Silicon single crystal irradiation thermal neutron fluence online monitoring signal calibration method

Abstract

The application provides a kind of silicon single crystal irradiation thermal neutron fluence online monitoring signal calibration method, it is related to neutron irradiation transmutation doping quality control technical field, purpose is to realize high accuracy, good economy, high flexibility and fast data feedback speed, including the following steps: selecting calibration aluminum analog body;Determine the calibration relationship factor ratio relationship of calibration silicon single crystal body and calibration aluminum analog body;Select the aluminum analog body of re-calibration that is consistent with the size of the silicon single crystal to be irradiated into the reactor irradiation;Determine the calibration relationship factor of re-calibration aluminum analog body;Obtain the calibration relationship factor of the silicon single crystal to be irradiated;Collect the online monitoring signal current value of the silicon single crystal to be irradiated in the process of reactor irradiation, obtain the irradiation thermal neutron fluence of the silicon single crystal to be irradiated.The application has the advantages of efficient processing, accuracy and good economy.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron irradiation transmutation doping quality control, and in particular to a method for online monitoring signal calibration of thermal neutron flux irradiated by silicon single crystals. Background Art

[0002] When conducting neutron irradiation transmutation doping of silicon single crystals in a reactor, it is necessary to precisely control the thermal neutron flux of the silicon single crystal to reach the target value to ensure that the impurities produced are 31 The concentration of P reached the target requirement.

[0003] Online measurement technology based on self-powered neutron detectors is widely used internationally for real-time monitoring of thermal neutron fluence in silicon single crystals. The activation method, a classic offline method for measuring reactor core neutron fluence, is widely used to measure thermal neutron fluence (rate) in silicon single crystals and to calibrate the online monitoring signal of self-powered neutron detectors. To ensure the accuracy of the online signal calibration of self-powered neutron detectors, it is crucial to ensure the accuracy of the overall thermal neutron fluence (rate) measured in the silicon single crystal. When using the activation method, the activation detectors must be placed on the silicon single crystal. Without damaging the integrity of the silicon, this can generally only be done on the outer surface of the silicon. However, the thermal neutron fluence rate on the outer surface of the silicon single crystal can differ significantly from the overall irradiation value, especially with larger silicon diameters. The ideal arrangement is to place the activation detectors within the silicon crystal, with multiple locations along the radial and axial directions. However, this approach is often difficult to achieve without damaging the silicon crystal. Furthermore, during the irradiation of the silicon body containing the activated detector, it is necessary to follow the entire irradiation process without interrupting the silicon body irradiation schedule. However, irradiation times vary for different silicon body products, limiting the choice of calibration time. Furthermore, after the activated detector is irradiated with the silicon body, it is typically removed from the irradiation tank and cooled for at least several days. Only after the radioactive dose has decayed to a satisfactory level can the activated detector be removed and data measurements taken. Therefore, the feedback time for measurement data is generally long.

[0004] The above factors pose great difficulties for the implementation of online monitoring signal calibration of self-powered neutron detectors corresponding to silicon single crystal irradiation. Therefore, it is necessary to establish a calibration method that can ensure the accuracy of online signal calibration, as well as good economy, high flexibility and fast data feedback speed. Summary of the Invention

[0005] The object of the present invention is to provide a method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation, which can achieve high accuracy, good economy, high flexibility and fast data feedback speed.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] A method for online monitoring signal calibration of thermal neutron flux during irradiation of a silicon single crystal comprises the following steps:

[0008] Selecting an aluminum scale simulating body, wherein the size of the aluminum scale simulating body is consistent with that of the silicon scale single crystal;

[0009] Obtaining an average value of the irradiated thermal neutron fluence rate and an average current value of the online monitoring signal of the aluminum dummy for calibration, and an average value of the irradiated thermal neutron fluence rate and an average current value of the online monitoring signal of the silicon single crystal for calibration, and determining a ratio relationship of the calibration relationship factors of the silicon single crystal for calibration and the aluminum dummy for calibration;

