Fractional Fourier detection of L\'evy Flights: application to Hamiltonian chaotic trajectories

A signal processing method designed for the detection of linear (coherent) behaviors among random fluctuations is presented. It is dedicated to the study of data recorded from nonlinear physical systems. More precisely the method is suited for signals having chaotic variations and sporadically appearing regular linear patterns, possibly impaired by noise. We use time-frequency techniques and the Fractional Fourier transform in order to make it robust and easily implementable. The method is illustrated with an example of application: the analysis of chaotic trajectories of advected passive particles. The signal has a chaotic behavior and encounter L\'evy flights (straight lines). The method is able to detect and quantify these ballistic transport regions, even in noisy situations

Beam transmission efficiency between injector and target in the GANIL complex

http://accelconf.web.cern.ch/AccelConf/c84/papers/j22.pdfInternational audienceIn order to achieve a maximum transmission efficiency, efforts have been made in three directions : beam measurements, understanding of the physical phenomenon, tuning method. The characteristics of the beam extracted from the three cyclotrons have been measured. The ensuing optical effects are analysed. The tuning of the transport-lines, depending on the characteristics of the extracted beams and the required beam properties on the target, is described

Application to the SPIRAL project at GANIL of a new kind of large acceptance mass separator

International audienc

Parameters of the eigenellipsoid for separated sector cyclotron

http://accelconf.web.cern.ch/AccelConf/c89/papers/g1-09.pdfInternational audienc

Six-dimensional beam matching for axial injection into a cyclotron

http://accelconf.web.cern.ch/AccelConf/c89/papers/g1-01.pdfInternational audienc

Stripping experiments in carbon foils with heavy ions in the energy range of 0.4-0.9 mev/a

We studied the properties of heavy ions stripped by carbon foils. Ni, I and Au ions of 0.4 - 0.9 MeV/A were used to bombard foils of 5 - 200 μg/cm 2. In these measurements the ions were detected in a Browne-Buechner spectrometer. We measured the angular straggling of the ions and the energy straggling. We looked for the behaviour of the foils under impact of large beam densities (several μAp/cm2 on an area of 1-2 mm2). We observed the thickness variations of the foils during bombardment in a vacuum of ∼ 10-6 and 10-7 torr. We looked for the evolution of the energy straggling during exposure and conclude that this parameter does not change in an important way. This means that neither thickening nor sputtering affects the homogeneity of the foil. Results on the lifetime of the bombarded foils are reported

The GANIL beam lines

http://accelconf.web.cern.ch/AccelConf/c81/papers/ep-36.pdfInternational audienceThe general optical functions of the beam lines are described. The principle of beam lines composed of sections with separated functions was adopted. The main technological characteristics of the equipments (guiding system, buncher, stripper, beam diagnostics and pumping system) are given

High intensity and space charge problems at GANIL

http://accelconf.web.cern.ch/AccelConf/c86/papers/g-04.pdfInternational audienceWe routinely accelerate up to micro-amperes of ionsat energies ranging from 25 to 95 MeV / A. Already atthese levels, space charge (S.C) problems drasticallyaffect the bunching efficiency between the ECRexternal ion-source and our Co compact injector.Moreover in the "2.5" version of GANIL we expectcurrents above 50 e\l A (Ar+6 for instance) and S.Ceffects will be of prime importance during accelerationin the injector and even in our first SSC. Wepresent our computer codes and our first results