| Paper | Title | Page |
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| TUPLS086 | Charge Breeding Exploration with the MAXEBIS | 1702 |
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| The demand of exotic ions prior to their injection into an accelerator has driven the development of the charge breeding method. Existing facilities like REX-ISOLDE or ISAC at TRIUMF are already using a charge state booster for the post acceleration of radioactive ions. Planned facilities like EURISOL for instance have identified the need of a breeding system. In order to be comparable to the efficiency to a brut force acceleration employing stripper, the efficiency of a charge breeder has to be maximized and the breeding time has to be shortened comparing the existing breeder systems. Therefore the exploration and optimization of the charge state breeding is mandatory and supported by the EU. The Frankfurt MAXEBIS has been modified within the past years towards high current electron beam and external injection of alkaline ions by a surface ionisation source. The electron gun, the inner electrode structure and the collector of the MAXEBIS have been modified. The system has been shipped to GSI and re-assembled. The goals of the following experiments will be systematic studies of the breeding efficiency. The new setup and first experimental results will be presented. | ||
| TUPLS087 | Recent Gains in Polarized Beam Intensities for the Cooler Synchrotron COSY at Jülich | 1705 |
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| Since January 1996, the cyclotron JULIC operates as the injector of H(-) or D(-) beams for the cooler synchrotron COSY at the IKP of the Forschungszentrum Juelich. Routinely about 8 microA of unpolarized or 1 microA of polarized H(-) ions are delivered for charge-exchange injection into COSY. A polarization in excess of 90 % was measured for protons inside the synchrotron COSY. Additionally, polarized and unpolarized D(-) ions have been delivered to experiments. A sequence of up to eight different polarization states for deuterons has been provided for experiments. By advancing the components of the polarized ion the number of polarized particles for injection into the cyclotron has been increased by a factor of three to 5,5x1012 protons, delivered in a 20 ms pulse with a repetition rate of 2 seconds. This report sums up the characteristics of the ion sources and the cyclotron in their present mode of operation and describes the achievements towards higher beam intensities as well as for providing unpolarized and polarized H(-) and D(-) beams with high reliability. | ||
| TUPLS088 | Energy Distribution of H- Ions from the ISIS Ion Source | 1708 |
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| We have used a specially designed retarding field energy analyzer with a resolution (Δ E /E) of approximately 2 x 10 -4 in order to measure the energy distribution, under different operating conditions, of the H- beam of the ISIS ion source. The poster presents the details of the analyzer and the first results obtained on the Ion Source Test Facility at RAL. | ||
| TUPLS089 | Pseudospark-sourced Beams of Electrons and Ions | 1711 |
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| A pseudospark discharge has undergone intensive studies with regard to its unusual and interesting discharge properties during last fifteen years. The pseudospark attracts significant attention from diverse fields such as pulsed-power switching, electron beam generation, free electron masers, ion beam generation, extreme-ultraviolet radiation sources, microthrusters and pseudospark-triggered wakefield acceleration. This paper will present experiments and measurements of pseudospark-sourced electron and ion beams for accelerators. Pulsed electron beams with current intensity over 108 Am-2, high brightness up to 1012A m-2 rad-2 and emittance of tens of mm mrad were produced from a multi-gap pseudospark discharge. The transportation of the pseudospark electron beams is also investigated in order to produce high peak current, high quality, short (~100 picosecond) or long duration (2~100ns) high-brightness electron beam pulses. Recent results from a high current density pseudospark-produced ion beam experimentally investigated with hydrogen gas will be presented. | ||
| TUPLS090 | LEBT Simulations and Ion Source Beam Measurements for the Front End Test Stand (FETS) | 1714 |
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| The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) is intended to demonstrate the early stages of acceleration (0-3MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories. Optimisation of the beam focussing within the Low Energy Beam Transport (LEBT) is necessary to minimise beam losses upon acceleration within the FETS RadioFrequency Quadrupole (RFQ). Simulations of the LEBT are currently under way using the General Particle Tracer package (GPT). Previous envelope calculations suggest weak and strong focussing solutions for the LEBT solenoids. Definitive beam dynamics simulations in GPT require further measurements of the transverse emittances and beam profile of the ion source beam, due to the sensitivity of the simulations on the initial beam profile and level of space charge compensation. A pepperpot emittance/profile measurement system has been designed for use on the ISIS ion source development rig. Results from this pepperpot system are used to constrain the initial conditions for the GPT simulations. | ||
| TUPLS092 | Implementations on the RF Charge Breeder Device BRIC with Test Measurements | 1717 |
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The Radioactive Ion Beam (RIB) production with ISOL technique should require a charge breeder device to increase the ion acceleration efficiency and reduce greatly the production cost. The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept RIB with charge state +1 and increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds and it has been assembled at the LNL (Italy) laboratory. BRIC could be considered as a solution for the charge state breeder of the SPES project under study also at the LNL. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) - Quadrupole aiming to filtering the unwanted masses and then making a more efficient containment of the wanted ions. The RF test measurements seem confirm, as foreseen by simulation results* that a selective containment can be obtained. Most accurate measurements, however, are needed and for that implementations of the system have been carried out.
