Author: Spiller, P.J.
Paper Title Page
MOPS054 Impedance of the Pulse Power Converter for the SIS100 Bipolar Extraction Kicker System 727
 
  • K. Samuelsson, V. Hinrichsen
    TU Darmstadt, Darmstadt, Germany
  • U. Blell, P.J. Spiller
    GSI, Darmstadt, Germany
  
  SIS100 will be op­er­at­ed with high in­ten­si­ty heavy-ion and pro­ton beams. The re­duc­tion of ring impedances is there­fore of great im­por­tance in order to avoid co­her­ent beam in­sta­bil­i­ties. The kick­er sys­tem is one of the main con­trib­u­tors to the over­all ring impedance in SIS100. This paper will focus on the con­tri­bu­tion of the ex­ter­nal net­work to the kick­er impedance. Cal­cu­la­tions as well as ex­per­i­men­tal impedance mea­sure­ments of the net­work con­tri­bu­tion have al­ready been car­ried out for the SIS18 and ESR kick­ers. The SIS100 will be equipped with a bipo­lar kick­er sys­tem, which uses a Pulse Form­ing Net­work (PFN) as en­er­gy stor­age. For po­ten­tial de­tach­ment pur­pos­es an in­su­la­tion trans­former will be in­stalled. Since this setup is new in sev­er­al ways it is im­por­tant to know its con­tri­bu­tion to the cou­pling impedance of the kick­er sys­tem. In this con­tri­bu­tion the cor­re­spond­ing nu­mer­i­cal cal­cu­la­tion is pre­sent­ed.  
 
TUPS007 Construction and Test of a Cryocatcher Prototype for SIS100* 1527
 
  • L.H.J. Bozyk, D.H.H. Hoffmann
    TU Darmstadt, Darmstadt, Germany
  • H. Kollmus, P.J. Spiller, M. Wengenroth
    GSI, Darmstadt, Germany
  
  Funding: EU-FP-7 project COLMAT, FIAS
The main ac­cel­er­a­tor, SIS100, of the FAIR-fa­cil­i­ty will pro­vide heavy ion beams of high­est in­ten­si­ties. Ion­iza­tion beam loss is the most im­por­tant loss mech­a­nism at op­er­a­tion with high in­ten­si­ty, in­ter­me­di­ate charge state heavy ions. A spe­cial syn­chrotron de­sign has been de­vel­oped for SIS100, aim­ing for hun­dred per­cent con­trol of ion­iza­tion beam loss by means of a ded­i­cat­ed cold ion catch­er sys­tem. To sup­press dy­nam­ic vac­u­um ef­fects, the cryo catch­er sys­tem shall also pro­vide a sig­nif­i­cant­ly re­duced ef­fec­tive des­orp­tion yield. The con­struc­tion and tests of a pro­to­type cryo ion catch­er is a work­pack­age of the EU-FP-7 pro­ject COL­MAT. A pro­to­type test setup in­clud­ing cryo­stat has been con­struct­ed, man­u­fac­tured and test­ed at GSI under re­al­is­tic con­di­tions with heavy ion beams of the of the heavy ion syn­chrotron SIS18. The de­sign and re­sults are pre­sent­ed. 		 
 
TUPS032 Overview of EuCARD Accelerator and Material Research at GSI 1602
 
  • J. Stadlmann, H. Kollmus, E. Mustafin, N. Pyka, P.J. Spiller, I. Strašík, N.A. Tahir, M. Tomut, C. Trautmann
    GSI, Darmstadt, Germany
  • L.H.J. Bozyk
    TU Darmstadt, Darmstadt, Germany
  
