Search

Vertical excursion fixed-field alternating gradient accelerators can be designed with tunes that are invariant with respect to momentum and trajectories that are scaled images of each other displaced only in the vertical direction. This is possible using guiding fields that have a vertical exponential increase, with a skew quadrupole component in the magnet body and a solenoid component at the magnet ends. Because of the coupling this introduces, orbit and optics calculations and optimisation of parameters need to be performed numerically. In this paper, idealised magnetic fields are calculated from first principles, taking into account end fields. The parameter dependence of the optics and the dynamic aperture of the ring are calculated for the example of a ring with an approximately 25 m circumference that accelerates proton beams from 3 MeV to 12 MeV. The paper reports for the first time the design of such an accelerator lattice using tools specifically devised to analyse transverse coupled optics without the need for approximations., 13 pages, 13 figures, to be published in a journal

A fixed rf frequency acceleration scheme is required for rapid-acceleration and producing high-intensity beam in non-relativistic energy region. For these requirements, new-type of fixed rf frequency acceleration scheme called serpentine acceleration is applied in scaling FFAG. To examine a longitudinal motion with serpentine acceleration, longitudinal hamiltonian in scaling FFAG with fixed rf frequency is derived analytically. Then details of serpentine acceleration scheme in scaling FFAG are presented. To demonstrate serpentine acceleration in scaling FFAG, beam experiment has been done with electron scaling FFAG ring. Results are analyzed and confirm the serpentine acceleration in scaling FFAG. Finally, longitudinal design for ADS proton driver with this scheme is presented.

Fixed field alternating gradient (FFAG) accelerators are recently subject to a strong revival. They are usually designed in a circular shape; however, it would be an asset to guide particles with no overall bend in this type of accelerator. An analytical development of a straight FFAG cell which keeps zero-chromaticity is presented here. A magnetic field law is thus obtained, called “straight scaling law”, and an experiment has been conducted to confirm this zero-chromatic law. A straight scaling FFAG prototype has been designed and manufactured, and horizontal phase advances of two different energies are measured. Results are analyzed to clarify the straight scaling law.

The harmonic number jump acceleration in scaling FFAG rings is considered in this paper. Constraints fixed by the acceleration scheme on the lattice design are detailed. An example of a 3.6 to 12.6 GeV muon lattice which satisfy these constraints is presented.

Fixed Field Alternating Gradient (FFAG) elements are usually designed in a circular shape, but straight sections can also be imagined. A demonstration using the scaling condition is first shown. Combining different scaling FFAG sections is then discussed and opens new possibilities for scaling FFAGs. As an example, an application with a new lattice proposal for the PRISM project is finally presented in this paper.

A way to accelerate muon beams rapidly with zero-chromatic fixed field alternating gradient (FFAG) rings is considered in this paper. It is based on the harmonic number jump acceleration and allows the use of constant frequency rf cavities, although the lattice is not isochronous. To overcome the limitations imposed by this acceleration method, a new type of zero-chromatic FFAG lattice, which includes dispersion suppressor insertions, is proposed. Design principles of such a lattice are presented. An example of a 3.6–12.6 GeV muon ring for the simultaneous acceleration of μ + and μ − beams is described. Step-wise particle tracking is used to demonstrate the large 6D acceptance of this scheme.

As an intense neutron source for the boron neutron capture therapy system, a FFAG storage ring with Energy/emittance Recovery Internal Target (ERIT) has been developed in the Kyoto University Research Reactor Institute (KURRI). In order to develop storage ring for ERIT scheme, the spiral sector and radial sector FFAG rings were designed and compared about performance in ERIT system. The 3-dimensional magnetic fields of these magnets were calculated with the field analysis code, TOSCA. The pole shape of magnet was carefully optimized checking the betatron tune. Tunes were computed by means of tracking simulations in field maps based on TOSCA models. In this paper, the FFAG magnet design for ERIT system and the construction of FFAG ring in KURRI are described.

The acceleration of intense and high-energy muon beams is one of the challenge of future neutrino factories. The acceleration of such beams using the synchrotron motion inside stationary rf buckets of scaling fixed field alternating gradient (FFAG) rings is considered in this paper. Possible parameters of a 3.6–12.6 GeV muon ring using 200 MHz rf cavities is presented. Detailed particle tracking simulations are used to demonstrate the large 6D acceptance as well as the relatively good tolerance to errors of this scheme. The improvement of the current neutrino factory baseline scenario, using this type of FFAG ring, is finally discussed.

