1. The Antiproton-Ion Collider EC, 500 KV NESR R. Krücken Technische Universität München for the Antiproton Ion Collider Collaboration

2. Neutron-skin thickness in Sn isotopes (1&2) RHB/NL3 (3) RHB/NLSH (4) HFB/SLy4 (5) HFB/SkP (p,p) (3 He,t) antiprotons M. Bender, P.H. Heenen, P.G. Reinhard Rev. Mod. Phys. 75 (2003) 122 AIC range normalized to NLSH

3. Why another method to measure radii? charge radii can reliably be measured (e.g. (e,e)) several methods are available for matter / neutron radii (p,p), ( ,  ’), ( 3 He,t), reaction cross section, antiprotonic atoms - BUT: (p,p) results based on little known p interaction in medium ( ,  ’), ( 3 He,t) results model dependent and normalized to theory antiprotonic atoms probe density at large distances We need a method that determines proton and neutron radii using the same method in the same experiment independently at the same time with low statistical and systematic errors solution: antiproton-ion collisions at high energies measures r n /r p and (r n -r p )/r n+p measurement across long isotopic chains (e.g. 104 Sn – 134 Sn) provides sensitive test of isospin dependence of effective interaction in combination with elastic electron scattering data absolute radii are measured

4. Theoretical cross-sections H. Lenske, P. Kienle, nucl-th/0502065 AIC range antiproton-absorption cross section at high energy is proportional to of the nucleus normalization at 58 Ni

5. Deceleration of antiprotons Option 1: deceleration in NESR polarity switching for NESR needed sensitive collider optics (beam diameters <80  m) needs to be achieved after each deceleration cycle (once every 1-2 days) allows NO use of NESR for RIBs parallel to HESR/FLAIR operation General needs for AIC: 70 kV electron cooler in ER UHV layout of ER for 10 -10 mbar (pbar beam lifetime of few days) transfer line to pbar-ring/ER polarity switching of CR and RESR within ~ 5 minutes (no particular problem) ER LSR

6. Deceleration of antiprotons Option 2: deceleration in RESR 70 kV electron cooler needed in RESR 30MeV extraction cavity in RESR sensitive collider optics (beam diameters <80  m) can be optimized and stays unchanged keep functions of rings separated as much as possible for efficient use of rings (NESR could be used for RIBs during FLAIR operation) Both options are being considered by accelerator group!! General needs for AIC: 70 kV electron cooler in ER UHV layout of ER for 10 -10 mbar (pbar beam lifetime of few days) transfer line to pbar-ring/ER polarity switching of CR and RESR within ~ 5 minutes (no particular problem) ER LSR

7. Detection of A-1 recoils 40 Ca 40 Ca  39 K 40 Ca  39 Ca 72 Ni  71 Co 72 Ni  71 Ni 132 Sn 132 Sn  131 In 132 Sn  131 Sn 72 Ni A~130: A & both A-1 nuclei in the acceptance  Schottky method using one ring setting  recoil detection A~70: A & and one A-1 nucleus in the acceptance  Schottky method using two ring settings  recoil detection A<60: A-1 nucleus not in the acceptance  recoil detection zz

8. Measurement of precise ratios Total absorption cross-section from reduction of primary ions with mass A cross-section for production of A-1 nuclei: ratio of mean square radii (no systematic errors!!) normalized differences of radii example: 68 Ni: SFRS yield: 3  10 8 s -1 N p = 10 6 in < 4h These precise results can be directly compared to theoretical predictions!

