Progress in Implementing High-Energy Low-Mix Laser Preheat for MagLIF.
Abstract not provided.
Harvey-Thompson, Adam James↗
Engineering topics
Woodbury, Daniel
Publications and source records attributed to Woodbury, Daniel.
Measurement of ultralow radiation-induced charge densities using picosecond mid-IR laser-induced breakdown
We demonstrate that avalanche ionization breakdown of air with picosecond mid-infrared (mid-IR) laser pulses is an exceptionally sensitive and quantitative probe of extremely low concentrations of charged species. By exponentially increasing the electron density in the vicinity of a single seed atom or molecule to detectable levels, mid-IR electron avalanche is an analogue of single photon detection in photomultiplier tubes and can be useful in a range of applications. We apply the technique to meter-scale standoff detection of a radioactive source, sensitive to extremely low concentrations of radiation-induced negative ions down to ~ 10 3 cm - 3 , limited only by background. By imaging the location of spatially isolated avalanche breakdown sites, we directly measure these low densities and benchmark the performance of standoff detection diagnostics. We discuss implementation of this radiation detection scheme at ranges of 10–100 m and adapting the avalanche probe to detection of other low-density plasmas.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Remote detection of radioactive material using mid-IR laser–driven electron avalanche
Remote detection of a distant, shielded sample of radioactive material is an important goal, but it is made difficult by the finite spatial range of the decay products. Here, we present a proof-of-principle demonstration of a remote detection scheme using mid-infrared (mid-IR) (λ = 3.9 μm) laser–induced avalanche breakdown of air. In the scheme’s most basic version, we observe on-off breakdown sensitivity to the presence of an external radioactive source. In another realization of the technique, we correlate the shift of the temporal onset of avalanche to the degree of seed ionization from the source. We present scaling of the interaction with laser intensity, verify observed trends with numerical simulations, and discuss the use of mid-IR laser–driven electron avalanche breakdown to detect radioactive material at range.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Experiments at Sandia?s Z Machine and Z Backlighter Laser Facility.
Abstract not provided.
Woodbury, Daniel↗