Deuteron acceleration and fast neutron generation with few-cycle, relativistic laser pulses at 1 Hz repetition rate (Conference Presentation)

The development of laser plasma accelerators has been centred around the optimisation of particle yield resulting from the interaction of high energy, single-shot lasers with very low average power. Here we aim at the already existing, high average power lasers with kHz repetition rate but low pulse energy. In our experiment, the SEA laser of ELI-ALPS provided ultrahigh contrast laser pulses of 12fs pulse duration and 20mJ energy on the 200 nm thick dPE foils. A rotating wheel target system allowed the laser interaction run at 1 Hz repetition rate in bursts of 75 shots. The accelerated deuterons, measured by Thomson spectrometers for each shot, hit a 0.1mm thick, 20 mm diameter deuterated-polyethylene disk. Neutrons were then generated via d+d fusion reaction with a mean energy of 2.45MeV. The neutron events were detected by four plastic scintillators at various angles around the chamber. From the ToF distributions we have concluded that an average of >3000 neutrons were generated in a shot, with a slight anisotropy to the forward direction. The upcoming development of kHz repetition-rate primary-target systems would boost the yield of neutrons in a second, that may exceed which can be achieved with PW class lasers..