Non-linear field generated by a distribution of conductors in a spiral FFAG

International audienceFFAGs accelertors re-appeared fifteen years ago to be of interest for new accelerator projects. These synchrotrons allow fast accceleration because of the fixed field magnets. To compensate the beam trajectory radius increase which would happen, the radial gradient follows a non-linear law B_0(r/R_0)^k. Amongst several methods, in the frame of the RACCAM project in France, a scaling spiral FFAG ring is developed for medical applications. Magnets have spiral edges to make beam focusing, and here is described the design study for flat horizontal poles that allow a low variation of the vertical tune. This study presents how to produce B_0(r/R_0)^k with distributed polar conductors

Symbolic evaluation of integrals occurring in accelerator orbit theory

AbstractDefinite integrals which appear in the perturbation theory of a particle's transverse oscillations and chromatic aberrations inside an accelerator are evaluated by symbolic computation. The symbolic program and the automatic FORTRAN coding of the generated functions are described. The results are checked by comparison with those obtained by direct numerical integration. It turns out that, once having established the FORTRAN function subprograms symbolically, their use for different parameters requires much less time than direct numerical integration

Neutrino-nucleus interaction rates at a low-energy beta-beam facility

We compute the neutrino detection rates to be expected at a low-energy beta-beam facility. We consider various nuclei as neutrino detectors and compare the case of a small versus large storage ring.Comment: 6 pages, 3 figure

Toward CP-even Neutrino Beam

The best method of measuring CP violating effect in neutrino oscillation experiments is to construct and use a neutrino beam made of an ideal mixture of $\bar{\nu}_e$ and $\nu_e$ of monochromatic lines. The conceptual design of such a beam is described, together with how to measure the CP-odd quantity. We propose to exploit an accelerated unstable hydrogen-like heavy ion in a storage ring, whose decay has both electron capture and bound beta decay with a comparable fraction.Comment: 6 pages, 2 figures, Published versio

θ13\theta_{13}, δ\delta and the neutrino mass hierarchy at a γ=350\gamma=350 double baseline Li/B β\beta-Beam

We consider a $\beta$-Beam facility where $^8$Li and $^8$B ions are accelerated at $\gamma = 350$, accumulated in a 10 Km storage ring and let decay, so as to produce intense $\bar \nu_e$ and $\nu_e$ beams. These beams illuminate two iron detectors located at $L \simeq 2000$ Km and $L \simeq 7000$ Km, respectively. The physics potential of this setup is analysed in full detail as a function of the flux. We find that, for the highest flux ($10 \times 10^{18}$ ion decays per year per baseline), the sensitivity to $\theta_{13}$ reaches $\sin^2 2 \theta_{13} \geq 2 \times10^{-4}$; the sign of the atmospheric mass difference can be identified, regardless of the true hierarchy, for $\sin^2 2 \theta_{13} \geq 4\times10^{-4}$; and, CP-violation can be discovered in 70% of the $\delta$-parameter space for $\sin^2 2 \theta_{13} \geq 10^{-3}$, having some sensitivity to CP-violation down to $\sin^2 2 \theta_{13} \geq 10^{-4}$ for $|\delta| \sim 90^\circ$.Comment: 35 pages, 20 figures. Minor changes, matches the published versio

The acceleration and storage of radioactive ions for a neutrino factory

The term beta-beam has been coined for the production of a pure beam of electron neutrinos or their antiparticles through the decay of radioactive ions circulating in a storage ring. This concept requires radioactive ions to be accelerated to a Lorentz gamma of 150 for 6He and 60 for 18Ne. The neutrino source itself consists of a storage ring for this energy range, with long straight sections in line with the experiment(s). Such a decay ring does not exist at CERN today, nor does a high-intensity proton source for the production of the radioactive ions. Nevertheless, the existing CERN accelerator infrastructure could be used as this would still represent an important saving for a beta-beam facility. This paper outlines the first study, while some of the more speculative ideas will need further investigations.Comment: Accepted for publication in proceedings of Nufact02, London, 200

Solving the degeneracy of the lepton-flavor mixing angle theta_atm by the T2KK two detector neutrino oscillation experiment