  Funding: EuCARD is co-funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 227579
Eu­CARD is a joined ac­cel­er­a­tor R&D ini­tia­tive fund­ed by the EU. With­in this pro­gram, GSI Darm­stadt is per­form­ing R&D on ma­te­ri­als for ac­cel­er­a­tors and col­li­ma­tors in WP8(Col­Mat). GSI cov­ers pro­to­typ­ing and test­ing of a cryo­genic ion catch­er for FAIR's main syn­chrotron SIS100, sim­u­la­tions and stud­ies on ac­ti­va­tion of ac­cel­er­a­tor com­po­nents e.g. halo col­li­ma­tiors as well as ir­ra­di­a­tion ex­per­i­ments on ma­te­ri­als fore­seen to be used in FAIR ac­cel­er­a­tors and the LHC up­grade pro­gram. Car­bon-car­bon com­pos­ites, sil­i­con car­bide and cop­per-di­a­mond com­pos­ite sam­ples have been ir­ra­di­at­ed with heavy ions at var­i­ous GSI beam­lines and their ra­di­a­tion in­duced prop­er­ty changes were char­ac­ter­ized. Nu­mer­i­cal sim­u­la­tions on the pos­si­ble dam­age by LHC and SPS beams to dif­fer­ent tar­gets have been per­formed. Sim­u­la­tions and mod­elling of ac­ti­va­tion and long term ra­di­a­tion in­duced dam­age to ac­cel­er­a­tor com­po­nents have start­ed. A pro­to­type ion catch­er has been built and first ex­per­i­ments have been per­formed in 2011. New col­lab­o­ra­tions with other in­sti­tutes and in­dus­try in the Eu­CARD frame­work have been es­tab­lished and find­ings of the joined R&D ef­fort in­flu­ence de­ci­sions in the FAIR pro­ject and LHC up­grade. 		 
 
WEPC059 Optimization of the Sextupole Scheme and Compensation of the Time-Dependent Field Errors during Slow Extraction from the Superconducting Synchrotron SIS300 2151
 
  • A. Saa Hernandez, P.J. Spiller
    GSI, Darmstadt, Germany
  • U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  The SIS300 syn­chrotron, planned for the new Fa­cil­i­ty for An­tipro­ton and Ion Re­search (FAIR) at GSI-Darm­stadt, will be­come the first su­per­con­duct­ing syn­chrotron world­wide using cos(θ) mag­nets for res­o­nant slow ex­trac­tion. A mul­ti-ob­jec­tive op­ti­miza­tion al­go­rithm has been de­vel­oped for the de­sign of the non-lin­ear mag­net scheme. The op­ti­miza­tion al­go­rithm makes use of the an­a­lyt­i­cal model for the slow ex­trac­tion from Kobayashi, the an­a­lyt­i­cal de­scrip­tion of the res­o­nance ex­ci­ta­tion and am­pli­tude-de­pen­dent tune-shift from Bengts­son, and cor­rects the chro­matic­i­ty in order to ful­fill the Hardt con­di­tion. As a re­sult, the place­ment of the chro­mat­ic and har­mon­ic sex­tupole mag­nets in SIS300, the num­ber of sex­tupole fam­i­lies and the gra­di­ents of these fam­i­lies have been op­ti­mized for a high ef­fi­cien­cy slow ex­trac­tion. The al­go­rithm ac­counts also for the sex­tupole er­rors on the dipole mag­nets, com­pen­sat­ing its ef­fects. Fur­ther­more, op­ti­mized time-de­pen­dent set­tings for the sex­tupole mag­nets are gen­er­at­ed to com­pen­sate the per­sis­tent cur­rent decay oc­cur­ring at slow ex­trac­tion. Tol­er­ances for the mag­nets are set for the lim­its where the com­pen­sa­tion is no longer valid.  
 
