A dose self-discrimination detection method and system for n-γ mixed radiation fields based on SERS technology

Abstract

This invention discloses a dose self-discrimination detection method and system for n-γ mixed radiation fields based on SERS technology, relating to the field of nuclear radiation detection technology. The method involves co-modifying a SERS substrate with neutron-sensitive molecules and gamma-ray-sensitive molecules (without crosstalk SERS characteristic fingerprints) to obtain a radiation-sensitive molecule-functionalized SERS substrate. Then, using interface self-assembly technology, this substrate is transferred to a solid substrate to obtain a SERS chip with an independent dose response to the n-γ mixed radiation field. The neutron and gamma doses are fitted using the relative intensities of SERS characteristic peaks to obtain a response function, which is then used to calibrate the SERS chip. The optical signal of the SERS chip is measured using a Raman spectrometer, and the neutron and gamma doses are retrieved by extracting SERS spectral characteristic information, achieving self-discrimination and sensitive detection of the n-γ mixed radiation field dose. This method solves the problems of mutual interference and insufficient sensitivity in traditional technologies and has significant application value in the field of nuclear radiation detection.

Description

Technical Field

[0001] This invention relates to the field of nuclear radiation detection technology, specifically to a dose self-discrimination detection method and system for n-γ mixed radiation fields based on SERS technology. Background Technology

[0002] In nuclear energy and technology applications such as nuclear facility operation, nuclear waste disposal, nuclear medicine diagnosis and treatment, nuclear emergency response, and manned spaceflight, neutrons and gamma rays often coexist, forming an n-γ mixed radiation field. Neutrons and gamma rays have different physical properties, leading to differences in their radiation biological effects. Accurately measuring the neutron and gamma ray doses in the n-γ mixed radiation field is crucial for protecting the health of workers and the public and optimizing radiation protection measures.

[0003] Currently, the conventional technique for measuring the dose in a mixed n-γ radiation field is based on the interaction characteristics between radiation and matter. Two dosimeters with significantly different responses to radiation are used in pairs (one responding to both neutrons and gamma rays, and the other only to gamma rays), such as paired thermoluminescent dosimeters or paired ionization chamber dosimeters. Then, through differential measurement, the neutron and gamma doses in the mixed radiation field can be determined separately. The main limitations of this technique are: (1) the dosimeter structure is not compact enough, limiting its applicability in confined spaces; (2) the measurement process is time-consuming, affecting overall measurement efficiency; and (3) the signal readout device is large, making portable measurement difficult.

[0004] Surface-enhanced Raman scattering (SERS) is a novel "molecular fingerprint spectroscopy" technique that enables detection and imaging at the single-molecule level, with an intrinsic enhancement factor as high as 10. 14 -10 15Due to its combination of high sensitivity and molecular fingerprint specificity, SERS technology has broad application prospects in analytical characterization and sensing detection. SERS technology has already been applied in single-type radiation detection (e.g., Journal of Raman Spectroscopy, 2018, 49(7): 1190-1197; Journal of Radiation Research and Radiation Processing, 2019, 37(4): 040701). However, compared with single neutron or gamma dose measurement, n-γ mixed radiation field dose measurement requires higher precision. It necessitates rigorous selection of radiation-sensitive molecules with intrinsically non-crosstalk molecular fingerprints and improved signal reproducibility of the SERS substrate to avoid interference from the interaction of the two types of radiation with the SERS substrate, which could lead to spectral signal superposition. Therefore, there are no reports on mixed field detection based on SERS technology. Currently, how to achieve self-discrimination and efficient detection of n-γ mixed radiation field doses while meeting the requirements of miniaturization and portability remains a pressing technical challenge in this field. Summary of the Invention

[0005] To address the aforementioned technical challenges, the present invention aims to provide a method and system for self-discriminative detection of dose in n-γ mixed radiation fields based on SERS technology. This method uses surface-enhanced Raman scattering (SERS) technology, which has high sensitivity, molecular fingerprint recognition, and rapid non-destructive measurement capabilities, as the detection technology. It uses radiation-sensitive molecules with non-overlapping SERS characteristic peaks as the detection medium. By measuring their SERS spectra before and after irradiation in the mixed radiation field and extracting and analyzing characteristic information, the method achieves simultaneous and efficient self-discriminative detection of dose in n-γ mixed radiation fields.

