CN111239796A

CN111239796A - Intelligent fixed photonic crystal preparation method and radiation imaging system

Info

Publication number: CN111239796A
Application number: CN202010057723.0A
Authority: CN
Inventors: 邓贞宙; 周凯
Original assignee: Lattice Power Jiangxi Corp
Current assignee: Lattice Power Jiangxi Corp; Nanchang University
Priority date: 2020-01-19
Filing date: 2020-01-19
Publication date: 2020-06-05

Abstract

The invention relates to the field of electronic information, in particular to an intelligent fixed photonic crystal manufacturing method and a radiation imaging system. The invention provides a method for preparing photonic crystals by an oil bath heating method, and then cutting and polishing are carried out to obtain crystals A and crystals B, wherein the A, B crystals are based on a mortise and tenon structure, and can be firmly and seamlessly formed into a square crystal array without glue after being assembled according to a certain sequence. The invention also provides a radiation imaging system which comprises a moving bed module, a photonic crystal module, a photoelectric conversion module and a signal acquisition module. The system absorbs the square crystal array used in the photonic crystal module of the high-energy particle, avoids the use of optical glue and adhesive, reduces the cost and complexity of the system, and meanwhile, the moving bed module in the system loads the small animal to be subjected to radiation imaging scanning, and can effectively and artificially move the body of the small animal in the image cabin.

Description

Intelligent fixed photonic crystal preparation method and radiation imaging system

Technical Field

The invention relates to the field of electronic information, in particular to an intelligent fixed photonic crystal preparation method and a radiation imaging system.

Background

The radiation imaging detector is applied to detecting and imaging various changes such as ionization effect, luminescence phenomenon or chemical reaction caused by nuclear radiation in gas, liquid or even solid. So far, the nuclear radiation detectors applied in the world have more types, and the working principles thereof have certain differences. Today's development of nuclear radiation detectors in medicine is in line with the state of the art of nuclear detection technology, which has undergone the development of detection, counting and imaging, such as PET.

Photonic crystals are an integral part of the radiation imaging detectors described above. Currently, perovskite materials are a new class of radiation imaging crystalline materials due to their many excellent properties, such as tunable direct band gap, high optical absorption coefficient, high carrier mobility and lifetime. However, the pulling method adopted in the prior art for preparing the compound is complex to operate and high in cost. In the prior art, optical glue is needed when the photonic crystal is used for preparing the crystal module, which can cause the defects of large gap width, low output efficiency, low image reconstruction quality and the like, and can also increase the cost of a radiation imaging system formed by the photonic crystal.

Therefore, there is a need for an improved method of preparing photonic crystals and radiation imaging system to overcome the above-mentioned shortcomings in the prior art.

Disclosure of Invention

The first purpose of the invention is to provide a preparation method of the intelligent fixed photonic crystal.

It is a second object of the present invention to provide an intelligent fixed photonic crystal radiation imaging system.

In order to achieve the first object, the invention provides a preparation method of a photonic crystal, which comprises the following specific steps:

s1, growing large-size photonic crystal coarse materials by using an oil bath heating method;

s2, cutting, grinding and polishing to obtain solid crystal strips with the thickness range of 10mm-20mm and the length and width ranges of 1mm-6 mm;

s3, cutting different notches by using the solid crystal strip obtained in the step S2 to obtain crystals A and crystals B;

s4, grinding and polishing the A crystal and the B crystal obtained in the step S3;

and S5, assembling the 1A crystal prepared in the step S4 and the 2B crystals prepared in the step S2 into a photonic crystal according to the correspondence of different notches.

The crystal in the step S1 is MNX₃Perovskite nanomaterials wherein M is a monovalent cation, including but not limited to Cs⁺ _、Ma⁺、Fa⁺N is a divalent cation, including but not limited to Pb²⁺、Sn²⁺、Ge²⁺X is a halide ion, in particular Cl^-、Br^-、I^-。

Preferably, the crystal is CsPbX₃All-inorganic halogen perovskite-type crystals;

more preferably, the crystal is CsPbBr₃。

The material for A crystal and B crystal is MNX₃Perovskite nanomaterials (X ═ Cl, Br, I), the crystals are used as materials for photonic crystals because of their outstanding photoelectric properties and excellent scintillation performance approaching the limits of energy resolution of inorganic scintillation crystals.

