A radioactivity measuring sensor
By combining a CsI crystal lens layer with an avalanche photodiode, along with a ring array ion exciter and a spherical protrusion design, the problems of poor energy resolution and large size of existing radiometric measurement sensors are solved, realizing a miniaturized radiometric measurement sensor with high sensitivity and low power consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHENGDU UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2023-06-20
- Publication Date
- 2026-06-09
AI Technical Summary
Existing radiometric sensors suffer from poor energy resolution, large size, and high cost.
By combining a CsI crystal lens layer with an avalanche photodiode, along with a ring array ion exciter and a spherical bump design, the energy resolution is improved and the size is reduced. The high sensitivity and high signal-to-noise ratio of the avalanche photodiode are utilized to achieve efficient measurement through gas ionization within the micropore.
A miniaturized radioactive measurement sensor with high energy resolution and low energy consumption has been developed, featuring a high signal-to-noise ratio, large output signal, and accurate and reliable measurement.
Smart Images
Figure CN116755135B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of quantitative radioactivity measurement technology, and in particular to a radioactivity measurement sensor. Background Technology
[0002] Radioactivity measurement includes quantitative measurement and localization measurement. Quantitative measurement refers to measuring radioactivity activity, energy, half-life, etc., while localization measurement visually displays the radioactivity in a sample. The radioactivity measurement discussed in this article belongs to quantitative measurement. Currently, the principles of existing quantitative radioactivity measurement mainly include ionization effect, fluorescence effect, photosensitivity effect, and Cherenkov effect. The ionization effect refers to the phenomenon where, when radiation passes through a gas, gas molecules and atoms are ionized under the influence of an electric field, producing a pair of ions (electrons and positive ions), and the electrical signal generated by the aggregation of these ions at the electrodes can be measured. The fluorescence effect refers to the phenomenon where, when radiation is absorbed by certain special substances, a portion of its energy is re-emitted as ultraviolet or visible light. The photosensitivity effect refers to the phenomenon where radiation acts on latex to produce a latent image. The Cherenkov effect refers to the phenomenon where high-speed charged particles can emit light (visible ultraviolet light) when passing through matter.
[0003] Currently, most existing radioactivity measurements utilize NaI probes, as seen in Chinese invention patents such as CN218956815U ("A Mobile Radioactive Inert Gas Monitoring Device") and CN116088025A ("A Marine Radioactive Adaptive Detection System and Method"). NaI(TI) has a high light yield, high PMT (photomultiplier tube) amplification gain, and relatively low price; therefore, NaI probes are highly favored in the field of energy spectrum measurement. However, when NaI(TI) is paired with a PMT as a probe, its energy resolution is poor, and it occupies a large volume.
[0004] Therefore, there is an urgent need to develop a simple, accurate, and reliable radiometric sensor. Summary of the Invention
[0005] To address the above problems, the present invention aims to provide a radioactivity measurement sensor. The technical solution adopted by the present invention is as follows:
[0006] A radioactivity measurement sensor, comprising:
[0007] Silicon substrate;
[0008] An avalanche photodiode is located on the silicon substrate layer;
[0009] An ion exciter, arranged in a ring array, is placed on the avalanche photodiode. The ion exciter includes: a charge layer embedded in the avalanche photodiode; a first electrode layer located on the charge layer; a CsI crystal lens layer located on the first electrode layer; and a micropore disposed in the center of the first electrode layer. A spherical protrusion is provided on the CsI crystal lens layer on the side away from the avalanche photodiode. The CsI crystal lens layer collects radiation and ionizes gas within the micropore.
[0010] The second electrode layer is located at the bottom of the silicon substrate layer.
[0011] Furthermore, an insulating buried oxide layer is disposed on the silicon substrate; the buried oxide layer encapsulates the lower part of the ion exciter and the avalanche photodiode.
[0012] Furthermore, a capacitor is embedded within the buried oxide layer; the capacitor is connected to the first electrode layer and the second electrode layer.
[0013] Furthermore, the avalanche photodiode includes:
[0014] An N-type silicon layer is disposed on a silicon substrate layer;
[0015] P-type silicon layer, integrated on N-type silicon layer;
[0016] A germanium absorber layer is integrated on a p-type silicon layer;
[0017] A silicon multiplication layer is integrated between the germanium absorber layer and the charge layer.
[0018] Furthermore, an electron absorption layer is disposed within the micropore; the outer side of the electron absorption layer is integrated on the first electrode layer.
[0019] Furthermore, a radioactive shielding layer is integrated on the lower side of the CsI crystal lens layer.
[0020] Furthermore, the radioactive shielding layer extends to the lower part of the charge layer.
[0021] Further, the capacitor includes:
[0022] A pair of electrode layers are connected one-to-one with the first electrode layer and the second electrode layer;
[0023] A dielectric layer is placed between the pair of electrode layers.
