Uranium layer thickness uniformity measuring method and uranium layer thickness uniformity measuring device

Abstract

The invention discloses a uranium layer thickness uniformity measuring and calculating method, which relates to the technical field of nuclear physical detection, and comprises the following steps: measuring the whole uranium layer on the surface of an electrode, firstly measuring the alpha particle emissivity of the whole surface of the electrode and a measured unit through a semiconductor detector, and then calculating to obtain the thickness uniformity of the uranium layer on the surface of the electrode. In the whole testing process, the semiconductor detector does not make contact with the electrodes, the uranium layer cannot be damaged, the semiconductor detector is high in precision and accurate in measurement result, and the uranium layer thickness uniformity can be reflected by the calculation result of the uranium layer thickness uniformity deviation coefficient. The invention further provides a uranium layer thickness uniformity measuring device which is applied to the uranium layer thickness uniformity measuring and calculating method, the alpha particles released by the uranium layer can be measured under the non-contact condition, the emissivity of the alpha particles is directly obtained, and data are provided for the uranium layer thickness uniformity deviation coefficient.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear physics detection, in particular to a method for calculating the uniformity of uranium layer thickness and a device for measuring the uniformity of uranium layer thickness. Background Art

[0002] The microfission chamber is an important device in the field of nuclear physics detection technology, which is used to detect the neutron injection rate of the reactor core. The microfission chamber is usually composed of an electrode and a shell, in which the electrode is a key part and needs to be plated with uranium. In order to ensure that the test meets the standard, the thickness of the uranium layer should be uniform. However, due to the small volume of the electrode and the extremely limited operating area, the determination of the uniformity of the thickness of the uranium layer is difficult. In the field of electrode manufacturing and measurement technology, the traditional method for measuring the uniformity of the thickness of the uranium layer is mainly through weighing measurement, that is, a high-precision balance weighs the entire electrode, calculates the total weight of the uranium layer, and then calculates the theoretical volume of the uranium layer by the weight of the uranium layer and the density of the uranium layer to estimate the average thickness of the uranium layer. However, the above method cannot accurately measure the thickness uniformity of the uranium layer, and direct contact with the uranium-plated electrode may cause damage to the uranium layer. In addition, the thickness of the uranium layer at the observation point can also be estimated by observing the appearance of the uranium layer, such as color, shape, etc., and the uniformity of the uranium layer thickness can be judged after summarizing the observation results.

[0003] However, the results obtained by the above methods are all estimated values, and there is no accurate result. Therefore, a method that can accurately measure the uniformity of the uranium layer thickness is needed. Summary of the invention

[0004] The purpose of the present invention is to provide a method for measuring the uniformity of uranium layer thickness to solve the problems existing in the above-mentioned prior art. First, the alpha particle emission rate of the entire electrode surface and the measured unit is measured by a semiconductor detector, and then the uniformity of the uranium layer thickness on the electrode surface can be obtained by calculation. During the entire test process, the semiconductor detector does not contact the electrode and will not damage the uranium layer. The semiconductor detector has high precision and accurate measurement results. The calculation result of the uranium layer thickness uniformity deviation coefficient can reflect the uniformity of the uranium layer thickness.

[0005] The present invention also provides a uranium layer thickness uniformity measuring device, which is applied to the above-mentioned uranium layer thickness uniformity measuring method, can measure the α particles released by the uranium layer without contact, directly obtain the α particle emission rate, and provide data for the uranium layer thickness uniformity deviation coefficient.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a method for calculating the uniformity of uranium layer thickness, comprising the following steps:

[0008] S1. Divide the outer cylindrical surface of the cylindrical electrode into A identical measurement areas along the circumferential direction, and number the measurement areas from 1 to A;

[0009] S2. Use a semiconductor detector to measure the measurement areas 1 to A in sequence to obtain the alpha particle emission rate of each measurement area, recorded as N 1 ~N A ;

[0010] S3, dividing each of the measurement areas into B identical measurement units in the axial direction, and the measurement units are numbered 11 to AB;

[0011] S4. Measure each measurement unit in each measurement area through a semiconductor detector to obtain the alpha particle emission rate of each measurement unit, which is recorded as N 11 ~N AB ;

[0012] S5. Calculate the total alpha particle emission rate of the electrode N = (N 1 +N 2 +···+N A )*k, where k is the edge correction coefficient and k is a constant;

[0013] S6. Calculate the average alpha particle emission rate for each measurement unit

[0014] S7. Calculate the uniformity deviation coefficient of uranium layer thickness for each measurement unit

[0015] Preferably, in step S1, the area of ​​each measurement region is at least one quarter of the side area of ​​the electrode.

