To meet the demand for intense highly charged stable ion beams for medical and nuclear physics a traveling-wave-tube (TWT) based RF generator has been installed and is in commissioning at the Advanced Electron Cyclotron Resonance Upgrade (AECR-U) ion source at the UMCG-PAR-TREC facility. The generator comprises 2 x 750W in-phase combining TWT RF generators with an output frequency range of 12.75-14.5 GHz. Frequency scanning routines have been incorporated in the control software which makes it possible to identify intense and stable ion-beam regimes within the plasma-heating frequency domain. The new RF generator replaces a 14.1 GHz fixed frequency klystron. In this paper we present the setup, the scanning methodology, the first measurements, and discuss the frequency scans measured from a helium and a xenon beam. These results improve the stability and increase the beam intensity at the UMCG-PARTREC facility.

The European Electron Cyclotron Resonance Ion Source (ECRIS) community has more than 20 years of experience working together in various EU-funded projects. In the recent project, called ERIBS (European Research Infrastructure - Beam Services), the community will focus on improving ion beam services for the EURO-LABS (European-Laboratories for Accelerator Based Sciences) research infrastructures. The EURO-LABS is a four-year project funded by the Horizon Europe program of the European Commission for years 2022 - 2026. In the ERIBS collaboration the best expertise, know-how and practices of the ECRIS community will be exploited and transferred between the partners to take full advantage of the European ion source infrastructure. The aim is to extend the beam variety available for the European user community by developing beam production methods and techniques. This development includes further improvement of technologies related to high temperature ovens, axial sputtering and MIVOC method for all the participating laboratories. We will also aim to improve both short- and long-term plasma and beam stability, as well as methods for online monitoring of these conditions. This can be realized, for example, by optical emission spectroscopy, identifying kinetic plasma instabilities by means of hard x-ray detection and using online beam current monitoring systems. An example of the recent developments is the new collaboration proposed by the CNRS-IPHC team to synthesize enriched MIVOC compounds for the other ERIBS partners. For example, the team successfully prepared an enriched chromocene compounds, which were needed to produce intensive Cr-54 and (50) Cr beams for the JYFL and GANIL nuclear physics programs, respectively.

The extraction system of the superconducting AGOR cyclotron consists of an electrostatic deflector and three electromagnetic channels. As the electrostatic deflector has only a moderate field strength (<100 kV/cm), the first electromagnetic channel (EMC1) has to generate a rather strong dipole component resulting in current densities up to 169 A/mm(2) in water-cooled copper coils. In the original design the coils consist of sections of hollow conductors, parallel to the beam path, vacuum-brazed to machined "bridges" over the beam aperture. Altogether there are over 200 brazed joints made in three subsequent cycles in the three coils (dipole, quadrupole and first harmonic corrector). In 25 years of operation two channels of this type have been "consumed". The channels developed water leaks due to erosion of the copper by the high speed cooling water flow in the "bridge" regions that ultimately could not be repaired anymore. To remedy this problem the channel has been redesigned using bent conductors. A production technique for small radius bends and a new joining method to avoid vacuum brazing have been developed. The coil support taking up the 10 kN/m Lorentz forces on the windings are now made from isolating material instead of anodized aluminium to prevent grounding errors. The new channel (EMC1-U) has been in operation now for two years without any failure. A detailed comparison of the old and new design will be presented.

Gas catchers are widely used to thermalize nuclear reaction products and subsequently extract them for precision measurements. However, impurities in the inert stopping gas can chemically react with the ions and thus influence the extraction efficiency. So far, chemical reactions in the gas-catcher have not been investigated in detail. Therefore, we are currently building a new setup to develop Chemical Isobaric SEparation (CISE) with the aim to understand the chemistry inside the gas-catcher and to explore its potential as a new technique for separation of isobars. In this paper, we give a short description of the setup together with the ion transportation studies performed via ion-optics simulations.

The hexapole support structure is made from an 7075 T6 aluminium cylinder in which spaces have been machined by wire cutting in which the six magnetic bars are mounted (Fig.1). The six magnet-bars, made of Nd-Fe-B material, are each build up by two rows of 10 blocks (Fig.1,2), and mounted in a stainless steel AISI 304 can to prevent the magnetic material to oxidize. All blocks are made of MCE N5064 material and have an identical shape with an easy axis of 43 +/2% deg (Fig.1f). During operation, the left over spaces around the bars are also used for cooling. The cooling water is directed specifically to the area of the loss-lines (Fig.1c), where the electrons hit the aluminium plasma chamber on the inside. This is done by filling up all the space around the bars with SS sheets and rods (not shown).

