Radiograph X-ray source based on interaction of femtosecond laser pulse with solid-state targets in an air medium

We study the charcteristics of X-ray radiation of a laser plasma generated in the interaction of a femtosecond pulse with solid targets in an air medium and conside the possibility of using it for radiography. We show that the mechanism for generating X-ray radiation in the interaction of short, powerful laser pulses with solid targets in a gas atmosphere is related to the generation of fast electrons in the gas breakdown region. We prove experimentally that under such conditions, even under relatively low laser radiation densities $<10^{15}$ W/cm$^2$, a copper target quite effectively emits photons with energies of up to $10$ keV. We measure the spectrum of such an X-ray source containing the expressed Cu $K_\alpha$ and Cu $K_\beta$ lines and moderate bremsstrahlung. We demonstrate that the source can be used to obtain micron-resolution absorption images of low-contrast objects in an air medium, and in the same way, open possibilities for studies of medical-biological objects in vivo.