Speaker
Description
We demonstrate that a compact, directional hard X-ray source driven by a picosecond, 100-TW-class laser interacting with an underdense gas jet reproduces the performance previously established on the Titan laser at the Jupiter Laser Facility, establishing the platform as robust and transferable across major high-energy-density-science (HEDS) facilities. Over the past decade, this platform has been developed across Titan, OMEGA-EP, and NIF-ARC, producing 10s–100s of nC of relativistic electrons via self-modulation instability and direct laser acceleration, and generating betatron, inverse Compton scattering (ICS), and bremsstrahlung X-rays.
In OMEGA-EP experiments (a₀ ≈ 5.4), we measure two-temperature electron spectra (T₁ ≈ 12–40 MeV, T₂ ≈ 36–70 MeV) that produce broadband X-ray emission. Betatron radiation produces 4–100 keV photons, while a 100-µm low-Z plasma mirror retro-reflects the drive pulse, enabling head-on ICS with the relativistic electron beam and extending the spectrum to 60–240 keV. Spectral reconstruction using forward-fitting and discrete Ross-pair / differential-averaged-transmission methods yields betatron amplitudes Ac = 0.4–57 × 10¹⁰ ph/keV/sr and ICS components A₁ = 8–43 × 10¹⁰ ph/keV/sr. ICS-enhanced shots increase photon yield by up to an order of magnitude while maintaining a ∼100 µm FWHM source size.
OMEGA-EP matches or exceeds Titan performance with up to 65 J less energy on target, attributed to improved focal spot quality from beam apodization. These results establish a tunable, sub-picosecond, directional backlighter spanning ∼10 keV phase-contrast imaging to >50 keV radiography, enabling applications in hydrodynamics, instability growth, and ρR diagnostics, and providing a clear path toward implementation on NIF-ARC.
Research Program (Fusion Energy Sciences) SCW-1575-1. Work performed by UCLA was supported by DOE grant DE-SC0010064, NNSA grant DE-NA0003873, & NSF Grant No. 2003354. Computational support was provided by NSERC under the m1157 account. This material is based upon work supported by the Department of Energy [National Nuclear Security Administration] University of Rochester “National Inertial Confinement Program” under Award Number DE-NA0004144, and the US Department of Energy, Office of Science, under Award Number DE-SC0021057.
| Working group | WG6 |
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