[0006] Specifically, the above-mentioned objective is achieved through the following technical solutions:

[0007] First, this application provides a dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology, including the following steps:

[0008] 1) Preparation of radiation-sensitive molecule functionalized SERS substrate: Neutron-sensitive molecules and gamma-ray-sensitive molecules were dispersed in a good solvent and mixed with a noble metal sol-type SERS substrate. The mixture was stirred and reacted at room temperature for 24 h. Then, it was centrifuged three times and resuspended in ultrapure water to complete the purification process and obtain the SERS substrate co-modified by neutron-sensitive molecules and gamma-ray-sensitive molecules.

[0009] 2) Preparation of SERS chips with independent dose response to n-γ mixed radiation field: The solid substrate was pretreated with Piranha solution for 1 h, then rinsed with ultrapure water, and dried at room temperature to obtain a hydrophilic solid substrate for later use.

[0010] Hexane was added to the radiation-sensitive molecular functionalized SERS substrate obtained in step 1) to form a water / hexane interface. Then, ethanol was added dropwise at a constant rate using an injection pump until a metallic luster appeared at the water / hexane interface. After the hexane evaporated and a continuous bright film floated on the water surface, a hydrophilic solid substrate was placed on top of the film to contact it, so that the radiation-sensitive molecular functionalized SERS substrate array was transferred to the solid substrate. After drying at room temperature, the SERS chip was obtained.

[0011] The aforementioned thin film is a tightly packed array formed by the self-assembly of a functionalized SERS substrate as a basic unit at the interface. Compared with liquid-phase colloidal SERS substrates, the advantages of this thin film are: a) it can be transferred to the surface of rigid or flexible solid-phase substrates to form solid-phase SERS substrates, which have higher storage stability and are more convenient to use (easy to integrate onto the surface of the object to be detected; compatible with portable Raman spectrometers, which can be directly detected); b) the signal uniformity of the SERS array is better, which is beneficial to improving detection accuracy.

[0012] 3) Calibrating the SERS chip: The SERS chip prepared in step 2) was placed under a standard neutron source and a gamma-ray source and irradiated with different doses. The SERS spectrum of the SERS chip after irradiation was measured using a Raman spectrometer. Based on the molecular structure transformation of radiation-sensitive molecules under irradiation conditions, characteristic peak positions were selected for quantitative analysis. The relative intensity of the characteristic peak positions was used to fit the neutron dose and gamma dose to obtain the dose response function of the SERS chip to neutrons and gamma rays, thus calibrating the SERS chip and obtaining a SERS chip with independent dose response. After calibration, the correlation coefficients of the neutron dose response function and the gamma-ray dose response function were both greater than 0.95.

[0013] 4) Measuring the optical signal of the SERS chip: Place the calibrated SERS chip in an n-γ mixed radiation field for irradiation. After irradiation is complete, remove the chip and place it on a Raman spectrometer to measure the SERS spectrum.

[0014] 5) Read out the radiation dosimetry information contained in the SERS chip: Extract the characteristic information of the SERS spectrum obtained in step 4), substitute it into the dose response function of neutron and gamma rays obtained in step 3), and invert the neutron dose and gamma ray dose to achieve self-discrimination of the n-γ mixed radiation field.