[0016] Preferably, in step S1, the bottom edge of the electrode is equally divided into A arc segments of equal length, the arc segments divided on the two bottom surfaces of the electrode correspond one to one, and the endpoints of the corresponding arc segments are drawn by line segments parallel to the electrode axis, so that the side of the electrode is divided into A identical measurement areas.

[0017] Preferably, in step S3, B-1 arc segments parallel to the bottom surface of the electrode are marked at equal intervals along the axial direction of the electrode in the measurement area to obtain B identical measurement units.

[0018] Preferably, in step S2 and step S4, after calibrating the alpha particle emission peak to 4.4 MeV, the alpha particles in the energy range of 0.4 MeV to 4.4 MeV are counted, and the total count value is recorded as X, X is not less than 2500, and X is divided by the counting time to obtain an average counting rate as the alpha particle emission rate.

[0019] Preferably, in step S4, the semiconductor measuring detector moves along the radial direction of the electrode.

[0020] Preferably, in step S2 and step S4, the operating voltage of the semiconductor detector is 100 volts and the operating temperature is 25 degrees Celsius.

[0021] The present invention also provides a uranium layer thickness uniformity measuring device, comprising a pulse test instrument, a detector bracket and an electrode bracket, wherein the detector bracket is arranged on the electrode bracket, the semiconductor detector is arranged on the detector bracket, and the incident window of the semiconductor detector is directly opposite to the electrode installed on the electrode bracket; the two bottom surfaces of the electrode are clamped on the electrode mounting position of the electrode bracket, and the electrode mounting position can rotate around the axis of the electrode.

[0022] Preferably, the detector bracket includes a mounting plate, a slide rail and a slider for setting the semiconductor detector, the mounting plate is set on the electrode bracket, the slide rail is set on the mounting plate, and the slider is set on the slider; the axis of the slide rail is parallel to the axis of the electrode.

[0023] Preferably, the semiconductor detector is a gold-silicon surface barrier detector.

[0024] Compared with the prior art, the present invention has achieved the following technical effects:

[0025] The present invention provides a method for measuring the uniformity of uranium layer thickness. The method comprises the following steps: firstly, the alpha particle emission rates of the entire electrode surface and the measured unit are measured by a semiconductor detector, and then the uniformity of the uranium layer thickness on the electrode surface can be obtained by calculation. During the whole test process, the semiconductor detector does not contact the electrode and will not damage the uranium layer. The semiconductor detector has high precision and accurate measurement results. The calculation result of the deviation coefficient of the uniformity of the uranium layer thickness can reflect the uniformity of the uranium layer thickness.

[0026] The present invention also provides a uranium layer thickness uniformity measuring device, which is applied to the above-mentioned uranium layer thickness uniformity measuring method, can measure the α particles released by the uranium layer without contact, directly obtain the α particle emission rate, and provide data for the uranium layer thickness uniformity deviation coefficient.

[0027] Compared with the prior art, the present invention has also achieved the following technical effects:

[0028] 1. In the present invention, after a sufficient number of α particles are collected, the α particle emission rate is determined by calculating the average emission rate. Compared with direct measurement in a short time, the present invention can better eliminate measurement errors.

[0029] 2. In the present invention, the electrode is divided into a plurality of measuring units. The more the number of measuring units is, the smaller the unit area to be measured is, and the more the measurement error can be eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 Schematic diagram of the structure of a uranium layer thickness uniformity measuring device in an embodiment of the present invention;

[0032] Figure 2 It is a structural schematic diagram of a detector bracket in an embodiment of the present invention;

[0033] Figure 3 Schematic diagram of the combined structure of the mounting frame and the slide rail in an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of the combined structure of the mounting frame, the slide rail and the slider in the embodiment of the present invention;

[0035] Figure 5 A schematic diagram of the structure of a semiconductor detector in an embodiment of the present invention;

[0036] Figure 6 It is a structural schematic diagram of a slider in an embodiment of the present invention;

[0037] Figure 7 Schematic diagram of the structure of the electrode support in an embodiment of the present invention;

[0038] Figure 8 Schematic diagram of the structure of the electrode in an embodiment of the present invention.

[0039] Among them, 1. Pulse test instrument; 2. Detector bracket; 201. Mounting frame; 202. Slide rail; 203. Slider; 204. Semiconductor detector; 3. Electrode bracket; 4. Electrode. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The purpose of the present invention is to provide a method for measuring the uniformity of uranium layer thickness to solve the problems existing in the above-mentioned prior art. First, the alpha particle emission rate of the entire electrode surface and the measured unit is measured by a semiconductor detector, and then the uniformity of the uranium layer thickness on the electrode surface can be obtained by calculation. During the entire test process, the semiconductor detector does not contact the electrode and will not damage the uranium layer. The semiconductor detector has high precision and accurate measurement results. The calculation result of the uranium layer thickness uniformity deviation coefficient can reflect the uniformity of the uranium layer thickness.

