Shields

About: Shields is a research topic. Over the lifetime, 1456 publications have been published within this topic receiving 10896 citations.

APS SR flexible bellows shield performance

Abstract: The Advanced Photon Source (APS) storage ring (SR) consists of long rigid vacuum chambers connected by flexible formed bellows components. These SR bellows and additional diagnostic chambers are designed with leaf spring beryllium-copper (Be-Cu) alloy contact fingers that insert into mating rigid sleeves to function as electromagnetic shields. The shields protect the bellows convolutions from particle beam image currents and RF energy and reduce beam-induced RF resonances in the diagnostics chambers. The beam aperture of the shields is approximately the same as that of the beam chambers so that the beam impedance of the SR is minimized. The bellows shields systems' thermal performance has been tested and is monitored during APS SR beam operations. Testing included infrared radiometer camera imaging and thermocouple instrumentation of the rigid sleeve. Direct results indicate that the liners perform well under all stored beam fill loadings through and including 100-mA, 8-bunch operations. Maximum temperatures of the bellows liner systems are typically 35-500 Celsius during standard 100 mAmp stored beam fills and 50-700 Celsius during fills, producing both maximum peak and total current simultaneously. The indirect observations of ring vacuum levels support the temperature data.

Magnetic shielding device for stationary induction electrical apparatus

Abstract: PROBLEM TO BE SOLVED: To prevent local overheat in magnetic material shields and a tank and the thermal degradation of insulators protecting the shields or the like, by a method wherein insulators are respectively provided vertically between the shields and the inside of the tank in the height direction of the tank to form cooling flow paths. SOLUTION: Magnetic material shields 8 formed by laminating silicon steel plates of a thin plate thickness in a width W are provided side by side at the positions opposing to inside and outside winding wires 4 and 5 on the inside of a tank 7 housed with a transformer body, comprising a main leg 1, side legs 2, upper yoke parts 3 and the inside and outside winding wires 4 and 5, via prescribed gap parts in the lateral directions, in such a way that the longitudinal directions of the shields 8 are made perpendicular and the shields 8 are respectively provided with press metal fittings. Insulators are provided for protecting the shields 8, and insulators 10 are respectively provided vertical between the insulators and the inside of the tank 7 in the height direction of the tank to form cooling flow paths 11. As a result, local overheating in the shields 8 and the tank 7 and the thermal degradation of the insulators for protecting the shields 8 can be prevented from being caused.

Benzoxazine resin as an interesting building block for advanced neutrons shields

Abstract: The design of lightweight neutrons shields has been restricted for quite some time to the use of the epoxy thermosets as the main building blocks. Meanwhile, the recent developments in the field of...

Activation and transmutation of tungsten boride shields in a spherical tokamak

Abstract: The FISPACT-II code is used to compute the levels of activation and transmutation of tungsten borides for shielding the central high temperature superconductor core of a spherical tokamak fusion power plant during operations at 200 MW fusion power for 30 years and after shutting down for 10 years. The materials considered were W2B, WB, W2B5 and WB4 along with a sintered borocarbide B0.329C0.074Cr0.024Fe0.274W0.299, monolithic W and WC. Calculations were made within shields composed of each material, for five reactor major radii from 1400 to 2200 mm, and for six 10B isotope concentrations and at five positions across the shield. The isotopic production and decay in each shield is detailed. The activation of boride materials is lower than for either W or WC and is lowest of all for W2B5. While isotopes from tungsten largely decay within 3 years of shut-down, those from boron have a much longer decay life. An acceptable 70% of the absorbing 10B isotope will remain after 30 years of operations behind the first wall for a 1400 mm radius tokamak. Gaseous production is problematic in boride shields, where 4He in particular is produced in quantities 3 orders of magnitude higher than in W or WC shields. The FISPACT-II displacements per atom (dpa) tend to increase with boron content, although they decrease with increased 10B isotopic content. The dpa ranges of boride shields tend to lie between those of W and WC. Overall, the results confirm that the favourable fusion reaction shielding properties of W2B5 are not seriously challenged by its irradiation and transmutation properties, although helium gas production could be a challenge to its thermal and mechanical properties.

Characteristics of shields composite coatings based on nanodisperse particles

Abstract: The dependences of shielding effectiveness of electromagnetic field on the structure of inhomogeneous nano-composite material are studied.