Silicon single crystal irradiation thermal neutron fluence on-line monitoring signal calibration method

Abstract

The invention provides a silicon single crystal irradiation thermal neutron fluence on-line monitoring signal calibration method, relates to the technical field of neutron irradiation transmutation doping quality control, and aims to realize high accuracy, good economy, high flexibility and fast data feedback speed, and the method comprises the following steps: selecting an aluminum simulation body for calibration; determining a scale relation factor ratio relation between the silicon single crystal body for the scale and the aluminum simulation body for the scale; selecting a re-graduated aluminum simulation body which is consistent with the size of the silicon single crystal to be irradiated into a pile for irradiation; determining a scale relation factor of the aluminum simulation body for re-scale; obtaining a scale relation factor of the silicon single crystal to be irradiated; and collecting an on-line monitoring signal current value of the to-be-irradiated silicon single crystal in the in-pile irradiation process, and obtaining the irradiation thermal neutron fluence of the to-be-irradiated silicon single crystal. The method has the advantages of being efficient and accurate in treatment and good in economical efficiency.

Description

Technical Field

[0001] The 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 injection of silicon single crystal irradiation. Background Art

[0002] When neutron irradiation transmutation doping of silicon single crystals is carried out in the reactor, it is necessary to accurately control the thermal neutron injection 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] The online measurement technology based on the self-powered neutron detector is an online technology widely used in the world for real-time monitoring of thermal neutron fluence of silicon single crystal irradiation. As a classic offline method for measuring neutron fluence in reactor core, the activation method is widely used for measuring thermal neutron fluence (rate) of silicon single crystal irradiation and for the online monitoring signal calibration of the self-powered neutron detector. In order to ensure the accuracy of the online monitoring signal calibration of the self-powered neutron detector, it is very important to ensure the measurement accuracy of the thermal neutron fluence (rate) of the overall irradiation of the silicon single crystal. When using the activation method for measurement, the activation detector needs to be arranged on the silicon single crystal. Under the premise of not damaging the integrity of the silicon body, the activation detector can generally only be arranged on the outer surface of the silicon body, but there will be a significant difference between the thermal neutron fluence rate value on the outer surface of the silicon body and its overall irradiation value, especially when the diameter of the silicon body is larger. The ideal arrangement is to arrange the activation detector inside the silicon body and arrange multiple points along the radial and axial directions, but this method is usually difficult to achieve without damaging the silicon body. In addition, during the irradiation of the silicon body with the activation detector, it is necessary to follow the entire irradiation process without interrupting the silicon body irradiation plan. However, the irradiation time of different silicon body products varies, so the selection of calibration time is limited. In addition, after the activation detector is irradiated with the silicon body, it is usually necessary to take it out of the irradiation tank and cool it for at least a few days. Only after the radioactive dose decays to a level that meets the requirements can the activation detector be taken out and data measurement be performed. Therefore, the feedback time of measurement data is generally longer.

[0004] The above factors have created great difficulties for the implementation of online monitoring signal calibration of the self-powered neutron detector 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 injection 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 implemented by the following technical solutions:

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

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

[0009] Obtaining the average value of the irradiated thermal neutron flux rate and the average current value of the online monitoring signal of the aluminum simulant for calibration, and the average value of the irradiated thermal neutron flux rate and the average current value of the online monitoring signal of the silicon single crystal for calibration, and determining the ratio relationship of the calibration relationship factor between the silicon single crystal for calibration and the aluminum simulant for calibration;

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

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

[0012] Based on the ratio relationship of the scale relationship factors and the scale relationship factors of the re-scaled aluminum simulation body, the scale relationship factors of the silicon single crystal to be irradiated are obtained;

[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 injection rate of the silicon single crystal to be irradiated and the irradiation thermal neutron injection integrated with the irradiation time.

[0014] Preferably, the method for determining the ratio relationship of the scale relationship factor between the scale silicon single crystal and the scale aluminum simulation body is:

[0015] The aluminum analog body 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 analog body for scale is determined:

[0016]

[0017] in, and are respectively the average values ​​of the irradiation thermal neutron injection rates of the aluminum simulation body 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 simulant 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 simulation 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 injection rate and the output signal is the 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 calibration relationship factor of the aluminum simulation body for recalibration, β′ Al is the burnup correction factor of the self-powered neutron detector when irradiated with the aluminum dummy body 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 when the silicon single crystal to be irradiated is irradiated.

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

[0025] Obtaining an online monitoring value of the irradiation thermal neutron injection 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 injection 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] Obtaining the irradiated thermal neutron injection φ′ of the silicon single crystal to be irradiated during the entire irradiation process th,Si :

[0029] φ′ th,Si =∫0 T φ′ th,Si (t)dt;

[0030] Where T is the total irradiation time.

[0031] Preferably, the silicon single crystal for calibration comprises at least two silicon bodies, which are stacked together, and a plurality of activation detectors are arranged along the radial direction and the axial direction of the side surfaces to determine the average value of the irradiated thermal neutron injection rate of the silicon single crystal for calibration.