The oil bath heating method in the step S1 specifically includes the steps of:

a. placing the solvent in a polytetrafluoroethylene beaker, adding MX and NX in a molar ratio of 1:1₂Stirring uniformly;

b. putting a polytetrafluoroethylene beaker into an oil bath pot heated to the volatilization temperature of the solvent;

c. and obtaining a crystal coarse material after the solvent in the beaker is volatilized.

The solvent is any one of dimethyl sulfoxide (DMSO) and N-methylpyrrolidone.

The crystal A in the step S3 is specifically as follows: the crystal is provided with two

notches

2101 and 2102, the two notches are symmetrical to the center of length, the length of the notch 2101 is 0.5 cross section length, the width of the notch is 1 cross section length, the depth of the groove is 1 cross section length, the length of the notch 2102 is 0.5 cross section length, the width of the notch is 1 cross section length, and the depth of the groove is 0.5 cross section length.

The crystal B in the step S3 is specifically as follows: the crystal is provided with two

notches

2201 and 2202, the two notches are symmetrical to the center of length, the length of the 2201 notch is 1 cross section length, the width of the notch is 1 cross section length, the depth of the groove is 0.5 cross section length, the length of the 2202 notch is 0.5 cross section length, the width of the notch is 0.5 cross section length, and the depth of the groove is 0.5 cross section length.

And in the step S5, the photonic crystal is prepared by splicing A, B crystals through a mortise and tenon structure.

The tenon-and-mortise structure originates from ancient Chinese buildings, is a fixed combination mode of traditional civil constructions of ancient nationalities of China, can save nails and ropes, does not need glue and various adhesives at the same time, and can lead various building materials to be closely associated only by constructing the shape and the interior into a specific structure. The tenon-and-mortise structure is introduced into the manufacturing of the scintillation crystal, the scintillation crystal is manufactured into specific shapes with different shapes, and then all the scintillation crystals are fixed through a certain assembling sequence to form a scintillation crystal module, so that the cost of the scintillation crystal module and the complexity of a system can be reduced.

In order to achieve the second objective, the invention provides an intelligent fixed photonic crystal radiation imaging system, which is formed by connecting a moving bed module 100, a photonic crystal module 200, a photoelectric conversion module 300, a signal acquisition module 400 and a data imaging module 500;

the moving bed module comprises a motor control module 110, a direct current motor module 120 and a fixed bed module 130; the moving bed module 130 consists of a direct current motor module, a motor control module and a fixed bed module, wherein the motor control module controls the direct current motor module through a circuit, the direct current motor module provides power for the fixed bed module, and the fixed bed module is used for fixing a measured object;

the photonic crystal module is composed of the photonic crystal prepared above;

the signal acquisition module comprises an ADC module 410 and a TDC module 420;

the data imaging module comprises a UDP information analysis module 510, an information preprocessing module 520 and a reconstruction module 530.

The fixed bed module 130 is composed of a carrier made of a phenolic resin plate having a length ranging from 10 to 50cm, a width ranging from 5 to 10cm, a height ranging from 5 to 10cm, and a restraint band having a width ranging from 2 to 5 cm.

The ADC module 410 includes an ADC clock signal module 411, a time sampling module 412, and a voltage threshold module 413.

The ADC clock signal module provides clock signals for the time sampling module, the time sampling module controls the sampling interval of the voltage threshold module, and the voltage threshold module performs voltage threshold on the analog signals to realize energy fitting.

The TDC module 420 includes a TDC clock signal module 421, a timing module 422, and a time calculation module 423.

The TDC clock signal module provides a clock signal for the timing module, the timing module is responsible for timing the rising edge time of the electric signal, and the time calculation module is responsible for calculating the delay time in the timing module so as to reduce time errors.

