End-to end simulations of LINAC4

Linac4 is a new H- linear accelerator presently studied at CERN. This machine consists of normal-conducting structures operating at 352.2 MHz and 704.4 MHz re-using the RF equipment from the decommissioned LEP collider. It consists of a 95 keV H- source, a 352 MHz RFQ bringing the energy the energy to 3 MeV, a Chopper line, a 352 MHz Drift Tube Linac bringing the energy to 40 MeV, a 352 MHz Coupled Cavity Drift Tube Linac bringing the energy to 90 MeV and a 704 MHz Side Coupled Linac bringing the energy to 160 MeV. Each section is designed and optimized as stand-alone machines for a good transmission and minimum possible emittance growth. End-to-end simulations starting from the RFQ have been carried out in order to validate and compare the multiparticle simulation codes PATH Manager and TRACEWIN used for beam dynamics calculations as well as to perform a global optimization of the structures in the context of a complex machine

Introduction by Guest Editors

This book grew out of conversations among the three guest editors, Mark Cammack, Michael Feener, and Clark Lombardi, in the summer of 2008 about the general lack of attention among scholars of Southeast Asian Islam on important questions about the foundations of the region’s Islamic legal structures. First, despite its evident importance, there has been little research on the process by which legislators and judges decide which interpretation of Islamic law will be formally applied by the state apparatus. Another important question that has been largely ignored by scholars concerns the qualifications of Islamic legal professionals. The three Southeast Asian states treated in this volume—Indonesia, Malaysia and Singapore—have separate systems of Islamic courts. Although the educational background of those who staff these courts will clearly inform the way they understand, interpret, and apply the law, to date little research has been done on the educational processes by which judges who serve on Islamic courts are trained to think about Islamic law. Studies on the means by which judges are appointed and regulated have also been lacking—even though the decision to favor one type of candidate surely affects the interpretation and application of Islamic law in the courts. Finally, lawyers who practice before Islamic courts play a crucial role in framing and presenting the issues for decision and in mediating between the courts that apply Islamic law and the public who have recourse to the state’s official Islamic legal institutions, but research on the professional training and governance of these lawyers is almost entirely lackin

Phase Rotation, Cooling And Acceleration Of Muon Beams: A Comparison Of Different Approaches

Experimental and theoretical activities are underway at CERN with the aim of examining the feasibility of a very-high-flux neutrino source. In the present scheme, a high-power proton beam (some 4 MW) bombards a target where pions are produced. The pions are collected and decay to muons under controlled optical condition. The muons are cooled and accelerated to a final energy of 50 GeV before being injected into a decay ring where they decay under well-defined conditions of energy and emittance. We present the most challenging parts of the whole scenario, the muon capture, the ionisation-cooling and the first stage of the muon acceleration. Different schemes, their performance and the technical challenges are compared.Comment: LINAC 2000 CONFERENCE, paper ID No. THC1

Enhanced shot noise in resonant tunneling: theory and experiment

We show that shot noise in a resonant tunneling diode biased in the negative differential resistance regions of the I-V characteristic is enhanced with respect to ``full'' shot noise. We provide experimental results showing a Fano factor up to 6.6, and show that it is a dramatic effect caused by electron-electron interaction through Coulomb force, enhanced by the particular shape of the density of states in the well. We also present numerical results from the proposed theory, which are in agreement with the experiment, demonstrating that the model accounts for the relevant physics involved in the phenomenon.Comment: 4 pages, 4 figure

Planetary Science Goals for the Spitzer Warm Era

The overarching goal of planetary astronomy is to deduce how the present collection of objects found in our Solar System were formed from the original material present in the proto-solar nebula. As over two hundred exo-planetary systems are now known, and multitudes more are expected, the Solar System represents the closest and best system which we can study, and the only one in which we can clearly resolve individual bodies other than planets. In this White Paper we demonstrate how to use Spitzer Space Telescope InfraRed Array Camera Channels 1 and 2 (3.6 and 4.5 µm) imaging photometry with large dedicated surveys to advance our knowledge of Solar System formation and evolution. There are a number of vital, key projects to be pursued using dedicated large programs that have not been pursued during the five years of Spitzer cold operations. We present a number of the largest and most important projects here; more will certainly be proposed once the warm era has begun, including important observations of newly discovered objects

Observation of mesoscopic conductance fluctuations in YBaCuO grain boundary Josephson Junctions

Magneto-fluctuations of the normal resistance R_N have been reproducibly observed in high critical temp erature superconductor (HTS) grain boundary junctions, at low temperatures. We attribute them to mesoscopic transport in narrow channels across the grain boundary line. The Thouless energy appears to be the relevant energy scale. Our findings have significant implications on quasiparticle relaxation and coherent transport in HTS grain boundaries.Comment: Revised version, minor changes. 4 pages, 4 figure