Keyword: heavy-ion
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MO1C3 High Voltage Upgrade of the 14UD Tandem Accelerator electron, simulation, operation, acceleration 1
 
  • T.B. Tunningley, S.T. Battisson, A. Cooper, J.K. Heighway, D.J. Hinde, C. Kafer, T. Kitchen, P. Linardakis, N.R. Lobanov, C. Notthoff, T. Tempra, B. Tranter, R. Tranter
    Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia
  • R.A. Bosch
    UW-Madison/SRC, Madison, Wisconsin, USA
  • J.E. Raatz
    NEC, Middleton, Wisconsin, USA
 
  The 14UD at the Australian National University’s Heavy Ion Accelerator Facility (HIAF) operated at a maximum voltage of 15.5 MV after the installation of tubes with a compressed geometry in the 1990s. In recent years, the performance of the accelerator has shown a gradual decline to a maximum operation voltage of ~14.5 MV. There are some fundamental factors that limit the high voltage performance, such as SF6 gas pressure, field enhancement due to triple junctions and total voltage effect. In 2019 ANU initiated the feasibility study of available options to upgrade the entire population of supporting posts, acceleration tubes and grading resistors. In this paper we will discuss the preferred technologies and strategies for successful implementation of this development. The chosen design is based on NEC tubes with magnetic electron suppression and minimized steering of ion beam. The new grading resistors mounting options and improved voltage distribution along accelerator column timeline will be discussed.  
slides icon Slides MO1C3 [28.718 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-MO1C3  
About • Received ※ 25 May 2022 — Revised ※ 27 June 2022 — Accepted ※ 10 August 2022 — Issue date ※ 19 September 2022
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MO3I3 Heavy Ion Stripping target, operation, synchrotron, linac 24
 
  • P. Gerhard, M.T. Maier
    GSI, Darmstadt, Germany
 
  Ion stripping is primarily an essential technique for heavy ion accelerators in order to reach higher beam energies within reasonable size and budget limits. Due to the nature of the stripping process, the resulting ion beam contains ions of different charge states. Therefore, high beam loss is typically associated, making the net stripping efficiency one of the decisive elements of the overall performance of an accelerator or facility. Several technical implementations of strippers have been and are still being developed in order to obtain optimal stripping for different ions and beam energies by employing different kinds of stripping targets, namely gaseous, solid and more recently fluid materials. High beam intensities resulting in prohibitive energy deposition and target destruction are challenging. Optimizing a stripper may potentially increase the overall performance by a large factor with less effort than other actions. This gave rise to the pulsed gas stripper project at the GSI UNILAC. This talk will give an overview of different strippers at GSI and beyond. The second part will give a detailed report on the introduction of hydrogen at the GSI gas stripper.  
slides icon Slides MO3I3 [53.513 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-MO3I3  
About • Received ※ 21 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022  
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MO4I2 Liquid Lithium Charge Stripper Commissioning with Heavy Ion Beams and Early Operations of FRIB Strippers operation, MMI, linac, vacuum 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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TUP06 Cryogenic Surfaces in a Room Temperature SIS18 Ioncatcher vacuum, cryogenics, 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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TH1C4 Cavity Designs for the CH3 to CH11 and Bellow Tuner Investigation of the Superconducting Heavy Ion Accelerator HELIAC cavity, SRF, simulation, niobium 140
 
  • T. Conrad, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • W.A. Barth, M. Basten, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, A. Rubin, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
 
  New CH-DTL cavities designs of the planned Helmholtz Linear Accelerator (HELIAC) are developed in collaboration of GSI, HIM and IAP Frankfurt. The in cw-mode operating linac with a final energy of 7.3 MeV/u, is intended for various experiments, in particular with heavy ions at energies close to the Coulomb barrier for research on SHE. Twelve sc CH cavities are foreseen, divided into four different cryostats each equipped with two dynamic bellow tuner. After successful beam tests with CH0, CH3 to CH11 were designed. Based on the experience gained so far, optimizations were made, which will lead to both an increase in performance in terms of reducing the peak fields limiting superconductivity and a reduction in manufacturing costs and time. In order to optimize manufacturing, attention was paid to design many parts of the cavity, such as lids, spokes, tuner and helium shell, with the same geometrical dimensions. In addition, a tuner test rig was developed, which will be used to investigate the mechanical properties of the bellow tuner. For this purpose, different simulations were made in order to realize conditions as close as possible to reality in the test rig.  
slides icon Slides TH1C4 [6.439 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TH1C4  
About • Received ※ 27 June 2022 — Revised ※ 19 July 2022 — Accepted ※ 10 August 2022 — Issue date ※ 19 September 2022
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TH3C2 Alternating Phase Focusing Based IH DTL for Heavy Ion Application cavity, focusing, operation, linac 162
 
