Measurement and application of electron stripping of ultrarelativistic 208Pb81+^{208}\textrm{Pb}^{81+}

New measurements of the stripping cross-section for ultrarelativistic hydrogen-like lead ions passing through aluminium and silicon have been performed at the Advanced Wakefield experiment at CERN. Agreement with existing measurements and theory has been obtained. Improvements in terms of electron beam quality and ion beam diagnostic capability, as well as further applications of such an electron beam, are discussed

The AWAKE Electron Spectrometer

The AWAKE experiment at CERN aims to use a proton driven plasma wakefield to accelerate electrons from 10–20 MeV up to GeV energies in a 10 m plasma cell. We present the design of the magnetic spectrometer which will measure the electron energy distribution. Results from the calibration of the spectrometer's scintillator and optical system are presented, along with a study of the backgrounds generated by the 400 GeV SPS proton beam

4MOST: Project overview and information for the First Call for Proposals

We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for the four-metre-class Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view (FoV) of 4.2 square degrees and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs ($R = \lambda/\Delta\lambda \sim 6500$), and 812 fibres transferring light to the high-resolution spectrograph ($R \sim 20\,000$). After a description of the instrument and its expected performance, a short overview is given of its operational scheme and planned 4MOST Consortium science; these aspects are covered in more detail in other articles in this edition of The Messenger. Finally, the processes, schedules, and policies concerning the selection of ESO Community Surveys are presented, commencing with a singular opportunity to submit Letters of Intent for Public Surveys during the first five years of 4MOST operations

Frictionless Telescopes in Antarctica: Why and How?

Seeing quality in Antarctica is in the hundredth arcseconds range out of the boundary layer. To take advantage of this quality telescopes should be in thermal equilibrium with the outside environment and should minimize the non linearity's like limit cycles which will deteriorate tracking. At the ESO Very Large Telescope (VLT) 8 m telescopes this is realized using oil bearings and direct drives on the axes to avoid slip stick effects on the motion. In Antarctica this could be realized using magnetic bearings, possibly combined with motors, on the axes, with also advantages concerning power consumptions and maintenance of the system

Structural Response of Extremely Large Telescopes

This paper is concerned with the extrapolation of the dynamic response of the primary mirror of current 10-meter class telescopes to the next generation of 30 to 40 m extremely large telescopes and future, even larger, ones. A numerical study is conducted on a family of primary mirrors of increasing size, and the results are compared with analytical scaling laws derived earlier from a much simpler analysis. The correlation between the numerical and the analytical results is quite good and, to a large extent, independent of the boundary conditions. This confirms that the analytical scaling laws can be used in confidence to conduct parametric studies in the preliminary design phase of extremely large segmented mirrors. Copyright © 2010 by R. Bastaits and A. Preumont. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Measurement and application of electron stripping of ultrarelativistic 208^{208}Pb81+^{81+}

International audienceAn electron beam derived from stripping of ultrarelativistic lead ions has been used to perform calibration measurements on the electron spectrometer of the Advanced Wakefield experiment at CERN. As part of this study, new measurements of the stripping cross-section for ultrarelativistic hydrogen-like lead ions passing through aluminium and silicon have been obtained which demonstrate good agreement with existing measurements and theory. Improvements in terms of electron beam quality and ion beam diagnostic capability, as well as further applications of such an electron beam, are discussed

Measurement and application of electron stripping of ultrarelativistic Pb-208(81+)

An electron beam derived from stripping of ultrarelativistic lead ions has been used to perform calibration measurements on the electron spectrometer of the Advanced Wakefield experiment at CERN. As part of this study, new measurements of the stripping cross-section for ultrarelativistic hydrogen-like lead ions passing through aluminium and silicon have been obtained which demonstrate good agreement with existing measurements and theory. Improvements in terms of electron beam quality and ion beam diagnostic capability, as well as further applications of such an electron beam, are discussed