[0032] Preferably, a plurality of 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 injection rate of the aluminum dummy for calibration and the aluminum dummy for recalibration.

[0033] Preferably, the activation detector is made of gold and / or cobalt and / or silver and / or iron and / or scandium.

[0034] Preferably, the aluminum simulant for calibration, the silicon single crystal for calibration, the aluminum simulant for re-calibration and the silicon single crystal to be irradiated are respectively irradiated in the same irradiation channel, and 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.

[0035] Preferably, the axial height of the self-powered neutron detector in the irradiation channel corresponds to the irradiation position of the aluminum simulation body for calibration, the silicon single crystal for calibration, the aluminum simulation body for re-calibration and the silicon single crystal to be irradiated.

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

[0037] The present invention uses an aluminum simulant to replace a silicon single crystal for online monitoring signal calibration, and the material can be reused, so that the activation detector can be flexibly arranged and loaded, and the calibration time can be flexibly arranged;

[0038] The present invention solves the problems of limited arrangement of activation detectors, limited selection of calibration time, slow feedback speed of calibration data, etc. when using silicon single crystal calibration.

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

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

[0041] The invention has reasonable design, simple acquisition of required materials and good economy, 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 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 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 schematic diagram of the activation detector arrangement provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 here 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 injection of silicon single crystal irradiation, referring to Figure 1 , including the following steps:

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

[0049] Step S2: obtaining the average value of the irradiated thermal neutron injection rate and the average current value of the online monitoring signal of the aluminum simulant for calibration, and the average value of the irradiated thermal neutron injection rate and the average current value of the online monitoring signal of the silicon single crystal for calibration, and determining the ratio relationship of the calibration relationship factor between the silicon single crystal for calibration and the aluminum simulant for calibration;

[0050] Step S3: selecting an aluminum simulant for recalibration having the same size as the silicon single crystal to be irradiated and putting it into the pile for irradiation, and the aluminum simulant for recalibration has no essential difference from the aluminum simulant for calibration;

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

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

[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 injection rate of the silicon single crystal to be irradiated and the irradiation thermal neutron injection integrated with the irradiation time.

[0054] The main principles of this embodiment are:

[0055] Based on the main nuclide of aluminum 27 Al (abundance 100%) and main nuclides 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 of signal calibration. Therefore, under the same irradiation conditions, determine the absolute value of the thermal neutron injection (rate) of 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; then determine the scale relationship factor of the online monitoring signal 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 between the two. Therefore, this embodiment first determines the ratio of the scale relationship factor using the aluminum simulant and the silicon single crystal for calibration; finally, according to the scale relationship factor, the ratio of the scale relationship factor is determined. The calibration relationship factor ratio relationship is determined by selecting an aluminum simulation body for recalibration to replace the silicon single crystal to be irradiated to arrange the activation detector, and the online monitoring signal is calibrated to obtain the calibration relationship factor corresponding to the aluminum simulation body for recalibration at this time, and then the calibration relationship factor corresponding to the silicon single crystal to be irradiated when it is put into the pile for irradiation is deduced, so as to achieve the effect of collecting the online monitoring signal current value of the silicon single crystal to be irradiated during the irradiation process of being put into the pile 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] This embodiment is based on the technical solution of embodiment 1, see Figure 2 , and further explain the specific implementation method of each step.

[0059] In this embodiment, 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 in step 2 is:

[0060] The aluminum analog body 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 analog body for scale is determined:

[0061]

[0062] in, and are respectively the average values ​​of the irradiation thermal neutron injection rates of the aluminum simulation body 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 simulant for scale and the silicon single crystal for scale during irradiation, β Al and β Si They are the burnup correction factors of the self-powered neutron detector when the aluminum simulation body for scale and the silicon single crystal for scale are irradiated, respectively. The self-powered neutron detector is used to monitor the irradiation thermal neutron injection rate online and the output signal is a current value; the burnup correction factor of the self-powered neutron detector is the ratio of the number of remaining atoms in the emitter of the self-powered neutron detector to the number of atoms before burnup when the sample is irradiated.

[0063] It should be noted in particular that the corresponding calibration relationship factor ratio relationship α is determined according to different silicon single crystal sizes and irradiation conditions. In actual applications, the α value corresponding to the corresponding silicon single crystal size and irradiation conditions is directly called to execute the subsequent steps, and there is no need to repeatedly perform calibration tests to determine the α value.

[0064] As a preferred solution of this embodiment, the method for determining the scale relationship factor of the re-calibration aluminum simulation body in step S4 is:

[0065]

[0066] Among them, SF′ Al is the calibration relationship factor of the aluminum simulation body for recalibration, β′ Al is the burnup correction factor of the self-powered neutron detector when irradiated with the aluminum dummy body 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.

[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 when the silicon single crystal to be irradiated is irradiated.

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

[0071] Obtaining an online monitoring value of the irradiation thermal neutron injection 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 injection 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] Obtaining the irradiated thermal neutron injection 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 methods 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 of the clamping surface and the axial direction of the side 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 injection rate of the aluminum dummy for calibration and the aluminum dummy for recalibration.

