First Observation of Self-Amplified Spontaneous Emission in a Free-Electron Laser at 109 nm Wavelength

We present the first observation of Self-Amplified Spontaneous Emission (SASE) in a free-electron laser (FEL) in the Vacuum Ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approx. 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width and intensity fluctuations all corroborate the existing models for SASE FELs.Comment: 6 pages including 6 figures; e-mail: [email protected]

Machine layout and performance

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC

Wake and Higher Order Mode Computations for the CMS Experimental Chamber at the LHC.

Wakefields and trapped Higher Order Modes (HOMs) in the CMS experimental chamber at the LHC are investigated using a geometrical model which closely reflects the presently installed vacuum chamber. The basic rf-parameters of the HOMs including the frequency, loss parameter, and the Q-value are provided. To cover also transient effects the short range wakefields and the total loss parameter has been calculated, too. Most numerical calculations are performed with the computer code MAFIA. The calculations of the Modes are complemented with an analysis of the multi-bunch instabilities due to the longitudinal and dipole modes in the CMS vacuum chamber

Influence of pre- and post-heat treatment of anode substrates on the properties of DC-sputtered YSZ electrolyte films

Yttria-stabilised zirconia (YSZ) electrolyte films for solid oxide fuel cell (SOFC) applications have been prepared by reactive DC sputtering. The pore structure of the anode substrates was modified by sintering at different temperatures between 1300 and 1400 degreesC and the influence of this microstructure on the gastightness of the deposited films was studied. The characterisation of the microstructure includes measurements of electrical conductivity as well as determination of porosity by image analysis and mercury porosimetry. At sintering temperatures of 1380 and 1400 degreesC, the surface of the anode substrate, coated by an anode functional layer, was dense. The 5- to 8-mum-thick sputtered electrolyte films were annealed again to increase the gastightness. At an annealing temperature of 1360 degreesC, a He leakage rate of 8 x 10(-8) mbar l/cm(2) s was achieved. (C) 2003 Elsevier Science B.V All rights reserved

Electrical and microstructural investigations of cermet anode/YSZ thin film systems

We describe the preparation, electrochemical and structural properties of the thin film Y-stabilized ZrO2 (YSZ), of interest for solid oxide fuel cell (SOFC) at an operating temperature of 800 degreesC. Thin films of YSZ were prepared by reactive sputtering deposition of Zr-Y targets in Ar-O-2 mixture atmospheres. The thickness of the YSZ film, deposited onto the porous NiO-YSZ substrates, is approximately 8 mum. The microstructure of the YSZ film was investigated using scanning electron microscope. The electrochemical properties of a thin film cell Ag/NiO-YSZ/YSZ/Ag were studied using impedance spectroscopy. The electrolyte and electrode (substrate) resistances were measured under different atmospheres as a function of temperature. Above 600 degreesC the ohmic resistance of the cermet electrode (substrate) is comparable to the ionic resistance of the solid electrolyte. This is probably influenced by the cermet electrode microstructure. (C) 2001 Elsevier Science Ltd. All rights reserved