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Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG In a recent MNRAS article, Raposo-Pulido and Pelaez (RPP) designed a scheme for obtaining very close seeds for solving the elliptic Kepler equation with the classical and modified Newton–Raphson methods. This implied an important reduction in the number of iterations needed to reach a given accuracy. However, RPP also made strong claims about the errors of their method that are incorrect. In particular, they claim that their accuracy can always reach the level of ∼5ε, where ε is the machine epsilon (e.g. ε = 2.2 × 10−16 in double precision), and that this result is attained for all values of the eccentricity e < 1 and the mean anomaly M ∈ [0, π], including for e and M that are arbitrarily close to 1 and 0, respectively. However, we demonstrate both numerically and analytically that any implementation of the classical or modified Newton–Raphson methods for Kepler’s equation, including those described by RPP, has a limiting accuracy of the order of ∼ε/2(1−e)−−−−−−−√⁠. Therefore the errors of these implementations diverge in the limit e → 1, and differ dramatically from the incorrect results given by RPP. Despite these shortcomings, the RPP method can provide a very efficient option for reaching such limiting accuracy. We also provide a limit that is valid for the accuracy of any algorithm for solving Kepler equation, including schemes like bisection that do not use derivatives. Moreover, similar results are also demonstrated for the hyperbolic Kepler equation. The methods described in this work can provide guidelines for designing more accurate solutions of the elliptic and hyperbolic Kepler equations. Axencia Galega de Innovación Agencia Estatal de Investigación | Ref. FIS2017-83762-P

A new watt balance experiment is under development at the Federal Institute of Metrology (METAS, Switzerland). Its scope is to link the mass unit to the Plank constant in order to set a new definition of the kilogram, which is no longer based on the international prototype. The experiment is performed in two steps with the same setup and requires that the magnetic field produced in the two steps by the magnet fitted in the setup remains stable within few parts per 10 8 . This paper describes the design, manufacture, and characterization of this magnet, which is performed through a collaboration between METAS and CERN.

The watt balance Mark II of the Federal Institute of Metrology METAS is ready to start the measurement of the Planck constant. After an intensive conception phase, the different modules of the experiment have been designed, realized and characterized in close collaboration with external partners. Beside an overview of the experimental setup and some results, the present paper shows also theoretical aspects and simulation results of the magnetic circuit. First results of the Planck constant should be available at the time of the conference.

Einstein, Podolsky and Rosen (EPR) pointed out that the quantum-mechanical description of "physical reality" implied an unphysical, instantaneous action between distant measurements. To avoid such an action at a distance, EPR concluded that Quantum Mechanics had to be incomplete. However, its extensions involving additional "hidden variables", allowing for the recovery of determinism and locality, have been disproved experimentally (Bell's theorem). Here, I present an opposite solution of the paradox based on the greater indeterminism of the modern Quantum Field Theory (QFT) description of Particle Physics, that prevents the preparation of any state having a definite number of particles. The resulting uncertainty in photons radiation has interesting consequences in Quantum Information Theory (e.g. cryptography and teleportation). Moreover, since it allows for less elements of EPR physical reality than the old non-relativistic Quantum Mechanics, QFT satisfies the EPR condition of completeness without the need of hidden variables. The residual physical reality does never violate locality, thus the unique objective proof of "quantum nonlocality" is removed in an interpretation-independent way. On the other hand, the supposed nonlocality of the EPR correlations turns out to be a problem of the interpretation of the theory. If we do not rely on hidden variables or new physics beyond QFT, the unique viable interpretation is a minimal statistical one, that preserves locality and Lorentz symmetry., Comment: Published version, with updated reference

The localization of possible electrical faults in superconducting accelerator magnets may, in most cases, be a complex, expensive and time-consuming process. In particular, inter-turn short circuits and failures of the ground insulation are well detectable when the magnet is collared, but often disappear after disassembly for repair due to the release of the pre-stress in the coils. The fault localization method presented in this paper is based on the measurement and analysis of the magnetic field generated inside the magnet aperture by a high voltage pulse. The presence of the fault modifies the distribution of the current in the coils and produces a distortion of the magnetic field. The described method aims at locating both the longitudinal and azimuthal position of the fault-affected area. The test method, the transient case FEM models and the implemented experimental set-up are presented and discussed for the LHC dipole models.