The Muon Ionization Cooling Experiment (MICE) will perform a detailed study of ionization cooling to evaluate the feasibility of the technique. To carry out this program, MICE requires an efficient particle-identification (PID) system to identify muons. The Electron-Muon Ranger (EMR) is a fully-active tracking-calorimeter that forms part of the PID system and tags muons that traverse the cooling channel without decaying. The detector is capable of identifying electrons with an efficiency of 98.6%, providing a purity for the MICE beam that exceeds 99.8%. The EMR also proved to be a powerful tool for the reconstruction of muon momenta in the range 100-280 MeV/$c$., 22 pages, 19 figures

We describe a novel configuration for a neutrino beam line that can simultaneously support both long and short baseline experiments. The neutrino beams originate from pions that are first focused by a magnetic horn, as in a conventional neutrino beam. However, in the case of nuPIL, the horn is followed by a magnetic lattice that is used to select the pion charge and then transports the pions in a production straight. This produces extremely pure neutrino and anti-neutrino beams, while minimizing the amount of beam power that is transported underground for the long-baseline physics program. This configuration greatly simplifies the civil construction leading to a large cost reduction. The principles of the design of nuPIL are presented, together with tracking results and the resulting neutrino flux. The potential of the facility for CP-violation searches, in the framework of the DUNE experiment, is discussed and compared to that of an optimized beam from LBNF.

Neutrino beams produced from the decay of muons in a racetrack-like decay ring (the so called Neutrino Factory) provide a powerful way to study neutrino oscillation physics and, in addition, provide unique beams for neutrino interaction studies. The Neutrinos from STORed Muons (nuSTORM) facility uses a neutrino factory-like design. Due to the particular nature of nuSTORM, it can also provide an intense, very pure, muon neutrino beam from pion decay. This so-called «Neo-conventional» muon-neutrino beam from nuSTORM makes nuSTORM a hybrid neutrino factory. In this paper we describe the facility and give a detailed description of the neutrino beams that are available and the precision to which they can be characterized. We then show its potential for a neutrino interaction physics program and present sensitivity plots that indicate how well the facility can perform for short-baseline oscillation searches. Finally, we comment on the performance potential of a «Neo-conventional» muon neutrino beam optimized for long-baseline neutrino-oscillation physics.

Poster presented at Cyclotrons'13 Conference in Vancouver, September 2013. WEPPT031

The nuSTORM facility has been designed to deliver beams of electron neutrinos and muon neutrinos (and their anti-particles) from the decay of a stored muon beam with a central momentum of 3.8 GeV/c and a momentum acceptance of 10%. The facility is unique in that it will: 1. Allow searches for sterile neutrinos of exquisite sensitivity to be carried out; 2. Serve future long- and short-baseline neutrino-oscillation programs by providing definitive measurements of electron neutrino and muon neutrino scattering cross sections off nuclei with percent-level precision; and 3. Constitutes the crucial first step in the development of muon accelerators as a powerful new technique for particle physics. The document describes the facility in detail and demonstrates its physics capabilities. This document was submitted to the Fermilab Physics Advisory Committee in consideration for Stage I approval. The nuSTORM facility has been designed to deliver beams of electron neutrinos and muon neutrinos (and their anti-particles) from the decay of a stored muon beam with a central momentum of 3.8 GeV/c and a momentum acceptance of 10%. The facility is unique in that it will: 1. Allow searches for sterile neutrinos of exquisite sensitivity to be carried out; 2. Serve future long- and short-baseline neutrino-oscillation programs by providing definitive measurements of electron neutrino and muon neutrino scattering cross sections off nuclei with percent-level precision; and 3. Constitutes the crucial first step in the development of muon accelerators as a powerful new technique for particle physics. The document describes the facility in detail and demonstrates its physics capabilities. This document was submitted to the Fermilab Physics Advisory Committee in consideration for Stage I approval.