9. absolute difference of radii (r n – r p ) Total absorption cross-section from reduction of primary ions with mass A cross-section for production of A-1 nuclei: Measure cross-section of reference isotopes with accurately known charge radius Measure Luminosity relative to reference measurement 1 Obtain r p from elastic electron scattering (ELISe) 2

10. Summary AIC allows measurement of rms proton and neutron radii independently in the same experiment using the same method (reliable way to determine neutron skins) radii along isotopic chains are sensitive to isospin dependence of effective nucleon-nucleon interaction other topics to be investigated: –neutron skins and the transition from halos to skins –shape transitions and shape coexistence –ispspin dependence of the antiproton-nucleon interaction additional information from AIC –measurement of the momentum distribution of annihilated nucleon –energy dependence of the annihilation cross-section may provide information on density distributions (under investigation) AIC is complementary to electron scattering Deceleration of antiprotons in RESR allows for parallel use of NESR for RIBs during HESR/FLAIR operation

11. Antiproton-Ion Collider Collaboration Spokesperson / Deputy:R. Krücken C / J. Zmeskal A Project Manager / Deputy:P. Kienle C / L. Fabbietti C Beller, Peter A Bosch, Fritz A Cargnelli, Michael B Fabbietti, Laura C Faestermann, Thomas C Frankze, Bernhard A Fuhrmann, Hermann B Hayano, Ryugo S. D Hirtl, Albert B Homolka, Josef C Kienle, Paul B,C Kozhuharov, Christophor A Krücken, Reiner C Lenske, Horst E Litvinov, Yuri A Marton, Johann B Nolden, Fritz A Ring, Peter C Shatunov, Yuri F Skrinsky, Alexander N. F Suzuki Ken, C Vostrikov, Vladimir A. F Yamaguchi, Takayuki G Widmann, Eberhard B Wycech, Slawomir H Zmeskal, Johann B Institute A,Gesellschaft für Schwerionenforschung, Darmstadt, Germany (GSI) Institute B,Stephan Meyer Institut, Vienna, Austria (SMI) Institute C,Technische Universität München, Munich, Germany (TUM) Institute D,University of Tokyo, Tokyo, Japan (UoT) Institute E,Justus-Liebig Universität Giessen., Giessen, Germany (JLU) Institute F,Budker Institute of Nuclear Physics, Novosibirsk, Russia (BINP) Institute G University of Saytama, Saytama, Japan.(UoS) Institute H,Andrzej Soltan Institute for Nuclear Studies, Warsaw, Poland (IPJ)

13. Limits due to T 1/2 >1s and production yield (>10 4 ) T 1/2 =1s Example: Z = 28-50

14. Examples IonT 1/2 yield Lumin.  total N p meas. Countsd(r n /r p )/(r n /r p ) [s] [pps] [cm -2 s -1 ][barn][s -1 ]time 55 Ni0.5 8·10 7 4·10 24 1.20.72~40 h 10 5 0.004 72 Ni4.1 9·10 6 4·10 24 1.30.55~60 h 10 5 0.004 104 Sn51 1·10 6 5·10 24 1.82.22~15 h 10 5 0.004 132 Sn931·10 8 9·10 26 2.1374~ 1 h 10 6 0.001 134 Sn2.7 8·10 5 2·10 23 2.10.09~72 h 2  10 5 0.009 required beam time for 104-134 Sn: (even-even only, min. 1 shift per isotope): 1-2 weeks

15. AIC cost estimates 70 kV electron coolers for ER1.5 M€ transfer line to ER0.5 M€ polarity switching for CR and RESR0.6 M€ UHV modification of ER0.3 M€ heavy ion detectors0.5 M€ (common with ELISe) Luminosity detectors0.1 M€ 2.9 M€ 70 kV electron coolers RESR1.5 M€ Extraction cavity for RESR1.0 M€ Total:2.5 M€ NESR polarity switching0.3 M€ LSR 30 MeV extraction0.3 M€ Total:0.6 M€ additional costs for pbar deceleration options deceleration in RESR deceleration in NESR general AIC equipment 5.4 M€ 3.5 M€

16. Optics of NESR and anitproton storage ring IP Antiproton Storage ring NESR 10 9 antiprotons transverse emittance: < 0.02  mm mrad @IP:  x =  y < 80  m 10 6 radioactive ions transverse emittance: 0.2   m mrad @IP:  x = 10  m  x = 70  m

