CN112526576B - Ophthalmic lens dose measurement device and method - Google Patents

Abstract

The invention discloses an eye lens dosage measuring device and a method, comprising a Si-EJ276 detector and a control module; the Si-EJ276 detector comprises a Si detector and an EJ276 crystal detector which are sequentially arranged along the incidence direction of radiation particles, the Si detector is coupled with the EJ276 crystal detector, and the EJ276 crystal detector comprises an EJ276 crystal and a silicon photomultiplier; the control module is arranged on the Si-EJ276 detector, the EJ276 crystal detector outputs signal waveforms with different speed components under the condition of different radiation particles, and the control module is used for carrying out pulse signal processing on output signals of the EJ276 crystal detector, distinguishing the radiation particles and obtaining the energy and flux of the radiation particles. According to the invention, the Si detector and the EJ276 crystal detector are coupled to form the Si-EJ276 detector, the EJ276 crystal has small density, the EJ276 crystal and the crystalline lens have good structural equivalence, the measurement precision of the detector is obviously improved, the charged particle type discrimination and energy measurement are realized, the measurement function of the energy transmission line density LET is realized, and the purpose of composite measurement is achieved.

Description

Ophthalmic lens dose measurement device and method

technical field

The present invention relates to the technical field of space radiation detection, and in particular, to an ocular lens dose measurement device and method.

Background technique

In the space station, astronauts are inevitably exposed to the space radiation environment in the cabin. Space ionizing radiation is one of the important factors affecting the health of astronauts in manned spaceflight. Because of the threat of space radiation to human space exploration activities, space radiation dose measurement has always been a matter of great concern to scientists. In particular, the risk of neurodegenerative diseases such as charged particles in space is high. The ocular lens is a radiation-sensitive organ, and the radiation monitoring of the ocular lens is of great significance to the health assessment of astronauts. At present, the detection of the radiation dose of the ocular lens relies on passive dose monitoring devices, such as thermoluminescence sheets, etc. For example, the measurement of the ocular lens only relies on passive thermoluminescence detectors to measure, only the accumulated dose is obtained, and real-time measurement is not possible. However, the density of scintillation crystals is quite different from that of ocular lenses, and the tissue equivalence is poor, so the measurement accuracy is poor.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, one object of the present invention is an ocular lens dose measurement device, comprising a Si-EJ276 detector and a control module;

The Si-EJ276 detector includes a Si detector and an EJ276 crystal detector arranged in sequence along the incident direction of the radiation particles, the Si detector and the EJ276 crystal detector are coupled, and the EJ276 crystal detector includes an EJ276 crystal and a silicon photomultiplier tube, the silicon photomultiplier tube is coupled with the EJ276 crystal;

The control module is set on the Si-EJ276 detector. The EJ276 crystal detector outputs signal waveforms of different fast and slow components in the case of different radiation particles. The control module is used to perform pulse signal processing on the output signal of the EJ276 crystal detector. Then, the radiated particles are distinguished and the energy and flux of the radiated particles are obtained.

Using the above technical solution, the EJ276 crystal has a diameter of 0.8-1.2 inches and a thickness of 0.8-1.2 inches.

Using the above technical solution, the EJ276 crystal has a diameter of 1 inch and a thickness of 1 inch.

With the above technical solution, the sensitive area of the Si detector is 15-20 mm in diameter and 280-320 μm in thickness.

With the above technical solution, the Si-EJ276 detector includes a casing that wraps the coupled Si detector and the EJ276 crystal detector.

Using the above technical solution, the Si-EJ276 detector includes a preamplifier and an analog-to-digital converter;

The output end of the Si detector and the output end of the silicon photomultiplier tube are respectively coupled with a preamplifier, and the preamplifier is used to preliminarily amplify the signal output by the Si detector and the electrical signal at the output end of the silicon photomultiplier tube;

The analog-to-digital converter is coupled to the output end of the preamplifier on the Si detector, and the analog-to-digital converter is used to perform analog-to-digital conversion on the signal amplified by the preamplifier.

Using the above technical solution, the Si-EJ276 detector further includes a bias power supply, and the bias power supply is arranged inside the Si-EJ276 detector.

Another object of the present invention is to provide a space radiation detection method, comprising:

When the radiation particles pass through the Si detector, they interact with Si atoms, and the energy loss value ΔE is recorded;

When the secondary particles generated by the interaction of radiation particles and Si atoms or the original radiation particles without interaction pass through the EJ276 crystal detector, the EJ276 crystal absorbs the remaining energy of the particles;

The energy loss value ΔE measured by the Si detector is divided by the thickness of the Si detector to obtain the energy transfer line density spectrum;

The EJ276 crystal detector generates signal waveforms with different fast and slow components in the case of different radiation particles. After the control module processes the output signal of the EJ276 crystal detector, it can distinguish the radiation particles and obtain the energy and flux of the radiation particles.

