Optimization of a fast rotating target to produce kHz X-ray pulses from laser-plasma interaction

We report the development of a fast rotating target to produce ultrashort incoherent X-ray pulses from bremsstrahlung. These short X-ray pulses are produced in the laser-plasma interaction of a 35 fs, 1 mJ pulse of a Ti:Sa laser of 1 kHz repetition rate, with a solid metallic target. In this paper, we report our developments to improve the stability of this micron size source of ultrashort X-rays. As the Rayleigh length is very small (<15 mu m), wobbling of the rotatory stage can reduce the intensity on target and change the characteristics of the source. We describe the methods we have developed to measure and adjust the stability of the focus on target. These advances are important for the development of sources with high average power and good stability. The X-ray source has a broad Maxwellian-like distribution with temperatures of around 10 - 40 KeV and could be used for advanced X-ray imaging such as absorption or phase contrast tomography.