17. Luminosity measurement using elastically scattered antiprotons  lab [degrees] 0 1 2 3 4 5 6 Diff. Cross-section [b/sr] 10 6 10 4 10 2 detector

18. Theoretical cross-sections Calculations by H.Lenske 200 MeV 400 MeV 300 MeV 0 20 40 60 80 100 120 05101520 sigABS(b) [mb] Impact Parameter b [fm] Antiproton-Nucleus Partial Absorption Cross Section 78Ni 50 MeV 100 MeV At lower energies one is more sensitive to the periphery of the density distribution (  energy scan) AIC range

19. Simulations of the reaction kinematics About 30% of produced A-1 nuclei survive 132 Sn Acceptance limit of NESR  A A-1 Measured momentum distribution is consistent with quasi-free scattering F. Balestra et al., NPA491, 541 (1989) LEAR data on Ne Measured momentum distribution gives insight into angular momenta of annihilated nucleons

20. Theoretical calculations – example 58 Ni Lenske, Wycech  A A-1 impact parameter b [fm] z=4fm z=-4fm P miss (z): probability that pions miss the residual A-1 nucleus P dh : probability that residual nucleus is cold (E * < S n,p ) About 30% of produced A-1 nuclei survive Nuclear density

21. AIC physics program benchmarking: radii for the Sn isotopic chain stable isotopes, measured with different techniques plan: extending from 104 Sn to 134 Sn radii along other closed-shell isotopic and isotonic chains behavior of radii across a shape transition e.g. from 80 Zr to 104 Zr Odd-even effects in nuclear radii study the antiproton-neutron interaction radii in light nuclei ( 22 O, 23,24 F) (transition from halos to skins)

22. Schottky method for identification and counting of A-1 nuclei von P. Kienle

23. Recoil Detection after NESR dipole section Existing ESR detector (TUM) 5 m 0.5 m +7% -6% Staged set of recoil detectors covers large momentum range

24. Floor plan

25. Luminosity

26. Compare to (p,p) 10 2 10 1 10 0 10 25 cm -2 s -1 10 28 cm -2 s -1 134 Sn: 2 per hour 50 hour experiment AIC: 10 5 annihilations in 60 hours   (  r np ) = 0,025 fm 132 Sn 134 Sn

27. Compare to (e,e) 10 25 cm -2 s -1 10 28 cm -2 s -1 132 Sn 134 Sn 10 2 10 1 10 0 10 -1 10 -2 10 -3 134 Sn: 1 per week 5% 0.15 fm

28.  r np from antiprotonic atoms

29. Compare with EXO-pbar From EXO-pbar TP EXO-pbar concentrates on tail of wave-function in short-lived near dripline nuclei  halo nuclei AIC concentrates on systematic trends in p and n rms-radii  skins, asymmetry energy, odd even effects Both methods are complementary

30. Optical potential 1/2 T-matrix: Scattering amplitude from optical theorem: With Gaussian Form-factor and Very small real part of potential

31. Optical potential 2/2 Lenske: DWBA+RMF densities

32. Cross-section

33. Count-rate estimate for Luminosity detector Only elastic scattering Distance of closest approach: D > R nucleus + R pbar + 2fm  Luminosity detector at  lab > 1º Count-rate estimate: For 132 Sn at 3º : 100 s -1 cm -2

34. Identification of antiprotons and pions

35. Antiproton Ion Collider (pbarA) Antiprotons collected in CR and RESR slowed to 30 MeV and cooled transferred to ER beam lifetime of few days with 10 -10 mbar in ER radioactive ions produced and separated in Super-FRS collected in CR and RESR continuous feeding into NESR all luminosity estimates based on coasting mode for both particles (detailed design study performed by Novosibirsk group) ER