The idea of using a muon storage ring to produce a high-energy ({approx_equal} 50 GeV) neutrino beam for experiments was first discussed by Koshkarev in 1974. A detailed description of a muon storage ring for neutrino oscillation experiments was first produced by Neuffer in 1980. In his paper, Neuffer studied muon decay rings with E{sub {mu}} of 8, 4.5 and 1.5 GeV. With his 4.5 GeV ring design, he achieved a figure of merit of {approx_equal} 6 x 10{sup 9} useful neutrinos per 3 x 10{sup 13} protons on target. The facility we describe here ({nu}STORM) is essentially the same facility proposed in 1980 and would utilize a 3-4 GeV/c muon storage ring to study eV-scale oscillation physics and, in addition, could add significantly to our understanding of {nu}{sub e} and {nu}{sub {mu}} cross sections. In particular the facility can: (1) address the large {Delta}m{sup 2} oscillation regime and make a major contribution to the study of sterile neutrinos, (2) make precision {nu}{sub e} and {bar {nu}}{sub e} cross-section measurements, (3) provide a technology ({mu} decay ring) test demonstration and {mu} beam diagnostics test bed, and (4) provide a precisely understood {nu} beam for detector studies. The facility is the simplest implementation of the Neutrino Factory concept. In our case, 60 GeV/c protons are used to produce pions off a conventional solid target. The pions are collected with a focusing device (horn or lithium lens) and are then transported to, and injected into, a storage ring. The pions that decay in the first straight of the ring can yield a muon that is captured in the ring. The circulating muons then subsequently decay into electrons and neutrinos. We are starting with a storage ring design that is optimized for 3.8 GeV/c muon momentum. This momentum was selected to maximize the physics reach for both oscillation and the cross section physics. See Fig. 1 for a schematic of the facility.

Harmonic number jump acceleration of muon beams in scaling FFAG rings is studied. General considerations about harmonic number jump acceleration lead to the necessity of designing rings with dispersion suppressed insertions, and in which both μ+ and μ− can be circulated in the same direction. Design principles of such a scaling FFAG ring are described. Example of a 3 to 10 GeV lattice is given, and 4D acceleration tracking is done in it.

Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections. An experiment to study zero-chromatic straight sections is in progress at KURRI.

Neutrino beams produced from the decay of muons in a racetrack-like decay ring (the so called Neutrino Factory) provide a powerful way to study neutrino oscillation physics and, in addition, provide unique beams for neutrino interaction studies. The Neutrinos from STORed Muons (nuSTORM) facility is a neutrino factory-like facility designed for short baseline neutrino oscillation and neutrino interaction studies. However, due to the particular nature of nuSTORM, it can also provide an intense, very pure, muon neutrino beam from pion decay, which is possibly suitable for long-baseline neutrino oscillation searches as well. This so-called “Neo-conventional” muon neutrino beam from nuSTORM makes nuSTORM a hybrid neutrino factory. In this paper, the facility is described and a description of the neutrino beams and the precision to which they can be determined is given. Sensitivity plots are presented that indicate how well the facility can perform for short-baseline oscillation searches and show its potential for a neutrino interaction physics program. Finally, the concept of the “Neo-conventional” muon neutrino beam available at the nuSTORM facility is briefly discussed.

Ce chapitre porte sur les usages de bases d'exercices en ligne par les professeurs enseignant les mathématiques, dans le premier comme dans le second degré. Cet objet d'étude nous a amenées à des développements théoriques et méthodologiques. Sur le plan théorique, il s'agit de prolonger l'approche instrumentale, issue de l'ergonomie cognitive, à l'étude d'un sujet professeur pour lequel les bases d'exercices en ligne sont des artefacts. Sur le plan méthodologique, il s'agit de concevoir un suivi dans la durée, qui permette de saisir évolutions et stabilités. Nous avons fondé ce suivi sur la notion de scénario. Nous exposons ici ces développements et présentons des exemples de leur mise en oeuvre dans des études de cas. Nous montrons comment les caractéristiques des bases d'exercices peuvent influencer les choix des professeurs, et comment, inversement, les connaissances des professeurs guident leurs choix pour l'usage des bases d'exercices.

Ce chapitre propose de porter un regard large sur l'activité professionnelle des professeurs de mathématiques, à plusieurs point de vue. Il s'agit d'abord de s'intéresser à toutes les ressources susceptibles d'intervenir dans cette activité professionnelle, élargissant l'intérêt porté aux technologies, tout en conservant une attention particulière pour les ressources en ligne. Il s'agit ensuite de prendre en compte toutes les facettes de cette activité, en classe et hors classe. Enfin, il s'agit de considérer non plus LE professeur, professionnel isolé, mais des collectifs impliquant DES professeurs. Nous exposons ici des développements théoriques et méthodologiques nécessaires pour opérer ce changement de point de vue. Nous présentons l'application de ces développements à deux études de cas, retenues pour la diversité qu'elles permettent de saisir. La première porte sur une association de professeurs, conceptrice de ressources : Sésamath. La deuxième concerne un dispositif institutionnel de formation continue : Pairform@nce. Au-delà des spécificités identifiées, une perspective commune se dégage sur l'articulation entre conception et usages, comme sur les conséquences du travail documentaire dans des collectifs.

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