122745639
All-sky search for periodic gravitational waves in LIGO S4 data
We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1000 Hz and with the frequency’s time derivative in the range −1×10^(−8)  Hz s^(−1) to zero. Data from the fourth LIGO science run (S4) have been used in this search. Three different semicoherent methods of transforming and summing strain power from short Fourier transforms (SFTs) of the calibrated data have been used. The first, known as StackSlide, averages normalized power from each SFT. A “weighted Hough” scheme is also developed and used, which also allows for a multi-interferometer search. The third method, known as PowerFlux, is a variant of the StackSlide method in which the power is weighted before summing. In both the weighted Hough and PowerFlux methods, the weights are chosen according to the noise and detector antenna-pattern to maximize the signal-to-noise ratio. The respective advantages and disadvantages of these methods are discussed. Observing no evidence of periodic gravitational radiation, we report upper limits; we interpret these as limits on this radiation from isolated rotating neutron stars. The best population-based upper limit with 95% confidence on the gravitational-wave strain amplitude, found for simulated sources distributed isotropically across the sky and with isotropically distributed spin axes, is 4.28×10^(−24) (near 140 Hz). Strict upper limits are also obtained for small patches on the sky for best-case and worst-case inclinations of the spin axes.
44501859
Beam impact studies on ILC collimators
Spoilers in the ILC Beam Delivery System are required to survive without failure a minimum of 1-2 direct impacts from each energetic electron or positron bunch of charged particles, in addition to maintaining low geometric and resistive wall wake fields. The transient shock wave resulting from rapid localised beam heating and its implications for spoiler design are studied using ANSYS. Shockwave propagation is modelled in 2 dimensions showing the effect of dilatational Shockwaves striking free surfaces, producing reflected dilatational and distortional waves. The implication of these reflected waves on the damage of the collimators is also discussed.
59931248
Reconstruction of the signal amplitude of the CMS electromagnetic calorimeter
The amplitude of the signal collected from the PbWO4 crystals of the CMS electromagnetic calorimeter is reconstructed by a digital filtering technique. The amplitude reconstruction has been studied with test beam data recorded from a fully equipped barrel supermodule. Issues specific to data taken in the test beam are investigated, and the implementation of the method for CMS data taking is discussed.
125782606
Energy Resolution Performance of the CMS Electromagnetic Calorimeter
122948333
Design of the superconducting end cap toroids for the ATLAS experiment at LHC
The ATLAS experiment proposed for LHC will use a toroidal magnet system to achieve high efficiency muon momentum resolution. The end cap toroids are designed to provide bending powers in the range 4-8 Tm over the rapidity span 1.5-2.8 in the important forward/backward regions. Each end cap toroid will have an outer diameter of approximately 11 m and an axial length of 5.6 m. This paper presents the magnetic, mechanical and cryogenic design of the end cap toroid magnet systems. Particular emphasis is placed on the interactive design issues imposed by the close proximity of the ATLAS barrel toroid. Proposals for the magnet fabrication and assembly are given.
16189981
Results of the first performance tests * of the CMS electromagnetic calorimeter
Abstract.Performance tests of some aspects of the CMS ECAL were carried out on modules of the "barrel" sub-system in 2002 and 2003. A brief test with high energy electron beams was made in late 2003 to validate prototypes of the new Very Front End electronics. The final versions of the monitoring and cooling systems, and of the high and low voltage regulation were used in these tests. The results are consistent with the performance targets including those for noise and overall energy resolution, required to fulfil the physics programme of CMS at the LHC.
117780445
Report of the Fixed-Target Proton-Accelerator Group
The fixed target proton accelerator group divided itself into two roughly equal parts. One sub-group concentrated on a high intensity (10/sup 14/ protons/sec) moderate energy (30 GeV) machine while the other worked on a moderate intensity (5 x 10/sup 11/ protons/sec) very high energy (20 TeV) machine. For experiments where the total available energy is adequate, the fixed target option added to a anti p p 20 TeV collider ring has several attractive features: (1) high luminosity afforded by intense beams striking thick solid targets; (2) secondary beams of hadrons, photons, and leptons; and (3) the versatility of a fixed target facility, where many experiments can be performed independently. The proposed experiments considered by the subgroup, including neutrino, photon, hadron, and very short lived particle beams were based both on scaled up versions of similar experiments proposed for Tevatron II at Fermilab and on the 400 GeV fixed target programs at Fermilab and CERN.
16578177
An Apparatus to Measure the Structure of the Pion
Abstract We discuss the design and performance of a large-acceptance double-magnet spectrometer used in Fermilab Experiment 615. The apparatus was used to measure the properties of high-invariant-mass muon pairs produced in collisions of a pion beam with a tungsten target in order to infer the distribution of quarks within the pion and to study the production mechanism in detail. The emphasis was on interactions in which a single quark, and subsequently the muon pair, carried a large fraction of the pion's momentum. A hardware trigger processor enabled the detector to extract the relatively weak signal while operating in a high-rate environment.