Vienna, 17 September 2008

1. CRYRING as LSR at FLAIR Håkan Danared Manne Siegbahn Laboratory Vienna, 17 September 2008

2. FLAIR Facility for Low-energy Antiproton and Ion Research A “next-generation” facility for low-energy antiprotons with ∼1×107 pbar/s, decelerated and phase-space cooled down to 20 keV in three successive deceleration rings Planning for FLAIR started in2003, after the original designof FAIR as described in the CDRof 2003 was made Letter of Intent submitted to GSIin early 2004 Technical Proposal submitted inits first version in early 2005 PAC evaluation of all proposed FAIRexperiments, including FLAIR, inspring 2005* Approved by STI as part of Core Experi-mental Facility in summer 2005 Definition of FAIR Phase A includes FLAIRin autumn 2007 Next step: establishing FAIR GmbH and signing ofConvention by member states *) “FLAIR will be the world's unique facility combining low energy antiprotons and exotic ions. It will provide forefront research opportunities on challenging physics in the 2010's. The committee evaluates its extraordinary significance and recommends it to become an integral part of the FAIR facilities.”

3. Antiproton Production at FAIR SIS 100 4×1013 p @ 29 GeV, 0.1 Hz SIS 18 5×1012 p @ 2 GeV, 5 Hz Proton Linac 5×1012 p @ 70 MeV, 5 Hz pbar Target 2×108 pbar @ 3 GeV, 0.1 Hz USR, HITRAP See Welsch, Quint CR/RESR 7×1010 pbar/h @ 3 GeV LSR ∼1×108 pbar @ 300 keV, ∼0,05 Hz NESR ∼1×108 pbar @ 30 MeV, ∼0,05 Hz Data on pbar production according to FAIR BTR

4. FLAIR Experiments F1 HCI, Eion < 130 MeV/u from NESR and LSRInteraction of low-energy HCI with composite and solid targetsA. Bräuning-Demian, GSI Darmstadt F2 HCI, E = 4 MeV/u; pbar, E = 4 MeV from NESR and LSRHITRAPW. Quint, GSI Darmstadt F3 HCI, E < 15 MeV/u; pbar, E = 30 MeV from NESRLow-energy Storage Ring (LSR)H. Danared, MSL, Stockholm F4 pbar, E < 300 keV from LSRUltra-low energy Storage Ring (USR)Carsten Welsch, Manfred Grieser, MPI, Heidelberg F5 pbar, E < 20 keV from USRAntihydrogen experimentJ. Walz, MPQ Garching F6 pbar, E < 20 keV to rest from USR and HITRAPAntihydrogen experimentE. Widmann, SMI, Vienna F7 pbar, 300 keV < E < 30 MeV from LSRNuclear and particle physics with antiprotonsD. Grzonka, FZ Jülich F8 pbar, 30 MeV < E < 300 MeV from NESRAntiproton interaction with biological probesM. Holzscheiter, Pbar Labs, USA F9 pbar, E < 20 keV from USR / HITRAP and RIBs from SFRSCusp trap for anti-H production, pbar atom formation, pbar radioactive nucleiM. Wada, Y. Yamazaki, Tokyo University F10 HCI and pbar in the keV energy range from HITRAPHeavy-ion experiments, ion surface interaction, collision dynamics, pbar atom X-ray spectroscopyW. Quint, GSI Darmstadt F5 F6 F9 F2 F10 F1 F4 F7 F8 F3

5. CRYRING CRYRING is a small synchrotron and storage ring with electron cooling, built for research in atomic, molecular and nuclear physics Design and construction of the storage ring started in 1986 The first stored beam was in January 1991 Start of experimental programme in June 1993 . . The Swedish Research Council decides to stop funding operation in June 2003 . . MSL will get a contract with the Research Council in autumn of 2008 for the transfer of CRYRING to FAIR as a Swedish in-kind contribution Circumference: 51.63 m Superperiodicity: 6 Maximum rigidity: 1.44 Tm Injection energy: 300 keV/u using RFQ Maximum energy: 96 (q/A)2 MeV/u Acceptance hor.: 200  mm mrad Acceptance vert.: 100  mm mrad Acceptance long.: 1.5 % Horizontal tune: 2.44 Vertical tune: 2.42 Horizontal chromaticity: -1.3 Vertical chromaticity: -3.2 Transition gamma: 2.23