If the atmospheric neutrino oscillation amplitude, sin^2 2theta_atm is not maximal, there is a two fold ambiguity in the neutrino parameter space: sin^2 theta_atm>0.5 or sin^2 theta_atm<0.5. In this article, we study the impact of this degeneracy, the so-called octant degeneracy, on the T2KK experiment, which is a proposed extension of the T2K (Tokai-to-Kaimoka) neutrino oscillation experiment with an additional water cherenkov detector placed in Korea. We find that the degeneracy between sin^2 theta_atm= 0.40 and 0.60 can be resolved at the 3sigma level for sin^2 2theta_rct>0.12 (0.08) for the optimal combination of a 3.0^circ off-axis beam (OAB) at SK (L=295km) and a 0.5^circ OAB at L=1000km with a far detector of 100kton volume, after 5 years of exposure with 1.0(5.0) time 10^21 POT/year, if the hierarchy is normal. We also study the influence of the octant degeneracy on the capability of T2KK experiment to determine the mass hierarchy and the leptonic CP phase. The capability of rejecting the wrong mass hierarchy grows with increasing sin^2 theta_atm when the hierarchy is normal, whereas it is rather insensitive to sin^2 theta_atm for the inverted hierarchy. We also find that the 1sigma allowed region of the CP phase is not affected significantly even when the octant degeneracy is not resolved. All our results are obtained for the 22.5 kton Super-Kamiokande as a near detector and without an anti-neutrino beam.Comment: 23 pages, 9 figure

The FFAG R&D and medical application project RACCAM

JACoW web site http://accelconf.web.cern.ch/AccelConf/e06/Pre-Press/WEPCH161.pdf WEPCH161International audienceThe RACCAM project (Recherche en ACCelerateurs et Applications Medicales) has recently obtained fundings, extending over three years (2006-2008), from the French National Research Agency (ANR). RACCAM is a tripartite collaboration, involving (i) the CNRS Laboratory IN2P3/LPSC, (ii) the French magnet industrial SIGMAPHI, and (iii) the nuclear medecine Departement of Grenoble Hospital. The project concerns fixed field alternating gradient accelerator (FFAG) research on the one hand, and on the other hand their application as hadrontherapy and biology research machines. RACCAM's goal is three-fold, (i) participate to the on-going international collaborations in the field of FFAGs and recent concepts of "non-scaling" FFAGs, with frames for instance, the Neutrino Factory (NuFact) and the EMMA project of an electron model of a muon FFAG accelerator, (ii) design, build and experiment a prototype of an FFAG magnet proper to fulfil the requirements of rapid cycling acceleration, (iii) develop the concepts, and show the feasibility, of the application of such FFAG beams to hadrontherapy and to biology research

Monochromatic neutrino beams

In the last few years spectacular results have been achieved with the demonstration of non vanishing neutrino masses and flavour mixing. The ultimate goal is the understanding of the origin of these properties from new physics. In this road, the last unknown mixing [Ue3] must be determined. If it is proved to be non-zero, the possibility is open for Charge Conjugation-Parity (CP) violation in the lepton sector. This will require precision experiments with a very intense neutrino source. Here a novel method to create a monochromatic neutrino beam, an old dream for neutrino physics, is proposed based on the recent discovery of nuclei that decay fast through electron capture. Such nuclei will generate a monochromatic directional neutrino beam when decaying at high energy in a storage ring with long straight sections. We also show that the capacity of such a facility to discover new physics is impressive, so that fine tuning of the boosted neutrino energy allows precision measurements of the oscillation parameters even for a [Ue3] mixing as small as 1 degree. We can thus open a window to the discovery of CP violation in neutrino oscillations

What about a beta-beam facility for low energy neutrinos?

A novel method to produce neutrino beams has recently been proposed : the beta-beams. This method consists in using the beta-decay of boosted radioactive nuclei to obtain an intense, collimated and pure neutrino beam. Here we propose to exploit the beta-beam concept to produce neutrino beams of low energy. We discuss the applications of such a facility as well as its importance for different domains of physics. We focus, in particular, on neutrino-nucleus interaction studies of interest for various open issues in astrophysics, nuclear and particle physics. We suggest possible sites for a low energy beta-beam facility.Comment: 4 pages, 1 figur