Ultrashort pulse microwave thermoacoustic imaging method and device

A technology of ultra-short pulse and thermoacoustic imaging, which is applied in measuring devices, material analysis using microwave means, instruments, etc., can solve problems affecting the resolution of thermoacoustic imaging, achieve improved thermoacoustic image resolution, work stability, The effect of high thermoacoustic conversion efficiency

Active Publication Date: 2011-12-07
SOUTH CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The resolution of photoacoustic imaging can reach tens of μm, while the resolution of thermoacoustic imaging system can only achieve mm level at present. In a sense, the pulse width of microwave seriously affects the resolution of thermoacoustic imaging.

Method used

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  • Ultrashort pulse microwave thermoacoustic imaging method and device
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  • Ultrashort pulse microwave thermoacoustic imaging method and device

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Experimental program
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Effect test

Embodiment 1

[0040] figure 1 It is a structural schematic diagram of the ultrashort pulse microwave thermoacoustic imaging device of the present invention, and the ultrashort pulse microwave generator in the device is a high voltage pulse generator based on a Tesla transformer structure. The whole high-voltage pulse generator is mainly composed of trigger circuit 1-1, control system 1-2, high-precision charging system 1-3, primary energy source 1-4, Tesla transformer 1-5, high-voltage pulse forming line 1-6, high-voltage gas switch 1-7 and so on. The trigger circuit 1-1 sends a trigger signal, and the control system 1-2 controls the working status of the high-precision charging system 1-3 and the primary energy source 1-4, such as pulse repetition frequency and voltage. The primary energy 1-4 is converted into electric pulses under the control of the control system 1-2, and the voltage is boosted through the high-voltage Tesla pulse transformer 1-5 and the high-voltage pulse forming line ...

Embodiment 2

[0046] Embodiment 2: Using the device of Embodiment 1 to realize thermoacoustic imaging of the object to be measured

[0047] (1) Fix the agar block to be tested in a coupling cell containing deionized water;

[0048] (2) The ultrashort pulse microwave generator outputs the ultrashort pulse microwave of 100ns pulse width under the control of trigger circuit 2-1, after image 3 The high-power helical antenna 2-5 of the shown structure evenly irradiates the agar block 2-6 to be measured (the distance between the agar block to be measured and the high-power helical antenna is 10cm, that is, the near-field area of ​​the antenna, to improve the energy density of the radiation area and uniformity), to generate thermoacoustic signals;

[0049] (3) The thermoacoustic signal 2-7 is received by the multiple array ultrasonic detector 2-8 placed 10cm away from the agar block to be tested, and the high-level digital logic signal output by the trigger circuit triggers the data acquisition ...

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Abstract

The invention discloses an ultrashort pulse microwave thermoacoustic imaging method and an ultrashort pulse microwave thermoacoustic imaging device. The device comprises an ultrashort pulse microwave generator, an ultrasonic detector and a data acquisition and image reconstruction device. The method comprises the following steps of: fixing an object to be detected in a coupling tank containing deionized water; making the ultrashort pulse microwave generator output ultrashort pulse microwaves under the control of a trigger circuit, making the ultrashort pulse microwaves uniformly irradiate theobject to be detected through a pulse transmitting antenna, and exciting to obtain thermoacoustic signals; and receiving the thermoacoustic signals by using the ultrasonic detector, making signals output by the trigger circuit trigger a data acquisition card to acquire the thermoacoustic signals, and recording and saving the thermoacoustic signals and reconstructing images by using a computer. The ultrashort pulse microwave generator with ns-level pulse width excites the thermoacoustic signals, the thermoacoustic signal exciting efficiency can be greatly improved, and a sample to be detected is subjected to high-resolution tomography. The device has high imaging resolution, simple structure and low cost, and is convenient to operate and easily promoted and applied in the field of nondestructive testing.

Description

technical field [0001] The invention belongs to the technical field of thermoacoustic imaging, and in particular relates to an ultrashort pulse microwave thermoacoustic imaging method and a device thereof. Background technique [0002] In recent years, the research on thermoacoustic effect and thermoacoustic imaging technology has received more and more attention. When a substance is irradiated with high-power short-pulse microwaves, the substance absorbs the microwave energy and causes an instantaneous temperature rise. In the case of a relatively narrow microwave excitation pulse width, the absorbed energy cannot undergo thermal diffusion within the duration of the microwave pulse, and the substance will Adiabatic expansion occurs, and heat energy is converted into mechanical energy in the form of ultrasonic radiation, which is the thermoacoustic effect. The thermoacoustic effect is actually an energy conversion process. According to the heat conduction equation and wave ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N22/00
Inventor 娄存广邢达
Owner SOUTH CHINA NORMAL UNIVERSITY
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