Controlling Quantum Wave Packet of Electronic Motion on Field-Dressed Coulomb Potential of H2+ by Carrier-Envelope Phase-Dependent Strong Field Laser Pulses

Solving numerically a non-Born-Oppenheimer time-dependent Schrödinger equation to study the dissociative-ionization of H subjected to strong field six-cycle laser pulses (I = 4 × 10 W/cm, λ = 800 nm) leads to newly ultrafast images of electron dynamics in H. The electron distribution in H oscillates symmetrically with laser cycle with θ + π periodicity and gets trapped between two protons for about 8 fs by a Coulomb potential well. Nonetheless, this electron symmetrical distribution breaks up for the H internuclear separation larger than 9 a.u. in the field-free region at a time duration of 24 fs as a result of the distortion of Coulomb potential where the ejected electron preferentially localizes in one of the double-well potential separated by the inner Coulomb potential barrier. Moreover, controlling laser carrier-envelope phase θ enables one to generate the highest total asymmetry A of 0.75 and -0.75 at 10 and 190, respectively, associated with the electron preferential directionality being ionized to the left or the right paths along the H molecular axis. Thus the laser-controlled electron slightly reorganizes its position accordingly to track the shift in the position of the protons despite much heavier the proton’s mass.

Analysis of field free region formed by parametric positioning of a magnet pair for targeted magnetic hyperthermia

One of the challenges that arise in the practical applications of magnetic fluid hyperthermia (MFH) is the limited control of magnetic nanoparticle oscillations. In this study, we investigated to manipulate field free region (FFR) form and location by symmetric and asymmetric displacements of a magnet pair (MP). Finite element method (FEM) simulation was used to predict gradient patterns (GPs) in the workspace. An experiment platform was produced and point probe measurements are taken. It is observed that FFR form and position can be manipulated with parametric distance and angle changes. FFR can shrink and its form can be transformed to the linelike or point-like areas. Focus of FFR can be moved off-center, and it can be directed to different parts of the target object. The mapping of GP produced by a MP for the use of targeted MFH is discussed for the first time in this study. And the findings provide insight into which GP is appropriate in which situations in targeted MFH.

The ASACUSA antihydrogen and hydrogen program: results and prospects

The goal of the ASACUSA-CUSP collaboration at the Antiproton Decelerator of CERN is to measure the ground-state hyperfine splitting of antihydrogen using an atomic spectroscopy beamline. A milestone was achieved in 2012 through the detection of 80 antihydrogen atoms 2.7 m away from their production region. This was the first observation of ‘cold’ antihydrogen in a magnetic field free region. In parallel to the progress on the antihydrogen production, the spectroscopy beamline was tested with a source of hydrogen. This led to a measurement at a relative precision of 2.7×10 −9 which constitutes the most precise measurement of the hydrogen hyperfine splitting in a beam. Further measurements with an upgraded hydrogen apparatus are motivated by CPT and Lorentz violation tests in the framework of the Standard Model Extension. Unlike for hydrogen, the antihydrogen experiment is complicated by the difficulty of synthesizing enough cold antiatoms in the ground state. The first antihydrogen quantum states scan at the entrance of the spectroscopy apparatus was realized in 2016 and is presented here. The prospects for a ppm measurement are also discussed. This article is part of the Theo Murphy meeting issue ‘Antiproton physics in the ELENA era’.

Behaviorof Ion Beams For Triplet Quadrupole Lenses

This research includes a study to understand the behavior of charged particles beam through consideration of systems of quadrupole triplet reaching to the optimum design of beam transport through a system of triplet quadrupole triplet lenses. In this work, tracing the path of charged particles beam has been within the free field space and quadrupole electrostatic lens system which include the triplet quadrupolelens by using matrices to described particle trajectories throughout the system. Matrix representation deals with ion beam as bunched and representing phase ellipse for both horizontal and vertical planes. The present work investigated the effect of the main parameters of triplet quadruple such as length of quadrupole, the distance between the lenses, voltage applying on lenses,second field free region length. Matlab program built to study these parameters, the results indicated that good focusing properties for both horizontal and vertical plane.

DEVELOPMENT OF A NOVEL DUAL TIME-OF-FLIGHT IMAGING MASS SPECTROMETER: PRINCIPAL, REALIZATION, AND OPTIMAL PERFORMANCE

A novel dual time-of-flight imaging analyzer has been developed for studies of gas phase reactions and the scattering or desorption of ions and molecules from surfaces. The analyzer is capable of experimentally selecting a two-dimensional slice of particles from a three-dimensional flux without the necessity for deconvolution of the resulting velocity images by the Abel transform. The analyzer operates through ionization of the scattered species and their subsequent flight through a field-free region. This initial flight allows a dispersion according to the species natural velocity distribution. The second time of flight deflects the ions through a right angle and through a flight tube allowing dispersion according to mass or charge before detection. The analyzer offers two modes of operation — the first of these produces a mass spectrum of the desorbing species, the second produces a two-dimensional velocity map of the desorbing species. Trial results using an effusive beam source and acetone as a test gas have demonstrated the operation of the analyzer. The operation of the analyzer has been simulated and optimized to reduce ion flight aberrations. A set of orthogonal two-dimensional polynomial functions have been derived to reduce residual aberrations across a broad range of operating conditions. An upper limit to the temporal resolution of the analyzer has been established and a set of working parameters for low distortion electron beam ionization have been presented.