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An ExB probe is a pass-band velocity filter for an ion beam. The ExB probe measurement is related to the ion velocity distribution function (IVDF); however, the finite pass-band filter window size leads to differences in the true IVDF and measured ExB probe spectrum. We derive for the first time an analytical ExB probe transmittancy matrix and use it to examine differences in the IVDF and the probe spectrum. The probe spectra are compared to a synthetically defined test IVDF to study how probe geometry and ion species affect the differences. It is found that the difference in the probe spectrum and the true IVDF is dependent on the ion species, and the deviation is larger for heavier ions. The peak velocity of the spectrum was shifted by up to 13%, and the velocity spread was broadened by up to 276%. The relative ion species fraction is calculated from the probe spectra by two different methods and compared to the true fraction. Using the approach of this work, direct integration of the spectrum resulted in a 2% difference, while a more common approach from literature overestimated one ion species by 184%. [ABSTRACT FROM AUTHOR]

Classical communication schemes exploiting wave modulation are the basis of our information era. Quantum information techniques with photons enable future secure data transfer in the dawn of decoding quantum computers. Here we demonstrate that also matter waves can be applied for secure data transfer. Our technique allows the transmission of a message by a quantum modulation of coherent electrons in a biprism interferometer. The data is encoded in the superposition state by a Wien filter introducing a longitudinal shift between separated matter wave packets. The transmission receiver is a delay line detector performing a dynamic contrast analysis of the fringe pattern. Our method relies on the Aharonov-Bohm effect but does not shift the phase. It is demonstrated that an eavesdropping attack will terminate the data transfer by disturbing the quantum state and introducing decoherence. Furthermore, we discuss the security limitations of the scheme due to the multi-particle aspect and propose the implementation of a key distribution protocol that can prevent active eavesdropping.

The Wien filter is one of the key components in ion optics to improve the mass separation performance. The KoBRA Wien filter will be installed at the low-energy beamline KoBRA of RAON in Korea. The specifications of the KoBRA Wien filter were determined based on the ion beams expected in the KoBRA beamline, especially, beam energies less than about 5 MeV/nucleon suitable for nuclear astrophysics experiments. The Wien filter is designed to have the maximum field intensities of 0.2 T for the magnetic field and 2.0 kV/mm for the electric field in the ± 75 (H) × ± 50 (V) × 2500 (L) mm 3 good-field region. Performance of the Wien filter was estimated by the ion optics calculations of the KoBRA beamline for 40Ar beams at 18.5 MeV/nucleon and 14O beams at 2.5 MeV/nucleon. The mass resolving powers are 42.65 and 517, respectively. Currently, the KoBRA Wien filter is being manufactured, and will perform a factory acceptance test. [ABSTRACT FROM AUTHOR]

We have designed and constructed a low-cost Wien filter based on strong permanent magnets and integrated it into an ion soft-landing instrument to enable parallel deposition as well as one- and two-dimensional surface patterning of mass-selected ions using dynamic fields. We show the capabilities of this device for separating ions from a multicomponent high-flux continuous ion beam and simultaneous deposition of ions of different mass-to-charge ratios onto discrete locations on a surface. When a dynamic electric field is applied parallel to the magnetic field, ions are deposited in one-dimensional arrays, laterally separated by mass. The field's strength, frequency, and waveform type determine both the lengths of the arrays and the density of ions across the 1-D pattern. Additionally, a second dynamic field from user-defined waveforms orthogonal to the magnetic field enables two-dimensional surface patterning of ions while maintaining mass separation. These experiments demonstrate the practical utility of a Wien filter for the controlled fabrication of interfaces with arbitrary patterns of mass-selected ions.

