Description
A laser-based neutron source was commissioned using the 1 kHz repetition rate SYLOS3 laser of ELI-ALPS, delivering 80mJ, sub-10 fs laser pulses on a colliding liquid jet. The cutoff energy of the deuterons accelerated from the actively stabilized liquid sheet of 600 nm exceeded 2 MeV. The average power of the laser-accelerated ion beam was greater than 10 W, whereas the deuteron beam was kept at 4 W for several hours of continuous operation. The accelerated deuterons induced a $^2$H+$^2$H fusion reaction on a rotating disk of deuterated polyethylene as well as on a heavy water neutron converter, resulting in neutrons with a mean kinetic energy of 3.2 MeV in the forward direction. We maximized the neutron yield per laser shot by tuning the dispersion, and hence the temporal shape of the laser pulse. At the optimum, the neutron yield for the dPE and heavy water converter was 6×10$^4$ neutron/shot and 4.5×10$^4$ neutron/shot, respectively. The average neutron flux on target exceeded 2×10$^7$ neutron/cm$^2$/s, while the flux rate of a neutron pulse was estimated around $10^{13}$ neutron/cm$^2$/s.
In an irradiation session of four hours, a total of 1.6 Gy dose was delivered on zebrafish embryos. The density of apoptotic cells as well as double-strand breaks in the zebrafish embryos was similar to that of the control group irradiated with cyclotron-generated neutrons. However, photomotor responses showed differences. In a second experimental campaign, ultrahigh-purity isotopes relevant to the medical industry have been produced.
