Speaker
Description
At ELI Beamlines facility there are two LWFA beamlines open for user access: ELBA and ALFA. ELBA [1] is a laser-electron accelerator, based on Ti:Sa L3-HAPLS laser, designed to deliver up to 30 J, 30 fs pulses at a 10 Hz repetition rate. ELBA receives the L3-HAPLS laser pulses after more than 100 meters propagation inside a vacuum laser beam line. ELBA is designed to collide 2 GeV electron beams with 1021 W/cm2 laser pulses. At the moment, ELBA has been commissioned with up to 15 J at 0.2 Hz and up to 8 J at 3.3 Hz, achieving GeV electron beams in self-guided regime, and multi-GeV energy in the waveguided regime. Six user experimental campaigns have so far been completed. ALFA is a kHz LWFA beamline powered by the ELI L1-ALLEGRA OPCPA laser, designed to deliver up to 100 mJ, 15 fs laser pulses at 1 kHz repetition rate. ALFA is the highest repetition rate LWFA machine operating in "multi-cycle" mode since the L1-ALLEGRA central bandwidth is 800 nm. This makes ALFA a highly requested machine from the user community to realize relativistic plasma physics experiments that require a very high (millions) number of shots. At present, ALFA has been commissioned with up to 50 mJ at 1 kHz repetition rate, achieving up to 50 MeV electron beams [2-4]. These high repetition rate high energy beams enable Gy/s average dose rate, that in combination with the TGy/s peak dose rate [5], are of great interest for the radio-biology user community. Nine user experimental campaigns have been completed. This presentation gives a brief overview of some of the significant theoretical pre-experimental evaluation/simulations work (using the FLUKA Monte Carlo Radiation Transport and Interaction code-package [6]) for our target areas, with a stronger and particular emphasis on ALFA), during not only the overall several weeks of beamtime but naturally during the very extended setups preparation periods. A range of selected applications is described and exposed, namely, those concerning radiation shielding and the prospects for Laser-muon production:
Shielding radiation for ALFA – L1 hall:
To the existing shielding panel in the experimental hall infra-structure consisting of a multi-layer of concrete and lead facing the beam, a small shielding stack of lead bricks (30 cm, due to setup structure constraints) is added and assembled to attenuate the radiation fields produced by the interaction of the incident ~ 25 MeV electrons with the chamber and shielding materials and any effect due to backscattering. A FLUKA model was the key element of the simulations, that comprises the region of interest between vacuum chamber components including the Glass flange, irradiation matrix and part of the experimental hall. The effective shielding efficiency was found to be greatly improved, reaching for the maximal incident electron energy applied in our preliminary simplified benchmark ALFA additional shielding study, orders of magnitude lower radiation levels.
Laser-muon production:
Ultra-intense laser pulses can accelerate electrons to multi-GeV energies, enabling muon pair production in the interaction with high-Z targets. By the combination of different numerical tools it is possible to study muon production as well as approaches for their detection in multi-petawatt laser–matter interactions. A first step of investigation was already performed, using FLUKA for the simulation of different configurations of a heavy tungsten low thickness converter target and for different incident electron beam energies (100 GeV range). Preliminary numerical simulations are presented.
References
1. https://up.eli-laser.eu/equipment/1723072676
2. C. Lazzarini et al., Phys. Plasmas 2024, 31, 030703;
3. I. Zymak et al., Photonics 2024, 11, 1208;
4. https://up.eli-laser.eu/equipment/alfa-1163296775
5. D. Horvath et al., Phys. Med. Biol. 2023, 68, 22NT01
6. FLUKA: A multi-particle transport code (Program version 2005), CERN INFN SLACTech. Rep. CERN-2005-010, SLAC-R-773, INFN-TC-05-11, CERN-2005-10, 10 2005