P. Sole

Charge state breeding applications with the ECR PHOENIX source: From low to high current production

The electron cyclotron resonance (ECR) charge state breeding method based on the PHOENIX source is first dedicated to the continuous high charge state radioactive ion production for cyclotrons, due to their q/m requirements, and to the high charge state production efficiency. It can be used as an injector for RFQ, linacs, and synchrotrons either in cw or pulsed operation. The efficiency of the 1+ to the n+ ion production and the charge breeding time are the fundamental parameters of the method, their dependence with regard to the 1+ ion beam emittance injected has been measured and will be discussed with regard to the radioactive ion beam acceleration. The efficiency of the process slightly decreases when injecting ion beam emittances higher than 30 π mm mrad, and remains constant in the 1+ radioactive intensity range available today and in the future. The ECR ion trap tuning associated with the afterglow mode permits the ionization, the accumulation, and the extraction of the injected primary beam keepin...

ECRIS development for stable and radioactive pulsed beams

The latest 28 and 37.5 GHz developments show that very intense pulsed beams of medium charge states can be produced with an ECRIS. We will present latest results obtained with PHOENIX 28 GHz in afterglow mode operation and specially the capacity of the source to produce high current of medium charge states despite a relatively low radial magnetic confinement system. Initially, these developments have been made for Pbn+ ion production for the LHC. A program is now underway by using a very strong ionic pumping effect in order to produce highly bunched beams of radioactive ions suitable for synchrotron acceleration for the CERN Beta-beam project. The purpose of this program consists of producing about 1012 of 6He or 18Ne ions/bunch within 100 μs pulse durations and with a 10 Hz repetition rate. This development must use two ECRIS advantages: the gas efficiency and the bunching capability. We will present a concept showing how we can bunch and ionize the radioactive gas injected in a cw operation source. Expe...

High current density production of multicharged ions with ECR plasma heated by gyrotron transmitter

In order to study the possibilities to produce high currents of pulsed heavy ion beams dedicated to synchrotron injection, two new approaches of ECR devices are now underway. The basic principle consists in maintaining a functioning point of the source with the highest density as possible and a minimum confinement time for the production of a given charge state. It means that for a constant neτi product we try to maximize ne and minimize τi. For this purpose two experiments are in progress at ISN/Grenoblea and IAP/Nizhny Novgorod.b The first one consists of using a minimum |B| magnetic structure with a 1.8 mirror ratio characteristic value with a 28 GHz frequency injection. In this case we explore different functioning points up to 10 kW of UHF power. The second one consists of a simple mirror magnetic system (simple mirror ion source, SMIS) working at 37.5 GHz with a mirror ratio up to 3 (2.5 T) where we study discharges with a peak power up to 100 kW. We will show that, in spite of a very short rising t...

Electron cyclotron resonance ion source for high currents of mono- and multicharged ion and general purpose unlimited lifetime application on implantation devices

The electron cyclotron resonance (ECR) ion sources were originally developed for high energy physic applications. They are used as injectors on linear accelerators and cyclotrons to further increase the particle energy via high charge state ions. This ECR technology is well suited for sources placed on a high voltage platform where ac power available is limited by insulated transformers. The PANTECHNIK family of ion source with its wide range of ion beam (various charge states with various beam currents) offers new possibilities and perspectives in the field of ion implantation. In addition to all these possibilities, the PANTECHNIK ion sources have many other advantages like: a very long lifetime without maintenance expense, good stability, efficiency of ionization close to 100% (this improves the lifetime of the pumping system and other equipment), the possibility of producing ion beams with different energies, and a very good reproducibility. The main characteristics of sources like Nanogan or SuperNan...

Electron cyclotron resonance charge breeder (invited)

Initially developed for radioactive ion beam production, the electron cyclotron resource (ECR) charge breeder shows that the beam injection of a primary beam inside an ECR ion source is a very general process for beam production. In this article we will review the latest results obtained on the ISN Grenoble test bench for the production of clockwise (CW) or pulsed metallic ion beams with the so-called “1+/n+” method. New results are given for CW operation where the efficiency is particularly optimized for application to multicharged radioactive ion production (for example, 3.5% for Zn1+→Zn9+, 4.2% for Pb1+→Pb24+, 5% for Rb1+→Rb15+). Different ion sources have been used to study the variation of the efficiency as a function of the energy of the 1+ primary beam. Charge state distributions are especially measured for Pb and Rb ions. A new mode of operation, the electron cyclotron resonance ion trap breeder/buncher, which permits the trapping and the bunching of the n+ ion beam is demonstrated and experimenta...