At KVI-CART, an upgrade of the AECR is in preparation with the main objective to increase the intensity and stability of the highly charged xenon beams. Specifically, we have studied, double frequency heating, gas mixing and the radial magnetic field of the ion source. A factor of 3 increase in beam intensity is seen for Xe-129(31+) beams due to the injection of additional 11.5 GHz RF power. Gas mixing with Oxygen increases the beam intensity of a Xe-124(27+), beam by a factor 30. In addition, an increase is expected by the installation of a new hexapole with magnetic pole-tip field of 0.82 T.

Transverse phase-space distributions of low-energy ion beams extracted from ECR ion sources often show higherorder effects caused by ion-optical aberrations. Understanding these effects is mandatory to keep emittance growth and the resulting beam losses in low-energy beam transport lines under control. We present results of an experimental and theoretical study of beam extraction and transport in the AGOR injection line at KVI. Particle tracking simulations have been performed of a multi-component neon ion beam extracted from an ECR ion source to calculate 4D phase-space distributions at various positions along the beam line. The simulations compare well with beam profile and emittance measurements.

A novel emittance meter has been developed to measure the four-dimensional, transverse phase-space distribution of a low-energy ion beam using the pepper-pot technique. A characteristic feature of this instrument is that the pepper-pot plate, which has a linear array of holes in the vertical direction, is scanned horizontally through the ion beam. This has the advantage that the emittance can also be measured at locations along the beam line where the beam has a large horizontal divergence. A set of multi-channel plates, scintillation screen, and ccd camera is used as a position-sensitive ion detector allowing a large range of beam intensities that can be handled. This paper describes the design, construction, and operation of the instrument as well as the data analysis used to reconstruct the four-dimensional phase-space distribution of an ion beam. Measurements on a 15 keV He(+) beam are used as an example.

A detailed experimental and simulation study of the extraction of a 24 keV He(+) beam from an ECR ion source and the subsequent beam transport through an analyzing magnet is presented. We find that such a slow ion beam is very sensitive to space-charge forces, but also that the neutralization of the beam's space charge by secondary electrons is virtually complete for beam currents up to at least 0.5 mA. The beam emittance directly behind the extraction system is 65 π mm mrad and is determined by the fact that the ion beam is extracted in the strong magnetic fringe field of the ion source. The relatively large emittance of the beam and its non-paraxiality lead, in combination with a relatively small magnet gap, to significant beam losses and a five-fold increase of the effective beam emittance during its transport through the analyzing magnet. The calculated beam profile and phase-space distributions in the image plane of the analyzing magnet agree well with measurements. The kinematic and magnet aberrations have been studied using the calculated second-order transfer map of the analyzing magnet, with which we can reproduce the phase-space distributions of the ion beam behind the analyzing magnet. Using the transfer map and trajectory calculations we have worked out an aberration compensation scheme based on the addition of compensating hexapole components to the main dipole field by modifying the shape of the poles. The simulations predict that by compensating the kinematic and geometric aberrations in this way and enlarging the pole gap the overall beam transport efficiency can be increased from 16% to 45%.

The AGOR-facility has an on-going upgrade program aiming at intensities beyond 10 12 pps for heavy ion beams up to Pb. The main elements of the program are: further development of the ECR-source, improvement of the transmission into and through the cyclotron, and protection of equipment against excessive beam loss. Further improvement of the ECR ion source is facilitated by the installation of a second source. Redesign of the Low Energy Beam-line, to compensate for aberrations, is in progress; simulations predict a significant increase in transmission. A new, cooled, electrostatic extractor is being commissioned and the beam loss control system has been completed. The main remaining issue is vacuum degradation induced by beam loss caused by charge exchange on the residual gas. Tracking calculations of the distribution of the beam losses over the vacuum chamber to determine the optimum location of scrapers are underway. A gold coating was recently applied to relevant parts of the vacuum chamber aiming at reduction of beam loss induced desorption.

This paper reports on work performed during the last two years to improve the performance of the KVI-AECR ion source, which is used as an injector for the AGOR cyclotron. We have installed stainless-steel screens at the injection and extraction sides and an additional collar around the extraction aperture resulting in better plasma stability and an increase of extracted ion currents. Source tuning is aided by continuously observing the visible light output of the plasma through the extraction aperture with a CCD camera. We now routinely extract 700 μA of O 6+ ions and 50 μA of Pb 27+ ions. Source optimization is supported by extensive computational modelling of the ion transport in the lowenergy beam line and measuring the transverse emittance of the extracted ion beam with a pepperpot emittance meter. These efforts have shown that second-order aberrations in the analyzing magnet lead to a significant increase of the effective beam emittance. Work is underway to compensate these aberrations.