[0042] The present invention also provides a uranium layer thickness uniformity measuring device, which is applied to the above-mentioned uranium layer thickness uniformity measuring method, can measure the α particles released by the uranium layer without contact, directly obtain the α particle emission rate, and provide data for the uranium layer thickness uniformity deviation coefficient.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] The present invention provides a method for calculating the uniformity of uranium layer thickness, comprising the following steps:

[0045] S1. Divide the outer cylindrical surface of the cylindrical electrode into A identical measurement areas along the circumferential direction, and number the measurement areas from 1 to A;

[0046] S2. Use semiconductor detectors to measure measurement areas 1 to A in turn to obtain the alpha particle emission rate of each measurement area, recorded as N 1 ~N A ;

[0047] S3, dividing each measurement area into B identical measurement units in the axial direction, and the measurement units are numbered 11 to AB;

[0048] S4. Measure each measurement unit in each measurement area through a semiconductor detector to obtain the alpha particle emission rate of each measurement unit, which is recorded as N 11 ~N AB ;

[0049] S5. Calculate the total alpha particle emission rate of the electrode N = (N 1 +N 2 +···+N A )*k, where k is the edge correction coefficient and k is a constant;

[0050] S6. Calculate the average alpha particle emission rate for each measurement unit

[0051] S7. Calculate the uniformity deviation coefficient of uranium layer thickness for each measurement unit

[0052] Particle emission rate is a concept in physics, which refers to the number of particles emitted by an ion source per second. Uranium-235 is usually used as a coating material on the electrodes of a micro-fission chamber. Uranium-235 will emit alpha particles due to decay. The energy of the alpha particles emitted by uranium-235 is about 4.4 mega-electron volts. The range of alpha particles in air is about 28 mm and the range in uranium is about 10 microns. Under normal circumstances, the thickness of uranium-235 on the electrode is about 0.1 micron to 1 micron, so the alpha particles generated by decay can completely transmit the uranium layer. At the same time, the thicker the uranium layer, the more alpha particles are generated by half-decay. Therefore, the number of alpha particles emitted by uranium-235 decay can be equivalent to the thickness of the uranium layer. The detection effect of semiconductor detectors on alpha particles is close to 100%, and the number of alpha particles can be well determined. Therefore, the present invention uses semiconductor detectors as alpha particle detectors.

[0053] In the step of calculating the uranium layer thickness uniformity deviation coefficient, the edge correction coefficient k is canceled, so the value of k does not affect the final value of the uranium layer thickness uniformity deviation coefficient. The edge correction coefficient k is introduced to correct the influence of α particles released at the connection between the bottom surface of the electrode and the side surface of the electrode on the measurement.

[0054] In step S1, the area of ​​each measuring region is at least one quarter of the side area of ​​the electrode. Under current technical conditions, in order to ensure that the semiconductor detector can effectively detect alpha particles, the incident window of the semiconductor detector is required to cover one quarter of the uranium plating area on the electrode surface. However, the number of alpha particles can be measured even if the incident window of the semiconductor detector covers less than one quarter of the electrode surface.

[0055] In step S1, the method of dividing the measurement area is to divide the bottom edge of the electrode into A arc segments of equal length. The arc segments divided on the two bottom surfaces of the electrode correspond to each other one by one. The endpoints of the corresponding arc segments are divided into A identical measurement areas by line segments parallel to the electrode axis.

[0056] In step S3, the method of dividing the measurement units is to mark B-1 arc segments parallel to the bottom surface of the electrode at equal intervals along the axial direction of the electrode in the measurement area to obtain B identical measurement units.

[0057] In step S2 and step S4, after the alpha particle emission peak is calibrated to 4.4 MeV, the alpha particles in the energy range of 0.4 MeV to 4.4 MeV are counted, and the total count value is recorded as X, X is not less than 2500, and X is divided by the counting time to obtain the average counting rate as the alpha particle emission rate.

[0058] In step S4, the semiconductor measuring probe moves along the radial direction of the electrode to switch the measuring unit under test.

[0059] In step S2 and step S4, the operating voltage of the semiconductor detector is 100 volts and the operating temperature is 25 degrees Celsius. At this time, the semiconductor detector is in the best working state. In a preferred embodiment, the present invention adopts the GM30 semiconductor detector developed by China Nuclear Control Systems Engineering Co., Ltd.

[0060] like Figures 1 to 8 As shown, the present invention also provides a uranium layer thickness uniformity measuring device, including a pulse test instrument 1, a detector bracket 2 and an electrode bracket 3, the detector bracket 2 is arranged on the electrode bracket 3, the semiconductor detector 204 is arranged on the detector bracket 2, the incident window of the semiconductor detector 204 is directly opposite to the electrode 4 installed on the electrode bracket 3, the two bottom surfaces of the electrode 4 are clamped on the electrode mounting position of the electrode bracket 3, the electrode mounting position can rotate around the axis of the electrode 4, and the detector bracket 2 can also drive the semiconductor detector 204 to rotate around the electrode 4.