Compared with the prior art, the invention has the beneficial effects that:

the photonic crystal prepared by the oil bath heating method has high photoelectric response rate, detection rate and external quantum efficiency, and simultaneously compared with the Czochralski method which needs numerous expensive equipment and is complex to operate, the oil bath heating method has simple process and low cost, only needs a common heating table and silicone oil, and is easy to grow in a large scale.

When the crystals in the photonic crystal module are combined, adhesives such as optical glue are not needed, and the crystals are not square crystal strips but are made into tenon-and-mortise structures, so that the manufactured photonic crystal module not only saves the use of the adhesives such as the optical glue and saves the manufacturing cost of a system, but also reduces the width of a gap between the crystal strips and the crystal strips, relatively increases the area for absorbing photons, increases the number of absorbed photons, improves the light output efficiency of scintillators, and improves the quality of image reconstruction.

The moving bed module applied to the radiation imaging system prepared by the invention is additionally provided with the motor and the controller on the basis of the traditional fixed bed module, so that the radiation imaging system can more flexibly control the detected object to detect each angle. Meanwhile, the position of the small animal can be better fixed, and the method is safer when detecting the dangerous small animal.

Drawings

FIG. 1 is a schematic structural diagram of an intelligent fixed photonic crystal radiation imaging system according to an embodiment of the present invention

FIG. 2 is a schematic diagram of information transfer of an intelligent fixed photonic crystal radiation imaging system according to an embodiment of the present invention, wherein C, D is a joystick

FIG. 3 is a schematic view of the structure of the A crystal in the photonic crystal prepared in the example of the present invention

FIG. 4 is a schematic view of the structure of B crystal in the photonic crystal prepared in the example of the present invention

FIG. 5 is a schematic structural view of a photonic crystal prepared in an embodiment of the present invention

FIG. 6 shows CsPbBr prepared in example 1 of the present invention₃XRD pattern

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and the scope of the present invention will be more clearly and clearly defined.

As shown in fig. 1, an intelligent fixed photonic crystal radiation imaging system is made up of five parts, wherein,

the first part is a moving bed module 100, the moving bed module 100 is effective to artificially move the body of the object to be measured in the region of interest (FOV) of the radiation imaging system and effectively fix the object to be measured without escaping, and comprises a motor control module 110, a dc motor module 120 and a fixed bed module 130, as shown in fig. 2, the motor control module 110 is positioned on the outer wall of the radiation imaging machine and is provided with an on-off key for controlling the power supply of the motor, and an experimenter controls the start and stop of the dc motor module 120 through the on-off key; the direct current motor module 120 and the fixed bed module 130 are located in the center of the radiation imaging machine, wherein the direct current motor module 120 is responsible for converting electric energy with voltage of 220V into mechanical energy, power is provided for the fixed bed module 130, the direct current motor module 120 is provided with control levers C and D, as shown in fig. 2, the control levers C and D have the functions of stretching, moving back and forth, moving left and right, and moving front and back, are made of phenolic resin and 5-10cm in length, and the fixed bed module 130 connected to the control levers C and D can move up, down, left, right, front and back by controlling the control levers C and D to move up, down, left, right, front and back. The fixed bed module 130 comprises a bearing frame and a restraint band, wherein the bearing frame is made of phenolic resin plates, the length of the bearing frame ranges from 5cm to 15cm, the width of the bearing frame ranges from 5cm to 10cm, the height of the restraint band ranges from 5cm to 10cm, the restraint band is used for placing a measured object, the width of the restraint band ranges from 2cm to 5cm, the length of the restraint band ranges from 10cm to 30cm, the restraint band is used for fixing the measured object, and the measured object is prevented from falling off from the bearing frame in the radiation imaging process.

