Research On Drive System Integration Of Carbon Nanotube X-ray Source Array

Today,breast cancer ranks first among female malignancies in China,and it is a major disease that threatens women's physical and mental health.Expanding screening,early detection,and early diagnosis and treatment can effectively reduce breast cancer mortality.Stationary Digital Breast Tomosynthesis(s-DBT)uses carbon nanotube(CNT)cold cathode instead of traditional hot cathode electron source as the X-ray source of s-DBT system.It is an imaging method that releases electrons by field emission.This system can effectively solve the problem of artifacts caused by the mechanical movement of the original light source through electronic scanning.Compared with the hot cathode electron source,the carbon nanotube X-ray source has low delay,high time resolution,normal temperature operation,and programmable emission advantage.The static digital mammography machine can increase the resolution of the scanned image,and the radiation dose to the patient can be controlled by adjusting the exposure time.First introduce the CNT field emission and material characteristics,and introduce the X-ray source array and static digital breast machine designed according to the relevant principles,and explain and analyze the overall structure and scanning method of the device.Then,according to the working characteristics and conditions of the static digital breast machine,a drive control system is designed.Field Programmable Gata Array(FPGA)is used as the system microprocessor.It uses the Verilog hardware description language on the Quartus II platform to realize the reception of the timing data of the host computer through serial communication,or to generate the timing data through logical calculation,and output 15 high-frequency short pulses with a certain duty cycle as low-voltage part drive control signals according to the time series data,one-to-one correspondence with 15 independent light sources of the carbon nanotube X-ray source array.In addition,it realizes the synchronous work of the detector through the synchronous trigger signal.The high-voltage part has designed a high-voltage control circuit based on insulated bipolar transistor(IGBT)elements,which can be used in conjunction with different gate high-voltage sources under different conditions.The high voltage part has designed a high voltage control circuit based on insulated bipolar transistor(IGBT)elements.It is used with different gate high-voltage sources under different conditions.The hardware circuit is simulated in Pspice software.Thousandvolt high-voltage loading is completed by IGBT series connection,and the PCB circuit is made with Cadence software to integrate the 15-channel drive circuit.Finally,the multi-channel pulse experiment was carried out in combination with the static digital mammary gland machine.In this thesis,for the purpose of integrating the s-DBT system driver,the static digital breast machine system control is completed,and the equipment collects the scanned image.