6. CRYRING ⇨LSR CRYRING is very well suited to its new role as antiproton (and ion) decelerator. It has the right energy interval, fast ramping, efficient electron cooling, good vacuum, it has been running with both positive and negative ions, both for acceleration and deceleration, ... Injection of antiprotons from NESR to LSR will be made at a fixed energy 30 MeV, and ions will be injected at the same magnetic rigidity. Extraction of antiprotons will take place at 300 keV, equal to the injection energy of the USR. Also extraction at other energies e.g, 4.2 MeV for HITRPAP, will be possible. Both fast (single-turn) and slow (resonant, multiturn) extraction will be implemented. The main modifications to CRYRING are thus new injection and extraction systems. CRYRING has a low-energy injector for singly charged ions, such as p and H–, which also will be transferred to FLAIR for commissioning of LSR, beamlines, etc. in the FLAIR hall without use of expensive antiprotons. Installation of an ECR source for commissioning and tests with highly charged ions is being considered.

7. Ions Stored in CRYRING and in most cases used for physics experiments Singly charged positive atomic ions: H+, D+, 3He+, 4He+, 7Li+, 9Be+,11B+,12C+, 14N+, 16O+, 40Ar+, 40Ca+, 45Sc+, 48Ti+, 56Fe+, 83Kr+, 84Kr+, 86Kr+, 88Sr+, 129Xe+, 131Xe+, 132Xe+, 138Ba+, 139La+, 142Nd+, 151Eu+, 197Au+, 208Pb+Multiply charged positive atomic ions:4He2+, 11B2+, 12C2+, 12C3+, 12C4+, 12C6+, 14N2+, 14N3+, 14N4+, 14N7+, 16O2+, 16O3+, 16O4+, 16O5+, 16O8+,19F6+, 19F9+, 20Ne2+, 20Ne5+, 20Ne6+, 20Ne7+, 20Ne10+, 28Si3+, 28Si11+, 28Si14+, 32S5+, 36Ar9+, 36Ar10+, 36Ar12+, 36Ar13+, 40Ar9+, 40Ar11+, 40Ar13+, 40Ar15+, 48Ti11+, 58Ni17+, 58Ni18+, 84Kr33+, 126Xe36+, 129Xe36+, 129Xe37+, 136Xe39+, 136Xe44+, 207Pb53+, 208Pb53+, 208Pb54+, 208Pb55+Singly charged postive molecular ions:H2+, HD+, H3+, D2+, H2D+, 3HeH+, 3HeD+, 4HeH+, D3+, He2+, LiH2+, D5+, BH2+, CH2+, NH2+, OH+, CH5+, NH4+, H2O+, H3O+, HF+, ND3H+, CD5+, ND4+, D3O+, C2H+, CN+, C2H2+, HCN+, C2H3+, HCNH+, C2H4+, CO+, N2+, 13CO+, N2H+, C2H5+, NO+, D13CO+, CH3O+, CF+, O2+, CH3NH3+, CH3OH+, CH3OH2+, H2S+, CD3O+, PD2+, N2H7+, D232S+, CD3OH2+, CD3OD+, H5O2+, D234S+, D332S+, CD3OD2+, 13CD3OD2+, D334S+, C3H4+, D5O2+, CH3CNH+, C3D3+, N2D7+, N3+, DCOOD2+, C3H7+, NaD2O+, CO2+, HCS+,C2H5O+, DN2O+, C2H5OH+, CO2D+, CD3CDO+, NO+·H2O, O3+, CD3OCD2+, C3D7+, CF2+, NO+·D2O, DC3N+, CD3OCD3+, N3H10+, DC3ND+, CD3ODCD3+, H7O3+, COS+, N2O2+, CH3OCOH2+, D7O3+, N3D10+, C4D9+, S18O2+, ArN2+, H9O4+, CD3COHNHCH3+, CD3CONHDCH3+, C6D6+, PO37Cl+, H11O5+, C2S2H6+, C2S2H7+, H13O6+, PO35Cl2+Multiply charged positive molecular ions:N22+Negative atomic ions:H–, Li–, F–, SI–, S–, Cl–, Se–, Te–Negative molecular ions:CN–, C4–, Si2–, Cl2–Range of energies per nucleon: 38 eV/u – 92 MeV/uRange of total energies: 5 keV – 1.4 GeV