[0010] When determining the scale relationship factor of the online monitoring signal of the silicon single crystal to be irradiated, an aluminum dummy for re-calibration having the same size as the silicon single crystal to be irradiated is selected and put into the stack for irradiation, and the aluminum dummy for re-calibration has no essential difference from the aluminum dummy for calibration;

[0011] Obtaining an average value of the irradiated thermal neutron flux rate of the recalibration aluminum dummy and an average current value of the online monitoring signal, and determining a calibration relationship factor of the recalibration aluminum dummy;

[0012] Obtaining the scale relationship factor of the silicon single crystal to be irradiated based on the ratio of the scale relationship factors and the scale relationship factor of the re-calibration aluminum simulant;

[0013] The online monitoring signal current value of the silicon single crystal to be irradiated during the irradiation process is collected to obtain the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated and the irradiation thermal neutron fluence integrated with the irradiation time.

[0014] Preferably, the method for determining the ratio of the scale relationship factors of the silicon single crystal for calibration and the aluminum analog body for calibration is:

[0015] The aluminum simulant for scale and the silicon single crystal for scale are irradiated under the same irradiation conditions, and the scale relationship factor ratio relationship between the silicon single crystal for scale and the aluminum simulant for scale is determined:

[0016]

[0017] in, and are respectively the average values ​​of the thermal neutron fluence rates of the aluminum simulant for scale and the silicon single crystal for scale in the irradiation, and are the average current values ​​of the online monitoring signals of the aluminum simulation body for scale and the silicon single crystal for scale during irradiation, β Al and β Siare the burnup correction factors of the self-powered neutron detector when the aluminum dummy body for scale and the silicon single crystal for scale are irradiated, respectively. The self-powered neutron detector is used for online monitoring of the irradiation thermal neutron flux rate and the output signal is a current value;

[0018] Preferably, when determining the corrected scale relationship factor of the silicon single crystal to be irradiated, an aluminum dummy for re-calibration having the same size as the silicon single crystal to be irradiated is selected, and the scale relationship factor of the aluminum dummy for re-calibration is determined by:

[0019]

[0020] Among them, SF′ Al is the scale relationship factor of the aluminum analog body for re-calibration, β′ Al is the burnup correction factor of the self-powered neutron detector when irradiated with the aluminum dummy for recalibration, and They are respectively the average value of the irradiation thermal neutron injection rate of the aluminum simulation body used for recalibration during irradiation and the average current value of the online monitoring signal.

[0021] Preferably, the method for obtaining the scale relationship factor of the silicon single crystal to be irradiated is:

[0022] SF′ Si =SF′ Al α / β′ Si ;

[0023] Among them, SF′ Si is the scale relationship factor of the silicon single crystal to be irradiated, β′ Si is the burnup correction factor of the self-powered neutron detector during irradiation of the silicon single crystal to be irradiated.

[0024] Preferably, the method for obtaining the irradiation thermal neutron fluence of the silicon single crystal to be irradiated is:

[0025] Obtain an online monitoring value of the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated:

[0026] φ′ th,Si (t) = SF′ Si I′ Si (t);

[0027] Among them, φ′ th,Si (t) is the online monitoring value of the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated, I′ Si (t) is the current value of the online monitoring signal from the self-powered neutron detector during the irradiation process of the silicon single crystal to be irradiated, and t represents the irradiation time;

[0028] acquire the irradiation thermal neutron fluence φ' of the to-be-irradiated silicon single crystal in the whole irradiation process th,Si :

[0029] φ' th,Si =∫0 T φ' th,Si (t)dt;

[0030] Wherein, T is the total irradiation time.

[0031] Preferably, the calibration silicon single crystal includes at least two silicon bodies, the silicon bodies are stacked together, a plurality of groups of activated detectors are arranged along the radial direction and the axial direction of the interface, and the average value of the irradiation thermal neutron fluence rate of the calibration silicon single crystal is determined.

[0032] Preferably, a plurality of groups of activated detectors are arranged along the radial direction and the axial direction of the inside of the calibration aluminum analog body and the recalibration aluminum analog body, and the average value of the irradiation thermal neutron fluence rate of the calibration aluminum analog body and the recalibration aluminum analog body is determined.

