Topic
Shields
About: Shields is a research topic. Over the lifetime, 1456 publications have been published within this topic receiving 10896 citations.
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TL;DR: In this paper, effective dose measurements from aircraft flights in the atmosphere are used to obtain the radiation shielding function of the earth's atmosphere, a very thick shield, and the results are then checked and used to predict the radiation dosage under thick shields such as planetary regolith and the atmosphere of Venus.
5 citations
TL;DR: In this paper, the influence of laser entrance hole shields on capsule symmetry and coupling efficiency of an ignition octahedral spherical hohlraum was studied using analytical model and three-dimensional Monte-Carlo simulations.
Abstract: In this paper, the influences of laser entrance hole shields on capsule symmetry and coupling efficiency of an ignition octahedral spherical hohlraum are studied using analytical model and three-dimensional Monte-Carlo simulations. As a result, there are two critical shield radii at which the capsule asymmetry tends to minimum, and the coupling efficiency from hohlraum to capsule reaches its maximum when the shield size is taken around the second critical radius. For the ignition octahedral hohlraums used in our study, the first critical radius is 0.625 mm with a capsule asymmetry of 0.24%, and the second is 0.86 mm with 0.26%, and the asymmetry is smaller than 0.58% for shields’ radius in the range of 0.44 and 0.88 mm, which therefore leaves much flexibility in the shield radius design even the shields have an expansion under radiation ablation. The initial shield radius can be taken around the first critical radius in the ignition target design, not only to have a minimum initial capsule radiation asymmetry, but also to get a minimum asymmetry and highest coupling efficiency during the main pulse of drive. Finally, the relative flux of laser spot, wall and shields is 2.2:1:0.6 for our ignition octahedral spherical hohlraum model from the Monte-Carlo simulations.
5 citations
TL;DR: In this article, the x-ray and debris spectra emanating from a region of compressed DT fuel representing the imploded configuration of a generic direct-drive ICF reactor pellet were analyzed.
Abstract: The authors report approximate x-ray and debris spectra emanating from a region of compressed DT fuel representing the imploded configuration of a generic direct-drive ICF reactor pellet. They show how the spectra are modified by spherical lead shields of various thicknesses placed near the pellet, and show that it is not possible to lessen the ablation of the first wall or blanket of a low-pressure ICF reactor chamber through use of such shields. Then they report that the calculated x-ray spectra alone (i.e., without the associated debris) cause vaporization of a first wall placed at a radius of 4 m that is much more than previously expected. This result increases the importance of understanding the details of the vaporization and condensation phenomena.
5 citations
TL;DR: In this article , a novel technique is proposed to mitigate dust on PV panels that operate light posts, and that is adding a windshield to the panel, which obstructs the dust carried by the wind to reach and settle on the PV panel.
5 citations
TL;DR: In this paper, a three-dimensional finite difference thermal analysis of a TFTR graphite calorimeter is presented which calculates its temperature response to selected power inputs, which is used to estimate power densities at the edge of TFTR plasmas.
Abstract: Graphite has become an important material in magnetically confined fusion devices, being used for components such as limiter blades, divertor plates, and Faraday shields. Langmuir‐calorimeter probes on the tokamak fusion test reactor (TFTR) and the Princeton large torus (PLT) have utilized graphite in probe heads, active elements, protective shields, and in an epoxy compound for various applications. Most recently, all‐graphite edge probes have been used successfully on these machines. The advantages and disadvantages of using this material as a collecting element and a heat resistant support are discussed, with reference to its survivability and usefulness in the TFTR environment. A three‐dimensional finite difference thermal analysis of a TFTR graphite calorimeter is presented which calculates its temperature response to selected power inputs. This was used to estimate power densities at the edge of TFTR plasmas.
5 citations