The 200TW laser system, (Ti:Sapphire CPA system) delivering 5J in 25fs pulse with a 10Hz repetition rate and a contrast ratio of 1:10^-11 at the fundamental 800nm frequency, is used at the Advanced Laser Light Source (ALLS) facility to develop new generation of x-ray and pulsed particle beam sources (electrons, protons, neutrons). Experimental results on the betatron emission and electron emission from high intensity (<10^19 W/cm2) interactions with gas jet targets (1cm long supersonic nozzle) and on proton generation during high intensity (10^20 W/cm2) laser interaction with thin foil (10nm) and thick (several µm) targets will be presented and discussed. With gas jet targets, very high-resolution single shot phase contrast imaging with 10-20 keV X-rays has been demonstrated, and electrons are currently generated in the GeV range. X-ray source characterization will be presented. With foil targets, the target expansion has been measured on both sides of the target as well as proton generation (15 MeV range) at these relativistic intensities with various diagnostics (folding wave interferometer, time of flight, Thomson parabola...) We will describe the progresses we are doing to move from the laboratory experiments system to the application levels with integrated systems and compact light sources, with a special emphasis on medical applications. We are exploring the use of these high power lasers as a basic tool to image in real time with X-rays (betatron emission) tumors during their irradiation by protons (accelerated by the same laser).
+ funded by NSERC, CIPI, CFI, FQRNT, MDEIE, INRS, CRC program.
Energetic electrons generation by longitudinal field acceleration from a laser pulse was demonstrated. The longitudinal field was generated by focusing a radially polarised TM01 ultrashort laser pulse (1,8 microns, 550 uJ, 15 fs) with a high numerical aperture parabola. The created longitudinal field was intense enough to ionised and accelerated electrons with a few tens of keV from a low density oxygen gaz. The energy, spectrum, number of charges per shot and divergence of the generated electron bunches have been measured and will be presented. Electron bunch pulse duration, space charge effects and energy tunability will also be discussed.