8. Intensity Limit in LSR/CRYRING Intensity in CRYRING is limited by space-charge, causing a tune shift . Assuming a certain permissible tune shift, the maximum intensity for (anti)protons can be plotted as a function of beam energy and emittance. In the case of a bunched beam, the maximum particle number is reduced by the bunching factor. Maximum number of protons stored in CRYRING at 300 keV is 4.7×109, at a beam emittance of approx. 15π mm mrad horisontally and 5π mm mrad vertically, indicating a tune shift of approx. -0.1. A similar maximum particle number of 4.1×109 has been obtained with alpha particles, which have the same r0. These intensities were obtained by stacking, using continuous injections while electron-cooling. The highest-intensity beams were quite unstable. Maximum intensity at deceleration is smaller due to higher demands on stability and because of bunching – see following slides. Ref: H. Danared et al., Proc COOL07, Bad Kreuznach 2007, p. 234, http://www.jacow.org

9. Electron Cooling of H− Ions Electron cooling is in the first approximation based on the Coulomb interaction between ions and electrons, and cooling rates should thus be sensitive only to the ion charge squared. However, the magnetic field in the cooler can make cooling rates depend on the sign of the ion charge. Such effects were seen in measurements in Novosibirsk where a stronger drag force was observed for negative particles. Transverse cooling of H− ions at 3 MeV (similar to expected cooling energy at FLAIR), initial emittance 5π mm mrad, which is more than expected at FLAIR. The beam reaches a cold equilibrium in ∼1.5 s. The figure shows the vertical beam profiles, as measured with a residual-gas-ionization beam-profile monitor. Cooling time for H− compared to previous measure-ments at CRYRING with positive ions. Electron density normalized to 1.7×1013 m−3. Cooling times for highly charged ions are scaled with q1.7/A. The points are shifted horizontally so that the time for reaching the cold equilibrium is similar for all ion species. Conclusion 1: We do not observe a significant difference between cooling of positive and negative particles. Conclusion 2: Cooling times are sufficiently short such that throughput of antiprotons at FLAIR will not be limited by cooling in the LSR.

10. Deceleration of Protons To verify the performance of CRYRING as a deceleration ring, protons have been decelerated through the same range of energies as at FLAIR, from 30 MeV to 300 keV.Injection of protons in CRYRING is always at 300 keV, so deceleration is made after acceleration to 30 MeV. Transmission 1 Start acceleration 93 %Cooling, acceleration ramp 100 %Start deceleration 99 %Deceleration ramp 92 % Complete cycle 0.95×0.97×0.84=85 %Deceleration only 0.99×0.92=91 % Transmission 2 Start acceleration 95 %Cooling, acceleration ramp 100 %Start deceleration 97 %Deceleration ramp 84 % Complete cycle 0.95×0.97×0.84=77 %Deceleration only 0.97×0.84=81 % Conclusion: CRYRING is already able to decelerate>1×108 (anti)protons with <10 % losses in <2 s, exceeding the intensity forseen from NESR and the commissioning target set by FAIR.

11. Simulations of Slow Extraction

12. Simulations of Slow Extraction

13. Current Status and Plans Nov 07 FAIR start event, Sweden decides to contribute 10 M€ to the construction of FAIR, including 2 M€ for CRYRING in-kind Mar 08 FLAIR decides to accept CRYRING as the LSR Jun 08 Swedish Research Council promises 30 MSEK to MSL for the transfer of the ring to FAIR Sept 08 Start of detailed design of new injection and extraction 2009-10 Modifications made to CRYRING and commissioned at MSL Dec 10 CRYRING disassembled and put in boxes for storage 2014? Reassembly in the FLAIR hall