We have carried out a series of measurements demonstrating the feasibility of using the Dresden electron beam ion source (EBIS)-A, a table-top sized, permanent magnet technology based electron beam ion source, as a charge breeder. Low charged gold ions from an AuGe liquid metal alloy ion source were injected into the EBIS and re-extracted as highly charged ions, thereby producing charge states as high as Au(60 +). The setup, the charge breeding technique, breeding efficiencies as well as acceptance and emittance studies are presented.

We report on experiments with a new superconducting electron beam ion source (EBIS-SC), the Dresden EBIS-SC, with the objective to meet the main requirements for their application in particle-therapy facilities. Synchrotrons as well as innovative accelerator concepts, such as high-gradient linacs which are driven by a large-current cyclotron (CYCLINACS) and direct drive RF linear accelerators may benefit from the advantages of EBISs in regard to their functional principle. First experimental studies of the production of low-Z ions such as H(+), H(2)(+), H(3)(+), C(4+), and C(6+) are presented. Particular attention is paid to the ion output, i.e., the number of ions per pulse and per second, respectively. Important beam parameters in this context are, among others, ion pulse shaping, pulse repetition rates, beam emittance, and ion energy spread.

Electron Beam Ion Sources (EBISs) provide highly charged ions (HCIs) for many applications, amongst others for particle injection into accelerators. Although EBISs are limited in ion output they feature a lot of advantages which qualify them for accelerator injection. The ion pulses extracted from the ion sources can be directly injected into an accelerator sequence which however requires ion pulses with distinct shape and length. The ions are produced by trapping in a high density electron beam for a certain time with electrostatic potentials providing for their axial trapping. Due to the ion energy distribution within the trapping region ion extraction can be controlled by controlling the trapping potential. A specific time dependent control mode of the trapping potential thus allow for the production of ion pulses with designated shape and length. Source parameters such as working gas pressure, electron beam current and energy influence the energy distribution of the ions which in turn influence the pulse shaping.

Highly charged ions (HCIs) are important tools in various fields of basic and applied research. However, the species of interest cannot always be directly produced by a primary ion source. Therefore, ‘charge breeding’ has become an important technique applied, e.g., in nuclear physics experiments with post-accelerated radioact ive beams or high-precision ion mass measurements. The machines commonly used in such experiments are high-power cryogenic electron beam ion sources (EBIS) [1, 2]. In 2009, we presented results showing that charge breeding is also possible with room-temperature electron beam ion traps of the Dresden EBIT type [3, 4] which opens up new possibilities for designing compact, resource efficient, relatively inexpensive charge breeding setups. In this report, we present follow-up measurements using the Dresden EBIS-A as a charge breeder. Like the EBIT, it is based on permanent magnet technology, yet, it has a higher trap capacity and a larger ion output per pulse [5]. We have investigated the electron beam properties as well as its per formance in breeding highly charged Au ions. Figure 1 shows the projection of an X-ray image of the electron beam region of the EBIS for typical operating parameters by which the radial electron distribution can be investigated (for details on the experimental method see [3]). Using the two common theoretical assumptions, box-shaped and gaussian radial distribution, fits result in characteristic radii ofr = 131μm andr80% = 137μm, respectively. The best agreement is reached using an average of the two for which an electon current density of je = 125±30A/cm can be given. The electron current density can be used to estimate the required ionization timeτq for a charge state q according to

We present measurements of the extraction of short time pulses of highly charged ions (4 keV, Ar(16+)) from the Dresden electron beam ion trap. Thereby the dependence of the extractable ionic charge on the extraction regime was investigated. The ion extraction time was varied between 20 ns and 1 micros. Furthermore the production of carbon ions and the influence of the extraction regime on the pulse widths was investigated to obtain information about the suitability of the Dresden EBIS-A in synchrotron based particle therapy facilities.

We give an overview about latest developments and measurements with the Dresden electron beam ion source family as compact and economically working table-top sources of highly charged ions. The ion sources are potential tools for various applications such as for use in combination with accelerators in medical particle therapy, as charge breeder or ion trap injector, as ion sources for a new generation of focused ion beam devices and for applications together with time-of-flight secondary mass spectrometers.

The Dresden EBIS-SC is a new superconducting EBIS designed for applications in medicine, basic research and other fields. After mechanical construction and a longer installation period first experiments have been accomplished to understand the source behavior and to get a well-founded sense about the working characteristics of the ion source. In a first step electrical properties were investigated and it was shown that the source works stable over a period of several days with electron beam currents I(e) of up to 500 mA at an electron beam transmission of better than 0.999 I(e). Actually using a cathode of 1.5 mm the source reaches electron beam currents up to 750 mA. All measurements were performed at magnetic fields of 6 T. First ion extraction experiments demonstrate that the H(2)(+) output at a pulse repetition frequency of 330 Hz and an electron beam current of 300 mA is higher than 1 x 10(8) ions per pulse. This output is sufficient for medical applications, e. g. in so-called CYCLINACs. Furthermore, the corresponding DC beam was measured to about 1 e mu A. The beam emittance of extracted carbon ions was determined to (7 ... 25) mm mrad. Extracted ion pulses show pulse FWHM in the order of (4 ... 12) mu s. In this paper first ion extraction spectra of highly charged carbon, argon and xenon ions are presented for different source operation regimes. Additionally energy-dispersive measured X-ray spectra from argon and xenon ions are shown and discussed.