[0061] like Figure 2 to Figure 7 As shown, the detector bracket 2 includes a mounting plate 201, a slide rail 202 and a slider 203 for setting the semiconductor detector 203. The mounting plate 201 is set on the electrode bracket 3, the slide rail 201 is set on the mounting plate 201, and the slider 202 is set on the slider 202. The axis of the slide rail 201 is parallel to the axis of the electrode 4 to ensure that the semiconductor detector 204 can move along the electrode. In a preferred embodiment, the electrode 4 has a length of 30 mm and a diameter of 5 mm. The incident window of the semiconductor detector 204 is initially set at a vertical position of 2 mm above the electrode 4. The shooting range of the incident window can be adjusted by changing the way the semiconductor detector 204 enters the electrode 4.

[0062] The semiconductor detector 204 in the present invention may be a gold-silicon surface barrier detector, a PIPS detector (passivated ion implanted planar silicon detector) or a silicon PIN detector (silicon photodetector).

[0063] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for calculating the uniformity of uranium layer thickness, characterized in that: The following steps are included: S1. Divide the outer cylindrical surface of the cylindrical electrode into A identical measurement areas along the circumferential direction, and number the measurement areas from 1 to A; S2, using a semiconductor detector to measure the measurement areas 1 to A in sequence, and obtain the alpha particle emission rate of each measurement area, recorded as N1 to N A ; S3, dividing each of the measurement areas into B identical measurement units in the axial direction, and the measurement units are numbered 11 to AB; S4. Measure each measurement unit in each measurement area through a semiconductor detector to obtain the alpha particle emission rate of each measurement unit, which is recorded as N 11 ~N AB ; S5. Calculate the total alpha particle emission rate of the electrode N = (N1 + N2 + ... + N A )*k, where k is the edge correction coefficient and k is a constant; S6. Calculate the average alpha particle emission rate for each measurement unit S7. Calculate the uniformity deviation coefficient of uranium layer thickness for each measurement unit 2. The method for calculating the uniformity of uranium layer thickness according to claim 1, characterized in that: In step S1, the area of ​​each measurement region is at least one quarter of the side area of ​​the electrode.

3. The method for calculating the uniformity of uranium layer thickness according to claim 1, characterized in that: In step S1, the bottom edge of the electrode is equally divided into A arc segments of equal length, the arc segments divided on the two bottom surfaces of the electrode correspond one to one, and the endpoints of the corresponding arc segments are divided into A identical measurement areas by line segments parallel to the electrode axis.

4. The method for calculating the uniformity of uranium layer thickness according to claim 1, characterized in that: In step S3, B-1 arc segments parallel to the bottom surface of the electrode are marked at equal intervals along the axial direction of the electrode in the measurement area to obtain B identical measurement units.

5. The method for calculating the uniformity of uranium layer thickness according to claim 1, characterized in that: In step S2 and step S4, after the alpha particle emission peak is calibrated to 4.4 MeV, the alpha particles in the energy range of 0.4 MeV to 4.4 MeV are counted, and the total count value is recorded as X, X is not less than 2500, and X is divided by the counting time to obtain the average counting rate as the alpha particle emission rate.

6. The method for calculating the uniformity of uranium layer thickness according to claim 1, characterized in that: In step S4, the semiconductor measuring probe moves in the radial direction of the electrode.

7. The method for calculating the uniformity of uranium layer thickness according to claim 1, characterized in that: In step S2 and step S4, the operating voltage of the semiconductor detector is 100 volts and the operating temperature is 25 degrees Celsius.

8. A device for measuring the uniformity of uranium layer thickness, characterized in that: The invention comprises a pulse test instrument (1), a detector support (2) and an electrode support (3), wherein the detector support (2) is arranged on the electrode support (3), the semiconductor detector (204) is arranged on the detector support (2), and the incident window of the semiconductor detector (204) faces the electrode (4) mounted on the electrode support (3); The two bottom surfaces of the electrode (4) are clamped on the electrode mounting position of the electrode bracket (3), and the electrode mounting position can rotate around the axis of the electrode (4).

9. The uranium layer thickness uniformity measuring device according to claim 8, characterized in that: The detector support (2) comprises a mounting plate (201), a slide rail (202) and a slider (203) for setting the semiconductor detector (203), the mounting plate (201) being arranged on the electrode support (3), the slide rail (201) being arranged on the mounting plate (201), and the slider (202) being arranged on the slider (202); The axis of the slide rail (201) is parallel to the axis of the electrode (4).

10. The uranium layer thickness uniformity measuring device according to claim 8, characterized in that: The semiconductor detector (204) is a gold-silicon surface barrier detector.

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