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A pepperpot emittance meter was used to measure the transverse emittance of multiply charged beams from REXEBIS, an Electron Beam Ion Source (EBIS) used for charge breeding of radioactive ion beams. The emittance meter is equipped with a Micro Channel Plate (MCP), a phosphor screen and a CCD camera for detection of the ion signal. The pulsed beam structure of low duty cycle imposes challenging constraints on the detector settings. In this article we give a careful analysis of the optimal operating parameters of the pepperpot emittance meter for ion beams of varying intensities. Emittance values for mass-separated and non-separated beams for different operating modes of the EBIS are presented. Furthermore we report on aberrations created in our injection ∕ extraction system.

Motion in vicinity of complex bodies is unstable due to the dynamic changing of the irregular gravitational field. Standard spacecraft power plants designed for interplanetary flights do not provide a stable orbital motion near irregular bodies. In this paper the effectiveness analysis of an electrospray engine power plant used as a sustainer engine in an asteroid exploration mission is considered. Authors describe mathematical models of the spacecraft's motion in an unstable gravitational field as the classical n-body problem. Using simple control schemes for the spacecraft's orbital motion allows basic requirements for the spacecraft's power plant to be defined: thrust level and exhaust velocity. Ion Electrospray Systems are designed to be installed on small satellites, however, effectiveness analyses shows that the characteristics of the calculated engine system is close enough to the characteristics of an electrospray system. Authors demonstrate that ion Electrospray System modules are effective enough to be installed on spacecraft in asteroid exploration missions.

This article discusses the design-ballistic optimization for spacecraft, which move under the influence of the gravitational fields of complex configuration and electric propulsion. Such conditions exist near asteroids, for example in the systems of two gravitating bodies, in the vicinity of the libration points. In this paper, we propose to use a method of iterative mission optimization for electric propulsion spacecraft, using sequences of the mathematically specified models of movement and the spacecraft design. The previously obtained analytical results, which describes the planar movement of spacecraft with solar electric propulsion, allows the initial approach in the iterative scheme of optimization to be constructed. A method of modeling and optimization of interplanetary missions ballistic schemes is developed, based on a combination of Pontryagin's maximum principle formalism conditions of transversality and methods of mathematical programming, allowing restriction characteristics for real interplanetary missions to be considered. Recommendations for the choice of the design-ballistic parameters of the interplanetary mission's spacecraft are obtained taking into account the features of a nuclear and solar power plant for purposes of the delivery of a payload to the required heliocentric orbit, to the Moon and near asteroid.

The problem of controlled spacecraft motion in vicinity of asteroids is an important flight dynamics task. Solution of the problem consists of gravitational field simulations and control trajectory scheme defininition. We propose to use the model of single gravity points for motion simulation of a spacecraft in an irregular gravitational field of the Eros 433 asteroid. The equations of spacecraft motion are the corresponding equations of the n-body problem. The motion trajectory can be split into a number of from-point-to-point motion parts. Each part can be considered as a two-point Boundary task. The Authors developed a concept of Boundary problem solution based on the Pontryagin's principle and modified Newton's step-by-step approximation method. The Authors developed a special software for the Boundary problem solutions. A boundary task of the controlled spacecraft's transfer between circular orbits from 200 km to 100 km is presented in the paper.

The paper aims to identify such a method of guidance and attitude control for the spacecraft motion in vicinity of objects with complex geometric shape as asteroids. Proposed methods provide both sufficient accuracy of the calculations and ease of use. The approach suggested by the authors is based on the model of point-focus concentrators and is based on the topological similarity of the gravitational field form obtained and the real form of the object. The control models are based on the locally optimal control laws.The first problem is to define particular law for every maneuvering task and correspondent coefficients that determine control program for an engine. The second problem is to define the low thrust engine, which is able to produce necessary exhaust velocity and thrust level. Authors suggest the algorithm of getting accurate design characteristics for the spacecraft. The paper materials are of practical value to the professionals involved in the problems solution of spacecraft control systems development when designing missions affecting maneuvering in close proximity to asteroids, comets and small planetary satellites.

