Characterization and performance of the Apollon short-focal-area facility following its commissioning at 1 PW level

Abstract

We present the results of the first commissioning phase of the short-focal-length area of the Apollon laser facility (located in Saclay, France), which was performed with the first available laser beam (F2), scaled to a nominal power of 1 PW. Under the conditions that were tested, this beam delivered on-target pulses of 10 J average energy and 24 fs duration. Several diagnostics were fielded to assess the performance of the facility. The on-target focal spot and its spatial stability, the temporal intensity profile prior to the main pulse, and the resulting density gradient formed at the irradiated side of solid targets have been thoroughly characterized, with the goal of helping users design future experiments. Emissions of energetic electrons, ions, and electromagnetic radiation were recorded, showing good laser-to-target coupling efficiency and an overall performance comparable to that of similar international facilities. This will be followed in 2022 by a further commissioning stage at the multi-petawatt level.

Acceleration of 60 MeV proton beams in the commissioning experiment of SULF-10 PW laser

“…For 4-μm-thick foils, the average cut-off energy of protons is 60 MeV according to the data from three shots, where the highest one achieves 62.5 MeV. This is among the state-of-the-art results in proton acceleration using femtosecond lasers according to previous reports [ 31 , 36 ] . Figures 5(c) and 5(d) show the raw IP data of TP1 and TP2 for the best case with the 4-μm Cu target, from which the proton energy spectra are extracted and presented in Figure 5(b).…”

“…The maximum energy of protons accelerated by intense ultrafast lasers is mainly determined by, but not limited to, the laser intensity, pulse duration and pulse contrast ratio, and thus is considered as an important perspective to find out a laser facility’s capabilities. The most widely studied mechanisms for laser-driven ion acceleration are target normal sheath acceleration (TNSA) [ 31 , 32 ] and radiation pressure acceleration (RPA) [ 33 , 34 ] , which require different laser and target parameters. In the commissioning experiment, under the current conditions of the SULF-10 PW described above, we focus on TNSA using micrometer-thick Cu foils.…”

Towards High-Repetition-Rate Fast Neutron Sources Using Novel Enabling Technologies

“…In the future, this versatile experimental platform will enable the detailed study of correlations between ion and neutron beam parameters and the dominant neutron-production mechanisms, in addition to allowing for facility-specific adjustments. Step-wise scaling of the operation of this platform to a high repetition rate will be enabled through consecutive experiments at current Ti:sapphire-based high-power laser facility with increasing repetition rates such as Gemini (RAL, UK, 1 shot/30 min) [113], Apollon (CNRS, France, 1 shot/min) [114,115], or VEGA-2 (CLPU, Spain, 1 shot/s) [116]. By scaling the operation of this platform to one shot every minute or even second, the average neutron flux given in Table 1 can be increased by two to four orders of magnitude, which is comparable to the performance of spallation sources.…”

Electron spin- and photon polarization-resolved probabilities of strong-field QED processes

“…Recent progress in laser technology [33][34][35][36][37][38][39] enables observation of nonlinear QED processes in ultrastrong fields and has stimulated the interest of theoretical investigations to the highly nonperturbative domain with a 0 ≫ 1 [40,41]. The radiation spectra in the strong field regime can be calculated in the Furry picture within the quantum theory if the solution of wave equations in the given external field is known, see e.g.…”