  • S. Lauber, K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, P. Forck, V. Gettmann, T. Kürzeder, J. List, M. Miski-Oglu, A. Rubin, S. Yaramyshev
    GSI, Darmstadt, Germany
  • K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev
    HIM, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, S. Lauber, J. List
    KPH, Mainz, Germany
  • M. Droba, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • H. Podlech
    HFHF, Frankfurt am Main, Germany
 
  The continuous wave (CW) operated HElmholtz LInear ACcelerator (HELIAC) is going to reach the next milestone with the commissioning of the superconducting (SC) Advanced Demonstrator cryomodule, comprising four SC Crossbar H-mode (CH) cavities and SC steerer magnets. In parallel with the commissioning of the SC main accelerator, the normal conducting injector consisting of an ECR ion source, a RFQ and two Interdigital H-mode (IH) cavities will be built based on an Alternating Phase Focusing (APF) beam dynamics scheme. Both IH cavities will provide a beam energy gain from 300 keV/u to 1400 keV/u with a maximum mass to charge ratio of 6, requiring only one external quadrupole triplet and beam steerer elements between them. The APF concept allows stable and effective beam transport with transverse and longitudinal focusing, enabling an efficient and compact design. Due to the stringent requirements of the APF concept on the voltage distribution and the CW operation, optimization of each cavity in terms of RF, mechanical and thermal properties is crucial for successful operation of the HELIAC injector. The current layout of the APF based and CW operated injector will be presented.  
slides icon Slides TH3C2 [1.603 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TH3C2  
About • Received ※ 21 June 2022 — Revised ※ 04 July 2022 — Accepted ※ 10 August 2022 — Issue date ※ 19 September 2022
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TH3C3 Recent UNILAC Upgrade Activities operation, rfq, quadrupole, linac 166
 
  • U. Scheeler, W.A. Barth, M. Miski-Oglu, H. Vormann, M. Vossberg, S. Yaramyshev
    GSI, Darmstadt, Germany
  • W.A. Barth, M. Miski-Oglu, S. Yaramyshev
    HIM, Mainz, Germany
  • W.A. Barth
    KPH, Mainz, Germany
 
  The GSI UNILAC is the section of the GSI accelerator facility that has been in operation the longest. UNILAC is able to accelerate ions from hydrogen to ura-nium up to 20 MeV (p+) and 13 MeV/u (uranium). The main focus of the recent upgrade measures is to meet the FAIR requirements and to provide reliable and long term beam operation conditions. Besides post stripper upgrade and upgrade of the UNILAC controls, a particular atten-tion is paid to improve the performance of the High Current Injector (HSI) [1-7] and to intensify spare part management for the ageing accelerator. In order to en-sure operational reliability, the main focus lies on exten-sive spare part management and replacement of outdated equipment. Modified beam dynamics design for the frontend system and the use of advanced technologies are needed to improve the UNILAC performance. Among other things, a modified Low and Medium Energy Beam Transport section design for the HSI and installation of reliable (non-destructive) high intensity beam diagnos-tics devices are in progress. This paper addresses the status of current development efforts and specific plans for the UNILAC upgrade.  
slides icon Slides TH3C3 [1.595 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TH3C3  
About • Received ※ 20 June 2022 — Revised ※ 28 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022
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TH4C3 High Intensity Proton Beams at GSI (Heavy Ion) UNILAC proton, operation, linac, ion-source 170
 
  • W.A. Barth, M. Miski-Oglu, U. Scheeler, H. Vormann, M. Vossberg, S. Yaramyshev
    GSI, Darmstadt, Germany
  • W.A. Barth, M. Miski-Oglu
    HIM, Mainz, Germany
 
  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 high intensity proton beam of up to 35 mA of 36 µs duration at a repetition rate of 4 Hz. The GSI heavy ion linac (UNILAC) is able to deliver intense heavy ion beam for injection into SIS18, but it is not suitable 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 new operational approach results in up to 3 mA of proton intensity at a maximum beam energy of 20 MeV, 100 µs pulse duration and a rep. rate of 4 Hz. For some time now, UNILAC proton beam operation with higher intensities has been offered as standard for users. Recent linac beam measurements will be presented, showing that the UNILAC is able to bridge the time until the FAIR-proton linac delivers high-intensity proton beams.  
slides icon Slides TH4C3 [3.539 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TH4C3  
About • Received ※ 11 June 2022 — Revised ※ 28 June 2022 — Accepted ※ 10 August 2022 — Issue date ※ 29 September 2022
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