Keyword: vacuum
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MO4I2 Liquid Lithium Charge Stripper Commissioning with Heavy Ion Beams and Early Operations of FRIB Strippers operation, heavy-ion, MMI, linac 31
 
  • T. Kanemura, N.K. Bultman, R. Madendorp, F. Marti, T. Maruta, Y. Momozaki, J.A. Nolen, P.N. Ostroumov, A.S. Plastun, H.T. Ren, A. Taylor, J. Wei, Q. Zhao
    FRIB, East Lansing, Michigan, USA
  • M.J. LaVere
    MSU, East Lansing, Michigan, USA
  • Y. Momozaki, J.A. Nolen
    ANL, Lemont, Illinois, USA
 
  Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) at Michi-gan State University is a 400 kW heavy ion linear accel-erator. Heavy ion accelerators normally include a charge stripper to remove electrons from the beams to increase the charge state of the beams thus to increase the energy gain. Thin carbon foils have been the traditional charge stripper but are limited in power density by the damage they suffer (sublimation and radiation damage) and con-sequently short lifetimes. Because of the high beam pow-er, FRIB had decided to use a liquid lithium charge strip-per (LLCS), a self-replenishing medium that is free from radiation damage. FRIB recently commissioned a LLCS with heavy ion beams (36Ar, 48Ca, 124Xe and 238U beams at energies of 17-20 MeV/u). Since there had been no exper-imental data available of charge stripping characteristics of liquid lithium, this was the first demonstration of charge stripping by a LLCS. The beams were successfully stripped by the LLCS with slightly lower charge states than the carbon foils of the same mass thickness. The LLCS started serving the charge stripper for FRIB user operations with a backup rotating carbon foil charge stripper. FRIB has become the world’s first accelerator that utilizes a LLCS.
 
slides icon Slides MO4I2 [6.337 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-MO4I2  
About • Received ※ 26 June 2022 — Revised ※ 27 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022
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TU1C4 A 3D Printed IH-Type Linac Structure - Proof-of-Concept for Additive Manufacturing of Linac RF Cavities cavity, linac, simulation, experiment 41
 
  • H. Hähnel, A. Ateş, U. Ratzinger
    IAP, Frankfurt am Main, Germany
 
  Funding: This research was funded by BBMBF grant number 05P21RFRB2.
Additive manufacturing ("AM" or "3D printing") has become a powerful tool for rapid prototyping and manufacturing of complex geometries. A 433 MHz IH-DTL cavity has been constructed to act as a proof of concept for additive manufacturing of linac components. In this case, the internal drift tube structure has been produced from 1.4404 stainless steel using 3D printing. We present the concept of the cavity as well as first results of vacuum testing and materials testing. Vacuum levels sufficient for linac operation have been reached with the AM linac structure.
 
slides icon Slides TU1C4 [5.326 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TU1C4  
About • Received ※ 20 June 2022 — Revised ※ 30 June 2022 — Accepted ※ 10 August 2022 — Issue date ※ 20 September 2022
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TUP05 Prototype Room Temperature Quadrupole Chamber with Cryogenic Installations cryogenics, quadrupole, simulation, synchrotron 75
 
  • S. Aumüller, L.H.J. Bozyk, P.J. Spiller
    GSI, Darmstadt, Germany
  • K. Blaum
    MPI-K, Heidelberg, Germany
 
  The synchrotron SIS100 at FAIR accelerator complex at the GSI Helmholtzzentrum will generate heavy ion beams of ultimate intensities. As medium charge states have to be used, the probability for charge exchange in collisions with residual gas particles of such ions is much lager than for higher charge states. In the last years, several measures have lowered the residual gas density to extreme high vacuum conditions. For example 55% of the circumference of SIS18 have already been coated with NEG, which provides high and distributed pumping speed. Nevertheless, this coating does not pump nobel and nobel-like components, which have very high ionization cross sections. A cryogenic environment at e.g. 50-80K provides a high pumping speed for all heavy residual gas particles. The only typical residual gas particle that cannot be pumped at this temperature is hydrogen. With the pumping speed of an additional NEG coating in these areas, the pumping will be optimized for all residual gas particles. The installation of cryogenic installations in the existing room temperature synchrotron SIS18 at GSI has been investigated. Measurements on a prototype chamber and simulations of SIS18 with cryogenic installations based on these measurements are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP05  
About • Received ※ 21 June 2022 — Revised ※ 30 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022
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TUP06 Cryogenic Surfaces in a Room Temperature SIS18 Ioncatcher cryogenics, heavy-ion, simulation, operation 79
 
  • L.H.J. Bozyk, S. Aumüller, P.J. Spiller
    GSI, Darmstadt, Germany
 
  For FAIR operation, the existing heavy ion synchrotron SIS18 at GSI will be used as booster for the future SIS100. In order to reach the intensity goals, medium charge state heavy ions will be used. Unfortunately, such ions have very high ionization cross sections in collisions with residual gas particles, yielding in beam loss and a subsequent pressure rise via ion impact stimulated gas desorption. To reduce the desorption yield, room temperature ioncatcher have been installed, which provide low desorption surfaces. Simulations including cryogenic surfaces show, that their high sticking probability prevents the vacuum system from pressure built-ups during operation. Such, the operation with heavy ion beams can be stabilized at higher heavy ion intensities, than solely with room temperature surfaces. A prototype ioncatcher containing cryogenic surfaces has been developed and built. The surfaces are cooled by a commercial coldhead, which easily allows this system being integrated into the room temperature synchrotron. The development and first laboratory tests including fast pressure measurements of this system will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP06  
About • Received ※ 21 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022  
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TH3I1 A Novel CW RFQ for Exotic and Stable Beams rfq, alignment, cavity, emittance 156
 
  • A. Palmieri, L. Bellan, M. Comunian, L. Ferrari, A. Pisent, C.R. Roncolato
    INFN/LNL, Legnaro (PD), Italy
 
  The SPES RFQ is designed in order to accelerate beams in CW with A/q ratios from 3 to 7 from the Charge Breeder through the MRMS and the selection and injection lines up to the MEBT (Medium Energy Beam Transport). The RFQ is composed of 6 modules about 1.2 m long each. Each module is basically composed of a Stainless Steel Tank and four OFE Copper Electrodes. A copper layer is plated on the tank inner surface and a spring joint between tank and electrode is used in order to seal the RF. In this contribution, the main design steps of the RFQ, the construction concepts and the results obtained for the first assembled modules are shown.  
slides icon Slides TH3I1 [7.615 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TH3I1  
About • Received ※ 20 June 2022 — Revised ※ 28 June 2022 — Accepted ※ 10 August 2022 — Issue date ※ 29 September 2022
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