*V. Variale and M. Claudione. "BRICTEST: a code for charge breeding simulations in RF quadrupolar field", NIM in Phys. res. A 543 (2005) 403-414. |
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| TUPLS093 | AG Acceleration using DPIS | 1720 |
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| We are investigating high current and high repetition rate ion production methods for various heavy ions which can be utilized for an injector of an FFAG accelerator. Direct Plasma Injection Scheme (DPIS) is one of the candidates of the ion production methods and to confirm the capability of the DPIS, we are now preparing for accelerating high intensity Ag15+ ions. The DPIS uses a combination of Laser Ion Source (LIS) and RFQ linac. The plasma goes into the linac directly without transportation line and the ions are extracted at RFQ entrance. To determine the specifications of new RFQ electrodes, the plasma properties were measured. With the Nd-glass laser (3 J / 30 ns), we could not obtain high charge state ions. A new Nd-YAG laser (2.3 J / 6 ns) enabled us to observe many high charged ions and the most produced ions were Ag15+. We completed the plasma distribution measurements. Based on these results, we designed the new RFQ, which will accommodate Q / M = 1 / 8 particles, supposing Ag+15. | ||
| TUPLS094 | Development of a Permanent Magnet Microwave Ion Source for Medical Accelerators | 1723 |
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| A permanent magnet microwave ion source was developed to improve availability of proton accelerator application systems based on industrial microwave ion source technologies. The ion source needs no filament in the discharge chamber, which leads to reliability improvement and less maintenance time. Because the ion source uses a permanent magnet, the ion source needs no coils, no coil power and no coil coolant. The hydrogen beam of over 60 mA has been extracted from a single 5mm diameter aperture with a proton fraction of 85% at a microwave power of 1.3kW. Rise times of the microwave power and beam current to 90 % of the final value were about 30 and 100μseconds respectively at a pulse operation mode with 400μseconds pulse width and 20 Hz repetition rate. These performance parameters are equal to the solenoid coil ion source parameters, making the ion source desirable for accelerator applications like proton therapy systems. | ||
| TUPLS095 | Recent Progress about DPIS | 0 |
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| We have focused on high brightness of induced plasma in Laser Ion Source (LIS) to provide intense highly charged ions efficiently. To take the advantage of the intrinsic density of the laser plasma, Direct Plasma Injection Scheme (DPIS) has been developed. The induced laser plasma has initial expanding velocity and can be delivered directly to the RFQ. Extraction electrodes and focusing devices in LEBT are not needed. Since 2004, a newly designed RFQ has been used to verify the capability of the new ion production scheme. We succeeded to accelerate 60 m A of Carbon beam and 60 mA of Aluminium beam. We have also tried to understand plasma properties of various species by measuring charge states distributions and time structures, and are now ready to accelerate heavier species. Currently Silver 15+ beam is planned to be accelerated. In the conference, design strategies and detailed techniques for the DPIS will be described based on the measured plasma properties of various elements and new findings obtained from recent acceleration experiments. The durability and the reproducibility will be also explained. | ||
| TUPLS096 | Strongly Focused He+ Beam Source for Alpha Particle Measurement at ITER | 1726 |
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| A He+ beam source for He0 beam probe for measurement of fusion produced alphas due to D-T nuclear reaction in a thermonuclear fusion plasma has been designed and constructed. The ion source consists of a 300 mm diameter and 280 mm length plasma chamber and a beam extraction system which has three concaved electrodes. Helium plasma is confined by line cusp magnetic fields produced by Sm-Co permanent magnets. The magnetic field strength near the extraction region is designed to be less than 20 gauss. Through the 100 mm diameter extraction area of the concaved electrodes 300 beamlets are formed with apertures of 4 mm. The focal length of the concaved electrodes is designed to be 750 mm. The beam quality of the extracted He+ beam will be measured by several beam diagnostic apparatuses. The total beam current, the beam profile and the beam emittance will be measured to design a proper alkali metal vapor cell for a He- beam production by a double charge exchange process and a beam transport line to the post accelerator up to MeV region. In the article, the details of the ion source and the beam diagnostic system will be described. | ||
