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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29 Jan 2014
TL;DR: In this article, the authors used thermal baffles to reduce the direct line-of-sight between room temperature and lower temperature components but leave many, low emissivity paths with only a single reflection required for the room temperature photons to strike the lower temperature surfaces.
Abstract: Accelerator cryomodules reduce the radiative thermal load to the 1.8 – 4.5 K components by enclosing them within low-emissivity shields cooled to 70–100 K. These heat shields are not continuous and have many penetrations, or holes, to allow for the connection of support structures and the many subsystems running from room temperature. The penetrations have thermal baffles to reduce, or eliminate if possible, the direct line-of-sight between room temperature and the lower temperature components but leave many, low emissivity, paths with only a single reflection required for the room temperature photons to strike the 1.8 – 4.5 K surfaces. To reduce this we are coating our baffles such that the surfaces which face lower temperatures have a low-emissivity while the surfaces which the photons may reflect from but do not have line-of-sight to lower temperature surfaces have a high-absorption. We measure emissivities of different coatings from the heat balance between absorption, from background radiation and the heater attached on the sample, and emission powers. In this paper, design details of our experiment and measurement results will be presented.
4 citations
TL;DR: In this article, the authors describe the Faraday room that shields the CUORE experiment against electromagnetic fields, from 50 Hz up to high frequency, using panels made of light shielding materials.
Abstract: The paper describes the Faraday room that shields the CUORE experiment against electromagnetic fields, from 50 Hz up to high frequency. Practical contraints led to choose panels made of light shielding materials. The seams between panels were optimized with simulations to minimize leakage. Measurements of shielding performance show attenuation of a factor 15 at 50 Hz, and a factor 1000 above 1 KHz up to about 100 MHz.
4 citations
TL;DR: In this paper, the authors deal with the calculation of RMS currents in shields of single-core cables at double-sided grounding of three-phase cable lines and derive the analytical expressions for RMS current in the shields of cables.
Abstract: This paper deals with the calculation of currents in shields of single-core cables at double-sided grounding of three-phase cable lines. We consider flat and trefoil cable lines and receive the analytical expressions for RMS currents in the shields of cables. These expressions allow reducing the shield current calculation error to value of 5 %. We analyze the known approximate expressions for RMS currents in the shields of cables and represent dependencies of corresponding calculation errors on cable line dimensionless parameters. These dimensionless parameters are determined by the distance between the axes of the cables, the radius and the resistance of shields.
4 citations
TL;DR: In this paper, the possible use of models to study gamma radiation penetration of complex shielding configurations is discussed with reference to the limitations of the available models. But the authors focus on the use of a model with 2 to 3 Mev gamma rays as a model of the relative intensities in thick concrete shields.
Abstract: The possible use of models to study gamma radiation penetration of complex shielding configurations is discussed with reference to the limitations. An iron model with 2 to 3 Mev gamma rays may serve as a model of the relative intensities in thick concrete shields. Experiments were carried out in which the penetration of 7-Mev gamma rays through a concrete shield was compared with that of 2.62Mev gammas through an iron model constructed on a 1 : 5.8 scale. Various shield configurations were studied, including shields with straight holes and holes with bends. The results show excellent correspondence between the spectra. (D.L.C.)
4 citations
02 Jul 2019
TL;DR: In this article, the U-shaped grid shield is used for the mitigation of a three-phase overhead line magnetic field by a U-shape grid shield, which is made of wires located in a vertical plane and two horizontal planes.
Abstract: The paper deals with the mitigation of a three-phase overhead line magnetic field by a U-shaped grid shield. The U-shaped grid shield is made of wires located in a vertical plane and two horizontal planes. All wires are connected in parallel. Shielding characteristics of four U-shaped grid shields and four U-shaped electromagnetic shields having equivalent quantity of metal are studied by numerical simulation. We found that the U-shaped grid shield is preferred because of its convenient and low cost erection. The length of arms is varied. Respectively the number of wires and their cross-sectional areas are varied for grid shields, and the thickness is varied for electromagnetic shields. The advisable length of arms and the advisable quantity of metal of the U-shaped grid shield are found out.
4 citations