A comprehensive characterization of the neutron fields produced by the Apollon petawatt laser

Since two decades, laser-driven neutron emissions are studied as they represent a complementary source to conventional neutron sources, with further more different characteristics (i.e. shorter bunch duration and higher number of neutrons per bunch). We report here a global, thorough characterization of the neutron fields produced at the Apollon laser facility using the secondary laser beam (F2). A double plasma mirror (DPM) was used to improve the temporal contrast of the laser which delivers pulses of 24 fs duration, a mean on-target energy of ∼10 J and up to 1 shot/min. The interaction of the laser with thin targets (few tens or hundreds of nm) in ultrahigh conditions produced enhanced proton beams (up to 35 MeV), which were then used to generate neutrons via the pitcher-catcher technique. The characterization of these neutron emissions is presented, with results obtained from both simulations and measurements using several diagnostics (activation samples, bubble detectors and Time-of-Flight detectors), leading to a neutron yield of ∼4×107neutrons/shot. Similar neutron emissions were observed during shots with and without DPM, while fewer X-rays are produced when the DPM is used, making this tool interesting to adjust the neutrons/X-rays ratio for some applications like combined neutron/X-ray radiography.