[0015] Preferably, the neutron-sensitive molecule and the gamma-ray-sensitive molecule in step 1) do not overlap in their SERS characteristic peak positions before and after irradiation, and the neutron-sensitive molecule possesses gamma radiation stability. Preferably, the neutron-sensitive molecule is 4-mercaptophenylboronic acid pinene ester, and the gamma-ray-sensitive molecule is glutathione. The good solvent is water or ethanol, and the dispersion concentration is 0.1-1 mM. The noble metal sol-type SERS substrate is a noble metal nanoparticle sol with a particle diameter of 30-100 nm. In the above substrate, the concentration of noble metal nanoparticles is 0.02-0.5 μM, and the material includes gold nanoparticles, silver nanoparticles, or gold / silver composite nanoparticles, etc. The molar mass ratio of neutron-sensitive molecule to noble metal sol-type SERS substrate and the molar mass ratio of gamma-ray-sensitive molecule to noble metal sol-type SERS substrate are both greater than 100:1 (based on the noble metal molar content in the SERS substrate being "1"). The centrifugation speed is not less than 5000 rpm, and the single centrifugation time is 5-10 min.

[0016] Preferably, in step 2), the solid substrate is any one of silicon wafer, glass slide, or polydimethylsiloxane film, the thickness of the solid substrate is 0.2-2 mm, the water contact angle of the prepared hydrophilic solid substrate is <30°, the volume ratio of radiation-sensitive molecular functionalized SERS substrate to hexane is 4:1, the ethanol dropping rate is 0.2 mL / min (to ensure the formation of a continuous film on the substrate surface), and the relative standard deviation (RSD) of the signal intensity of the SERS chip is ≤10%.

[0017] Preferably, in step 3), the same SERS chip is subjected to more than 10 SERS spectral measurements and the average value is taken; the neutron response characteristic peak position of the SERS chip corresponds to the characteristic wavenumber region of the boron-containing functional group before and after neutron irradiation, and the gamma ray response characteristic peak position corresponds to the characteristic wavenumber region of the redox-active functional group before and after gamma ray irradiation; the dose response function is fitted by the least squares method, and the correlation coefficient is greater than 0.95.

[0018] Preferably, the Raman spectrometer used in step 4) is a commercially available instrument, such as the MiniRam portable Raman spectrometer manufactured by B&W Tek in the example.

[0019] Preferably, the characteristic information of the SERS spectrum in step 5) is the relative intensity change of the SERS characteristic peak position caused by neutrons or gamma rays.

[0020] Secondly, this invention further provides a dose self-discrimination detection system for n-γ mixed radiation fields based on SERS technology. This system includes a SERS chip with an independent dose response to the n-γ mixed radiation field, a portable Raman spectroscopy acquisition module (i.e., a Raman spectrometer), a SERS spectral feature information extraction module, and a radiation dose information readout module. The SERS spectral feature information extraction module analyzes the spectral feature information acquired in step 4). The radiation dose information readout module substitutes the extracted feature information into the dose response function to convert it into a radiation dose and read it out. The SERS chip and the portable Raman spectroscopy acquisition module are coupled via an optical fiber probe (such as the commercially available BAC100B, B&W Tek). The portable Raman spectroscopy acquisition module, the SERS spectral feature information extraction module, and the radiation dose information readout module are connected via a conventional USB data transmission interface / data cable. The SERS chip is used to detect the dose of the n-γ mixed radiation field; the portable Raman spectroscopy acquisition module is used to quickly measure the SERS spectrum of the SERS chip, realizing miniaturization and portability; the SERS spectral feature information extraction module is used to extract and calculate the relative intensity of the characteristic peaks of the SERS spectrum; and the radiation dose information readout module is used to convert the SERS spectral feature information into the dose information of the n-γ mixed radiation field, realizing the self-discrimination of neutron dose and gamma ray dose.

[0021] Compared with existing technologies, the beneficial technical effects of the n-γ mixed radiation field dose self-discrimination detection method and system based on SERS technology provided by this invention are:

[0022] (1) By integrating radiation-sensitive molecules with non-overlapping SERS characteristic peaks, dosimeters can be used in pairs without the need for measuring mixed radiation fields. Simultaneous self-discrimination detection of neutron and gamma ray doses can be achieved in a single dose. This system is suitable for measuring neutron / gamma mixed radiation fields or neutrons or gamma rays. This system can improve the structural compactness, measurement efficiency and applicability of dosimeters.