[0033] Preferably, the material of the activated detector is selected from gold and / or cobalt and / or silver and / or iron and / or scandium.

[0034] Preferably, the calibration aluminum analog body, the calibration silicon single crystal, the recalibration aluminum analog body and the to-be-irradiated silicon single crystal are respectively subjected to in-pile irradiation in the same irradiation hole, a self-powered neutron detector is arranged on the outer wall of the irradiation hole, the self-powered neutron detector is used for online monitoring of the irradiation thermal neutron fluence rate, and the output signal is a current value.

[0035] Preferably, the axial height of the self-powered neutron detector in the irradiation hole corresponds to the irradiation positions of the calibration aluminum analog body, the calibration silicon single crystal, the recalibration aluminum analog body and the to-be-irradiated silicon single crystal.

[0036] The technical scheme of the embodiment of the present application has at least the following advantages and beneficial effects:

[0037] The present application uses an aluminum analog body to replace a silicon single crystal for online monitoring signal calibration, the material can be reused, the activated detector can be arranged and taken out flexibly, and the calibration time can be arranged flexibly.

[0038] The present application solves the problems of limited arrangement of activated detectors, limited selection of calibration time and slow data feedback speed when using a silicon single crystal for calibration.

[0039] The present application has the characteristics of good flexibility, high efficiency, fast data feedback speed, good economy and good sample reusability on the basis of ensuring calibration accuracy.

[0040] The present invention can quickly obtain the online monitoring signal scale relationship factor during silicon single crystal irradiation through the aluminum simulation body, and the measurement data feedback time is timely, thereby solving the problem of slow feedback speed of scale data;

[0041] The invention has reasonable design, simple and economical acquisition of required materials, easy arrangement and execution of required steps, and is convenient for promotion and implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic flow chart of a method for online monitoring and signal calibration of thermal neutron flux during irradiation of a silicon single crystal provided in Example 1 of the present invention;

[0043] Figure 2 A schematic flow chart of a method for online monitoring and signal calibration of thermal neutron flux during irradiation of a silicon single crystal provided in Example 2 of the present invention;

[0044] Figure 3 This is a structural diagram of the activation detector arrangement provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0046] Example 1

[0047] This embodiment provides a method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation. Figure 1 , including the following steps:

[0048] Step S1: Selecting an aluminum dummy for scale, wherein the size of the aluminum dummy for scale is consistent with that of the silicon single crystal for scale;

[0049] Step S2: obtaining an average value of the irradiated thermal neutron fluence rate and an average current value of the online monitoring signal of the aluminum dummy for calibration, and an average value of the irradiated thermal neutron fluence rate and an average current value of the online monitoring signal of the silicon single crystal for calibration, and determining a ratio relationship of the calibration relationship factors of the silicon single crystal for calibration and the aluminum dummy for calibration;

[0050] Step S3: selecting an aluminum dummy for re-calibration with the same size as the silicon single crystal to be irradiated and putting it into the stack for irradiation, wherein the aluminum dummy for re-calibration has no essential difference from the aluminum dummy for calibration;

[0051] Step S4: obtaining an average value of the irradiated thermal neutron flux rate of the aluminum dummy for recalibration and an average current value of the online monitoring signal, and determining a calibration relationship factor of the aluminum dummy for recalibration;

[0052] Step S5: obtaining the scale relationship factor of the silicon single crystal to be irradiated based on the ratio relationship of the scale relationship factors and the scale relationship factor of the re-calibration aluminum simulant;

[0053] Step S6: collecting the online monitoring signal current value of the silicon single crystal to be irradiated during the irradiation process, and obtaining the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated and the irradiation thermal neutron fluence integrated with the irradiation time.