Using the above technical solution, the described distinguishing radiation particles and obtaining the energy and flux of the radiation particles include:

Integrate the decayed slow components in the signal waveform to obtain the neutron event, and obtain the energy spectrum and flux information of the fast neutron in the neutron event;

The fast component in the signal waveform is identified as a gamma ray event, and the energy spectrum information of the gamma ray is obtained after distinguishing the gamma ray from the neutron.

Using the above technical solution, the energy and flux of thermal neutrons and fast neutrons are obtained in the event of neutrons, including;

In the event of neutrons, the energy spectrum and flux information of fast neutrons are obtained by inverting the kinetic energy of protons.

The beneficial effects of the present invention: the present invention adopts the Si detector and the EJ276 crystal detector to couple to form a Si-EJ276 detector, the density of the EJ276 crystal is small, the tissue equivalence between the EJ276 crystal and the lens is good, and the performance of the detector is significantly improved. The measurement accuracy can realize the measurement function of the linear energy transfer density LET while realizing the type identification and energy measurement of charged particles, so as to achieve the purpose of compound measurement. The depth distribution information can meet the real-time detection requirements.

Description of drawings

FIG. 1 is a system block diagram of Embodiment 1 of the present invention.

Figure 2 is a schematic structural diagram of the Si-EJ276 detector of the present invention.

FIG. 3 is a bottom view of FIG. 2 .

FIG. 4 is a partial enlarged schematic view of the part A in FIG. 3 .

FIG. 5 is a schematic flowchart of Embodiment 2 of the present invention.

6 is a schematic diagram of the principle of the Si detector pulse signal processing circuit of the present invention.

7 is a schematic diagram of the principle of the pulse signal processing circuit of the EJ276 pulse amplitude discriminator of the present invention.

FIG. 8 is a schematic diagram of the functional structure of the data processing and communication control unit of the present invention.

Description of the symbols in the figure: 11, Si detector; 12, EJ276 crystal detector; 13, shell; 14, silicon photomultiplier; 15, preamplifier; 16, analog-to-digital converter; 17, EJ276 crystal; 2, control module.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments.

Examples of such embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

Example 1

Referring to FIG. 1 , Embodiment 1 of the present invention provides an ocular lens dose measurement device, including a Si-EJ276 detector and a control module 2. The Si-EJ276 detector includes a Si detector 11 and a Si detector 11 and EJ276 crystal detector 12, Si detector 11 is coupled with EJ276 crystal detector 12, EJ276 crystal detector 12 includes EJ276 crystal 17 and silicon photomultiplier tube 14, silicon photomultiplier tube 14 is coupled with EJ276 crystal 17, EJ276 crystal 17 uses silicon The photomultiplier tube 14 performs photoelectric conversion, and the silicon photomultiplier tube 14 can transmit at the speed of light and realize photoelectric conversion in a very short time; In the case of outputting signal waveforms with different fast and slow components, the control module 2 is used to process the output signal of the EJ276 crystal detector 12 by pulse signal, distinguish the radiation particles and obtain the energy and flux of the radiation particles.

The EJ276 crystal 17 has a diameter of 0.8-1.2 inches and a thickness of 0.8-1.2 inches. Preferably, the diameter of the EJ276 crystal 17 in this embodiment is 1 inch and the thickness is 1 inch. In addition, the sensitive area of the Si detector is 15-20 mm in diameter and 280-320 μm in thickness. In order to match the EJ276 crystal 17 with a diameter of 1 inch, this embodiment uses a Si detector 11 with a sensitive area diameter of 18 mm and a thickness of 300 μm. The Si detector 11 is coupled to the front end of the EJ276 crystal detector 12 to obtain the energy transfer line density The spectral LET, for example, the energy loss value ΔE measured by the Si detector 11 is divided by the thickness of the Si detector 11 to obtain the energy transfer linear density spectrum LET. There are also space high-energy particles that can be incident on the EJ276 crystal detector 12 from all directions, and the high-energy particles can penetrate the entire EJ276 crystal detector 12, and the particles penetrating in different directions can be traced in the EJ276 crystal detector 12. The lengths are different and the energy of the particles cannot be estimated by the energy deposition of the EJ276 crystal detector 12. Therefore, in this embodiment, a Si detector 11 is coupled to the front end of the EJ276 crystal detector 12, and a coincidence measurement is performed between the Si detector 11 and the EJ276 crystal detector 12, so as to realize only the detection of the Si detector 11 and the EJ276 crystal detector. 12 particles were measured.

