1. Bertram Blank CEN Bordeaux-Gradignan IVICFA 's Fridays: EXPERIMENTAL PHYSICS, October 3, 2014 Discovery of radioactive decays One-proton radioactivity Two-proton radioactivity Future studies

2. … off the valley of stability stable nuclei

3. … off the valley of stability stable nuclei  unstable nuclei

4. … off the valley of stability stable nuclei  unstable nuclei particle-unstable nuclei

5. Henry BecquerelPierre & Marie CurieErnest RutherfordOtto Hahn  decay  decay Fission Discovery of radioactivity

6. Prdicted by Goldansky in the 60’s Discovered in 1981 Exotic radioactivities Goldansky 1960 : Y.B. Zel’dovich and V. Goldansky predict exotic decay modes for nuclei at the proton drip-line : 1p radioactivity for odd Z nuclei 2p radioactivity for even Z nuclei Discovered in 2002

7. One-proton radioactivity

8. Proton-rich nuclei: One-proton radioactivity One-proton- emitter for odd Z from Z = 53 - 83

9. FMA in Argonne Fusion-evaporation reactions (e.g. 78 Kr + 92 Mo) Separation and selection of nuclei with Argonne FMA Correlation of implantation and decay in DSSD One-proton radioactivity T 1/2, E p

10. physics to be learnt  Test of nuclear mass models Nuclear structure beyond particle stability - Sequence of single-particle levels and their energy - “j content” of nuclear wave function - Forme of nuclear potential quantum tunneling through 3D barrier model calculations to determine single- particle level sequence 29 proton emitters experimentally observed and studied One-proton radioactivity

11. Two-proton radioactivity

12. two 2p emission types: - ground state emission long-lived: 45 Fe, 48 Ni, 54 Zn short-lived: 6 Be, 12 O, 16 Ne, 19 Mg - emission from excited states β-delayed: 22 Al, 31 Ar, … others: 14 O, 18 Ne, 17 Ne to be measured: proton energies proton-proton angle sequential emission: three-body decay: 2 He emission: Two-proton radioactivity

13. Emission of one proton not possible « 2 He» emission: common tunneling separation after barrier Two-proton radioactivity X

14. parameters: Q value tunnel probability  -decay half-life best candidats: 45 Fe, 48 Ni, 54 Zn possible candidats: 42 Cr, 49 Ni Two-proton radioactivity candidates

15. Two-proton emission for even-Z nuclei Proton-rich nuclei

16. GSI GANIL Experimental facilities  projectile fragmentation NSCL

17. Two-proton radioactivity of 45 Fe at GANIL and GSI

18. Primary beam: 58 Ni @ 75 MeV/A intensity  Ae SISSI target: nat Ni 200  g  cm  spectrometer LISE3 : degrader Be (50  m) Wien filter detection setup silicon telescope identification of implanted fragments DSSSD (X-Y): 2 x 16 x 3 mm - veto for light particles - residual energy, x-y position - energy loss - time of flight: micro-channel plate detectors RF cyclotron GANIL / LISE3

19. identification of 22 45 Fe implantations identification of 45 Fe: Two-proton radioactivity of 45 Fe: GANIL data J. Giovinazzo et al., PRL 89 (2002) 102501

20. Decay time spectrum  spectrum: T 1/2 = 16.7±7.0 ms 1.14 MeV peak J. Giovinazzo et al., PRL89 (2002) 102501  Q value in agreement with prediction  no  pile-up for peak  half-life short enough for 2p decay  data for second decay in agreement with daughter decay  no  ’s in coincidence with 1.14 MeV peak Decay energy spectrum Two-proton radioactivity of 45 Fe: GANIL data

21. 6 implantations M. Pfützner et al., EPJA14 (2002) 279 A/Z 0 1 2 3 4 5 6 0 Energy (MeV) 5 correlated decay events: four 2p events one  -delayed decay Two-proton radioactivity of 45 Fe: GSI data

22. Q 2p = 1.14 MeV T 1/2 = 3.8 ms   discovery of two-proton radioactivity: 2002 Decay of 45 Fe

23.  2004 : Decay of 54 Zn and 48 Ni at GANIL with the same set-up 48 Ni 54 Zn B. Blank et al., Phys. Rev. Lett. 94 (2005) 232501 C. Dossat et al, Phys. Rev. C 75 (2005) 054315 Two-proton decay of 54 Zn and 48 Ni

24. Grigorenko et al. Brown and Barker Rotureau et al. agreement with 3-body model, SMEC, and R-matrix model Comparison with theory 45 Fe 48 Ni 54 Zn

25. However: - only total decay energy, half-life, no beta, daughter decay - no individual energies - no proton-proton angle TPC new development… what one would like to measure: - individual protons - proton energies - proton-proton angle

26.  Gas ionisation  Drift of electrons  Detection on the X-Y plan ion identification drift of ionisation electrons emitter protons X-Y detector electric field  Tracking in 3D ! Energy signals Track particle in 2D + Time signals Z component B. Blank et al, Nucl. Instr. And Meth. A 613 (2010) 65 Time projection chamber

27. GANIL/LISE3 experiments with the TPC Time projection chamber

28. Two-proton radioactivity of 45 Fe at GANIL with the TPC

29. Y strip numberX strip number Energy signal (a.u.) Y strip number X strip number Energy signal (a.u.) Analysis of TPC events X proton2 proton1 beam Y Z Implantation Decay

30. 45 Fe two-proton event in TPC of CENBG L. Audirac et al.

