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| TUPVA116 | Commissioning of the New Heavy Ion Linac at the NICA Project | 2362 |
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| The new accelerator complex Nuclotron-based Ion Collider fAcility (NICA) is now under development and construction at JINR, Dubna. This complex is assumed to operate using two injectors: modernized old Alvarez-type linac LU-20 as the injector of light polarized ions and a new Heavy Ion Linear Accelerator HILAc - injector of heavy ions beams. The new heavy ion linac accelerate ions with q/A values above 0.16 to 3.2 MeV/u is under commissioning. The main components are 4-Rod-RFQ and two IH drift tube cavities is operated at 100.6 MHz. Main results of the HILAc commissioning with carbon beam from the laser ion source are discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA116 | |
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| THPIK002 | Development of a Range of High Peak Power Solid-State Amplifiers for Use in the Heavy Ion Linac at JINR, Dubna | 4108 |
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| A range of LDMOS based amplifiers rated for up to 340kW peak power and operating at 100.625MHz were developed for use as RF sources for driving cavities in the heavy ion LINAC (HILac) at JINR, Dubna. The final solution had to be compact and competitive while addressing technical challenges such as phase and amplitude stability, long term reliability, reflected power handling and serviceability. Design considerations and performance results are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK002 | |
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| MOPAB039 | Development of a Control System Based on Experimental Data for Space Charge Lenses | 166 |
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Space charge lenses use a confined electron cloud for the focusing of ion beams. The electron density gives the focusing strength whereas the density distribution influences the mapping quality of the space charge lens and is related to the confinement. The major role of the electron density with respect to the focusing quality has been pointed out many times in the past *,**. With an automated measurement system the radial light density profile, plasma stability and mean value of the electron density have been measured in respect to the confining fields and the pressure. The results are summarized in 3D-maps. The theoretical model approximations for space charge lenses predicts high electron densities then measured. With the automated system the realistic 3D-maps can be considered instead of an approximation of a theoretical density including knowledge of the most stable electron cloud achievable within the parameter range of the lens. The experimental results of the automated measurement system will be presented here and a concept of a control system for this type of space charge lenses will be explained.
* O. Meusel, 'Focussing and transport of ion beams using space charge lenses', PhD thesis, 2006 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB039 | |
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| MOPVA054 | High Power RF Coupler for the CW-Linac Demonstrator at GSI | 990 |
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| The planned super-heavy element (SHE) research project investigates heavy ions near the coulomb barrier in future experiments. A superconducting (sc) continuous wave (cw) CH-Linac Demonstrator was developed and installed behind the High Charge State Injector (HLI) at GSI Darmstadt, Germany. In future the advanced cw-LINAC setup, with several CH-cavities, will accelerates the heavy ion beam from HLI with an energy of 1.4 MeV/u up to 3.5 - 7.3 MeV/u. The RF power of several kW will be coupled capacitively into the CH-cavities with minimal reflection at an operation frequency of 217 MHz. Two ceramic windows (Al2O3) are installed inside the RF coupler, to reduce the premature contamination of the cavity and as an additional vacuum barrier. The CH-cavity will be operated at cryogenic temperature (4 K) and will be increased to room temperature along the RF coupler. The optimally adapted RF coupler design, providing minimal RF losses and simultaneously maximal performance, was optimized by electromagnetic simulations. An RF coupler design with a reflection-free RF adaptor as well as the temperature distribution along the coupler will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA054 | |
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| TUPAB147 | The Final RF-Design of the 36 MHz-HSI-RFQ-Upgrade at GSI | 1678 |
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| In Darmstadt/Germany the existing accelerator cite GSI is expanding to one of the biggest joint research projects worldwide: FAIR, a new antiproton and ion research facility with so far unmatched intensities and quality. The existing accelerators will be used as pre-accelerators and therefor need to be upgraded to fulfill the requirements with respect for intensity and beam quality. In a first step the 9.2 m long 36 MHz-HSI-RFQ for high current beams will obtain new electrodes to reach the specific frequency and to allow a higher electric strength. Therefor several simulations with CST MWS have been done. The final RF-design will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB147 | |