Production of multicharged radioactive ion beams: New results for the 1+→n+ method with the MINIMAFIOS and SARA-CAPRICE electron cyclotron resonance ion sources

The backward and forward injection of a 1+ ion beam in a MINIMAFIOS type electron cyclotron resonance ion source (ECRIS) have given good results for the 1+→n+ method. Due to the technological simplicity of the forward injection, additional experiments have been performed with this configuration. Different primary sources (1+) have been used for the injection (2.45 GHz ECRIS, hollow cathode source, simplified 10 GHz NANOGAN type ECRIS), an increase of the performances has already been obtained (Zn, Kr, Ar), and a measurement of the absolute efficiency with the NANOGAN type-MINIMAFIOS association is performed. Due to the high performance of the 10 GHz CAPRICE source used as a highly charged ion injector in the first cyclotron of SARA (Systeme Accelerateur Rhone-Alpes), it has been tested as a different n+ source for the 1+→n+ method. In this purpose, a low energy spread–low emittance thermoionization Rb ion source has been used as 1+ injector. A standard operation of the SARA-CAPRICE source has been kept wi...

ECRIS charge breeding: High resolution spectra and emittance

The charge breeding process, consisting of a low charge state ion beam (1+) plasma capture followed by a multi-ionization process, has been developed for more than ten years in LPSC Grenoble (previously ISN) using ECRIS. The challenge has been to optimize the 1+ capture and then the reextraction of the multicharged ions produced, keeping a “reasonable ECRIS working.” There are now three ECRIS PHOENIX Booster in the world (LPSC-Grenoble, CLRC-Daresbury, and TRIUMF-Vancouver). The LPSC-ECRIS has recently been set up in a completely renewed test bench equipped with a high resolution n+ mass spectrometer and a high resolution emittance meter. The CLRC-ECRIS is dedicated to online experiments with radioactive ions at REX-ISOLDE and the TRIUMF-ECRIS will soon be ready to undergo a validation process. We will present the preliminary results obtained with the new setup of the LPSC PHOENIX Booster with a special attention to the 1+ emittance and the characterization of the unwanted beams (usually called “impuritie...

Advanced magnetic calculations for high magnetic field compact ion source

The design of the advanced electronic cyclotronic resonance ion source (ECRIS) requires relatively high axial and radial magnetic inductions to allow the ECR frequency increase and to take advantage of the subsequent density increase (scaling laws). The last improvements of the commercial rare-earth magnet characteristics open new opportunities for ECRIS and enable the design of very high hexapolar magnetic fields for next generation compact ECRIS. Moreover, the high temperature superconducting (HTS) wires allow designing reliable and compact axial field coils (30 K cooled) at a very effective cost. It is thus very relevant to study a compact hybrid ECRIS using high remanence magnet and HTS technologies. In such a design, the volume of the plasma chamber is a free parameter that can be adjusted to the user requirement. It can be dedicated to very high ionic current production or high charge state production, pulsed, or cw operations. This paper presents the three-dimensional overall simulation of a 3 T ax...

ECRIS as ion source and charge breeder

Abstract We will recall the main characteristics of ECR ion sources and their very good property of ionization efficiency. We will start with a review of on line use of ECR ion sources for production of mono or multicharged radioactive ions, and then we will specially focus our attention on charge breeding process for multicharged ion production. Initially developed for the PIAFE project from ISN Grenoble, the ECR charge breeder shows that the beam injection of a primary beam inside an ECR ion source is a very general process for beam production. We will review the latest results obtained on the ISN Grenoble test bench for the production of CW or pulsed metallic ion beams with the so called ‘1 + / n + ’ method. New results are given for CW operation where the efficiency is particularly optimized for application to multicharged radioactive ion production (for example, 3.5% for Zn 1+ →Zn 9+ , 4.2% for Pb 3+ →Pb 24+ , 5% for Rb 1+ →Rb 15+ ). Different ion sources have been used to study the variation of the efficiency as a function of the energy of the 1 + primary beam. Charge-state distributions are especially measured for Pb and Rb ions. A new mode of operation, the Electron Cyclotron Resonance Ion Trap (ECRIT) breeder/buncher, which permits the trapping and the bunching of the n + ion beam is demonstrated and experimentally verified. This new method shows that it is possible to modify the time structure of the injected beam, just by trapping the ions inside the plasma and reextracting them by using the ‘afterglow pulsed mode’. We will finish by the presentation of the first result obtained with the first especially dedicated ECR booster developed at the ISN and called PHOENIX.

Micro-PHOENIX: Intense deuton beams production for SPIRAL II

The development of electron cyclotron resonance ion source (ECRIS) at LPSC Grenoble (previously ISN) covers a wide range of applications. Micro-PHOENIX is a compact source whose magnetic confinement is fully generated by permanent magnets. The extraction geometry has been specially designed to manage high currents with a double electrode extraction system to improve the beam characteristics at high voltage. The ECRIS can accept a microwave power frequency from 10 to 18 GHz. It has been installed as a universal injector on the new charge breeder test bench in order to perform the widest range of experiments including mono- or multicharged ion injections. To characterize the analyzed extracted beam, a new emittance meter based on electrostatic deflection plates has been set up and permits one to obtain online high resolution measurements. The first objective of the experiments was to fulfill the future SPIRAL II requirements. After a technical description of the Micro-PHOENIX ECRIS and its beam analysis sys...