[0054] The main principles of this embodiment are:

[0055] Aluminum-based main nuclide 27 Al (abundance 100%) and the main nuclide of silicon 28 Si (abundance 92.223%), 29 Si (4.685%) and 30 The absorption cross section and scattering cross section of Si (3.092) vary very little, so an aluminum simulant can be used instead of a silicon single crystal to arrange an activation detector for online monitoring signal calibration. Therefore, under the same irradiation conditions, the absolute values ​​of the thermal neutron flux (rate) irradiated by the aluminum simulant and the silicon single crystal for calibration, as well as the online monitoring signal current value output by the self-powered neutron detector are determined; then the scale relationship factors of the online monitoring signals corresponding to the aluminum simulant and the silicon single crystal for calibration (corrected by the self-powered neutron detector emitter burnup), as well as the ratio relationship between the two are determined. Therefore, in this embodiment, the scale relationship factor ratio relationship is first determined by using the aluminum simulant and the silicon single crystal for calibration; finally, according to the calibration, the scale relationship factor ratio relationship is determined. The calibration relationship factor ratio relationship is obtained by selecting an aluminum dummy body for recalibration to replace the silicon single crystal to be irradiated to arrange the activation detector, and calibrating the online monitoring signal to obtain the calibration relationship factor corresponding to the aluminum dummy body for recalibration at this time, and then deriving the calibration relationship factor corresponding to the silicon single crystal to be irradiated when it is put into the pile for irradiation, thereby achieving the effect of collecting the online monitoring signal current value of the silicon single crystal to be irradiated during the irradiation process to obtain the irradiation thermal neutron injection rate of the silicon single crystal to be irradiated and the irradiation thermal neutron injection integrated with the irradiation time.

[0056] It is particularly noted that the corresponding aluminum simulant can be processed into a variety of structures according to the requirements of the activation detector layout. 27 Al generates nuclides through radiation capture reaction 28 The half-life of Al is 2.24 min, and the aluminum simulant can be reused for calibration tests.

[0057] Example 2

[0058] The embodiment is based on the technical solution of Embodiment 1, and refer to Figure 2 The specific implementation method of each step is further described.

[0059] In the embodiment, the method for determining the scale relationship factor ratio relationship of the scale silicon single crystal and the scale aluminum analog body in step 2 is as follows:

[0060] The scale aluminum analog body and the scale silicon single crystal are irradiated under the same irradiation condition, and the scale relationship factor ratio relationship of the scale silicon single crystal and the scale aluminum analog body is determined:

[0061]

[0062] wherein, and are the average irradiation thermal neutron flux of the scale aluminum analog body and the scale silicon single crystal in irradiation, respectively, and are the average online monitoring signal current value of the scale aluminum analog body and the scale silicon single crystal in irradiation, respectively, Al and Si are the self-sustaining neutron detector burnup correction factors of the scale aluminum analog body and the scale silicon single crystal in irradiation, respectively, the self-sustaining neutron detector is used for online monitoring of the irradiation thermal neutron flux and outputs a signal in the form of current value; the self-sustaining neutron detector burnup correction factor is the ratio of the remaining atomic number of the self-sustaining neutron detector emitter to the atomic number before the burnup occurs.

[0063] It is particularly pointed out that the corresponding scale relationship factor ratio relationship a is determined according to different silicon single crystal sizes and irradiation conditions, and in actual application, the corresponding a value of the silicon single crystal size and the irradiation condition is directly called to execute the following steps, and it is not necessary to repeatedly determine the a value by performing the scale test.

[0064] As a preferred scheme of the embodiment, the method for determining the scale relationship factor of the rescale aluminum analog body in step S4 is as follows:

[0065]

[0066] wherein, SF′ Al is the scale relationship factor of the rescale aluminum analog body, β′ Al is the self-sustaining neutron detector burnup correction factor of the rescale aluminum analog body in irradiation, and are the average irradiation thermal neutron flux and the average online monitoring signal current value of the rescale aluminum analog body in irradiation, respectively.

[0067] Next, in step S5, the method for obtaining the scale relationship factor of the silicon single crystal to be irradiated is:

[0068] SF′ Si =SF′ Al α / β′ Si ;

[0069] Among them, SF′ Si is the scale relationship factor of the silicon single crystal to be irradiated, β′ Si is the burnup correction factor of the self-powered neutron detector during irradiation of the silicon single crystal to be irradiated.

