy transfer probe within a nanoscale luminescent probe. This resonant energy transfer probe exhibits a specific response to the chemical state of the nuclide, converting differences in the chemical state of the nuclide into differences in the energy transfer efficiency of the resonant energy transfer probe. This also includes: Step 21: Distribute two probe precursors, including a trapping group precursor and a quantum dot precursor, in the test area. Use the loss light corresponding to the effective detection signal defined by the third harmonic component in step 13 to irradiate and photolyze the trapping group precursor, so that the photolyzed trapping group precursor and the quantum dot precursor undergo a click chemical reaction, and a resonant energy transfer probe is formed in situ assembled in the nanoscale luminescent probe. Step 22: The trapping group in the resonant energy transfer probe assembled in step 21 is bound to the nuclide. The energy transfer efficiency of the energy relay station is changed by the trapped group after binding, so that the energy transfer ratio of the energy relay station to the quantum dot array changes with the chemical state of the nuclide, and a multicolor signal with characteristic ratio determined by nuclides in different chemical states is obtained. Step 23: Using the excitation light that has undergone wavefront pre-distortion in Step 1, the fluorescence lifetime of each color channel in the multicolor signal is measured through a two-photon absorption excitation energy relay station to obtain the nuclide chemical state information characterized by both color and lifetime. Step 3: Excitation light is emitted in the form of picosecond pulses, and the emission signals of the nuclide are collected at different time windows after excitation to obtain the initial signal intensity corresponding to different chemical states; Step 4: Introduce an inert reference object fixed to the matrix of the test object, monitor the signal of the inert reference object in real time to establish an environmental disturbance function, and use the environmental disturbance function to correct the initial signal intensity. Step 5: Calculate the ratio of the corrected initial signal intensity and compare the ratio with the preset threshold range to determine the chemical state of the nuclide at the current nanoscale luminescent probe position; Step 6: Move the nanoscale luminescent probe to perform spatial scanning on the surface of the analyte, and repeat steps 2 to 5 at each scanning position to reconstruct the chemical state distribution map of the analyte surface.

2. The non-destructive testing method for the purity of radioactive isotopes based on online detection according to claim 1, characterized in that, Step 3 includes: Step 31: Apply controllable chirping to the excitation light that has undergone wavefront pre-distortion in step 1 to form a chirped pulse excitation light. Use the chirped pulse excitation light to excite the multicolor fluorescence signal output in step 23 to obtain a composite time decay waveform containing spectral and lifetime information. Step 32: Inject the composite time decay waveform obtained in step 31 into the circular delay line for cyclic time broadening, and amplify the signal during the cyclic broadening process to obtain a broadened and amplified composite electrical signal. Step 33: Using the chirped encoding rules of the chirped pulse excitation light in step 31, the broadened and amplified composite electrical signal obtained in step 32 is back-mapped into attenuation curves of different wavelength channels. The attenuation curves are then cross-correlated with the characteristic attenuation templates pre-calibrated and stored in step 23 to obtain the proportion data of each chemical state in the current nanoscale luminescent probe.

3. The non-destructive testing method for the purity of radioactive isotopes based on online detection according to claim 2, characterized in that, Step 3 also includes: Step 34: Collect the output signal of the single-photon detector that has not been processed in step 32, record the absolute arrival time of each photon and calculate the time interval between adjacent photons, construct a real-time time interval histogram based on the time interval, and check the consistency between the histogram and the theoretical time interval distribution corresponding to the characteristic attenuation template. Use the check result as the confidence label of the proportion data of each chemical state obtained in step 33. Step 35: Monitor the confidence level tag obtained in step 34. When the confidence level is lower than a predetermined threshold, adjust the peak power or pulse repetition frequency of the chirped pulse excitation light in subsequent step 31 according to the confidence level tag, or trigger step 21 to perform in-situ assembly of the resonant energy transfer probe again in the nanoscale luminescent probe.

4. The non-destructive testing method for the purity of radioactive isotopes based on online detection according to claim 3, characterized in that, Step 4 includes: Step 41: In the test matrix region where the nanoscale luminescent probe is located, as confirmed in step 13, a set of inert reference arrays with orthogonal responses to a single environmental parameter are implanted. The emission spectra of each reference in the reference array do not overlap with each other and do not overlap with the emission spectrum of the probe in step 2, thereby obtaining an optical signal source that can report different single environmental parameters. Step 42: Using the excitation light that has undergone wavefront pre-distortion in Step 1, the reference array implanted in Step 41 is sequentially excited in a time-division multiplexing manner, and the signals of each reference are sequentially acquired according to the time window synchronized with the excitation to obtain a multi-dimensional environmental parameter vector synchronized with the detection process. Step 43: Input the multidimensional environmental parameter vector obtained in step 42 into the pre-stored environmental-light field transfer function, calculate in real time the compensating light field distortion required to maintain the nanoscale luminescent probe in step 1, and adjust the wavefronts of the excitation light and loss light in step 11 and the frequency shift of the loss light in step 12 according to the compensating light field distortion.