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| TUPAB148 | Investigation of a Splitring-RFQ for High Current Ion Beams at Low Frequencies | 1680 |
| SUSPSIK042 | use link to see paper's listing under its alternate paper code | |
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| For hadron linacs RFQs are the first stage of acceleration. To reach high intensities a new Splitring-RFQ is investigated. Not only a high current and high beam quality/brilliance should be achieved, also a good tuning flexibility and comfort for maintenance are part of the study. It will consist of two stages with 27 MHz and 54 MHz to accelerate ions with an A/q of 60 up to energies of 200 keV/u. Therefor RF simulations with CST MWS were done to study the quality factor and the shunt impedance as well as tuning possibilities. First results and the status of the project will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB148 | |
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| TUPVA055 | Further Investigations for a Superconducting cw-LINAC at GSI | 2197 |
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| For superconducting (sc) accelerator sections operating at low and medium beam energies very compact accelerating-focusing structures are strongly required, as well as short focusing periods, high accelerating gradients and very short drift spaces. The Facility for Antiproton and Ion Research (FAIR) is going to use heavy ion beams with extremely high peak current from UNiversal Linear ACcelerator (UNILAC) and the synchrotron SIS18 as an injector for the SIS100. To keep the GSI-Super Heavy Element program competitive on a high level and even beyond, a standalone sc continuous wave LINAC in combination with the upgraded GSI High Charge State injector is envisaged. In preparation for this, testing of the first LINAC section (financed by HIM and GSI) as a demonstration of the capability of 216 MHz multi gap Crossbar H-structures (CH) is still ongoing, while an accelerating gradient of 9.6 MV/m (4K) at a sufficient quality factor has been already reached in a horizontal cryostat. As a final R&D step towards an entire LINAC three advanced cryo modules, each comprising two short CH cavities, should be built until 2019, serving for first user experiments at the coulomb barrier. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA055 | |
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| TUPVA061 | Beam Dynamics Study for the HIM&GSI Heavy Ion SC CW-LINAC | 2217 |
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| A sc cw-linac with variable output energy from 3.7 to 7.5 MeV/u for ions with mass to charge ratio of A/Z<6 is recently under development at HIM and GSI. Following the results of the latest RF-tests with the newly constructed sc CH-DTL cavity, even heavier ions up to Uranium 28+ could be potentially accelerated with the already reached higher RF-voltage. Also the possibility for an up to 10 MeV/u increased output energy, using the same 13 independent cavities, is under consideration. All these options require an advanced beam dynamics layout, as well as a versatile procedure for transverse and longitudinal beam matching along the entire linac. The proposed algorithms are discussed and the obtained simulation results are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA061 | |
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| TUPVA062 | Construction of the MYRRHA Injector | 2221 |
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| A collaboration of SCK•CEN, IAP and BEVATECH GmbH is currently constructing the room temperature CH section of the 16.6 MeV CW proton injector for the MYRRHA project. The elaboration of all the construction readiness files for the construction of the accelerating cavities of the first CH section (1.5 to 5.9 MeV) is ongoing. In parallel, the planning, development and fabrication of all further components of this accelerator section is in progress, while the full study for the remaining section is under preparation. This contribution is documenting the most recent status. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA062 | |
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| TUPVA068 | The New Injector Design for MYRRHA | 2234 |
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| The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project is a planned accelerator driven system (ADS) for the transmutation of long-living radioactive waste. A critical passage for the beam quality and especially for the emittance is the injector. Therefore, a new injector design with improved beam dynamics has been developed, featuring low emittance growth rates while using only room temperature structures. The previous design consisted of a 4-Rod RFQ, 7 room temperature and 5 superconducting CH-DTL cavities and 2 rebuncher cavities, whereas the superconducting cavities in the new design have been replaced by 8 room temperature CHs and an additional rebuncher. The main challenge during the development is achieving the required reliability to reduce the thermal stress inside the planned reactor. Therefore, simulations with CST MICROWAVE STUDIO have been made to compare several cooling concepts and to optimize the cavities, especially in terms of the shunt impedance. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA068 | |