[0070] Finally, in step S6, the method for obtaining the irradiation thermal neutron fluence of the silicon single crystal to be irradiated is:

[0071] Obtain an online monitoring value of the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated:

[0072] φ′ th,Si (t) = SF′ Si I′ Si (t);

[0073] Among them, φ′ th,Si (t) is the online monitoring value of the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated, I′ Si (t) is the current value of the online monitoring signal from the self-powered neutron detector during the irradiation process of the silicon single crystal to be irradiated, and t represents the irradiation time;

[0074] Obtain the irradiation thermal neutron flux φ′ of the silicon single crystal to be irradiated during the entire irradiation process th,Si :

[0075] φ′ th,Si =∫0 T φ′ th,Si (t)dt;

[0076] Where T is the total irradiation time.

[0077] Example 3

[0078] This embodiment is based on the technical solution of embodiment 1, see Figure 3 , further explain the construction method of each data measurement.

[0079] In this embodiment, the silicon single crystal for calibration includes at least two silicon bodies, which are stacked together. Multiple groups of activation detectors are arranged along the radial direction and axial direction of the clamping surface to determine the average value of the irradiated thermal neutron injection rate of the silicon single crystal for calibration.

[0080] On the other hand, multiple groups of activation detectors are arranged along the inner radial and axial positions of the aluminum dummy for calibration and the aluminum dummy for recalibration to determine the average value of the irradiated thermal neutron fluence rate of the aluminum dummy for calibration and the aluminum dummy for recalibration.

[0081] Furthermore, the activation detector can be constructed using a combination of different materials to mitigate measurement effects introduced by differences in the radiation capture cross section between the activation detector material and the target nuclide in the irradiated object. Specifically, the activation detector needs to be sensitive to thermal neutrons, and preferred materials include gold, cobalt, silver, iron, and / or scandium.

[0082] As a preferred embodiment, the calibration aluminum dummy, the calibration silicon single crystal, the recalibration aluminum dummy, and the to-be-irradiated silicon single crystal are each irradiated in the same irradiation channel. A self-powered neutron detector is installed on the outer wall of the irradiation channel. The self-powered neutron detector is used to online monitor the irradiation thermal neutron flux rate and outputs a current signal. In steps S4-S5, the calibration relationship factor is corrected for the self-powered neutron detector burnup in order to uniformly correct it to the value before burnup for ease of comparison. The corrected calibration relationship factor is the value under the self-powered neutron detector burnup conditions when the to-be-irradiated silicon single crystal is irradiated in the stack, so as to correspond to the self-powered neutron detector output current signal. Since the calibration relationship factor can be obtained through the aluminum dummy calibration test, there is no need to conduct a silicon single crystal calibration test.

[0083] Finally, the axial height of the self-powered neutron detector in the irradiation channel corresponds to the irradiation positions of the calibration aluminum dummy, the calibration silicon single crystal, the recalibration aluminum dummy and the silicon single crystal to be irradiated.

[0084] It should be noted that the irradiation thermal neutron fluence rate is the absolute value obtained by converting the online monitoring signal current value of the self-powered neutron detector during the irradiation process of the silicon single crystal to be irradiated into the pile, and is also the absolute value of the thermal neutron fluence rate actually received by the silicon single crystal to be irradiated during the irradiation process.