[0024] Compared with the prior art, the present invention has the following beneficial effects:
[0025] (1) This invention uses a CsI crystal lens layer to obtain the maximum light collection efficiency. Since the average atomic number and density of CsI are higher than those of NaI, it absorbs more gamma rays, obtains more ionization energy, and thus excites more ions. This invention uses a matched combination of CsI crystal and avalanche photodiode, which has higher detection efficiency and better energy resolution.
[0026] (2) The present invention uses a combination of CsI crystal and avalanche photodiode for matching, which results in a smaller probe size compared to NaI(TI) matched PMT (photomultiplier tube).
[0027] (3) The present invention provides spherical protrusions and gathers rays into micropores to achieve gas ionization, which concentrates energy and further improves energy resolution.
[0028] (4) By setting an avalanche photodiode, the quantum efficiency of the avalanche photodiode is more than five times that of a photomultiplier tube, and it has low energy consumption, small size, and built-in gain of around 100. The avalanche photodiode has a high signal-to-noise ratio, high energy spectrum resolution, and large output signal, which is convenient for accurate measurement.
[0029] (5) The present invention uses a ring array to set up ion exciters, which has a large coverage area. When ionizing ions, it is superior to a single integral ion exciter of the same shape and size, that is, the effective ionization area of several ion exciters is greater than the effective ionization area of a single integral ion exciter. The present invention increases the effective ionization contact area by setting up several distributed micropores. Under the convergence effect of the CsI crystal lens layer, ionization is more easily generated in the micropores, which facilitates the generation of avalanche gain and improves sensitivity.
[0030] In summary, this invention has the advantages of simple structure and accurate and reliable measurement, and has high practical and promotional value in the field of quantitative radioactivity measurement technology. Attached Figure Description
[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope of protection. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a schematic diagram of the internal structure of the present invention.
[0033] Figure 2 This is a cross-sectional schematic diagram of the present invention.
[0034] Figure 3 for Figure 2An enlarged diagram of A in the diagram.
[0035] Figure 4 This is a schematic diagram of the ray transmission path of the present invention.
[0036] In the above figures, the component names corresponding to the reference numerals are as follows:
[0037] 100, Silicon substrate layer; 200, Buried oxide layer; 300, Capacitor; 400, Ion exciter; 110, N-type silicon layer; 120, P-type silicon layer; 130, Germanium absorber layer; 140, Silicon multiplication layer; 150, Charge layer; 160, First electrode layer; 170, CsI crystal lens layer; 180, Electron absorber layer; 190, Radioactive shielding layer; 310, Electrode layer; 320, Dielectric layer; A, Region where the ion exciter is located. Detailed Implementation
[0038] To make the objectives, technical solutions, and advantages of this application clearer, the present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.
[0039] Example
[0040] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.
[0041] The terms "first" and "second," etc., used in the specification and claims of this embodiment are used to distinguish different objects, not to describe a specific order of objects. For example, "first target object" and "second target object," etc., are used to distinguish different target objects, not to describe a specific order of target objects.
[0042] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.
[0043] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more. For example, multiple processing units means two or more processing units; multiple systems means two or more systems.
[0044] like Figures 1 to 4 As shown, this embodiment provides a radioactivity measurement sensor that uses a combination of CsI crystal and avalanche photodiode, which improves sensitivity while reducing size. In this embodiment, the avalanche photodiode is a through-type. Specifically, the radioactivity measurement sensor of this embodiment mainly includes: a second electrode layer, a silicon substrate layer 100, an avalanche photodiode, an ion exciter 400, a buried oxide layer 200, and a capacitor 300. The buried oxide layer 200 encloses the lower part of the ion exciter 400 and the avalanche photodiode. The avalanche photodiode is electrically connected to the second electrode layer. After acquiring radiation, the ion exciter 400 ionizes electrons and positive ions in a micropore. The positive ions are absorbed by the avalanche photodiode, generating avalanche gain, which is ultimately transferred to the capacitor 300. In this embodiment, the capacitor 300 serves as a positive and negative electron storage device and is externally connected to pins to obtain the measured data.
[0045] In this embodiment, the avalanche photodiode is disposed on a silicon substrate 100. From bottom to top, it consists of an N-type silicon layer 110, a P-type silicon layer 120, a germanium absorber layer 130, and a silicon multiplication layer 140. The charge layer 150 receives ionized positive ions, which are then amplified by the silicon multiplication layer 140 and absorbed by the germanium absorber layer 130. The avalanche gain of the avalanche photodiode follows a well-known principle for this type of diode and will not be elaborated further here.