Classical communication schemes exploiting wave modulation are the basis of our information era. Quantum information techniques with photons enable future secure data transfer in the dawn of decoding quantum computers. Here we demonstrate that also matter waves can be applied for secure data transfer. Our technique allows the transmission of a message by a quantum modulation of coherent electrons in a biprism interferometer. The data is encoded in the superposition state by a Wien filter introducing a longitudinal shift between separated matter wave packets. The transmission receiver is a delay line detector performing a dynamic contrast analysis of the fringe pattern. Our method relies on the Aharonov–Bohm effect but does not shift the phase. It is demonstrated that an eavesdropping attack will terminate the data transfer by disturbing the quantum state and introducing decoherence. Furthermore, we discuss the security limitations of the scheme due to the multi-particle aspect and propose the implementation of a key distribution protocol that can prevent active eavesdropping.

A recoil mass separator SECAR has been designed for the purpose of studying low-energy ( p , γ ) and ( α , γ ) reactions in inverse kinematics with radioactive beams for masses up to about A = 65. Their reaction rates are of importance for our understanding of the energy production and nucleosynthesis during explosive hydrogen and helium burning. The radiative capture reactions take place in a windowless hydrogen or He gas target at the entrance of the separator, which consists of four Sections . The first Section selects the charge state of the recoils. The second and third Sections contain Wien Filters providing high mass resolving power to separate efficiently the intense beam from the few reaction products. In the following fourth Section , the reaction products are guided into a detector system capable of position, angle and time-of-flight measurements. In order to accept the complete kinematic cone of recoil particles including multiple scattering in the target in the center of mass energy range of 0.2 MeV to 3.0 MeV, the system must have a large polar angle acceptance of ± 25 mrad. This requires a careful minimization of higher order aberrations. The present system will be installed at the NSCL ReA3 accelerator and will be used with the much higher beam intensities of the FRIB facility when it becomes available. [ABSTRACT FROM AUTHOR]

For the first time a vertically polarized electron beam has been used for physics experiments at MAMI in the energy range between 180 and 855 MeV. The beam-normal single-spin asymmetry A n , which is a direct probe of higher-order photon exchange beyond the first Born approximation, has been measured in the reaction C 12 ( e → , e ′ ) C 12 . Vertical polarization orientation was necessary to measure this asymmetry with the existing experimental setup. In this paper we describe the procedure to orient the electron polarization vector vertically, and the concept of determining both its magnitude and orientation with the available setup. A sophisticated method has been developed to overcome the lack of a polarimeter setup sensitive to the vertical polarization component. [ABSTRACT FROM AUTHOR]

The conventional Wien filter is a device with orthogonal static magnetic and electric fields, often used for velocity separation of charged particles. Here we describe the electromagnetic design calculations for a novel waveguide RF Wien filter that will be employed to solely manipulate the spins of protons or deuterons at frequencies of about 0.1–2 MHz at the COoler SYnchrotron COSY at Jülich. The device will be used in a future experiment that aims at measuring the proton and deuteron electric dipole moments, which are expected to be very small. Their determination, however, would have a huge impact on our understanding of the universe. [ABSTRACT FROM AUTHOR]

We are planning test experiments of fundamental symmetries based on the intrinsic properties of francium. It is expected that the laser cooling and trapping of francium will produce precision measurements. The pilot experiment using rubidium was performed with the goal of francium trapping. The ion beam generated with a francium ion source was investigated using a Wien filter. Each piece of equipment still must be studied in more detail, and the equipment should be upgraded in order to trap radioactive atoms. [ABSTRACT FROM AUTHOR]

In this article, we report the development of a new 200-kV analytical electron microscope equipped with a monochromator with an integrated double Wien-filter system. It enables us to study the electronic structures of materials in detail using electron energy-loss spectroscopy (EELS) analysis at an atomic scale. A highly monochromated and isotropically round electron probe is produced on the specimen plane. The ultimate energy resolutions with 0.1-s acquisition times are measured to be 36 meV at 200 kV and 30 meV at 60 kV. In an EELS mapping experiment performed on SrTiO3 with a monochromated electron probe whose energy resolution is 146 meV, an elemental map exhibits atomic resolution. [ABSTRACT FROM AUTHOR]

