Radiation Characteristics Study Of The Flash Generated By Hypervelocity Impact Dolomite Target

When a hypervelocity impact occurs, a visible light flash is produced because ofplastic deformation. Analysis of the impact flash can be used to probe the early-timeimpact process responsible for its generation and evolution. For experimental impactsinto metal targets, this flash is of very short duration (on the order of microseconds).because the light sources are mainly atomic and molecular emission lines and bands.The experiment is loaded by two stage light gas gun, the impact flash phenomenawhich was generated by Polycarbonate projectile impacted into dolomite target at closeimpact velocity and different impact angles of45o,60o,is measured by using transientpyrometer measurement system.Related data program is compiled on MATLAB,so theprogress becomes much more simple.Based on the theory of the transmission of light,the program about calculation andsmooth of flash intensity is compiled. The light intensity curve reveals two maincomponents to the flash evolution:(1) a broad peak, and (2) a long-lasting decay. Theintensity evolves from the first contact between the projectile and the target.and itssubsequent decay depend on the distribution and cooling rate of the radiating source.The properties of these components are highly dependent on initial conditions(e.g.,velocity, impact angle, view orientation). For example the peak intensity enhanceswith the increase of collision speed, When most of the initial impact conditions areknown,the remaining variables can be constrained by analyzing the flash photometry.The thermal evolution of the impact flash also contains information aboutearly-time cratering processes. Based on the Planck blackbody radiation theory,by usingratio method and related theory,the radiation temperature is fitted by PMT whichcontains4channels. The temperature curve keeps pace with intensity curve, the temperature subsequently decreases when it increases to maximum, with a decay rateaffected by initial conditions.Flash intensity is integrated in the visible light and infrared wavelength range,thenthe radiation energy per unit area is got in the visible light and infrared wavelengthrange.The long-duration “tail” of the intensity signal contains a significant portion ofthe total radiated energy, with as much as30%of the visible-wavelength luminousenergy being emitted after the intensity peak.