In this paper we present a simple model that we developed to reconstruct the 4D trace space distribution from the convoluted spatial images of a pepperpot emittance meter. Straightforward analysis of the images is hampered because of multiple and/or overlapping beamlets emerging from a single hole in the pepper plate. The model allows us to unambiguously assign each transmitted beamlet to its corresponding hole in the pepper plate from which it emerged. We will illustrate our analysis model with the reconstruction of the 4D trace space distribution behind the analyzing magnet of a He 1+ beam extracted from an electron cyclotron resonance ion source.

The demand for intense highly-charged ion beams at the AGOR facility has triggered a study to improve the beam-line transport efficiency. In the framework of this study an emittance meter (KVI-4D) to measure the 4D phase-space of a beam has been developed. The device is also intended for use at GSI with the MS-ECRIS, which is being built in the framework of the EURONS-ISIBHI project. The demand for intense beams is pushing the development of ECR ion sources to areas where the formation of ion beams in the extraction region is affected by the strong fringe field of the solenoids and extracted intense beams are influenced by space charge effects. With the KVI-4D emittance meter we hope to gain more understanding of beam formation and transport and thus to improve overall efficiency. In the following we will describe the design and the main parameters characterizing the instrument. Measurements will be presented where we compare data taken with an Allison [1] scanner and with the KVI-4D [2] emittance meter for the same beam. An exploration of the 4D phase-space data shows how beam filamentation can be investigated.

An emittance meter has been developed to measure the full 4D phase space distribution for low energy ion beams. The instrument will be installed at different locations, where the expected shape of the phase space distribution is highly variable. To cope with these different conditions the instrument combines the pepperpot and scanning techniques. The phase space distribution is imaged on a CCD-camera using a MCP + phosphor screen combination. In the first commissioning experiments the single ion response of the instrument has been measured and emittance measurements have been performed.

Ion source development at KVI is focused on increasing the beam intensity from the electron cyclotron resonance ion source injector and optimizing the beam transport and injection into the superconducting AGOR cyclotron. We describe several modifications that have resulted in a significant performance increase of the ion source. We also present the first results of ion transport simulations that have been performed to better understand beam losses in the extraction region and in the low-energy beam transport system. Finally, a new emittance meter based on a combination of the pepperpot and scanning techniques will be described, which will be used to benchmark the simulation studies of ion extraction and transport in detail. (c) 2008 American Institute of Physics.

Intense heavy ion beam production with electron cyclotron resonance (ECR) ion sources is a common requirement for many of the accelerators under construction in Europe and elsewhere. An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained up to now since the time of pioneering experiment of R. Geller at CEA, Grenoble, and this trend is not deemed to get the saturation at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 10(13) cm(-3) and very high current of multiply charged ions are expected with the use of 28 GHz microwave heating and of an adequate plasma trap, with a B-minimum shape, according to the high B mode concept [S. Gammino and G. Ciavola, Plasma Sources Sci. Technol. 5, 19 (1996)]. The MS-ECRIS ion source has been designed following this concept and its construction is underway at GSI, Darmstadt. The project is the result of the cooperation of nine European institutions with the partial funding of EU through the sixth Framework Programme. The contribution of different institutions has permitted to build in 2006-2007 each component at high level of expertise. The description of the major components will be given in the following with a view on the planning of the assembly and commissioning phase to be carried out in fall 2007. An outline of the experiments to be done with the MS-ECRIS source in the next two years will be presented.

The design of each component of the Multipurpose Superconducting ECR Ion Source (MS-ECRIS) has been completed and some items are ready. The magnets and the cryostat are under construction at ACCEL and the commissioning is scheduled for March 2007. The mechanical have been optimized and their construction is under way, the microwave system is under refurbishment and the 65kV power supply is available and upgraded for afterglow operations. Pumping and extraction system were adapted to the EIS testbench of GSI Darmstadt. The description of,each part will be given in the paper along with a schedule of the forthcoming development and experiments.

The design of each component of the Multipurpose Superconducting ECR Ion Source（MS-ECRIS） has been completed and some items are ready.The magnets and the cryostat are under construction at ACCEL and the commissioning is scheduled for March 2007.The mechanical have been optimized and their construction is under way;the microwave system is under refurbishment and the 65kV power supply is available and upgraded for afterglow operations.Pumping and extraction system were adapted to the EIS testbench of GSI Darmstadt.The description of each part will be given in the paper along with a schedule of the forthcoming development and experiments.

A facility for experiments with radioactive ion beams, produced in inverse kinematics with heavy ion beams, has been built at the KVI. The experiments require primary beam intensities ≥5 × 10 12 pps, corresponding to ~1 kW beam power, for beams up to Pb. The upgrade of the superconducting AGOR cyclotron to meet this requirement is described and the present status given. The on-going work to validate critical aspects is discussed.