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| TUPVA069 | Test of a High Power Room Temperature CH DTL Cavity | 2237 |
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| The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) is planned to deliver ultra-short neutron pulses at high intensities and repetition rates. As part of FRANZ a 175 MHz room temperature 5-gap CH DTL cavity was designed and built. Its main task will be focusing the particle bunch longitudinally at 2 MeV particle energy. Furthermore the CH cavity can also be used to increase the energy as well as decrease it by 0.2 MeV. The rebuncher and its cooling system is optimized to work with a 5 kW amplifier. The amplification system is intended to provide continuous power (cw mode). Due to its operating parameters being nearly identical to the requirements of the MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project, experience for future cavity designs was gained. This includes considerations concerning cooling with use of a 12 kW amplifier. The recent results of conditioning and high power tests will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA069 | |
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| TUPVA070 | Dipole Compensation of the 176 MHz MYRRHA RFQ | 2240 |
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The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project is planned as an accelerator driven system (ADS) for the transmutation of long-living radioactive waste. For this project a cw 4-Rod-RFQ with 176 MHz and a total length of about 4 m is required. It is supposed to accelerate protons from 30 keV up to 1.5 MeV*. One of the main tasks during the development of the RFQ is the very high reliability of the accelerator to limit the thermal stress inside the reactor. Another challenge was to compensate the dipole component of the MYRRHA-RFQ which is due to the design principle of 4-Rod-RFQs. This dipole component is responsible for shifting the ideal beam axis from the geometrical center of the quadrupole downwards. Design studies with CST MICROWAVE STUDIO have shown that the dipole component can be almost completely compensated by widening the stems alternately so that the current paths of the lower electrodes are increased.
* C. Zhang, H. Podlech: NEW REFERENCE DESIGN OF THE EUROPEAN ADS RFQ ACCELERATOR FOR MYRRHA. In Proceedings of IPAC'14, 3223-3225 (2014) |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA070 | |
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| TUPVA071 | The MYRRHA-RFQ - Status and First Measurements | 2243 |
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Funding: H2020, European Commission, grant agreement number 662186 (MYRTE) The MYRRHA project requires a proton linac with an energy of 600 MeV with a beam current of 4 mA in cw operation. As first RF structure a 176 MHz 4-Rod RFQ has been chosen because of tuning possibilities, maintenance, lower capital costs and technological risk compared to a 4-Vane-RFQ. The aim of beam dynamics design was to preserve excellent beam quality and to avoid the creation of halo particles especially in the longitudinal plane. Using the NFSP (New Four-Section Procedure) with a soft and symmetric pre-bunching with full 360° acceptance it was possible to reach the requirements. The simulated transmission of the 4 m long RFQ is close to 100%. The electrode voltage has been chosen to 44 kV which gives enough transverse focusing but limits the required RF losses to about 25 kW/m. The cooling has been optimized for reliable operation and a new method of dipole compensation has been applied. The RFQ has been built and tuned with respect to field flatness. The paper describes the status of the RFQ and first measurements. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA071 | |
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| TUPVA072 | Conceptual Injector Design for an Electron-Ion-Collider Front-End | 2246 |
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| An electron-hadron collider (EIC) could be the next large-scale nuclear physics facility in the United States. A hadron linac with a final energy of 40 AMeV (heavy ions) and up to 130 MeV for protons with an upgrade path to higher energies is required as the first step of the hadron accelerator chain. From a cost point of view superconducting technology seems to be the better choice above an energy of about 5 AMeV compared to a room temperature (rt) solution. This paper describes the conceptual design of a rt front-end up to an energy of 5 AMeV appropriate as initial element of the EIC hadron linac. It consists of two separate injectors based on efficient H-mode cavities, one optimized for heavy ions (Pb30+) and the other optimized for protons and deuterons. Beam dynamics and first RF simulations are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA072 | |