[0023] (2) This application uses SERS technology, which has high sensitivity and molecular fingerprint recognition capability, as the detection technology, which solves the problem of mutual interference in the dose detection of n-γ mixed radiation field, which makes it difficult to distinguish signals;

[0024] (3) The signal reading device adopts a portable or handheld Raman spectrometer, which can meet the requirements of miniaturization (the volume is less than 1 / 5 of the volume of existing detection instruments) and portability measurement. Attached Figure Description

[0025] Figure 1 This is a flowchart of the dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology in this invention.

[0026] Figure 2 This is a schematic diagram of the n-γ mixed radiation field dose self-discrimination detection system based on SERS technology in this invention;

[0027] Among them, 1-n-γ mixed radiation field, 2-SERS chip with independent dose response to n-γ mixed radiation field, 3-optical coupling interface, 4-portable Raman spectroscopy acquisition module, 5-data transmission interface, 6-SERS spectral feature information extraction module, 7-data coupling interface, and 8-radiation dose information readout module.

[0028] Figure 3 This is a SEM image of the SERS chip prepared according to an embodiment of the present invention.

[0029] Figure 4 The SERS spectrum of the SERS chip prepared in this embodiment of the invention is shown in the unirradiated state. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0031] Unless otherwise specified, all instruments or devices mentioned in the following examples are commercially available.

[0032] 4-Mercaptophenylboronic acid pinene alcohol ester solution was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0033] Glutathione solution was purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0034] The gold nanoparticles (60nm in diameter) were purchased from Suzhou Beike Nanotechnology Co., Ltd.

[0035] The silicon wafer (20mm×20mm×0.725mm) was purchased from Lijing Electronics Co., Ltd.

[0036] Example 1

[0037] This embodiment provides a dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology (such as... Figure 1 (As shown), including the following steps:

[0038] 1) Preparation of radiation-sensitive molecular functionalized SERS substrate: 4-mercaptophenylboronic acid pinene ester solution (1mM, 1mL) and glutathione solution (1mM, 1mL) were mixed with gold nanoparticle sol (1μM, 5mL) and stirred at room temperature for 24h. Then, the mixture was centrifuged three times at 8000rpm (10min each time) and resuspended in 4mL of ultrapure water to complete the purification process and obtain radiation-sensitive molecular functionalized SERS substrate.

[0039] 2) Preparation of SERS chip with independent dose response to n-γ mixed radiation field: The silicon wafer was pretreated with Piranha solution (98% concentrated sulfuric acid and 30% hydrogen peroxide solution mixed in a volume ratio of 7:3) for 1 hour, then rinsed with ultrapure water, and dried at room temperature to obtain a hydrophilic silicon wafer substrate for later use.

[0040] Add 1 mL of hexane to the radiation-sensitive molecular functionalized SERS substrate (4 mL) obtained in step 1) to form a water / hexane interface. Then, use a syringe pump to add ethanol dropwise at a constant rate of 0.2 mL / min until a metallic luster appears at the water / hexane interface. Stop adding ethanol dropwise and wait for the hexane to evaporate and a continuous bright film to float on the water surface. Then, place a hydrophilic silicon wafer substrate on top of the film and contact it to transfer the radiation-sensitive molecular functionalized SERS substrate array to the silicon wafer substrate. After drying at room temperature, the SERS chip is obtained.

[0041] Figure 3 The image shows the SEM image of the SERS chip prepared in this step. The gold nanoparticles are densely packed on the substrate with a uniform size distribution, indicating that the radiation-sensitive molecule functionalized SERS substrate array was well transferred to the solid substrate.

[0042] Figure 4 The SERS spectrum of the SERS chip (unirradiated) prepared in this step shows that at 1574 and 1585 cm⁻¹... -1 The BO-related characteristic peaks of pinene 4-mercaptophenylboronic acid pinene ester appeared at 2540, 680, 2950, ​​and 1750 cm⁻¹. -1 The presence of characteristic peaks related to SH, CS, OH, and C=O of glutathione indicates that the co-modification of the SERS substrate by neutron-sensitive and gamma-ray-sensitive molecules has been successfully achieved.