| TUPLS097 | Application of DPIS to IH Linac | 1729 |
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| We are now designing a Laser Ion Source (LIS), which will be operated with an Inter-digital H (IH) structure linac using the Direct Plasma Injection Scheme (DPIS). The DPIS has been applied to RFQ linacs and has successfully achieved very high current with simple structure. The IH structure linac was designed to accept 40 keV proton beam which could be produced by the DPIS. The combination of the DPIS and IH structure linac will realize quite compact accelerator complex with intense proton beam. The detailed design study of a plasma production chamber with a cryogenic cooler is investigated. | ||
| TUPLS099 | The New 14 GHz Ion Source for the U-400 Heavy Ion Cyclotron | 1732 |
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| The new 14 GHz ion source DECRIS-4, to be used as a second injector of heavy multiply charged ions for the U-400 cyclotron and, in the future, also as a "charge breeder" (the "1+ -> n+" method) for the second phase of the DRIBs project, has been designed and constructed at the FLNR. The main feature of the ion source design is the creation of the extended resonance zone in a comparatively compact ECRIS. For this purpose the axial magnetic field is formed with a flat minimum by mounting only one additional solenoid coil to the classical CAPRICE magnetic structure. In this case the superposition of the axial magnetic field and the radial field of the permanent magnet hexapole, made from NdFeB, allows one to create a larger resonance volume. First results of the ion source tests show that in this resonance volume electrons are heated very efficiently which allows to produce intense beams of medium charge state ions with comparatively low level of input microwave power. The basic design features, construction issues and the first results of ion source tests are presented. | ||
| TUPLS100 | Generation of Highly Charged Ions Using ND-glass Laser | 1735 |
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The parameters of ions (charge state distributions, currents and pulse durations) were measured in laser plasma generated by 3 J/30 ns Nd-glass laser for wide range of elements from 12C to 181Ta and for different laser power densities at the target surface. It is shown that such a laser can effectively generate highly charged ions for elements from 12C to 56Fe. Registered ion charge states significantly drops for heavier elements because of recombination losses of highly charged ions during laser produced plasma expansion into vacuum. Absolute currents and numbers of ions with different charge states were obtained by normalization of charge state distributions summary on total ion currents measured by Faraday cup for 1011 W/cm2 and 1012 W/cm2 laser power densities at the target surface. The results obtained are very useful for Laser Ion Source (LIS) development, in particular, for Direct Plasma Injection Scheme (DPIS) study*.
*M. Okamura et al. Laser and Particle Beams, 20, 2002, pp. 451 - 454. |
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| TUPLS103 | Further Development of a Low Inductance Metal Vapor Vacuum Arc (LIZ-MeVVA) Ion Source | 1738 |
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A Low Impedance Z-Discharge Metal Vapor Vacuum Arc (LIZ-MeV) ion source* is being explored as an alternate pre-injector for the Brookhaven Relativistic Heavy Ion Collider (RHIC). With the vacuum arc operating at tens of kiloamperes and an aluminum electrode, LIZ-MeV has been run in two regimes: an LC dominated "ringing" arc of period 4.1 microseconds, which decays after about 6 cycles, and a 1-3 microsecond wide "pulsed" arc, where a small series resistance has been added to critically damp ringing. Metal ions are extracted from the plasma using a two-grid system with a triggered, variable-delay voltage of up to 10 kV. Time-of-Flight (TOF) measurements are taken using a Faraday cup located at the end of a 15-76 cm drift tube. TOF measurements from both arc regimes have been obtained suggesting generation of about a billion ions per pulse of charge states +1 and +2, and occasionally +3 states. TOF results are compared with simple theoretical models.
*B. M. Johnson, et al. Two approaches to electron beam enhancement of the metal vapor vacuum arc ion source. Laser and Particle Beams 21, 103 (2003). |