Electron-positron generation by irradiating various metallic materials with laser-accelerated electrons

Abstract

We examined electron–positron pair production in solid iron, zinc, tungsten, and lead targets irradiated by a laser-accelerated electron beam generated with a 100 TW laser. These targets were assessed at the target thickness of 0.5, 1.25, and 2.0 radiation lengths for each material. Using a 0.75-T-magnetic spectrometer, we measured the electron and positron yields and spectra, producing 3 × 108 positrons per shot with a peak leptonic density of 4 × 1012 cm−3. These experimental results agree very well with Monte Carlo simulations conducted with the simulation code Geant4. Importantly, our findings show that normalizing the target thickness to each material’s radiation length results in consistent electron and positron yields across the materials, effectively reducing discrepancies due to material differences.

Keywords

• Electron-positron pair production
• Laser wakefield acceleration
• GEANT4 simulations
• Laser-plasma physics