[0043] 3) Scaled SERS chip:

[0044] The SERS chip obtained in step 2) was placed in a moderated Am-Be neutron source (300 mCi) and 60Irradiation was performed at different doses (neutron and gamma doses of 1–50 mGy) using a Co gamma-ray source (2 μCi). The SERS spectra of the SERS chips after irradiation were measured using Raman spectroscopy (12 measurements per chip). Based on the molecular structural transformation of radiation-sensitive molecules under irradiation conditions, characteristic peak positions were selected for quantitative analysis, utilizing the 1574 and 1585 cm⁻¹ peaks. -1 The dose response function of the SERS chip to neutrons was obtained by least-squares fitting of the relative intensity at the characteristic peak position to the neutron dose (y = 9.482x + 0.105, R0). 2 =0.981), using 510 and 2540cm -1 The relative intensity at the characteristic peak position was fitted to the gamma dose using the least squares method to obtain the dose response function of the SERS chip to gamma rays (y = 6.955x + 0.326, R). 2 =0.974), to achieve calibration of the SERS chip;

[0045] 4) Measuring the optical signal of the SERS chip: Place the calibrated SERS chip in a source containing an Am-Be neutron source (300mCi) / 60 Irradiate the SERS chip in a mixed n-γ radiation field generated by a Co gamma-ray source (2μCi) combined with a Co-60 source (the mixed field is obtained by placing an Am-Be neutron source and a Co-60 source together). After irradiation is completed, the chip is removed (the neutron dose and gamma-ray dose during irradiation are measured by a standard dosimeter, which are 20mGy and 2mGy, respectively). The irradiated SERS chip is then placed on a portable Raman spectrometer to measure the SERS spectrum.

[0046] 5) Read the radiation dosimetry information contained in the SERS chip: Extract the 1574 and 1585 cm⁻¹ spectra of the SERS spectrum obtained in step 4). -1 The relative intensities at characteristic peak positions (correlation with neutron-sensitive boron-containing group transitions), 510 and 2540 cm⁻¹ -1 The relative intensity of the characteristic peak position (related to the transformation of gamma-ray sensitive redox active groups) is substituted into the dose response function of neutrons and gamma rays obtained in step 3) to invert the neutron dose and gamma ray dose, thereby achieving self-discrimination of the n-γ mixed radiation field.

[0047] Tests showed that, compared to the measurements of a standard dosimeter, the relative deviations of this embodiment for neutron dose and gamma ray dose were 4.6% and 5.2%, respectively, meeting the requirements of ISO 14146:2024. This indicates that the method can effectively achieve self-discrimination and accurate detection of dose in n-γ mixed radiation fields.

[0048] Figure 2This is a schematic diagram of the self-discriminating detection system used in this embodiment. Under the action of the n-γ mixed radiation field 1, the SERS chip 2 generates an independent dose response to the n-γ mixed radiation field. It is coupled to the portable Raman spectroscopy acquisition module 4 through the optical coupling interface 3 (BAC100B, B&W Tek) and acquires and measures the SERS spectrum. Then, through the data transmission interface 5 (CM219-15918, UGREEN), the spectral data is transmitted to the SERS spectral feature information extraction module 6 via a data line to extract and analyze the feature information of the SERS spectrum. Then, through the data coupling interface 7 (CM219-15918, UGREEN), the neutron dose response function and the gamma ray dose response function are further combined through a data line to identify and give the neutron dose and gamma ray dose in the radiation dose information readout module 8.

Claims

1. A dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology, characterized in that, The specific steps are as follows: 1) Disperse neutron-sensitive molecules and gamma-ray-sensitive molecules in a good solvent to obtain a dispersion solution; add a noble metal sol-type SERS substrate and mix, stir and react; centrifuge and resuspend in ultrapure water to obtain a radiation-sensitive molecule-functionalized SERS substrate for later use; The neutron-sensitive molecule is 4-mercaptophenylboronic acid pinene ester, the gamma ray-sensitive molecule is glutathione, and the good solvent includes at least one of water or ethanol. The noble metal sol-type SERS substrate is a noble metal nanoparticle sol, and the noble metal nanoparticles include one of gold nanoparticles, silver nanoparticles or gold / silver composite nanoparticles. In terms of molar ratio, the ratio of neutron-sensitive molecules to noble metal nanoparticles is >100:1, and the ratio of gamma-ray-sensitive molecules to noble metal nanoparticles is >100:

1. 2) The solid substrate is pretreated by immersing it in Piranha solution, then cleaned and dried to obtain a hydrophilic solid substrate for later use; The radiation-sensitive molecular functionalized SERS substrate array prepared in step 1) was transferred to a hydrophilic solid substrate and dried to obtain a SERS chip. The step of transferring the radiation-sensitive molecular functionalized SERS substrate array prepared in step 1) to the hydrophilic solid substrate refers to adding hexane to the radiation-sensitive molecular functionalized SERS substrate, then adding ethanol dropwise until a metallic luster appears at the water / hexane interface, and then stopping the dropwise addition. After the hexane evaporates and a continuous bright film floats on the water surface, the hydrophilic solid substrate is placed above the film and in contact with it, so that the radiation-sensitive molecular functionalized SERS substrate array is transferred to the solid substrate. 3) Place the SERS chip prepared in step 2) under a standard neutron source and a gamma ray source and irradiate it with different doses. Use a Raman spectrometer to test the SERS spectrum of the SERS chip after irradiation. Quantitative analysis was performed by selecting characteristic peak positions. The relative intensities of the characteristic peak positions were used to fit the neutron dose and gamma dose to obtain the dose response functions of the SERS chip to neutrons and gamma rays, thus achieving the calibration of the SERS chip. After calibration, the correlation coefficients of the neutron dose response function and the gamma ray dose response function were both greater than 0.

95. 4) Place the calibrated SERS chip from step 3) into an n-γ mixed radiation field for irradiation. After irradiation is complete, remove the chip and place it on a Raman spectrometer to measure the SERS spectrum. Extract the characteristic information of the SERS spectrum obtained in step 4) and substitute it into the dose response function of neutron and gamma rays obtained in step 3) to obtain the neutron dose and gamma ray dose, thereby achieving self-discrimination of the n-γ mixed radiation field; the dose response function is fitted by the least squares method and the function correlation coefficient is greater than 0.

95.

2. The dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology according to claim 1, characterized in that, Step 1) The concentration of the dispersion solution is 0.1~1 mM.

3. The dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology according to claim 1, characterized in that, Step 1) The concentration of the noble metal nanoparticle sol is 0.02~0.5 μM, and the diameter of the nanoparticles is 30~100 nm.

4. The dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology according to claim 1, characterized in that, Step 2) The solid substrate includes any one of silicon wafers, glass slides, and polydimethylsiloxane films.

5. The dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology according to claim 1, characterized in that, In step 2), the volume ratio of the radiation-sensitive molecule-functionalized SERS substrate to hexane is 4:

1.

6. The dose self-discrimination detection method for n-γ mixed radiation fields based on SERS technology according to claim 3, characterized in that, Step 5) The dose response function refers to the neutron dose response function as y = 9.482x + 0.105, R 2 =0.981; the dose response function for gamma rays is y = 6.955x + 0.326, R 2 =0.

974.

7. A dose self-discrimination detection system for an n-γ mixed radiation field based on the detection method of any one of claims 1-6, characterized in that, The system includes a SERS chip, a portable Raman spectroscopy acquisition module, a SERS spectral feature information extraction module, and a radiation dose information readout module. The SERS chip and the portable Raman spectroscopy acquisition module are coupled through an optical fiber probe, and the portable Raman spectroscopy acquisition module, the SERS spectral feature information extraction module, and the radiation dose information readout module are connected through a data transmission interface and a data cable. The portable Raman spectroscopy acquisition module is a Raman spectrometer; The SERS spectral feature information extraction module analyzes the spectral selection feature information acquired by the portable Raman spectroscopy acquisition module to obtain feature information; The radiation dose information readout module substitutes the feature information into the dose response function, converts it into radiation dose, and reads it out.

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