[0085] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for online monitoring signal calibration of thermal neutron flux during irradiation of a silicon single crystal, characterized in that: The following steps are involved: Selecting an aluminum scale simulating body, wherein the size of the aluminum scale simulating body is consistent with that of the silicon scale single crystal; Obtaining an average value of the irradiated thermal neutron fluence rate and an average current value of the online monitoring signal of the aluminum dummy for calibration, and an average value of the irradiated thermal neutron fluence rate and an average current value of the online monitoring signal of the silicon single crystal for calibration, and determining a ratio relationship of the calibration relationship factors of the silicon single crystal for calibration and the aluminum dummy for calibration; Select a rescaled aluminum simulant with the same size as the silicon single crystal to be irradiated and place it into the pile for irradiation; Obtaining an average value of the irradiated thermal neutron flux rate of the recalibration aluminum dummy and an average current value of the online monitoring signal, and determining a calibration relationship factor of the recalibration aluminum dummy; Obtaining the scale relationship factor of the silicon single crystal to be irradiated based on the ratio of the scale relationship factors and the scale relationship factor of the re-calibration aluminum simulant; Collecting the online monitoring signal current value of the silicon single crystal to be irradiated during the irradiation process of the silicon single crystal to be irradiated, and obtaining the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated and the irradiation thermal neutron fluence integrated with the irradiation time; The method for determining the ratio of the scale relationship factors of the silicon single crystal for scale and the aluminum analog body for scale is: The aluminum simulant for scale and the silicon single crystal for scale are irradiated under the same irradiation conditions, and the scale relationship factor ratio relationship between the silicon single crystal for scale and the aluminum simulant for scale is determined: ; in, and are respectively the average values ​​of the thermal neutron fluence rates of the aluminum simulant for scale and the silicon single crystal for scale in the irradiation, and are respectively the average current values ​​of the online monitoring signals of the aluminum simulant for scale and the silicon single crystal for scale during irradiation, and are the burnup correction factors of the self-powered neutron detector when the aluminum dummy body for scale and the silicon single crystal for scale are irradiated, respectively. The self-powered neutron detector is used for online monitoring of the irradiation thermal neutron flux rate and the output signal is a current value; The selected aluminum dummy for re-calibration has the same size as the silicon single crystal to be irradiated, and the method for determining the scale relationship factor of the aluminum dummy for re-calibration is as follows: ; in, is the scale relationship factor of the aluminum analog body for re-calibration, is the burnup correction factor of the self-powered neutron detector when irradiated with the aluminum dummy for recalibration, and are the average thermal neutron flux rate of the aluminum dummy for recalibration and the average current value of the online monitoring signal during irradiation, respectively; The method for obtaining the scale relationship factor of the silicon single crystal to be irradiated is: ; in, is the scale relationship factor of the silicon single crystal to be irradiated, is the burnup correction factor of the self-powered neutron detector when irradiating the silicon single crystal to be irradiated; The method for obtaining the irradiation thermal neutron fluence of the silicon single crystal to be irradiated is: Obtain an online monitoring value of the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated: ; in, is the online monitoring value of the irradiation thermal neutron fluence rate of the silicon single crystal to be irradiated, is the current value of the online monitoring signal from the self-powered neutron detector during the irradiation process of the silicon single crystal to be irradiated. represents the irradiation time; Obtaining the irradiated thermal neutron flux of the silicon single crystal to be irradiated during the entire irradiation process : ； in, is the total irradiation time.

2. The method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation according to claim 1, characterized in that: The silicon single crystal for calibration includes at least two silicon bodies, which are stacked together. Multiple groups of activation detectors are arranged along the radial direction and axial direction of the clamping surface to determine the average value of the irradiated thermal neutron injection rate of the silicon single crystal for calibration.

3. The method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation according to claim 1, characterized in that: A plurality of activation detectors are arranged along the radial and axial positions inside the aluminum dummy for calibration and the aluminum dummy for recalibration to determine the average value of the irradiated thermal neutron fluence rate of the aluminum dummy for calibration and the aluminum dummy for recalibration.

4. A method for online monitoring signal calibration of thermal neutron flux during irradiation of a silicon single crystal according to claim 2 or 3, characterized in that: The activation detector is made of gold and / or cobalt and / or silver and / or iron and / or scandium.

5. The method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation according to claim 1, characterized in that: The aluminum dummy for calibration, the silicon single crystal for calibration, the aluminum dummy for recalibration and the silicon single crystal to be irradiated are respectively placed in the same irradiation channel for irradiation. A self-powered neutron detector is provided on the outer wall of the irradiation channel. The self-powered neutron detector is used for online monitoring of the irradiation thermal neutron injection rate and the output signal is a current value.

6. The method for online monitoring signal calibration of thermal neutron flux during irradiation of a silicon single crystal according to claim 5, characterized in that: The axial height of the self-powered neutron detector in the irradiation channel corresponds to the irradiation positions of the calibration aluminum dummy, the calibration silicon single crystal, the recalibration aluminum dummy and the silicon single crystal to be irradiated.

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