Referring to Figure 2, Figure 3, Figure 4, the Si-EJ276 detector further includes a casing 13, the casing 13 wraps the coupled Si detector 11 and the EJ276 crystal detector 12, and is packaged through the casing 13, which can be well coupled Si detector 11 and EJ276 crystal detector 12 . When in use, the Si-EJ276 detector is installed in the space station to measure charged particles, gamma rays and neutrons.

1, the Si-EJ276 detector includes a preamplifier 15 and an analog-to-digital converter 16. The output end of the Si detector 11 and the output end of the silicon photomultiplier tube 14 are respectively coupled with the preamplifier 15. The preamplifier 15 is used for preliminarily amplifying the signal output by the Si detector 11 and the electrical signal at the output end of the silicon photomultiplier tube 14; the analog-to-digital converter 16 is coupled to the output end of the preamplifier 15 on the Si detector 11, the The digital converter 16 is used for analog-to-digital conversion of the signal amplified by the preamplifier 15 .

In addition, the Si-EJ276 detector needs to set a bias voltage, so the Si-EJ276 detector in this embodiment also includes a bias voltage power supply, and the bias voltage power supply is arranged inside the Si-EJ276 detector.

Among them, compared with the scintillation crystal, the EJ276 crystal 17 has a smaller density, and the tissue equivalence between the EJ276 crystal 17 and the lens is better, which significantly improves the measurement accuracy of the detector.

Example 2

Referring to FIG. 5 , Embodiment 2 of the present invention provides a method for detecting space radiation, including the following steps:

In step 101, the radiation particles interact with Si atoms when passing through the Si detector 11, and the energy loss value ΔE is recorded.

For example, when radiation particles (including charged and uncharged particles) are incident from the front end, the radiation particles interact with Si atoms when passing through the Si detector 11, and the energy loss value ΔE in the Si detector 11 is recorded, because The volume of the Si detector 11 is not very large. After the space radiation particles with high energy interact with the Si atoms, the generated secondary particles or the uninteracted original radiation particles have a high probability that they will continue along the incident direction or interact with the Si atoms. The incident direction moves at an angle.

In step 102 , when the secondary particles generated by the interaction between the radiation particles and the Si atoms or the original radiation particles that have not interacted pass through the EJ276 crystal detector 12 , the EJ276 crystal 17 absorbs the remaining energy of the particles.

In step 103 , the energy loss value ΔE measured by the Si detector 11 is divided by the thickness of the Si detector 11 to obtain a linear energy transfer density spectrum LET.

For example, using a Si detector to measure, the energy resolution is within 10%, and the measurement function of the linear energy transfer density LET can be realized. The measurement accuracy of the dose is within 10%, and the LET measurement index index of 0.4keV/μm～750keV/μm can also be satisfied at the same time. Considering the characteristics of space particle energy spectrum, LET spectrum measurement covers protons, α, ⁶ Li, ¹² C, ²⁴ Si, ⁵⁶ Fe, etc., and the energy covers protons of 10MeV/u–1GeV. Therefore, LET covers 0.42keV/μm-320keV /μm.

In step 104, the EJ276 crystal detector 12 generates signal waveforms with different fast and slow components in the case of different radiation particles, the control module 2 performs pulse signal processing on the output signal of the EJ276 crystal detector 12, differentiates the radiation particles and obtains the radiation particles energy and flux.

For example, first, the EJ276 crystal detector 12 generates signal waveforms with different fast and slow components in the case of different radiation particles; then the decayed slow components in the signal waveform are integrated to obtain neutron events, and the fast components in the signal waveform are identified as Gamma-ray events.

For example, in the event of neutrons, the energy spectrum and flux information of fast neutrons are obtained by inferring the kinetic energy of protons, and the energy spectrum information of gamma rays is obtained after distinguishing gamma rays from neutrons.

For example, the control module includes a pulse signal processing unit and a data processing and communication control unit. On the one hand, the pulse signal processing unit mainly includes the Si detector pulse signal processing circuit and the EJ276 pulse amplitude discriminator pulse signal processing circuit. After the output signal of the silicon detector is passed through the charge preamplifier, the waveform is first adjusted by the pole-zero cancellation circuit. , and then divided into 2 channels for filtering and shaping for amplitude measurement, and the other for fast amplification for trigger time analysis. Figure 6 shows the pulse signal processing circuit of the Si detector. In addition, for the EJ276 crystal output, in order to measure the energy in a large dynamic range, the output signal is amplified with high and low gain. The pulse signal processing circuit of the EJ276 pulse amplitude discriminator is shown in Figure 7. On the other hand, the data processing and communication control unit mainly includes a multi-channel amplitude signal acquisition circuit, a multi-channel time signal discrimination circuit, a module state monitoring circuit, a main control circuit and a communication interface circuit. The specific structure is shown in Figure 8. The EJ276 crystal detector ignites, records the signal amplitude and time, and the n/γ discrimination factor for the measurement of neutrons, γ, and charged particles.