The second part is a photonic crystal module 200, the photonic crystal module 200 is used for absorbing high-energy photons emitted from the body of the object to be tested, as shown in fig. 5, the photonic crystal module comprises an a crystal 210 and a B crystal 220, specifically, one photonic crystal module needs 1 a crystal and 2B crystals. Wherein the crystal A is shown in FIG. 3, the thickness range is 10mm-20mm, the length and width range of the crystal A is 1mm-6mm solid crystal strip is provided with two

notches

2101 and 2102, the two notches are symmetrical to the length center, the length of the notch 2101 is 0.5 cross section length, the width of the notch is 1 cross section length, the depth of the groove is 1 cross section length, the notch 2102 is on the surface rotated by 90 degrees, the length of the notch 2102 is 0.5 cross section length, the width of the notch is 1 cross section length, the depth of the groove is 0.5 cross section length, the material used by the crystal A and the crystal B is CsPbX₃(X ═ Cl, Br, I), CsPbX was used therefor₃The all-inorganic halogen perovskite crystal is used as a material of a photonic crystal because the crystal has excellent scintillation properties such as outstanding photoelectric properties and a limit value close to the energy resolution of an inorganic scintillation crystal. The B crystal is shown in FIG. 4, and has a thickness of 10-20 mm and two solid crystal strips with length and width of 1-6 mmThe two notches are symmetrical to each other in length center, the length of the 2201 notch is 0.5 cross section length, the width of the notch is 1 cross section length, the depth of the notch is 1 cross section length, the 2202 notch is arranged on a face rotated by 90 degrees, the length of the 2202 notch is 0.5 cross section length, the width of the notch is 0.5 cross section length, and the depth of the notch is 0.5 cross section length.

The third part is a photoelectric conversion module 300, which is used for absorbing the visible photons emitted from the photonic crystal 200 to perform photoelectric conversion, and converting the absorbed visible photons into photoelectrons, so as to prepare for the subsequent mode-to-electricity conversion and image reconstruction, because the signals required by the image reconstruction are electrical signals, and the information required by the image reconstruction cannot be directly obtained from the optical signals. The device for photoelectric conversion is a position sensitive photomultiplier PS-PMT, and a detector formed by the position sensitive photomultiplier PS-PMT not only has high spatial resolution (1.2mm) but also has very good time resolution (less than 1 ns). The operating principle of the position sensitive photomultiplier PS-PMT is, as shown in fig. 2, realized by a photocathode, a plurality of dynodes and a photo-anode, and the voltage on each dynode is sequentially increased. In this embodiment, when visible light irradiates the photocathode, primary electron emission is generated, and when the emitted photoelectrons are accelerated by an electric field in the vacuum tube to reach the first dynode, each photon causes emission of 4-5 secondary electrons, and is accelerated to the next dynode, which causes emission of more electrons at the dynode, and so on. Most photomultiplier tubes have 9 dynodes, and when this process is repeated 9 times, each of the first electrons will produce 106-107 electrons. Finally, the electrons are collected by the photo-anode to generate a photo-current so as to achieve the purpose of detecting optical signals. The detected weak illuminance is converted into a current signal with certain intensity through the action of a photomultiplier tube.

The fourth part is an information acquisition module 400, which is used for performing analog-to-digital conversion and clock control on the analog current signal converted by the photoelectric conversion module 300 to obtain a time signal and an energy signal in the electrical signal. The system comprises an ADC module 410 and a TDC module 420, wherein the ADC module 410 further comprises an ADC clock signal module 411, a time sampling module 412 and a voltage threshold module 413, wherein the ADC clock signal module 411 provides a clock signal for the time sampling module 412, the time sampling module 412 controls the sampling interval of the voltage threshold module 413, and the voltage threshold module 413 performs voltage threshold on an analog signal to realize energy fitting so as to obtain energy information; the TDC module 420 includes a TDC clock signal module 421, a timing module 422, and a time calculation module 423, wherein the TDC clock signal module 421 provides a clock signal for the timing module 422, the timing module 422 is responsible for timing the rising edge time of the electrical signal, and the time calculation module 423 is responsible for calculating the delay time in the timing module 422 to reduce the time error and obtain the time information and the UDP packet.