This paper summarizes the results of studies to enhance the performance of Dresden Electron Beam Ion Traps regarding aspects which are important for charge breeding, i.e. the injection of externally produced low charged ions and their conversion to highly charged ions. The properties of the electron beam of this compact room-temperature operated EBIT were investigated via position sensitive X-ray detection. A detailed analysis of the spatial distribution as well as the energy of the X-ray photons emitted from the electron beam region allowed for the determination of the source parameters needed to guarantee optimal ion trapping conditions and ionization rates. The parameters found in this investigation were applied for the successful realization of charge breeding with the Dresden EBIT.

Highly charged ions (HCIs) are an important tool in various fields of basic and applied physical research. However, in many cases the species of interest cannot be produced directly by a primary ion source. Therefore, charge breeding, i.e. the conversion of singly charged ions to highly charged ions, is an essential part of projects such as nuclear or astrophysical experiments with post accelerated beams of radioactive ions [1] or precise nuclear mass measurements with ions stored in penning traps [2]. At GSI’s HITRAP facility [3] HCIs up to U92+ can be provided using an accelerator complex to strip electrons of f the initially low charged ions at high velocities. In case the beam from the accelerator structure is not available, tests can be run using a compact room-temperature electron beam ion trap, the SPARC-EBIT [4], which was designed to produce HCIs from gaseous materials injected through a needle valve. To broaden the range of particles which can be fed to the source we have investigated its abilities as a charge breeder. The setup for the charge breeding experiments includes a surface ion source for the creation of the singly charged alkali metal ions. The measurements presented in this paper were performed using potassium. These primary ions are guided straight towards the SPARC-EBIT where the charge breeding process takes place. It can be divided into three phases: K 1+ injection, breeding, and re-extraction of a pulse of highly charged ions from the EBIT. During the re-extraction phase a quadrupole bender mounted in between the two ion sources is switched from ground to high voltage to bend the ion trajectories by 90 degrees and send the pulse towards the multi passage spectrometer (MPS) where it can then be analyzed by magnetic A/q separation. A typical A/q spectrum of charge bred potassium measured with the MPS is presented in figure 1. The source parameters given in the picture were found to be optimal for continuous potassium ion injection. After a breeding time of tbreed= 3 s the charge state distribution has reached its equilibrium. Since the electron beam energy of the EBIT was set close to the ionization energy of the K-shell, helium-like potassium shows the highest relative abundance in the spectrum. Bare potassium ions have been detected, though only in small amounts. Further on, it was discovered that an injection time of tinj = 20 ms at the beginning of the breeding time, tbreed, is sufficient to achieve the maximum ion output for high charge states. The capture efficiency during the measurement resulted in ≈ 2·10−4. Breeding efficiencies for different charge states

Highly charged ions significantly differ in their physical properties compared to "classical" low charged ions. With the Dresden EBIT/EBIS family (EBIT: Electron Beam Ion Trap, EBIS: Electron Beam Ion Source) a compact, economic and long-term stable Source setup for highly charged ions is available providing the platform technology for various applications. Beside the use in basic as well as in applied research this technology is also suitable for nanotechnology and medical applications. Potential applications and first proof-of-principle experiments are discussed. The integration of ail EBIT in a FIB setup is exemplified.

In this work, highly charged ions have been extracted from the advanced Electron Beam Ion Source（EBIS-A）developed in a scientific cooperation between the Dresden University of Technology and the DREEBIT GmbH Dresden.The charge state distributions of ions extracted from the EBIS-A are measured in the pulse and leaky modes under different operation conditions. Ar 16+ ions with current of 2pA are produced and extracted in the leaky mode. 3×10~5 Ar 18+ ions per pulse are extracted in the pulse mode.The ion charge state distribution is a function of the ionization time.

The evolution of the charge state distribution inside an electron beam ion source or trap (EBIS/T) is determined by interactions of the electron beam with the ions in the trap region. Hence, detailed information about the electron beam is required for evaluations of spectroscopic and ion extraction measurements performed at EBIS/T facilities. This article presents the results of investigations on the electron beam properties of an ion source of the Dresden EBIS type. For the first time theoretical predictions of the shape of the beam were tested for a noncryogenic EBIS working with low magnetic flux densities provided by permanent magnets. Position and width of the electron beam were measured at different electron energies showing an oscillation in the beam structure. At an energy of E(e)=16 keV and an emission current of I(e)=30 mA the beam is compressed to a radius of r(e)=57 mum (80% current). This refers to an average current density of j(e)=232 A/cm(2).

