Gamma-ray beam produced by a plasma lens focused electron bunch

An accelerator electron bunch is focused and modulated in a plasma lens and then converted into a gamma-ray source using bremsstrahlung radiation in a dense material. In the linear regions with beam density much smaller than plasma density, a proper plasma density needs to be chosen to produce a high quality gamma-ray beam with a small spot size and low divergence, which can be applied in the radiograph of complex and dense objects with sub-millimeter resolution. As the bunch charge increases and bunch density approaches plasma density, micro-bunching of the bunch due to the nonuniform transverse wakefield and bunch energy chirp is observed, leading to a significant increase in gamma-ray beam divergence.