The fifth part is a data imaging module 500 that functions to perform image reconstruction using the time and energy signals from the information acquisition module 400. It includes a UDP information parsing module 510, an information preprocessing module 520, and a reconstruction module 530. The UDP information parsing module 510 extracts time, energy, and position information in the UDP packet output by the information obtaining module 400, and the extracted three information passes through the information preprocessing module 520, which filters and amplifies the extracted information, so that the three information can enter the reconstruction module 530 for image reconstruction.

Example 1

A preparation method of an intelligent fixed photonic crystal comprises the following specific steps:

The oil bath heating method comprises the following specific steps:

a. heating the dimethyl silicon oil in an oil bath pot containing 4/5 pans to 190 ℃ on a heating table;

b. taking the cleaned measuring cylinder, measuring dimethyl sulfoxide (DMSO), and pouring into a polytetrafluoroethylene beaker (as a solvent;

c. respectively weighing cesium bromide (CsBr) and lead bromide (PbBr) with electronic scale₂) (pouring the mixture into the polytetrafluoroethylene beaker, and uniformly stirring the mixture by using a glass rod;

d. fixing the prepared solution beaker on an iron support, and putting the polytetrafluoroethylene beaker into heated silicone oil as much as possible, wherein the uppermost surface of the solution in the polytetrafluoroethylene beaker is required to be lower than the uppermost surface of the silicone oil in the oil bath pan;

e. and obtaining crystals after the solvent in the beaker is volatilized.

In step S5, the crystal a is shown in fig. 3, the crystal B is shown in fig. 4, and the crystal a and the crystal B are spliced into a photonic crystal shown in fig. 5 through a mortise and tenon structure.

An intelligent fixed photon crystal radiation imaging system, wherein a photon crystal module is composed of a plurality of photon crystals prepared as above, as shown in fig. 2, a 6 x 6 grid is arranged in a 6 x 6 photon crystal array composed of 36 photon crystals, the grid is composed of 5 x 5 quartz glass strips, the length and width range of the quartz glass strips is 6 x 36mm, the thickness range is 0.5 x 1mm, when the 6 x 6 photon crystal array is packaged, five surfaces of the array are wrapped by aluminum foil, and the sixth surface is packaged by quartz glass and connected with a photoelectric conversion module. Wherein, the parameters of the processing data are as follows:

the voltage of a direct current motor adopted in the module 100 is 220V, the lengths of the operating rods C and D are 5cm, and the size of the fixed bed is 10cm multiplied by 5 cm;

the length and width of the A crystal and the B crystal in the photonic crystal adopted in the module 200 are both 1mm, and the thickness is 10 mm;

the photomultiplier tube employed in the module 300 is a position sensitive photomultiplier tube PS-PMT;

the reconstruction algorithm employed in block 500 is a Filtered Back Projection (FBP) algorithm;

example 2

Wherein, the parameters of the processing data are as follows:

the voltage of a direct current motor adopted in the module 100 is 220V, the lengths of the operating rods C and D are 7cm, and the size of the fixed bed is 12cm multiplied by 7 cm;

the length and width of the A crystal and the B crystal in the photonic crystal adopted in the module 200 are both 3mm, and the thickness is 15 mm;

the reconstruction algorithm employed in block 500 is a Filtered Back Projection (FBP) algorithm.

The rest is the same as example 1.

Example 3

Wherein, the parameters of the processing data are as follows:

the voltage of a direct current motor adopted in the module 100 is 220V, the lengths of the operating rods C and D are 10cm, and the size of the fixed bed is 15cm multiplied by 10 cm;

the length and width of the A crystal and the B crystal in the photonic crystal adopted in the module 200 are both 6mm, and the thickness is 20 mm;

The rest is the same as example 1.

CsPbBr prepared in example 1₃Crystals with CsPbBr₃A comparison was made with a standard PDF card (00-054-₃The crystal has a peak shape similar to that of a standard card, so that the photonic crystal prepared by the oil bath heating method has high photoelectric response rate, detection rate and external quantum efficiency, and meanwhile, compared with a pulling method which needs numerous expensive equipment and is complex to operate, the oil bath heating method has the advantages of simple process and low cost, only needs a common heating table and silicone oil, and is easy to grow in a large batch.