To sum up, the present invention adopts Si detector and EJ276 crystal 17 detector to couple to form a Si-EJ276 detector. The measurement accuracy of the device can realize the type of charged particle identification and energy measurement, and at the same time, it can realize the measurement function of the linear energy transfer density LET, and achieve the purpose of compound measurement. , dose depth distribution information, to meet real-time detection requirements.

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims (10)

1. an eye lens dose measuring device, is characterized in that, comprises Si-EJ276 detector and control module; The Si-EJ276 detector includes a Si detector and an EJ276 crystal detector arranged in sequence along the incident direction of the radiation particles, the Si detector and the EJ276 crystal detector are coupled, and the EJ276 crystal detector includes an EJ276 crystal and a silicon photomultiplier tube, the silicon photomultiplier tube is coupled with the EJ276 crystal; The control module is set on the Si-EJ276 detector. The EJ276 crystal detector outputs signal waveforms of different fast and slow components in the case of different radiation particles. The control module is used to perform pulse signal processing on the output signal of the EJ276 crystal detector. Then, the radiated particles are distinguished and the energy and flux of the radiated particles are obtained. 2 . The ocular lens dose measurement device according to claim 1 , wherein the EJ276 crystal has a diameter of 0.8-1.2 inches and a thickness of 0.8-1.2 inches. 3 . 3 . The ocular lens dose measuring device according to claim 2 , wherein the EJ276 crystal has a diameter of 1 inch and a thickness of 1 inch. 4 . 4 . The ocular lens dose measurement device according to claim 1 , wherein the sensitive area of the Si detector is 15-20 mm in diameter and 280-320 μm in thickness. 5 . 5 . The ocular lens dose measurement device according to claim 1 , wherein the Si-EJ276 detector comprises a casing, and the casing encloses the coupled Si detector and the EJ276 crystal detector. 6 . 6. The ocular lens dose measurement device according to claim 1, wherein the Si-EJ276 detector comprises a preamplifier and an analog-to-digital converter; The output end of the Si detector and the output end of the silicon photomultiplier tube are respectively coupled with a preamplifier, and the preamplifier is used to preliminarily amplify the signal output by the Si detector and the electrical signal at the output end of the silicon photomultiplier tube; The analog-to-digital converter is coupled to the output end of the preamplifier on the Si detector, and the analog-to-digital converter is used to perform analog-to-digital conversion on the signal amplified by the preamplifier. 7 . The ocular lens dose measurement device according to claim 5 , wherein the Si-EJ276 detector further comprises a bias power supply, and the bias power supply is arranged inside the Si-EJ276 detector. 8 . 8. A method for measuring ocular lens dose, comprising: When the radiation particles pass through the Si detector, they interact with Si atoms, and the energy loss value ΔE is recorded; When the secondary particles generated by the interaction of radiation particles and Si atoms or the original radiation particles without interaction pass through the EJ276 crystal detector, the EJ276 crystal absorbs the remaining energy of the particles; The energy loss value ΔE measured by the Si detector is divided by the thickness of the Si detector to obtain the energy transfer line density spectrum; The EJ276 crystal detector generates signal waveforms with different fast and slow components in the case of different radiation particles. After the control module processes the output signal of the EJ276 crystal detector, it can distinguish the radiation particles and obtain the energy and flux of the radiation particles. 9. The method for measuring ocular lens dose as claimed in claim 8, wherein the distinguishing radiation particles and obtaining the energy and flux of the radiation particles comprises: Integrate the decayed slow components in the signal waveform to obtain the neutron event, and obtain the energy spectrum and flux information of the fast neutron in the neutron event; The fast component in the signal waveform is identified as a gamma ray event, and the energy spectrum information of the gamma ray is obtained after distinguishing the gamma ray from the neutron. 10. The ocular lens dose measurement method according to claim 9, wherein the obtaining energy spectrum and flux information of fast neutrons in the event of neutrons comprises: In the event of neutrons, the energy spectrum and flux information of fast neutrons are obtained by inverting the kinetic energy of protons.

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