31. 45 Fe two-proton event in TPC of CENBG L. Audirac et al.

32. 45 Fe two-proton event in TPC of CENBG L. Audirac et al.

33. 45 Fe two-proton event in TPC of CENBG L. Audirac et al.

34. average = 50% sigma = 7,2 %  perfect energy sharing between the two protons energy fraction (%) Energy sharing between the two protons Grigorenko et al. exp.

35. A two-hump structure is observed, as predicted by the model of Grigorenko 3D angular distribution of the two protons L. Audirac et al., EPJA 48 (2012) 179

36. Two-proton radioactivity of 45 Fe at NSCL with the OTPC

37. 45 Fe Daughter decay 2p M. Pfützner et al. Daughter decay 45 Fe two-proton events in OTPC of Warsaw at NCSL

38. K. Miernik et al., PRL 99 (2007) 192501 45 Fe two-proton correlations with OTPC at NSCL

39. Two-proton radioactivity of 54 Zn at GANIL with the TPC

40. P. Ascher et al. 54 Zn two-proton event in TPC of CENBG

41. P. Ascher et al. 54 Zn two-proton event in TPC of CENBG

42. P. Ascher et al. 54 Zn two-proton event in TPC of CENBG

43. P. Ascher et al. 54 Zn two-proton event in TPC of CENBG

44. P. Ascher et al. 54 Zn two-proton event in TPC of CENBG

45. P. Ascher et al. 54 Zn two-proton event in TPC of CENBG

46.  perfect energy sharing between the two protons perfect agreement with 3-body model (L.V. Grigorenko et al.) Energy sharing between the two protons P. Ascher et al., PRL 107 (2011) 102502

47.  3D angular distribution from 3 -body model of Grigorenko et al. Projected angle between the two protons P. Ascher et al.  strong p 2 content  study of the wave function

48. Conclusions observation of 2p radioactivity Q values  mass model tests test of wave function  strong p 2 contribution, not expected in simple SM

49. Nuclei of interest: 59 Ge, 63 Se, 67 Kr Production: 78 Kr fragmentation at 360 MeV/u, 100pnA Separation: BigRIPS Detection: standard BigRIPS detection + silicon telescope with DSSSD (1mm) + Germanium detectors Settings: 59 Ge, rate = 9 ppd Settings: 63 Se, rate = 6 ppd Settings: 67 Kr, rate = 4 ppd New isotopes: 59 Ge, 63 Se, 68,67 Kr

50. New TPC based on ASICs and a pad structure J. Pibernat, CENBG  General electronics for TPCs: GET  16384 channels

51. demonstratorprototype 2048 channels (12.8 x 6.4 cm 2 ; 2 CoBo ; 8 AsAd) full-size detector16384 pads (16 CoBo ; 64 AsAd) various geometries (for 2-proton radioactivity or reaction studies) schematic view of the detector for 2-proton radioactivity studies Demonstrator and full-size detector

52. 5*10 11 pps of primary beam, 600 MeV/A, 4 sec per pulse 4 g/cm 2 of Be 58 Ni: 48 Ni: 7*10 -4 pps  70 per day 78 Kr: 59 Ge: 1*10 -2 pps  1000 per day 63 Se: 5*10 -3 pps  500 per day 67 Kr: 2*10 -3 pps  200 per day 92 Mo: 70 Sr: 5*10 -5 pps  5 per day 71 Sr: 1*10 -3 pps  100 per day 74 Zr: 2*10 -5 pps  2 per day 75 Zr: 6*10 -4 pps  60 per day 78 Mo: 6*10 -6 pps  0.6 per day 79 Mo: 1*10 -4 pps  10 per day 124 Xe: 97 Sn: 6*10 -6 pps  0.6 per day 98 Sn: 1*10 -4 pps  10 per day FAIR + SFRS … 2020…? Wie Brezelbacken….

53. Collaborations GANIL experiments CEN Bordeaux-Gradignan (France) GANIL Caen (France) IAP Bucharest (Romania) Warsaw University (Poland) NSCL-MSU (USA) University of Santiago di Compostella (Spain) IPN Orsay (France) LPC Caen (France) KU Leuven (Belgium) GANIL experiments CEN Bordeaux-Gradignan (France) GANIL Caen (France) IAP Bucharest (Romania) Warsaw University (Poland) NSCL-MSU (USA) University of Santiago di Compostella (Spain) IPN Orsay (France) LPC Caen (France) KU Leuven (Belgium) GSI experiment Warsaw University (Poland), GSI Darmstadt (Allemagne), CEN Bordeaux-Gradignan (France), GANIL Caen (France), ORNL (Tennessee / USA), Edinburg University (UK) GSI experiment Warsaw University (Poland), GSI Darmstadt (Allemagne), CEN Bordeaux-Gradignan (France), GANIL Caen (France), ORNL (Tennessee / USA), Edinburg University (UK) MSU experiment Warsaw University (Poland), MSU (USA), ORNL (Tennessee / USA), University of Tennessee (USA) MSU experiment Warsaw University (Poland), MSU (USA), ORNL (Tennessee / USA), University of Tennessee (USA)