Investigation On Radiation Performance And Application From 300kV Pulsed X-ray Source

Because of short pulse and high intensity,pulsed x-ray source is widely used in physics research,one of which is transient process diagnosis,mainly including transmission imaging and diffraction imaging.The transmission imaging is also known as flash radiography for bremsstrahlung of pulsed x-ray source.When the object is high areal density,photon energy should incline to high energy,and vice versa for high sensitivity of low areal density detection.Diffraction imaging is based on the diffraction between crystal and characteristic radiation of pulsed x-ray source to research the crystal response of compression,dislocation,and phase transition under dynamic loading.Because atoms or molecules spacing is about 1-?10 angstroms,the wavelength of x-ray is not too short after considering engineering and the photon energy is low energy.At the same time,high characteristic radiation and good monochromaticity are required.These show that different imaging application results in different photon energy and spectrum requirement for pulsed x-ray source.Several hundred kilo-volts pulsed x-ray source based on pulsed power technology aimed at diffraction imaging and transmission imaging of low areal density is one appropriate choice.So,it has been favored by relevant organizations both at home and abroad.Many research achievements have been obtained,focusing on application technologies.However,it is also found:1)the application results of the theory of interaction between electron and target could not provide adequate support for the design of pulsed x-ray source and it is not enough for understanding of influence of target parameters on radiation law;2)Up to now,the K? radiation characteristic of diode applying for diffraction imaging has not been reported and its parameter configuration method is unclear;3)There are some limitations for common methods to determine energy spectrum of several hundred kilo-volts pulsed x-ray source.At the same time,early closure brings uncertainty to the energy spectrum due to intense-beam and low-impedance of diode,and associating real-time electrical parameters with energy spectrum is a new valuable method for research.So,this paper researches on investigation of radiation and application of 300kV pulsed x-ray source.The main research results and conclusions are as follows:1.The law of interaction between electron and target was studied.Within the energy range of 20keV-600keV:1)under thick target,the proportion in the backward will tend to saturation,and the proportion will reach the peak for 300keV round;2)Under thick target,the angle range of 120 degree to 180 degree is good for bremsstrahlung and closer to 180 degree for K? radiation;3)Under thin target,bremsstrahlung and K? radiation in backward direction rise with the increase on the inclination of thin target,especially bremsstrahlung;besides,the bremsstrahlung asymmetry intensifies on the both sides of the normal direction of target in forward and backward direction.Under thick target,the increase on the inclination of target has little influence on forward direction.The bremsstrahlung asymmetry intensifies on the both sides of the normal direction of target in backward direction;4)With the increase of the atom number for Cu,Mo,and W?bremsstrahlung gradually improves and K? radiation decrease under thick target in backward direction,and efficiency of Mo is higher than Cu and W in forward direction.Under thin target,bremsstrahlung gradually improves and K? radiation decreases.2.The radiation and imaging application of 300kV pulsed x-ray source were investigated.1)In the diode voltage range of 120kV-?300kV,K? radiation shows a trend of increase;20%-30%proportion of photon energy at 17keV-18keV agrees with MC simulation;2)Blade and high depth cathode reflected diode have their respective advantages on intensity and proportion of K? radiation;3)Low impedance diode has a certain advantage in stability of radiation intensity and spatial distribution,especially for K? radiation;4)Proper A-C distance will be beneficial to improving the intensity of K? radiation;5)That the energy of K characteristic lines combines with the K edge of the imaging metal in the domain of low areal density transmission imaging could improve SNR further.3.The real-time energy spectrum prediction was studied.The method to predict the real-time energy spectrum of reflected diode could be used as one powerful tool for radiation and imaging research.Main innovation points:1.It is first time to obtain some regular understandings of effect of target parameters on radiation characteristic and this provides guide for design of several hundred kilo-volts pulsed x-ray source.2.This paper investigates the K? radiation characteristic of reflected diode,obtains the trend of K? radiation under different diode configuration and affords the configuration method for diffraction imaging.3.One method to predict the real-time energy spectrum of reflected diode is proposed and the calculating model is established.