Compact broadband Compton spectroscopy used for intense laser-driven gamma rays

• Published in: Review of scientific instruments Vol. 92; no. 5; pp. 053546 - 53555
• Main Authors: Yang, Tao, Hu, Guang-yue, Li, Meng-ting, Lian, Chang-wang, Zhang, Zhen-chi, Luo, Wen, Ma, Yue, Zheng, Jian
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.05.2021
• Subjects: Broadband; Elastic scattering; Electron beams; Gamma ray sources; Gamma rays; High energy electrons; Lasers; Magnets; Nonuniform magnetic fields; Scientific apparatus & instruments; Spectra; Spectral resolution; Spectrum analysis
• ISSN: 0034-6748; 1089-7623; 1089-7623
• DOI: 10.1063/5.0028098

A compact broadband Compton spectrometer is designed to measure the continuous spectrum of gamma-ray sources driven by an intense laser. The incident gamma rays are converted into electrons in low-Z materials by Compton scattering. Produced by a pair of stepped magnets, a weaker-front–stronger-rear nonuniform magnetic field in the electron magnetic spectrometer is used to spectrally resolve the scattered electrons, leading to a broadband gamma-ray spectral coverage of 2–20 MeV in a compact volume. Flat imaging-plate detectors are placed near the focused imaging points of the magnetic spectrometer to record the dispersed electrons, thereby achieving an optimal spectral resolution of 6%–13% in the energy range of 3–20 MeV. The spectrometer is used successfully to measure the gamma-ray spectrum generated by the high-energy electron beams produced by a femtosecond-laser-driven wakefield.