M. Bai, GSI GSI Helmholtzzentrum fr Schwerionenforschung GmbH - PowerPoint PPT Presentation

GSI Helmholtzzentrum für Schwerionenforschung GmbH Current Technical Capabilities M. Bai, GSI GSI Helmholtzzentrum für Schwerionenforschung GmbH

Achieved nominal beam intensity https://www.gsi.de/work/beschleunigerbetrieb/beschleuniger.htm?no_cache=1 GSI Helmholtzzentrum für Schwerionenforschung GmbH

GSI Facilities uniqueness  versatileness and flexibilities  unique hadron facility for multi users  both dedicated operation as well as parallel operation mode  variety of operation modes  relative short transition in between Histogram of experiment durations courtesy of R. Steinhagen courtesy of S. Reimann D. Severin GSI Helmholtzzentrum für Schwerionenforschung GmbH

Core competence  Variety of ion sources available for operation to fulfill the needs of ion species with the desired charge High Charge state Injector state  Penning Ionization Gauge (PIG) ion source  Multi Cusp Ion Source (MUSIC)  highly charged gas ions  Cold or Hot Reflex Discharge Ion Source  Metal Vapor Vacuum Arc Ion Source (MEVVA)  low charge state high current source  Electron Cyclotron Resonance Ion Source (ECRIS)  high charge state ion source  Excellent ion preparation  always well-prepared and flexible  desired 107Ag2+ separated, and high intensity of 5 emA in UH1 reached.1mA 208Pb4+ was obtained from nature materials GSI Helmholtzzentrum für Schwerionenforschung GmbH

Core competence: Deceleration ESR Stripper 400 MeV/u 400 MeV/u UNILAC FRS CRYRING SIS ESR 4 K 4 MeV/u HITRAP 4 MeV/u … 100 keV/u 10 MeV/u CRYRING HITRAP GSI Helmholtzzentrum für Schwerionenforschung GmbH

Current known technical limitation  Ion source on-going R&D  High current uranium source FAIR mode  ECR for fulfilling users. Most demanding/challenging are from the cw users w.r.t. the ion species and intensity  UNILAC  HSI no heavy ions A/Q > 43, i.e. no Pb and no Uranium  mitigation: replace HSI-RFQ electrodes during summer shutdown  Operation modes that require LEBTQQ to be ramped at average repetition rate above 1Hz  mitigation options: 1. new beam pipe with less eddy current effects 2. avoiding cycling LEBTQQ at high repetition rate by regulating the ion beam intensity with pulse gas striper  no fine energy adjustment for UNILAC users  mitigation: repair ER1 GSI Helmholtzzentrum für Schwerionenforschung GmbH

Current HSI RFQ limitation on heavy ion intensity  The calculation assumes  # of loss free turns for the multi-turn injection: 12  SIS18 injection+ ramping time: 1 sec  SIS18extraction time: 2 sec  For unranium5+, since the HSI RFQ can only reach up to 80% required voltage, additional 50% reduction of nominal transmission through UNILAC is assumed on top of the available current directly out of the ion source  For Pb208, it was planned to provide the Pb4+ from the high current source. Nevertheless, this source for Pb5+ can experience stability issues. Hence, the Pb5+ for operation 2018 will be provided from PIG  For Bi, it is mono isotope and will be provided from the high current ion source GSI Helmholtzzentrum für Schwerionenforschung GmbH

Current known technical limitation  SIS18  Long extraction pulse vs. high ramp rate of 10T/s not simultaneously  Slow extraction beam quality  electrostatic septum is too weak for 100% extracting highest momentum beam  feedback for macro-spill structure not yet operational  ideas for smoothing micro-spill structure investigated, not yet available for routine operation, especially at high energies  air-core quad feedback  spill cavity  its user operation is not-yet compatible with ESR operation  expect to be addressed by Engineering run in 2019 GSI Helmholtzzentrum für Schwerionenforschung GmbH

Current known technical limitation  Limited function and scope of LSA/FESA based FAIR controls  not-yet reliable parallel operation mode  Storage ring re-commissioning  At the moment, only the synchrotron mode of operating ESR is available from the FAIR controls.  The storage ring mode operation that is required for restoring all ESR capability, i.e. beam accumulation, fine control/tuning for deceleration etc, is scheduled to be commissioned in the engineering run of 2019  complete commissioning of CYRING with beam from ESR is scheduled in the engineering run of 2019  Vacuum level in the CRYRING is not yet ideal for long storage of highly charged heavy ions. GSI Helmholtzzentrum für Schwerionenforschung GmbH

The Art of Deceleration  Deceleration requires many careful machine tuning and beam manipulation  Be able to have controls to allow stand-alone tuning of the machine settings is highly critical Cycle for deceleration of beam from SIS18 U92+ from 300 MeV/u to 15 MeV/u with intermediate cooling at 30 MeV/u. intermediate preparation for cooling deceleration final acceleration M. Steck, et al, Proceedings of EPAC 2000, Vienna, Austria GSI Helmholtzzentrum für Schwerionenforschung GmbH

Discussion  FAIR Phase 0 requirements  forseen 2 order of magnitude higher intensity w.r.t advertised in 2017  1 st priority is to reproduce the performance back in the good old days!  FAIR requirements  Ion source: 2.7Hz Uranium  pLINAC 35mA. Design for current 70mA  SIS18: 1.5x10 11 Uranium28+ per cycle, 2 bunches per cycle  Machine Development reached 4e10 uranium28+ 1Hz in 8 hours (2007) UNILAC 4.5mA at SIS18 injection (LG)  need to reproduce asap  UNILAC eached 2 times higher of 4.5mA U28+ at 1.4MeV/u (WB)  SIS100: 5x10 11 Uranium28+ per cycle  Action item for all MKs  provide the achieved performance, ion species and corresponding parameters (intensity, brightness etc): routine operation as well as best performance GSI Helmholtzzentrum für Schwerionenforschung GmbH