55284518
High current, high frequency ECRIS development program for LHC havy ion beam application
A research program with the aim of producing pulsed currents with hitherto unequalled intensity of Pb 27+ , with length and repetition rate compatible with those desired by CERN (1 mAe / 400 μs / 10 Hz in the context of future heavy ion collisions at LHC) is organised in a collaboration between CERN/GSI/CEA-Grenoble and IN2P3-ISNGrenoble. Two main experimental programs will be carried out : (i) tests with the LNS-Catania team on the SERSE superconducting source with a 28 GHz gyrotron, (ii) tests on a nonsuperconducting source (new source at Grenoble) with a 28 GHz gyrotron. For this purpose CEA/DRFMC has borrowed from CEA a 28 GHz 10 kW gyrotron transmitter. The project includes also the construction of a source body, by ISNG, with conventional coils and permanent magnets for working at the frequency of about 28 GHz and biased up to 60 kV. This source called PHOENIX will run on a test bench at ISN. PHOENIX is an improvement of the present ECR4-14.5 GHz/CERN source, having a mirror ratio R=2 at 14.5 GHz, and R=1.7 at 28 GHz (possibly reaching 2.1 T on the axis of the source), and with a plasma volume up to 2.5 larger. Experiments at 28 GHz will be performed on the SERSE source in Catania at INFN/LNS where both the axial and the hexapolar fields will be varied so that the mirror ratio is continuously varied up to R=1.6 ; the SERSE source will be also operated at lower magnetic fields such as those which can be produced by conventional magnets (less than 2 T axial field at injection far from the 28 GHz High-B mode).
115300845
Status and first beam measurements on the CERN RFQ
119401628
The Electron Cooling Device for LEAR
The experiments1,2,3 in which low energetic protons were cooled by a “cold” electron beam have proved that this method is a very powerful technique to improve low energy beams and to increase their phase space density by several orders of magnitude in short times. The theoretical understanding of the cooling process is well advanced4,5,6. The applications of this technique, which was invented and developed in Novosibirsk, are manifold7. It seems to be clear that its main domain is the cooling of non-relativistic ions. However, also at extremely high energies, cooling of protons and antiprotons with stored electrons (cooled themselves by synchrotron radiation) can be contemplated8,9.
102555920
The LHC Lead Ion Injector Chain
121894301
Studies on ECR4 for the CERN ion program
The CERN heavy ion community, and some other high energy physics experiments, are starting to demand other ions, both heavy and light, in addition to the traditional lead ions. Studies of the behavior of the afterglow for different operation modes of the ECR4 at CERN have been continued to try to understand the differences between pulsed afterglow and continuous operation, and their effect on ion yield and beam reproducibility. The progress in adapting the source and ion beam characteristics to meet the new demands will be presented, as will new information on voltage holding problems in the extraction.
55729922
Experiments on a 14.5 GHz ECR Source
A device for measuring the speed of the wind at medium altitude by the Doppler effect within the visible frequency range comprises a laser which emits pulses of light, a telescope which receives a scattered light and an interferometer used to measure the spectral shift of the scattered light in relation to the emitted pulse of light. The interferometer is a Fabry-Perot interferometer in which a part of one of the two mirrors of the interferometer is covered with an excess thickness of silica to form two separate filters. The spacing of the two mirrors and the excess thickness of silica are determined in such a manner that the pass bands of each one of the two filters thus constructed are centered on the flanks of the spectral distribution of the backscattered light.
11057739
Initial experience with the CDF layer 00 silicon detector
We report on initial experience with the CDF Layer 00 Detector. Layer 00 is an innovative, low-mass, silicon detector installed in CDF during the upgrade for Run 2A of the Tevatron. Noise pickup present during operation at CDF is discussed. An event-by-event pedestal correction implemented by CDF is presented. This off-line solution prevents L00 from being used in the current incarnation of the on-line displaced track trigger. Preliminary performance of Layer 00 is described.
119087450
Exact equivalence of the D=4 gauged Wess-Zumino-Witten term and the D=5 Yang-Mills Chern-Simons term
We derive the full Wess-Zumino-Witten term of a gauged chiral Lagrangian in D=4 by starting from a pure Yang-Mills theory of gauged quark flavor in a flat, compactified D=5. The theory is compactified such that there exists a B{sub 5} zero mode, and supplemented with quarks that are 'chirally delocalized' with q{sub L} (q{sub R}) on the left (right) boundary (brane). The theory then necessarily contains a Chern-Simons term (anomaly flux) to cancel the fermionic anomalies on the boundaries. The constituent quark mass represents chiral symmetry breaking and is a bilocal operator in D=5 of the form: q{sub L}Wq{sub R}+h.c, where W is the Wilson line spanning the bulk, 0{<=}x{sup 5}{<=}R, and is interpreted as a chiral meson field, W=exp(2i{pi}-tilde/f{sub {pi}}), where f{sub {pi}}{approx}1/R. The quarks are integrated out, yielding a Dirac determinant which takes the form of a 'boundary term' (anomaly flux return), and is equivalent to Bardeen's counterterm that connects consistent and covariant anomalies. The Wess-Zumino-Witten term then emerges straightforwardly, from the Yang-Mills Chern-Simons term, plus boundary term. The method is systematic and allows generalization of the Wess-Zumino-Witten term to theories of extra dimensions, and to express it in alternative and more compact forms. We give a novelmore » form appropriate to the case of (unintegrated) massless fermions.« less
14252776
Electroweak symmetry breaking and extra dimensions
Abstract Electroweak symmetry can be naturally broken by observed quark and gauge fields in various extra-dimensional configurations. No new fundamental fields are required below the quantum gravitational scale (∼ 10–100 TeV). We examine schemes in which the QCD gauge group alone, in compact extra dimensions, forms a composite Higgs doublet out of ( t , b ) L and a linear combination of the Kaluza–Klein modes of t R . The effective theory at low energies is the Standard Model. The top-quark mass is controlled by the number of active t R Kaluza–Klein modes below the string scale, and is in agreement with experiment.
4238450
A possible practical application of heavy quark physics
A POSSIBLE method for storing very large amounts of useable energy within small volumes is described here. Our proposal is based on the existence of two new, virtually stable, forms of matter that annihilate each other with enormous energy release, but neither of which annihilates ordinary matter (and can thus be stored easily). The existence of these new forms of matter is suggested1,2 by the phenomenology of heavy quarks and also by a large class of widely discussed unified field theories.
112091395
Power Distribution in a CMS Tracker for the SLHC
An upgraded tracker for CMS will need a new architecture for powering to keep the power dissipated in the power cables to acceptable levels. Inductor topologies to reduce the stray magnetic field are discussed together with measurements of the magnetic field produced by prototype inductors. A transformer based DC-DC converter has the potential to produce a high stepdown ratio whilst producing a low stray field and retaining high efficiency. The relative merits of buck configuration and transformer based DC-DC converters are discussed.