Atomic Beam

	Atomic Beam Atomic beam is special case of particle beam; it is the collimated flux (beam) of neutral atoms. The imaging systems using the slow atomic beams can use the Fresnel zone plate A zone plate is a device used to Focus (optics), focus light or other things exhibiting wave character.G. W. Webb, I. V. Minin and O. V. Minin, “Variable Reference Phase in Diffractive Antennas”, ''IEEE Antennas and Propagation Magazine'', ... ( Fresnel diffraction lens) of a Fresnel diffraction mirror as focusing element. The imaging system with atomic beam could provide the sub-micrometre resolution. Particle accelerators {{accelerator-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Particle Beam A particle beam is a stream of charged or neutral particles. In particle accelerators, these particles can move with a velocity close to the speed of light. There is a difference between the creation and control of charged particle beams and neutral particle beams, as only the first type can be manipulated to a sufficient extent by devices based on electromagnetism. The manipulation and diagnostics of charged particle beams at high kinetic energies using particle accelerators are main topics of accelerator physics. Sources Charged particles such as electrons, positrons, and protons may be separated from their common surrounding. This can be accomplished by e.g. thermionic emission or arc discharge. The following devices are commonly used as sources for particle beams: * Ion source * Cathode ray tube, or more specifically in one of its parts called electron gun. This is also part of traditional television and computer screens. * Photocathodes may also be built in as a part of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Fresnel Zone Plate A zone plate is a device used to focus light or other things exhibiting wave character.G. W. Webb, I. V. Minin and O. V. Minin, “Variable Reference Phase in Diffractive Antennas”, ''IEEE Antennas and Propagation Magazine'', vol. 53, no. 2, April. 2011, pp. 77-94. Unlike lenses or curved mirrors, zone plates use diffraction instead of refraction or reflection. Based on analysis by French physicist Augustin-Jean Fresnel, they are sometimes called Fresnel zone plates in his honor. The zone plate's focusing ability is an extension of the Arago spot phenomenon caused by diffraction from an opaque disc. A zone plate consists of a set of concentric rings, known as Fresnel zones, which alternate between being opaque and transparent. Light hitting the zone plate will diffract around the opaque zones. The zones can be spaced so that the diffracted light constructively interferes at the desired focus, creating an image there. Design and manufacture To get constructive interference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Fresnel Diffraction Lens A zone plate is a device used to focus light or other things exhibiting wave character.G. W. Webb, I. V. Minin and O. V. Minin, “Variable Reference Phase in Diffractive Antennas”, ''IEEE Antennas and Propagation Magazine'', vol. 53, no. 2, April. 2011, pp. 77-94. Unlike lenses or curved mirrors, zone plates use diffraction instead of refraction or reflection. Based on analysis by French physicist Augustin-Jean Fresnel, they are sometimes called Fresnel zone plates in his honor. The zone plate's focusing ability is an extension of the Arago spot phenomenon caused by diffraction from an opaque disc. A zone plate consists of a set of concentric rings, known as Fresnel zones, which alternate between being opaque and transparent. Light hitting the zone plate will diffract around the opaque zones. The zones can be spaced so that the diffracted light constructively interferes at the desired focus, creating an image there. Design and manufacture To get constructive inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Fresnel Diffraction Mirror In atomic physics, a ridged mirror (or ridged atomic mirror, or Fresnel diffraction mirror) is a kind of atomic mirror, designed for the specular reflection of neutral particles (atoms) coming at a grazing incidence angle. In order to reduce the mean attraction of particles to the surface and increase the reflectivity, this surface has narrow ridges. Reflectivity of ridged atomic mirrors Various estimates for the efficiency of quantum reflection of waves from ridged mirror were discussed in the literature. All the estimates explicitly use the de Broglie theory about wave properties of reflected atoms. Scaling of the van der Waals force The ridges enhance the quantum reflection from the surface, reducing the effective constant ~C~ of the van der Waals attraction of atoms to the surface. Such interpretation leads to the estimate of the reflectivity : \displaystyle r \approx r_0\!\left( \frac \ell L C,\!~K\sin(\theta)\right), where ~\ell~ is width of the ridges, ~L~ is dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]