The single-line-of-sight, time-resolved x-ray imager diagnostic on OMEGA

Abstract

The single-line-of-sight, time-resolved x-ray imager (SLOS-TRXI) on OMEGA is one of a new generation of fast-gated x-ray cameras comprising an electron pulse-dilation imager and a nanosecond-gated, burst-mode, hybrid complementary metal-oxide semiconductor sensor. SLOS-TRXI images the core of imploded cryogenic deuterium–tritium shells in inertial confinement fusion experiments in the ∼4- to 9-keV photon energy range with a pinhole imager onto a photocathode. The diagnostic is mounted on a fixed port almost perpendicular to a 16-channel, framing-camera–based, time-resolved Kirkpatrick–Baez microscope, providing a second time-gated line of sight for hot-spot imaging on OMEGA. SLOS-TRXI achieves ∼40-ps temporal resolution and better than 10-μm spatial resolution. Shots with neutron yields of up to 1 × 1014 were taken without observed neutron-induced background signal. The implosion images from SLOS-TRXI show the evolution of the stagnating core.

The National Direct-Drive Inertial Confinement Fusion Program

“…The strategy of the enhanced-capability approach is highlighted in figure 3 showing the areal density plotted as a function of the primary neutron yield with the calculated contours of hot-spot pressure overlaid. It involves improvements to the OMEGA laser [1][2][3], targets [8], and diagnostics [9][10][11][12], and new modeling and simulation capabilities [13][14][15][16][17][18], to increase the areal density and yield of the implosion. These improvements will be applied to the α ~ 3.5 DT cryogenic implosion where the highest hot-spot pressure (56 ± 7 Gbar) was achieved with an energy-scaled generalized Lawson parameter of 0.6-0.64 [27], which extrapolates to 125 kJ of fusion yield on a symmetric NIF LDD implosion [30].…”

“…Three-dimensional (3D) diagnostics (i.e. more than three diagnostic lines of sight (LOS)) are being developed to study multidimensional effects on the hot-spot at stagnation [9][10][11][12]. X-ray [9] and nuclear [10,11,32] diagnostics are being developed to study hot-spot formation and stagnation.…”

“…more than three diagnostic lines of sight (LOS)) are being developed to study multidimensional effects on the hot-spot at stagnation [9][10][11][12]. X-ray [9] and nuclear [10,11,32] diagnostics are being developed to study hot-spot formation and stagnation. 3D gated x-ray imaging of the hot-spot formation and disassembly with less than 5 µm spatial, ~10 ps temporal resolution is being developed [9].…”

“…X-ray [9] and nuclear [10,11,32] diagnostics are being developed to study hot-spot formation and stagnation. 3D gated x-ray imaging of the hot-spot formation and disassembly with less than 5 µm spatial, ~10 ps temporal resolution is being developed [9]. The neutron spectrum will be diagnosed with the neutron time of flight detectors along multiple LOS to infer the hot-spot ion temperature, the compressed areal density of the DT shell, spatial variations in these quantities, the fusion yields, and evidence of residual flows in the hot-spot [10,11,32].…”

“…The 100 Gbar Campaign on OMEGA explores the formation of hot-spot conditions relevant for ignition at the megajoule (MJ) scale using hydrodynamically scaled implosions of layered DT cryogenic targets [1][2][3]. The enhancedcapability approach of the 100 Gbar Campaign involves improvements to the OMEGA laser [1][2][3], targets [8], diagnostics [9][10][11][12] along with new modeling and simulation capabilities [13][14][15][16][17][18] to increase the areal density and yield of the implosion. While these improvements are underway, the 100 Gbar Campaign has a parallel effort using a statistical approach to search for the optimum DT cryogenic implosion on OMEGA having the highest combination of areal density and primary neutron yield using the current capabilities [19].…”