Long term stability of a kHZ laser-plasma accelerator

Laser-plasma acceleration enables the generation and acceleration of electrons beams over very short distances due to extreme longitudinal accelerating fields, orders of magnitude higher than in conventional radio-frequency accelerators. We are developing a kilohertz laser-plasma accelerator that benefits from increased stability and high mean current due to the high repetition rate. We recently achieved a stable and continuous operation over a 5 hours period, with a world record of over 18 millions consecutive accelerated electron beams. This performance was made possible by the active laser stabilization at several points in the chain, as well as the use of a newly designed one-sided shock gas jet that stabilizes electron injection into the accelerator.  

These results, published in Physical Review Accelerators and Beams, represent an important step toward the use of laser-plasma accelerators for applications such as electron-diffraction or radio-biology experiments. This enhanced stability already allowed us to use our accelerator to study the effect on radio-toxicity of fractioning the dose delivered to cancer cells.

Figure: Energy distribution of the electron beam recorded over 5 hours. The data shows an extremely stable distribution at 2 MeV for about 3 hours. Data from L. Rovige et al., Phys. Rev. Acc. & Beams 23, 093401 (2020)