2017/05/24 by Shaw, J. M., Bernstein, A. C., Zgadzaj, R. +19
#Accelerator Physics (physics.acc-ph) #FOS: Physical sciences
paper · doi:10.48550/arxiv.1705.08637
We convert a GeV laser-plasma electron accelerator into a compact femtosecond-pulsed γ-ray source by inserting a 100 μm-thick glass plate ∼3 cm after the accelerator exit. With near-unity reliability, and requiring only crude alignment, this glass plasma mirror retro-reflected spent drive laser pulses (photon energy ℏωL = 1.17 eV) with >50% efficiency back onto trailing electrons (peak Lorentz factor 1000 < γe < 4400), creating an optical undulator that generated ∼108 γ-ray photons with sub-mrad divergence, estimated peak brilliance ∼1021 photons/s/mm2/mrad2/0.1% bandwidth and negligible bremsstrahlung background. The γ-ray photon energy Eγ= 4γe2 ℏωL, inferred from the measured γe on each shot, peaked from 5 to 85 MeV, spanning a range otherwise available with comparable brilliance only from large-scale GeV-linac-based high-intensity γ-ray sources.