WEPC091 Studies with a Particle Tracking Code for the SIS100 Resonant Extraction System 2220
 
  • M.M. Kirk, G. Franchetti, H. Klingbeil, P. Moritz, N. Pyka, H. Ramakers, P.J. Spiller, H. Welker
    GSI, Darmstadt, Germany
  
  Sev­er­al is­sues con­cern­ing the en­vis­aged SIS100 res­o­nant ex­trac­tion at GSI can be re­solved with a sim­u­la­tion-lead ap­proach for which a par­ti­cle track­ing code was de­vel­oped. Ap­pli­ca­tions to date have in­clud­ed: de­sign and test­ing of data sup­ply al­go­rithms for the ac­cel­er­a­tor con­trol sys­tem; re­quire­ments anal­y­sis for the power con­vert­er rip­ple in the quadrupoles form­ing the dou­blet fo­cus­ing; and ver­i­fi­ca­tion of the RF Knock-Out ex­citer's per­for­mance.  
 
WEPS003 SIS18 – Intensity Record with Intermediate Charge State Heavy Ions 2484
 
  • P.J. Spiller
    GSI, Darmstadt, Germany
  • L.H.J. Bozyk
    FIAS, Frankfurt am Main, Germany
  • P. Puppel
    HIC for FAIR, Frankfurt am Main, Germany
  
  Funding: Project partly funded by the European Community DIRAC-PHASE-1 / Contract number: 515876
In order to reach the de­sired in­ten­si­ties of heavy ion beams for the ex­per­i­ments at FAIR, SIS18 and SIS100 have to be op­er­at­ed with in­ter­me­di­ate charge states. Op­er­a­tion with in­ter­me­di­ate charge state heavy ions at the in­ten­si­ty level of about 1011 ions per cycle has never been demon­strat­ed else­where and re­quires a ded­i­cat­ed up­grade pro­gram for SIS18 and a ded­i­cat­ed ma­chine de­sign for SIS100. The spe­cif­ic prob­lems com­ing along with the in­ter­me­di­ate charge state op­er­a­tion in terms of charge ex­change pro­cess­es at col­li­sions with resid­u­al gas atoms, pres­sure bumps by ion in­duced des­orp­tion and cor­re­spond­ing beam loss ap­pears far below the typ­i­cal space charge lim­its. Thus, new de­sign con­cepts and new tech­ni­cal equip­ment ad­dress­ing these is­sues are de­vel­oped and re­al­ized with high­est pri­or­i­ty. The up­grade pro­gram of SIS18 ad­dress­ing the goal of min­i­mum ion­iza­tion beam loss and sta­ble resid­u­al gas pres­sure con­di­tions has been de­fined in 2005. A major part of this up­grade pro­gram has been suc­cess­ful­ly re­al­ized, with the re­sult of a world record in ac­cel­er­at­ed num­ber of in­ter­me­di­ate charge state heavy ions. 		 
 
WEPS094 Dynamic Vacuum Stability in SIS100 2724
 
  • P. Puppel, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • P.J. Spiller
    GSI, Darmstadt, Germany
  
  SIS100 is the main syn­chrotron of the FAIR pro­ject. It is de­signed to ac­cel­er­ate high in­ten­si­ty in­ter­me­di­ate charge state ura­ni­um beams from 200 MeV/u up to 2.7 GeV/u. In­ter­me­di­ate charge state heavy ions are ex­posed to a high prob­a­bil­i­ty of charge ex­change due to col­li­sions with resid­u­al gas molecules. Since the charge ex­change pro­cess changes the mag­net­ic rigid­i­ty, the in­volved ions are lost be­hind dis­per­sive el­e­ments, and an en­er­gy-de­pen­dent gas des­orp­tion takes place. The StrahlSim code has been used to pre­dict the sta­bil­i­ty of the resid­u­al gas pres­sure in SIS100 under beam loss driv­en dy­nam­ic con­di­tions. The re­sults show, that a sta­ble op­er­a­tion at high­est U28+ in­ten­si­ties is pos­si­ble, under the con­straint that the vac­u­um cham­bers of the ion catch­er sys­tem are cold enough to pump hy­dro­gen. Fur­ther­more, in order to de­ter­mine the load to the cryo­genic sys­tem, the av­er­age beam en­er­gy de­po­si­tion onto the ion catch­er sys­tem has been cal­cu­lat­ed.