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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.

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.

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.

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.

A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm2 and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

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