[0046] In this embodiment, the ion exciter 400 ring array is placed on the avalanche photodiode. If a single, uniformly sized, integral ion exciter is used in this embodiment, the equivalent area of its focused beam is relatively small. Therefore, by using several ion exciters 400, each with corresponding micropores, and then using a charge layer 150 for focusing, the equivalent area is larger than that of the integral ion exciter. In other words, the integral ion exciter focuses the beam at its center, and when the micropores are too large, the ionization energy is more dispersed, resulting in lower sensitivity.
[0047] In this embodiment, the ion exciter 400 includes a charge layer 150 embedded in a silicon multiplication layer 140, a first electrode layer 160 located on the charge layer 150, a CsI crystal lens layer 170 located on the first electrode layer 160, a micropore disposed in the center of the first electrode layer 160, an electron absorption layer 180 disposed within the micropore and integrated on the first electrode layer 160, and a radioactive shielding layer 190 integrated on the lower side of the CsI crystal lens layer 170. The radioactive shielding layer 190 can extend to the lower part of the charge layer 150 to shield rays incident from the sidewalls of the first electrode layer 160, the charge layer 150, and the CsI crystal lens layer 170. Rays incident in this direction will not be concentrated within the micropore and will not ionize. In this embodiment, an insulating barrier is used between the bottom of the first electrode layer 160 and the electron absorption layer 180 and the charge layer 150, which can be filled with a buried oxide layer 200 of insulating material.
[0048] In this embodiment, to achieve X-ray focusing and transmission into the micropore, a spherical protrusion is provided on the CsI crystal lens layer 170, on the side away from the avalanche photodiode. This embodiment utilizes the CsI crystal lens layer 170 to focus the X-rays and ionize the gas within the micropore.
[0049] In this embodiment, to achieve positive and negative electron storage, the capacitor 300 is embedded in the buried oxide layer 200, and the buried oxide layer 200 is made of an insulating material. The capacitor 300 includes a pair of electrode layers 310 and a dielectric layer 320. The electrode layers 310 are respectively connected to the first electrode layer 160 and the second electrode layer, and the dielectric layer 320 is placed between the electrode layers 310.
[0050] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any changes made based on the design principles of the present invention, or any non-creative modifications made thereon, shall fall within the scope of protection of the present invention.
Claims
1. A radioactivity measurement sensor, characterized in that, include: Silicon substrate (100); An avalanche photodiode is located on the silicon substrate (100); An ion exciter (400) is arranged in a ring array on the avalanche photodiode. The ion exciter (400) includes: a charge layer (150) embedded in the avalanche photodiode; a first electrode layer (160) located on the charge layer (150); a CsI crystal lens layer (170) located on the first electrode layer; and a micropore disposed in the center of the first electrode layer (160). A spherical protrusion is disposed on the CsI crystal lens layer (170) on the side away from the avalanche photodiode. The CsI crystal lens layer (170) collects radiation and ionizes the gas in the micropore. The CsI crystal lens layer (170) collects radioactive radiation and ionizes the gas in the micropore to generate ion pairs. The ion pairs are absorbed by the avalanche photodiode through the charge layer (150) and generate avalanche gain. The second electrode layer is located at the bottom of the silicon substrate layer (100).
2. The radioactivity measurement sensor according to claim 1, characterized in that, An insulating buried oxide layer (200) is disposed on the silicon substrate layer (100); the buried oxide layer (200) encloses the lower part of the ion exciter (400) and the avalanche photodiode.
3. A radioactivity measurement sensor according to claim 2, characterized in that, A capacitor (300) is embedded in the buried oxide layer (200); the capacitor (300) is connected to the first electrode layer (160) and the second electrode layer.
4. A radioactivity measurement sensor according to claim 1, 2, or 3, characterized in that, The avalanche photodiode includes: An N-type silicon layer (110) is disposed on a silicon substrate layer (100); A P-type silicon layer (120) is integrated on an N-type silicon layer (110); A germanium absorber layer (130) is integrated on a p-type silicon layer (120); A silicon multiplication layer (140) is integrated between a germanium absorber layer (130) and a charge layer (150).
5. A radioactivity measurement sensor according to claim 1, characterized in that, An electron absorption layer (180) is disposed inside the micropore; the outer side of the electron absorption layer (180) is integrated on the first electrode layer (160).
6. A radioactivity measurement sensor according to claim 1, characterized in that, A radioactive shielding layer (190) is integrated on the lower side of the CsI crystal lens layer (170).
7. A radioactivity measuring sensor according to claim 6, characterized in that, The radioactive shielding layer (190) extends to the lower part of the charge layer (150).
8. A radioactivity measurement sensor according to claim 3, characterized in that, The capacitor (300) includes: A pair of electrode layers (310) are connected one-to-one with the first electrode layer (160) and the second electrode layer; A dielectric layer (320) is placed between a pair of electrode layers (310).