| Paper | Title | Page |
|---|---|---|
| MOPP059 | Study and Design of the High Power RF Coupler for the CH-Cavity of the Fair pLINAC | 187 |
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| At GSI a proton Linac has been designed and developed in order to provide a 70 MeV proton beam for the FAIR facility. The pLINAC consists of an RFQ followed by six CH-DTL accelerating cavities and the electromagnetic field inside each cavity is generated by seven Klystrons providing up to 2.8 MW power at 325.224 MHz. The high power RF coupling between the Klystron and the accelerating CH-cavity has been studied and an inductive coupling loop has been designed. The coupler insertion inside the cavity and the rotation angle with respect to the magnetic field lines have been adjusted and the results of the analysis of the coupler positioning are presented. A prototype coupler is under construction and the measurement of RF coupling with the CH-cavity is scheduled within this year. | ||
| MOPP078 | RF Power Systems for the FAIR Proton Linac | 236 |
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| In the framework of collaboration between the FAIR project, GSI, and CNRS, the IPNO lab is in charge of providing the high power RF components for a cavity test stand and for the planned FAIR proton Linac. This Linac will be connected to the existing GSI synchrotron SIS18 for serving as an injector for the new FAIR facility. The 70 MeV FAIR proton Linac design contains a 3 MeV RFQ, and a DTL based on Cross-bar H-mode cavities (CH). It will operate with pulsed RF at 325.224 MHz with a width of 200 μs and a repetition rate of 4 Hz. The planned RF systems of the proton Linac will be presented as well as the description of the test stand. The first power test results are obtained with a Thales klystron developed jointly with CNRS. Three solid state amplifiers made by Sigmaphi Electronics for the bunchers will also be described in this paper. | ||
| TUPP056 | High Current Proton Beam Operation at GSI UNILAC | 550 |
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| A significant part of the experimental program at FAIR is dedicated to pbar physics requiring a high number of cooled pbars per hour. The primary proton beam has to be provided by a 70 MeV proton linac followed by two synchrotrons. The new FAIR Proton LINAC will deliver a pulsed proton beam of up to 35 mA of 36 μs duration at a repetition rate of 4 Hz. The current GSI heavy ion linac (UNILAC) is able to deliver world record uranium beam intensities for injection into the synchrotrons, but it is not dedicated for FAIR relevant proton beam operation. In an advanced machine investigation program it could be shown, that the UNILAC is able to provide for sufficient high intensities of CH3-beam, cracked (and stripped) in a supersonic nitrogen gas jet into protons and carbon ions. This advanced operational approach results in up to 2 mA of proton intensity at a maximum beam energy of 20 MeV, 100 μs pulse duration and a rep. rate of 4 Hz. Recent linac beam measurements will be presented, showing that the UNILAC is able to serve as a proton FAIR injector for the first time, while the performance is limited to 17% of the FAIR requirements. | ||
| TUPP058 | RF System Development for the New 108 MHz Heavy Ion High-Energy Linac at GSI | 556 |
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| The GSI UNILAC is in operation successfully since about 40 years. A replacement of the post stripper section is proposed to provide heavy ion beams for the future FAIR facility. Design studies for a new 108 MHz high-energy (HE) linac optimized to accelerate high brilliance and high current ion beams up to U28+ for synchrotron injection are in progress. Thus, the UNILAC will be converted into a short-pulse accelerator, the RF duty cycle being reduced from around 30 % to <2 %. To feed the future HE linac and to prepare for the FAIR commissioning, a major modernisation of the existing post stripper RF systems is planned from 2015 to 2017. Besides, the development of a new 1.8 MW cavity amplifier prototype was started recently, based on the widely-used THALES tetrode TH558SC promising an availability for at least 25 years. New 120 - 150 kW solid state driver amplifiers will replace the existing tube drivers. A digital LLRF system designed by industry was integrated into an existing amplifier driving a single gap resonator and was tested including ion beam tests. An overview of the RF system design and of the planned upgrades will be reported including some results of the LLRF tests. | ||
| THPP015 | Status of the FAIR Proton Source and LEBT | 863 |
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| The unique Facility for Antiproton and Ion Research – FAIR will deliver stable and rare isotope beams covering a huge range of intensities and beam energies. A significant part of the experimental program at FAIR is dedicated to antiproton physics that requires an ultimate number 7x1010 cooled pbar/h. The high-intensity proton beam that is necessary for antiproton production will be deliver by a dedicated 75 mA/70 MeV proton linac. The injector section of this accelerator is composed by an ECR source, delivering a pulsed 100 mA H+ beam (4 Hz) at 95 keV and a low energy beam transport (LEBT) line required to match the beam for the RFQ injection. The proposed design for the LEBT is based on a dual solenoids focusing scheme. A dedicated chamber containing several diagnostics (Alisson scanner, Wien filter, SEM grid, Iris, Faraday Cup) will be located between the two solenoids. At the end of the beam line, an electrostatic chopper system is foreseen to inject up to 50μseconds long beam pulses into the RFQ. The status of LEBT simulations, design and fabrication of the FAIR proton injector will be presented. | ||
| THPP063 | Beam Diagnostics Layout for the FAIR Proton Linac | 998 |
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| The planned proton Linac for FAIR (Facility of Antiproton an Ion Research) will be - additionally to the existing GSI UNILAC - a second injector for the FAIR accelerator chain. It will inject a 70 MeV, (up to) 70 mA proton beam with a nominal pulse length of 30 us into the SIS18. The beam diagnostics system for the proton Linac comprises nine current transformers for pulse current determination and fourteen BPMs for position, mean beam energy and relative current measurement. SEM-Grids and stepping motor driven slits will be used for profile as well as for emittance measurements. A wire-based bunch shape monitor is foreseen, additionally a bending magnet for longitudinal emittance determination during commissioning. Presently, main efforts are conducted concerning the BPM system. Detailed signal simulations with the finite element code CST are performed. An electronics board using digital signal processing is evaluated by detailed lab-based characterization and beam-based measurements at the UNILAC. In this paper we present the general layout and the status of the diagnostics systems as well as key results from our measurements and simulations. | ||
THPP064 |
First CH Power Cavity for the FAIR Proton Injector | |
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| For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW Klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. In 2012, the assembly and tuning of the first power prototype was finished. Until then, the cavity was tested with a preliminary aluminum drift tube structure, which was used for precise frequency and field tuning. In 2013 the final drift tube structure has been welded inside the main tanks and the preparation for copper plating has taken place. This paper will report on the main tuning and commissioning steps towards that novel type of DTL and it will show the latest results measured on a fully operational and copper plated CH proton cavity. | ||