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| THPIK021 | Structural Mechanical Analysis of 4-Rod RFQ Structures in View of a Newly Revised CW RFQ for the HLI at GSI | 4142 |
| SUSPSIK091 | use link to see paper's listing under its alternate paper code | |
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Funding: BMBF Contr. No. 05P15RFRBA The High Charge State Injector (HLI) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, serves as one of the two injector linacs for the UNILAC as well as dedicated injector for the upcoming cw linac project for super heavy element research. As the front end of the HLI is planned to be upgraded for cw operation a newly revised cw capable RFQ structure with an operating frequency of 108 MHz is required. The existent 4-rod structure, which was commissioned at the HLI in 2010, suffers from severe modulated rf power reflections originating from mechanical oscillations of the electrodes that both limit the achievable performance and impede stable operation*. Besides preceding vibration measurements that were done by GSI using a laser vibrometer**, the structural mechanical behavior of the 4-rod geometry was extensively analyzed using ANSYS Workbench. Thereby the crucial mechanical eigenmodes could be identified and their impact on the rf properties was investigated by simulations using CST MWS. A completely newly revised 4-rod RFQ design with optimized structural rigidity was developed of which a 6-stem prototype is currently being manufactured. *P. Gerhard et al., Experience With a 4-Rod CW Radio Frequency Quadrupole, LINAC12, THPLB07 **P. Gerhard et al., In Situ Measurements of Mechanical Vibrations of a 4-Rod RFQ at GSI, LINAC14, TUPP057 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK021 | |
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| THPVA005 | Investigation of Electron Beam Assisted Density Boosting in Plasma Traps Using the Example of a Gabor Plasma Lens | 4421 |
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Gabor lenses are plasma traps that can be used for focusing an ion beam linearly without aberrations* by the electric field of a confined electron cloud. They combine strong electrostatic focusing with the possibility of space charge compensation and provide an attractive alternative to conventional ion beam optics in a LEBT section. The focusing performance strongly depends on the density and distribution of the enclosed electron plasma*. As the Gabor lens is usually operated close to the ion source, residual gas ionization is supposed to be the central electron generation mechanism. An electron source is introduced in order to investigate the possibility of boosting the electron density in plasma traps using the example of a Gabor lens. This way, a Gabor lens could be operated under XUHV conditions, where residual gas ionization is suppressed. The particle in cell code bender** was used to simulate the injection into the confining fields of the space charge lens in different geometrical configurations and a prototype experiment was constructed consisting of a Gabor lens and an electron source system. In this contribution, simulations and measurements will be presented.
* Schulte, K., et al. Electron cloud dynamics in a Gabor space charge lens. 2012 ** Noll, D., et al. The particle-in-cell code bender and its application to non-relativistic beam transport. 2015 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA005 | |
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| THPVA006 | Space-Charge Compensation in the Transition Area Between LEBT and RFQ | 4425 |
| SUSPSIK061 | use link to see paper's listing under its alternate paper code | |
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Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) #05P15RFRBA and by HORIZON 2020 for the MYRRHA project #662186 The transition from a space charge compensated beam in the LEBT to an uncompensated beam in the RFQ will influence the beam parameters. To investigate the impact of the electric fields on the space charge compensation, an insulated cone is used as a repeller electrode in front of the RFQ. Depending on the time dependent potential of the RFQ rods respectively to the beam potential, the compensation electrons may be prevented from moving into the RF field which oozes out of the RFQ entrance. The simulation studies are performed with the particle-in-cell code bender*. The simulations may substantiate measurements at the CW-operated RFQ in Frankfurt University** as well as at the foreseen MYRRHA LEBT-RFQ interface.*** In this contribution, a study on a LEBT-RFQ interface is shown. Results of numerical and experimental investigations will be compared. *Noll, D. et al.The Particle-in-Cell Code Bender and Its Application to Non-Relativistic Beam Transport, WEO4LR02, HB'14 **Meusel, O. et al.FRANZ Accelerator Test Bench and Neutron Source.,MO3A03, LINAC'12 ***R. Salemme et al.Design Progress of the MYRRHA Low Energy Beam Line, MOPP137, LINAC'14 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA006 | |
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