Abstract: A new segmented silicon-array called MUSETT has been built for the study of heavy elements using the Recoil-Decay-Tagging technique. MUSETT is located at the focal plane of the VAMOS spectrometer at GANIL and is used in conjunction with a γ-ray array at the target position. This paper describes the device, which consists of four 10×10cm2 Si detectors and its associated front-end electronics based on highly integrated ASICs electronics. The triggerless readout electronics, the data acquisition and the analysis tools developed for its characterization are presented. This device was commissioned at GANIL with the EXOGAM γ-ray spectrometer using the fusion–evaporation reaction 197Au(22Ne,5n)214Ac. Additionally, the performance of the VAMOS Wien filter used during the in-beam commissioning is also reported. [Copyright &y& Elsevier]

Abstract: We report the development of a monochromator for an intermediate-voltage aberration-corrected electron microscope suitable for operation in both STEM and TEM imaging modes. The monochromator consists of two Wien filters with a variable energy selecting slit located between them and is located prior to the accelerator. The second filter cancels the energy dispersion produced by the first filter and after energy selection forms a round monochromated, achromatic probe at the specimen plane. The ultimate achievable energy resolution has been measured as 36meV at 200kV and 26meV at 80kV. High-resolution Annular Dark Field STEM images recorded using a monochromated probe resolve Si–Si spacings of 135.8pm using energy spreads of 218meV at 200kV and 217meV at 80kV respectively. In TEM mode an improvement in non-linear spatial resolution to 64pm due to the reduction in the effects of partial temporal coherence has been demonstrated using broad beam illumination with an energy spread of 134meV at 200kV. [Copyright &y& Elsevier]

In this work we present the design, the construction and the measurements of the magnet for a so-called spin-rotator (Wien filter), a beam line device used to rotate the spin direction (and the associated magnetic moment) of muons in a beam used for condensed matter research at the Swiss Muon Source at the Paul Scherrer Institute. The design parameters—originating both from the properties of the preferred particle beam as well as the technological constraints for the high-voltage components generating the necessary electric field—were optimized for device compactness, cost and high beam transmission. [ABSTRACT FROM PUBLISHER]

Abstract: The differential algebra (DA) method has been employed to compute the optical properties and aberrations up to the fifth order of multipole systems containing electrostatic and magnetic round, quadrupole, hexapole and octopole lenses, and Wien filters. A new software package has been developed, which computes the geometrical and chromatic aberrations up to the fifth order by using a single DA ray trace. It also has an optimization module where a weighted set of aberrations can be minimized by the automatic adjustment of a set of user-defined system variables. In this paper, we present our new method for designing and optimizing multipole systems including Wien filters, and illustrate its application with three relevant examples. [Copyright &y& Elsevier]

Abstract: Many references on historic and modern papers dealing with the Wien filter are given. Basic optic properties, advantages and disadvantages as well as applications are summarized. Then uncommon systems consisting of Wien filters with different azimuthal orientations, i.e. orthogonal deflection sections, are considered. The corresponding paraxial ray equation and the eight fundamental trajectories of such systems are introduced and the computation of the aberrations up to the third rank is briefly covered. As an example an electron monochromator with four Wien filters is discussed in detail. Finally, a novel mass separator with two Wien filters for a low-voltage focussed ion beam column with a liquid metal ion source is treated. [Copyright &y& Elsevier]

Abstract: Monochromators used in electron microscopes have been reviewed. There are three steps in its progress. At the first step, monochromator is used in retarding mode. Wien filter monochromator and analyzer are floating on the high voltage connected to the gun high voltage. It provides very high energy resolution of about 10meV at 60kV accelerating voltage. In the second step, various gun monochromators; the Wien filter (fringe field monochromator, single focus monochromator and double focus monochromator) and electrostatic omega type are proposed and some of which are commercialized. The double Wien filter and the electrostatic omega monochromators have functions of astigmatic focus on the slit plane and the compensation of the dispersion at the last focus. As the third step, the earth potential monochromator is proposed. Only highly stabilized beam can go through the earth potential monochromator slit, whose magnetic field is stabilized around the 10−8, even if the beam stability from the gun is not so high. This function will be useful in the future high spatial resolution electron microscopy. [Copyright &y& Elsevier]