Electron Beam Ion Sources and Traps (EBIS/T) of the Dresden EBIS/T type have been proven to be efficient and reliable sources of highly charged ions in many applications [1]. At GSI, a Dresden EBIT named SPARC-EBIT is currently being installed as an ion injector at the HITRAP facility. It will serve as an off line ion source for test runs and experiments. Plans for the future also envision the application of the SPARC-EBIT or other Dresden EBIS/T systems for charge breeding purposes. In this regard, the project presented here focuses on testing the performance of these sources as charge breeders. Charge breeding with EBIS/T facilities using superconducting solenoid coils for the compression of the electron beam has been achieved successfully with breeding efficiencies into one charge state of more than 10 % [2]. The Dresden EBIS/T concept, however, is based on the usage of permanent magnets. The absence of refrigeration technology or liquid cooling gases results in many advantages such as low initial and running costs, easy operation, and a compact design which allows for transportation of the sources. On the other hand, their relatively short ion trap regions, shallow trap potentials, and low magnetic field strengths create challenges in trapping injected ions.

The Dresden electron beam ion trap (EBIT)/electron beam ion source (EBIS) family are very compact and economically working table-top ion sources. We report on the development of three generations of such ion sources, the so-called Dresden EBIT, Dresden EBIS, and Dresden EBIS-A, respectively. The ion sources are classified by different currents of extractable ions at different charge states and by the x-ray spectra emitted by the ions inside the electron beam. We present examples of x-ray measurements and measured ion currents extracted from the ion sources at certain individual operating conditions. Ion charge states of up to Xe48+ but also bare nuclei of lighter elements up to nickel have been extracted. The application potential of the ion sources is demonstrated via proof-of-concept applications employing an EBIT in a focused ion beam (FIB) column or using an EBIT for the production of nanostructures by single ion hits. Additionally we give first information about the next generation of the Dresden EBIS series. The so-called Dresden EBIS-SC is a compact and cryogen-free superconducting high-B-field EBIS for high-current operation.

We present first experimental investigations on the Dresden EBIS-A, an advanced design of the Dresden EBIT. The Dresden EBIS-A, an EBIT machine working at roomtemperature is equipped with a NdFeB ring magnet system producing a magnetic field on axis of about 620 mT. The measurement of integral ion pulses from the ion source yield a number of extracted elementary charges in the order of 109 per ion pulse. It is shown that the width of the ion pulse can be changed from microseconds up to several tens of microseconds varying the potential of the third drift tube section. The measurement of separated charge states provides an indication of an increased ion output compared to that of the Dresden EBIT. X-ray spectra account for the production of ions such as Ar17+, Xe44+ and Ce49+in the electron beam of the ion source.

Gallium liquid-metal ion sources that have been introduced in the late 1970s have allowed the development of a new class of micro- and nanofabrication tools collectively denominated as focused ion beam (FIB) machines. To investigate the potential of a helium beam in such a FIB instrument the authors have tested a room-temperature electron beam ion trap coupled with a high resolution FIB machine. In this letter they present their first results in target imaging using a helium beam with a resolution that allows to account for a beam diameter in the submicrometer range. (c) 2007 American Institute of Physics.

A new ion irradiation facility for the formation of beams of highly charged ions in a wide range of kinetic energy from about 10V×q up to MeV is presented. The ions are produced in sources of the Dresden EBIT type which allow the production of a wide spectrum of highly charged ions such as C6+, Ar18+, Ni28+, Kr35+ and Xe44+, respectively. The integral ion output of these ion sources is in the order of some μA per pulse at pulse widths of 2μs up to about 10μs. For individual ion charge states ion currents of up to about 100 nA per pulse can be obtained. In DC extraction mode (leaky mode) ion currents in the order of hundreds of pA are detected. An advanced Dresden EBIT type source, the Dresden EBIS-A, is employed at an irradiation facility. The target chamber comprises a sample manipulation and transfer system as well as numerous preparation and diagnostic tools. The facility will provide an experimental environment for basic research in atomic and solid state physics as well as for applied technology in areas such as surface engineering, surface analysis, nanostructuring and nanobiotechnology.

The Dresden EBIT is a room-temperature EBIT producing highly charged ions for x-ray spectroscopy as well as for materials modifications and other applications. In the past we have demonstrated the production of ions such as Ar18+, Fe26+, Kr35+, Xe46+, and Ir67+. Here we give a report on the further development of this ion source to increase the electric trap capacity involving the production of a greater amount of highly charged ions.