Collimated gamma beams with high peak flux driven by laser-accelerated electrons. (21st March 2023)

• Record Type: Journal Article
• Authors: Fan, Lulin; Xu, Tongjun; Li, Shun; Xu, Zhangli; Xu, Jiancai; Zhu, Jianqiang; Shen, Baifei; Ji, Liangliang
• Is Part Of: High power laser science and engineering. Volume 11(2023)
• Publication Date: 2023-03-21
• Subjects: bremsstrahlung -- Compton scattering -- gamma-ray beam -- laser-electron acceleration spectrometer; High power lasers -- Periodicals; 621.366
• DOI: 10.1017/hpl.2023.25
• Languages: English
• ISSNs: 2095-4719

Abstract

Abstract: Laser-accelerated electrons are promising in producing gamma-photon beams of high peak flux for the study of nuclear photonics, obtaining copious positrons and exploring photon–photon interaction in vacuum. We report on the experimental generation of brilliant gamma-ray beams with not only high photon yield but also low divergence, based on picosecond laser-accelerated electrons. The 120 J 1 ps laser pulse drives self-modulated wakefield acceleration in a high-density gas jet and generates tens-of-MeV electrons with 26 nC and divergence as small as $1.51{}^{\circ}$ . These collimated electrons produce gamma-ray photons through bremsstrahlung radiation when transversing a high- Z solid target. We design a high-energy-resolution Compton-scattering spectrometer and find that a total photon number of $2.2\times {10}^9$ is captured within an acceptance angle of $1.1{}^{\circ}$ for photon energies up to $16\;\mathrm{MeV}$ . Comparison between the experimental results and Monte Carlo simulations illustrates that the photon beam inherits the small divergence from electrons, corresponding to a total photon number of $2.2\times {10}^{11}$ and a divergence of $7.73{}^{\circ}$ .