In this paper we report on our results from the design study of an advanced Electron Beam Ion Source (EBIS) based Charge Breeder (ECB). The ECB should fulfill the requirements of the HIE-ISOLDE upgrade, and if possible be adapted for ion injection into TSR@ISOLDE, as well as serve as an early prototype of a future EURISOL ECB. Fulfilling the HIE-ISOLDE/TSR@ISOLDE specifications requires simultaneous increase in electron beam energy, current and current density in order to provide the requested beams with proper charge state, high intensity and with a specified pulse repetition rate. We have carried out a study on the technical requirements of the ECB. The obtained parameters were optimized to comply with technical limitations arising from the electron beam technology and plasma physics in an ECB.

International audience; TwinEBIS is an Electron Beam Ion Source (EBIS) recently made operational at CERN. The device is similar in construction to the REXEBIS charge breeder operating at the ISOLDE facility. After relocation of the solenoid from the Manne Siegbahn Laboratory (MSL) Stockholm, TwinEBIS was commissioned at CERN and serves as a test bench dedicated to manipulation of low-energy highly charged ions. In this paper we give an overview of the setup and present advanced numerical simulations of the electron optics. In addition, the alignment procedure of the solenoid magnetic field is described and measurement results are presented. Results from cathode investigations, electron beam tests and ion extraction modulation are presented in a follow-up paper.

In this work we present our progress in the design study of a new Electron Beam Ion Source (EBIS) to be installed as a charge breeder for reacceleration of rare ions at ISOLDE. The work is triggered by the HIE-ISOLDE upgrade [1] and the planned TSR@ISOLDE project [2] . To fulfill the requests of the user community the new EBIS should reach an electron beam density of 104 A/cm2 at electron energies up to 150 keV and, provide UHV environment and ion cooling in the breeding region to ensure confinement of the ions long enough to reach the requested charge states. We report on the established design parameters and first prototyping steps towards production and testing of suitable equipment.

An electron-beam simulation technique for high-resolution complete EBIS/T modelling is presented. The technique was benchmarked on the high compression HEC2 test-stand with an electron beam current, current density and energy of 10 A, 10 kA/cm2 and 49.2 keV, and on the immersed electron beam at REXEBIS for electron beam characteristics of 0.4 A, 200 A/cm2 and 4.5 keV. In both Brillouin-like and immersed beams the electron-beam radius varies from several millimeters at the gun, through some hundreds of micrometers in the ionization region to a few centimeters at the collector over a total length of several meters. We report on our approach for finding optimal meshing parameters, based on the local beam properties such as magnetic field-strength, electron energy and beam radius. This approach combined with dividing the problem domain into sub-domains, and subsequent splicing of the local solutions allowed us to simulate the beam propagation in EBISes from the gun to the collector using a conventional PC in about 24–36 h. Brillouin-like electron beams propagated through the complete EBIS were used to analyze the beam behavior within the collector region. We checked whether elastically reflected paraxial electrons from a Brillouin-like beam will escape from the collector region and add to the loss current. We have also studied the power deposition profiles as function of applied potentials using two electrode geometries for a Brillouin-like beam including the effects of backscattered electrons.

We report on the development of the HEC2 (High Energy Compression and Current) charge breeder, a possible high performance successor to REXEBIS at ISOLDE. The new breeder would match the performance of the HIE-ISOLDE linac upgrade and make full use of the possible installation of a storage ring at ISOLDE (the TSR@ISOLDE initiative [1]). Dictated by ion beam acceptance and capacity requirements, the breeder features a 2-3.5 A electron beam. In many cases very high charge states, including bare ions up to Z=70 and Li/Na-like up to Z=92 could be requested for experiments in the storage ring, therefore, electron beam energies up to 150 keV are required. The electron-beam current density needed for producing ions with such high charge states at an injection rate into TSR of 0.5-1 Hz is between 10 and 20 kA/cm2, which agrees with the current density needed to produce A/q, Comment: 9 pages, 8 figures, EBIST14 conference paper