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

[0082] As a preferred solution, the aluminum simulant for calibration, the silicon single crystal for calibration, the aluminum simulant 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 to monitor the irradiation thermal neutron injection rate online and the output signal is a current value. In steps S4-S5, the scale relationship factor is corrected by the burnup of the self-powered neutron detector in order to uniformly correct it to the value before burnup occurs for the convenience of comparison. The corrected scale relationship factor is the value under the burnup condition of the self-powered neutron detector when the silicon single crystal to be irradiated is placed in the stack for irradiation, so as to correspond to the output current signal of the self-powered neutron detector. Since the scale relationship factor can be obtained through the aluminum simulant 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 position of the aluminum simulation body for calibration, the silicon single crystal for calibration, the aluminum simulation body for re-calibration and the silicon single crystal to be irradiated.

[0084] It should be noted that the irradiation thermal neutron injection 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 injection rate actually received by the silicon single crystal to be irradiated during the irradiation process.

[0085] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation, characterized in that: The following steps are involved: Selecting an aluminum analog body for scale, wherein the size of the aluminum analog body for scale is consistent with that of the silicon single crystal for scale; Obtaining the average value of the irradiated thermal neutron flux rate and the average current value of the online monitoring signal of the aluminum simulant for calibration, and the average value of the irradiated thermal neutron flux rate and the average current value of the online monitoring signal of the silicon single crystal for calibration, and determining the ratio relationship of the calibration relationship factor between the silicon single crystal for calibration and the aluminum simulant for calibration; Select a re-scaled aluminum simulant with the same size as the silicon single crystal to be irradiated and put it into the pile for irradiation; Obtaining an average value of the irradiated thermal neutron injection rate of the aluminum simulant for recalibration and an average current value of the online monitoring signal, and determining a calibration relationship factor of the aluminum simulant for recalibration; Based on the ratio relationship of the scale relationship factors and the scale relationship factors of the re-scaled aluminum simulation body, the scale relationship factors of the silicon single crystal to be irradiated are obtained; 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 injection rate of the silicon single crystal to be irradiated and the irradiation thermal neutron injection integrated with the 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 method for determining the ratio relationship of the scale relationship factor of the silicon single crystal for scale and the aluminum analog body for scale is: The aluminum analog body 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 analog body for scale is determined: in, and are respectively the average values ​​of the irradiation thermal neutron injection rates of the aluminum simulation body 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 simulant for scale and the silicon single crystal for scale during irradiation, β Al and β Si They are respectively the burnup correction factors of the self-powered neutron detector when the aluminum simulation body for scale and the silicon single crystal for scale are irradiated. The self-powered neutron detector is used for online monitoring of the irradiation thermal neutron injection rate and the output signal is the current value.

3. The method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation according to claim 2, characterized in that: The selected aluminum simulant for re-calibration has the same size as the silicon single crystal to be irradiated, and the method for determining the calibration relationship factor of the aluminum simulant for re-calibration is: Among them, SF′ Al is the calibration relationship factor of the aluminum simulation body for recalibration, β′ Al is the burnup correction factor of the self-powered neutron detector when irradiated with the aluminum dummy body 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.

4. The method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation according to claim 3, characterized in that: The method for obtaining the scale relationship factor of the silicon single crystal to be irradiated is: SF′ Si =SF′ Al α / β′ Si ; 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 when the silicon single crystal to be irradiated is irradiated.

5. The method for online monitoring signal calibration of thermal neutron flux of silicon single crystal irradiation according to claim 4, characterized in that: The method for obtaining the irradiation thermal neutron flux of the silicon single crystal to be irradiated is: Obtaining an online monitoring value of the irradiation thermal neutron injection rate of the silicon single crystal to be irradiated: φ′ th,Si (t)=SF′ Si I′ Si (t); Among them, φ ′ tj,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; Obtain the irradiation thermal neutron injection φ of the silicon single crystal to be irradiated during the entire irradiation process ′ th,Si : Where T is the total irradiation time.

6. 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.

7. 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 groups of activation detectors are arranged along the radial and axial positions inside the aluminum dummy for calibration and the aluminum dummy for re-calibration to determine the average value of the irradiated thermal neutron injection rate of the aluminum dummy for calibration and the aluminum dummy for re-calibration.

8. A method for online monitoring signal calibration of thermal neutron flux during irradiation of a silicon single crystal according to claim 6 or 7, characterized in that: The material of the activation detector is selected from gold and / or cobalt and / or silver and / or iron and / or scandium.

9. 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 simulant for calibration, the silicon single crystal for calibration, the aluminum simulant for re-calibration and the silicon single crystal to be irradiated are respectively placed in the same irradiation channel for irradiation. A self-powered neutron detector is arranged 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.

10. The method for online monitoring signal calibration of thermal neutron flux during irradiation of silicon single crystal according to claim 9, characterized in that: The axial height of the self-powered neutron detector in the irradiation channel corresponds to the irradiation position of the aluminum simulation body for calibration, the silicon single crystal for calibration, the aluminum simulation body for re-calibration and the silicon single crystal to be irradiated.

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