Only three weeks after the beginning of commissioning, the new ultrabright synchrotron source ELETTRA was able to deliver the first experimental test data. We briefly discuss these test experiments, which produced a series of photoelectron micrographs of different specimens. This success concludes, to the best of our knowledge, the most rapid first phase of commissioning ever of a synchrotron radiation source.

We show that supersymmetric theories with R -parity breaking naturally give rise to significant neutrino magnetic moments. In the minimal supersymmetric standard model the transition magnetic moment μ ν e ν μ can be as large as 10 −13 μ B ( μ B is the Bohr magneton). By requiring an SU (2) H horizontal symmetry of the lagrangian in the Yukawa-less limit, μ ν e ν μ may be one order magnitude larger. In this case the main naturalness constraint on the maximum μ ν e ν μ attainable is the electron mass value rather than the bound on the neutrino mass itself.

A superconducting undulator wound with Nb-Ti based conductor, will be used in the LHC as a key part of the synchrotron radiation profile monitor system. Two undulators are needed, one per each circulating beam, providing 5 T in a 60 mm bore over two periods of 280 mm each. A full scale prototype has been designed and successfully tested in the end of 2004. In this paper, the electromagnetic and the mechanical design of the undulator are summarized. The fabrication of the prototype is described and the successful cold test results, both power test and magnetic flux density measurements, are reported.

A hybrid permanent-magnet undulator is under development in Ansaldo Ricerche for the LISA FEL experiment. The criteria adopted to optimize the magnetic and mechanical design of the undulator and the results of field measurements on an eight-period prototype will be discussed. The device used for measuring the permanent-magnet blocks and the code developed for their sorting will be described.

24 dipole magnets, 108 quadrupoles, 72 sextupoles and 82 steerers are needed in the storage ring. The very stringent requirements for the magnet field quality were met with the use of a combination of 2D and 3D magnetic design. The dipoles are combined function elements with a field index n=13 and a maximum magnetic field of 1.5 T at the central orbit. The curved (R=5.5 m) pole profiles were obtained by matching the stacked laminations. The quadrupoles and sextupoles are made by assembled pole pairs in a C shaped structure with the aperture on the outer side of the ring. To insert the vacuum chamber inside the magnets this structure allows a symmetric opening of the yoke. The steerer magnets provide both horizontal and vertical magnetic fields; an inverted U shape with a 3D optimization of the vertical field coils and positions was studied to provide space for the connection of vacuum pumps. >

The Elettra storage ring will be filled with a 2 GeV electron beam from its full energy linear accelerator. Two pulsed septum magnets will be housed in a vacuum tank and four identical fast kicker magnets in air, with an internal ceramic vacuum chamber, will be symmetrically placed around the mid-point of a single straight section. The layout of the injection section, the design of the main individual components, their manufacture and the results of the relevant test are presented and discussed. >

ANKA, a 2.5 GeV synchrotron light source will be built within the next three years at the Research Centre Karlsruhe, Germany. This source is dedicated to the fabrication of microstructures (LIGA-technique) and X-ray analysis. With four double-DBA structures, a magnetic field of 1.5 T and a circumference of 110.4 m, an emittance of 39 nm/spl middot/rad can be reached. ANKA has four long (6 m) straight sections for the installation of insertion devices. Additional four short (2.2 m) straight sections host the injection scheme, four ELETTRA-type cavities (two cavities per section) and one short insertion device. The RF power will be provided by two 250 kW klystron. The pre-acceleration will be done with a 22-50 MeV linac or microtron. As injector a 500 MeV booster synchrotron with a repetition rate of 3 to 10 Hz is foreseen. The ramping from 0.5 GeV to 2.5 GeV will be done in around one minute. Eleven out of thirty-two available bending magnet radiation ports will be equipped with beam lines in the first phase.

In LHC it will be important to measure with precision and in a non‐destructive way the proton beam profiles from 450 GeV to 7 TeV. The chosen monitor will make use of a 5 T superconducting Undulator with two periods coupled to the D3 bending magnet built by BNL. From the various variants studied, this combination is the only one which could cover the whole LHC energy range. By locating both magnets in the same cryostat, it will be possible to minimise the light source length for best precision. The choice of the undulator parameters and its basic design will be described. The evolution of the synchrotron radiation patterns along the energy ramp will be given, as well as the performance with respect to sensitivity, depth of field and diffraction, with a description of the simulation codes used.