119994412
A drift chamber telescope for heavy ion track detection
Abstract A drift chamber telescope consisting of six individual drift chambers has been exposed to the heavy ion beam at the Lawrence Berkeley Laboratory, Ca, USA. This is a study for employing drift chambers in a cosmic ray isotope experiment. An amplitude discrimination against δ-rays which accompany the heavy ions is possible. The track detection efficiency for different nuclei is measured and discussed. It is recommended to run the chambers at low sense wire voltage in order to avoid space charge effects. The spatial resolution for Fe nuclei of 518 MeV/nucleon was measured to be σ = 0.3 mm.
122399752
The ALICE instrument and the measured cosmic ray elemental abundances
Abstract A Large Isotopic Composition Experiment (ALICE) is a balloon-borne spectrometer which can determine the elemental and isotopic composition of galactic cosmic rays with energies near 1 GeV/nucleon. ALICE was flown from Prince Albert, Canada in August 1987, and remained at float altitude (120000 feet) for 14.7 hours. In this paper, we describe the experimental methods and analysis which will be used for subsequent isotopic analysis. We obtained very precise charge resolution over the entire designed range: 0.10 and 0.16 charge units at neon and iron, respectively. Results on the galactic cosmic ray abundances and absolute fluxes of the elements from neon through nickel are reported.
122146103
An isotope experiment using Cherenkov range technique
Abstract The ALICE balloon experiment utilizes the Cherenkov-range technique to determine the isotopic composition of the cosmic radiation in the elemental range magnesium through iron. The instrument operates in the energy range 350 MeV/nucleon to 800 MeV/nucleon. Particle charge and energy are determined from scintillation and Cherenkov radiation emissions within light diffusion chambers. Trajectories of incoming particles are determined by means of large area gas drift chambers. The stopping range of the particles is measured in a cellulose nitrate range stack. This paper reports details of the experimental technique and results of the balloon flight.
118323779
Local Scale-Invariance in Disordered Systems
Dynamical scaling and ageing in disordered systems far from equilibrium is reviewed. Particular attention is devoted to the question to what extent a recently introduced generalization of dynamical scaling to local scale-invariance can describe data for either non-glassy systems quenched to below T c or for spin glasses at criticality. The dependence of the scaling behaviour on the distribution of the random couplings is discussed. It is shown that finite-time corrections to scaling can become quite sizable in these systems. Numerically determined ageing quantities are confronted with available experimental results.
122109393
Remarks on the mass spectrum on noncritical coset models from Toda theories
The authors discuss how coset lattice models perturbed in the appropriate direction should still be obtained by projections of non-critical integrable vertex models. The latter are described in the continuum limit by Toda field theories. By studying the mass spectrum of these theories and the projection mechanism, they conjecture without explicit construction of the S matrix the mass spectrum of the simplest coset models. Among cases considered are the unitary series perturbed in Phi 13 direction, the zn models, the tricritical Ising and tricritical three-state Potts models perturbed by the thermal operator. The latter exhibit an E7 and E6 structure respectively. Some numerical checks are presented.
8645816
Intermittency studies in directed bond percolation
Abstract The self-similar cluster fluctuations of directed bond percolation at the percolation threshold are studied using techniques borrowed from intermittency-related analysis in multi-particle production. Numerical simulations based on the factorial moments for large (1 + 1)-dimensional lattices allow one to handle statistical and boundary effects and show the existence of weak but definite intermittency patterns. The extracted fractal dimensions are in agreement with scaling arguments leading to a new relation linking the intermittency indices to the critical exponents and the fractal dimension of directed percolation clusters.