5. The non-destructive testing method for the purity of radioactive isotopes based on online detection according to claim 4, characterized in that, Step 4 also includes: Step 44: While assembling the resonant energy transfer probe in step 21, a dumb probe with the same structure as the resonant energy transfer probe but unable to bind nuclides is introduced into the same nanoscale luminescent probe. The multicolor signal of the dumb probe is monitored in real time. The multicolor signal of the dumb probe is compared with the chemical state ratio data obtained in step 35 by performing nonlinear difference operation to remove the nonlinear signal distortion caused by the environment and obtain the corrected chemical state signal. Step 45: Perform correlation analysis on the historical multidimensional environmental parameter vector accumulated in step 42 and the corrected chemical state signal output in step 44 to identify the correlation between environmental change patterns and precursors of signal distortion. When a precursor correlation is detected again, trigger steps 43 and 44 to perform compensation operations in advance.

6. The non-destructive testing method for the purity of radioactive isotopes based on online detection according to claim 5, characterized in that, Step 5 includes: Step 51: Input the chemical state percentage data output in step 33, the confidence label output in step 34, the multidimensional environmental parameter vector output in step 42, and the corrected chemical state signal output in step 44 into the hardware lock-in amplifier network in parallel. Use the modulation frequency of the chirped pulse in step 31 and the modulation frequency of time division multiplexing in step 42 as reference signals to perform hardware coherent demodulation and obtain a set of analog characteristic voltages. Step 52: Input a set of simulated characteristic voltages obtained in step 51 into a chemical state space mapping network composed of an array of simulated comparators in parallel. Each comparator in the array of simulated comparators corresponds to a preset chemical state and has a set of simulated comparator thresholds corresponding to the chemical state. By combining the logic levels output in parallel by all comparators, the chemical state determination result of the nuclide at the current nanoscale luminescent probe position is obtained. Step 53: Continuously acquire the chemical state determination result output in step 52 and the corresponding analog characteristic voltage output in step 51. For multiple analog characteristic voltages corresponding to the same chemical state determination result, calculate the mean and broadening of the characteristic voltage cluster. When the deviation of the mean relative to the initial calibration point exceeds a preset threshold, generate a threshold fine-tuning signal based on the mean. The threshold fine-tuning signal is used to update the analog comparator threshold group of the analog comparator corresponding to the chemical state in step 52.

7. The non-destructive testing method for the purity of radioactive isotopes based on online detection according to claim 6, characterized in that, Step 6 includes: Step 61: During the spatial scanning process, the intensity of the effective detection signal defined by the third harmonic component in step 13 is monitored in real time. Based on the change in the intensity of the effective detection signal, a displacement compensation signal perpendicular to the surface of the object under test is generated in real time. The relative axial position of the nanoscale luminescent probe and the surface of the object under test is adjusted according to the displacement compensation signal. Step 62: After completing the dynamic adjustment of the axial position in step 61, obtain the chemical state determination result output in step 52 at the current scanning position. Based on the chemical state determination result and the chemical state determination result of its neighboring position, adjust the scanning step size and scanning direction in real time to generate a non-uniform adaptive scanning path. After executing steps 2 to 5 at each scanning position, reconstruct the chemical state distribution map of the surface of the test object based on the chemical state determination results and coordinates collected at all scanning positions.

8. A non-destructive testing system for the purity of radioactive isotopes based on online detection, applied to any one of the non-destructive testing methods for the purity of radioactive isotopes based on online detection as described in claims 1-7, characterized in that, include: The probe construction module is used to construct an excitation source consisting of a central excitation light and an outer loss light, and to obtain a compressed detection region as a nanoscale luminescent probe. The probe response module is used to introduce a resonant energy transfer probe into a nanoscale luminescent probe. The resonant energy transfer probe has a specific response to the chemical state of the nuclide, converting the difference in the chemical state of the nuclide into the difference in the energy transfer efficiency of the resonant energy transfer probe. The signal acquisition module is used to emit excitation light in the form of picosecond pulses and acquire the nuclide emission signals at different time windows after excitation to obtain the initial signal intensity corresponding to different chemical states; The signal correction module is used to introduce an inert reference fixed to the matrix of the test object, monitor the signal of the inert reference in real time to establish an environmental disturbance function, and use the environmental disturbance function to correct the initial signal intensity. The chemical state determination module is used to calculate the ratio of the corrected initial signal intensity and compare the ratio with a preset threshold range to determine the chemical state of the nuclide at the current nanoscale luminescent probe position. The distribution reconstruction module is used to move the nanoscale luminescent probe to perform spatial scanning on the surface of the analyte, and repeatedly execute the probe response module, signal acquisition module, signal correction module and chemical state determination module at each scanning position to reconstruct the chemical state distribution map of the analyte surface.

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