Finally, it should be emphasized that the above-described preferred embodiments of the present invention are merely examples of implementations, rather than limitations, and that many variations and modifications of the invention are possible to those skilled in the art, without departing from the spirit and scope of the invention.

Claims

1. The preparation method of the intelligent fixed photonic crystal is characterized by comprising the following preparation steps:

2. The method for preparing an intelligent fixed photonic crystal as claimed in claim 1, wherein the large-size photonic crystal coarse material in step S1 is MNX₃Perovskite nanomaterials, said MNX₃Where M is a monovalent cation, including but not limited to Cs⁺ _、Ma⁺、Fa⁺(ii) a N is a divalent cation, including but not limited to Pb²⁺、Sn²⁺、Ge²⁺(ii) a X is a halide ion, in particular Cl^-、Br^-、I^-。

3. The method for preparing an intelligent fixed photonic crystal according to claim 2, wherein the oil bath heating method in step S1 comprises the following steps:

c. obtaining a photonic crystal coarse material after the solvent in the beaker is volatilized;

the solvent is any one of dimethyl sulfoxide (DMSO) and N-methylpyrrolidone.

4. The method for preparing an intelligent fixed photonic crystal according to claim 1, wherein the crystal a in step S3 is specifically: the crystal is provided with two notches (2101) and (2102), the two notches are symmetrical to the center of length, the length of the 2101 notch is 0.5 cross section length, the width of the notch is 1 cross section length, the depth of the groove is 1 cross section length, the length of the 2102 notch is 0.5 cross section length, the width of the notch is 1 cross section length, and the depth of the groove is 0.5 cross section length.

5. The method for preparing an intelligent fixed photonic crystal according to claim 1, wherein the B crystal in step S3 is specifically: the crystal is provided with two notches (2201) and (2202), the two notches are symmetrical to the length center, the length of the 2201 notch is 1 cross section length, the width of the notch is 1 cross section length, the depth of the groove is 0.5 cross section length, the length of the 2202 notch is 0.5 cross section length, the width of the notch is 0.5 cross section length, and the depth of the groove is 0.5 cross section length.

6. The method for preparing an intelligent fixed photonic crystal according to claim 1, wherein the photonic crystal is prepared by assembling A, B crystals in a mortise and tenon joint structure in step S5.

7. An intelligent fixed photonic crystal radiation imaging system is characterized by being formed by connecting a moving bed module (100), a photonic crystal module (200), a photoelectric conversion module (300), a signal acquisition module (400) and a data imaging module (500); the moving bed module comprises a motor control module (110), a direct current motor module (120) and a fixed bed module (130); the photonic crystal module consists of a photonic crystal prepared by the photonic crystal preparation method of any one of claims 1 to 6 and a quartz glass strip; the signal acquisition module comprises an ADC module (410), a TDC module (420); the data imaging module comprises a UDP information analysis module (510), an information preprocessing module (520) and a reconstruction module (530).

8. The smart fixed photonic crystal radiation imaging system of claim 7, wherein the motor control module controls the dc motor module and the fixed bed module through a circuit, the motor control module is provided with joysticks C and D, and the joysticks C and D are connected to the fixed bed module.

9. The smart fixed photonic crystal radiation imaging system of claim 7, wherein the fixed bed module (130) consists of a carrier made of phenolic resin board with a length in the range of 10-50cm, a width in the range of 5-10cm, a height in the range of 5-10cm and a restraining strip with a width in the range of 2-5 cm.

10. The smart fixed photonic crystal radiation imaging system of claim 7, wherein the ADC module (410) is connected by an ADC clock signal module (411), a time sampling module (412), and a voltage threshold module (413); the TDC module (420) is formed by connecting a TDC clock signal module (421), a timing module (422) and a time calculation module (423).