The motion of a projectile inside a gun barrel results in the unwanted heating and wear of the interior rifling of the barrel, which necessitates squad machine-gunners carrying multiple spare barrels. Therefore, the ability to do in- barrel characterization (interior ballistics) to image kinetics of the moving projectile before it exits the barrel is critically important for gun barrel design. Here we report on the development of a high-speed X-ray imaging system capable of imaging a projectile as it travels at high speed inside the barrel of a gun. A key component of the system is a specially designed scintillator that serves as the X-ray-to-light converter. This custom-developed scintillator has an extremely fast decay time, high X-ray absorption efficiency, and very bright emission. The optical image generated by X-ray conversion within the scintillator is captured using a custom intensified CMOS camera that allows mega-pixel resolution and up to 500,000 frames per second data rates. The X- ray source is a series of four pulsed X-ray units, each of which produces a single 20 ns burst of high intensity X-rays. Triggering electronics were developed to fire the X-ray sources sequentially such that the detector integration window and the pulse duty cycle are synchronized. Here we will discuss our results imaging .30 caliber bullets traveling at ~1,000 m/s while still in the barrel. Information on bullet deformation, pitch, yaw and integrity are the main goals of this experimentation. Planned future upgrades for imaging large caliber projectiles will also be discussed.

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