Measurement of the uniformity of ablation for 0.53 μm laser irradiation of spherical targets
Optics Communications 67:1 (1988) 11-15
Abstract:
A novel technique of time-resolved monochromatic X-ray imaging has been used to measure the spatial variation of burn through time of an ablator layer on spherical targets irradiated by twelve laser beams of wavelength 0.53 μm and pulse duration 0.8 ns at adsorbed irradiance up to 1014 W cm-2. The effect of beam overlap on uniformity has been studied. © 1988.A pinhole camera for monochromatic x-ray imaging
Optics Communications 62:1 (1987) 1-4
Abstract:
An instrumental technique for recording monochromatic X-ray images of laser-produced plasmas has been developed using a Layered Synthetic Microstructure in combination with a pinhole camera. Well resolved images in 6 Å X-ray emission from 10 μm gold microdots are demonstrated. © 1987.CoordGate: efficiently computing spatially-varying convolutions in convolutional neural networks
British Machine Vision Association
Abstract:
Optical imaging systems are inherently limited in their resolution due to the point spread function (PSF), which applies a static, yet spatially-varying, convolution to the image. This degradation can be addressed via Convolutional Neural Networks (CNNs), particularly through deblurring techniques. However, current solutions face certain limitations in efficiently computing spatially-varying convolutions. In this paper we propose CoordGate, a novel lightweight module that uses a multiplicative gate and a coordinate encoding network to enable efficient computation of spatially-varying convolutions in CNNs. CoordGate allows for selective amplification or attenuation of filters based on their spatial position, effectively acting like a locally connected neural network. The effectiveness of the CoordGate solution is demonstrated within the context of U-Nets and applied to the challenging problem of image deblurring. The experimental results show that CoordGate outperforms existing approaches, offering a more robust and spatially aware solution for CNNs in various computer vision applications.Kinetic simulations of fusion ignition with hot-spot ablator mix
Physical Review E American Physical Society
Abstract:
Inertial confinement fusion fuel suffers increased X-ray radiation losses when carbon from the capsule ablator mixes into the hot-spot. Here we present one and two-dimensional ion VlasovFokker-Planck simulations that resolve hot-spot self heating in the presence a localised spike of carbon mix, totalling 1.9 % of the hot-spot mass. The mix region cools and contracts over tens of picoseconds, increasing its alpha particle stopping power and radiative losses. This makes a localised mix region more severe than an equal amount of uniformly distributed mix. There is also a purely kinetic effect that reduces fusion reactivity by several percent, since faster ions in the tail of the distribution are absorbed by the mix region. Radiative cooling and contraction of the spike induces fluid motion, causing neutron spectrum broadening. This artificially increases the inferred experimental ion temperatures and gives line of sight variations.Preparations for a European R&D Roadmap for an Inertial Fusion Demo Reactor
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences Royal Society, The