MEASUREMENTS FOR THE R PROCESS AT IGISOL Anu Kankainen University of Jyväskylä
Ion-Guide Isotope Separator On-Line (IGISOL) MCC-30 K-130 Offline ion source Mass number A Light ion ion guide RFQ Cooler & Buncher A. Nieminen et al., PRL 88 (2002) 094801 IGISOL method - chemically insensitive and fast I.D. Moore et al., NIM B 317 (2013) 208 Hyperfine Interact 223 (2014) 17 JYFLTRAP Mass measurements & Post-trap spectroscopy T. Eronen et al., Eur. Phys. J. A 48 (2012) 46 The r-process: connecting FRIB with the cosmos, June 8 2016
Penning traps BB V 0 BB HYPERBOLIC CYLINDRICAL Lorentz force: FF = qqvv BB EIGENMOTIONS: magnetron ν - reduced cyclotron ν + axial ν z νν cc = νν + + νν = 1 qqbb 2ππ mm (IDEAL TRAP) The r-process: connecting FRIB with the cosmos, June 8 2016 3
JYFLTRAP Double Penning trap JYFLTRAP review: T. Eronen et al., Eur. Phys. J. A 48 (2012) 46 Purification trap Mass-selective buffer gas cooling A=123 Precision trap TOF-ICR method 123 Cd m 123 Cd m/ m 3x10 4 ν c = qb 2πm 85% isomer 15% g.s. The r-process: connecting FRIB with the cosmos, June 8 2016 4
Isomer purification DIPOLAR RAMSEY CLEANING m/ m 10 6 T. Eronen et al., NIM B 266 (2008) 4527 achievable! Purification trap Precision trap from RFQ Pure 123 Cd g.s. extraction set ν + here The r-process: connecting FRIB with the cosmos, June 8 2016 5
JYFLTRAP mass measurements Measured at JYFLTRAP: ~280 ground states ~30 isomeric states Neutron-rich Neutron-def. 1-µb contour for p- induced fission on nat U at 25 MeV Motivation: 78 Ni and 132 Sn regions Evolution of shell gaps Onset of deformation Odd-even staggering Isomeric states The r-process: connecting FRIB with the cosmos, June 8 2016 6
Sensitivity studies M. Mumpower et al., PPNP 86 (2016) 86 M. Mumpower et al., PRC 92 (2015) 035807 The region close to 132 Sn has consistently a high impact on the r-process calculations Focus of this talk FRDM2012 model 4 astrophysical scenarios The r-process: connecting FRIB with the cosmos, June 8 2016 7
JYFLTRAP measurements around 132 Sn 25 MeV p beam on nat U or 232 Th at IGISOL First measurements! Ground states: J. Hakala et al., PRL 109 (2012) 032501 Isomers: A. Kankainen et al., PRC 87 (2013) 024307 The r-process: connecting FRIB with the cosmos, June 8 2016 8
Shell gaps: N=82 vs theory HFB-24 agrees well with the experimental values Does the gap decrease below Z=50? Only FRDM2012 predicts a flat trend. The r-process: connecting FRIB with the cosmos, June 8 2016 9
Neutron pairing gap at N=82 Three-point odd-even staggering formula: (3) (N)=(-1) N [ME(Z,N+1)-2ME(Z,N)+ME(Z,N-1)]/2 A. Kankainen, J. Äystö and A. Jokinen, J. Phys. G 39 (2012) 093101 N=82 N=126 stronger quenching in the pairing gap for Sn than for Te and Xe The r-process: connecting FRIB with the cosmos, June 8 2016 10
Odd-even staggering in the SbSbTe region Trend for N=83 unexplained by EDF models: something missing in the models? J. Hakala et al., PRL 109, 032501 (2012) Theor. calculations: J. Dobaczewski and M. Kortelainen b) spherical HFB c) HFODD (v2.51i) code for deformed d) Projected Lipkin-Nogami (HFBTHO code) = particle number conserving The r-process: connecting FRIB with the cosmos, June 8 2016 11
Shell-model calculations explain the trend Charge-dependent (CD-Bonn) nucleon-nucleon potential Protons: 0g7/2, 1d5/2,1d3/2, 0h11/2, and 2s1/2 Neutrons: 1f7/2, 2p3/2, 2p1/2, 0h9/2, 1f5/2, and 0i13/2 Single-particle and single-hole energies based on experimental spectra e.g. from 131 Sn, 133 Sb, and 133 Sn L. Coraggio et al., PRC 88 (2013) 041304(R) The r-process: connecting FRIB with the cosmos, June 8 2016 12
Measuring single-particle energies with a Penning trap: 1/2 - isomers in 129,131 In In (Z=49) proton-hole in the 2p 1/2 shell Excitation energy increases from N=78 to N=80 50 28 1g 9/2 2p 1/2 1f 5/2 2p 3/2 A. Kankainen et al., PRC 87 (2013) 024307 Old values based on betadecay energy differences The r-process: connecting FRIB with the cosmos, June 8 2016 13
11/2 - isomers in 121,123,125 Cd Odd neutron in the 1h 11/2 shell JYFLTRAP values similar trend as for Te isotopes 82 50 1h 11/2 3s 1/2 2d 3/2 2d 5/2 1g 7/2 NUBASE 2003 values JYFLTRAP agrees with the literature values of the well-known isomers in 121 Cd, 130 Sn and 134 Sb. A. Kankainen et al., Phys. Rev. C 87 (2013) 024307 The r-process: connecting FRIB with the cosmos, June 8 2016 14
Comparison between JYFLTRAP and CPT JYFLTRAP values already included in the AME12 JYFLTRAP: J. Hakala et al., PRL 109 (2012) 032501 CPT: J. Van Schelt et al., PRL 111 (2013) 061102 The r-process: connecting FRIB with the cosmos, June 8 2016 15
Comparison between JYFLTRAP and CPT JYFLTRAP: J. Hakala et al., PRL 109 (2012) 032501 CPT: J. Van Schelt et al., PRL 111 (2013) 061102 To achieve not only precise but also accurate mass values, we need more than one measurement, preferably at different facilities! What will be the AME2016 values for 133 Te or 140 Te? The r-process: connecting FRIB with the cosmos, June 8 2016 16
S 2n measurements and the onset of deformation JYFLTRAP mass measurements: U. Hager et al., PRL 96 (2006) 042504 U. Hager Nucl. Phys. A 793 (2007) 20 U. Hager et al., PRC 75 (2007) 064302 S. Rahaman et al, Eur. Phys. J. A 32 (2007) 87 J. Hakala et al., Eur. Phys. J. A 47 (2011) 129 N=50 DEFORMATION A. Kankainen, J. Äystö and A. Jokinen, J. Phys. G 39 (2012) 093101 B. Cheal and K.T. Flanagan, J. Phys. G 37 (2010) 113101 P. Campbell, I.D. Moore and M. Pearson, PPNP 86 (2016) 127 The r-process: connecting FRIB with the cosmos, June 8 2016 17
The onset of deformation in the Zr chain The kink is not so obvious looking at theoretical S 2n values, β 2 values predicted correctly by some models β 2 (exp)=0.343(9) How about unknown regions? The rare earth peak? The r-process: connecting FRIB with the cosmos, June 8 2016 18
Mass measurements of neutron-rich nuclei provide essential data for testing the present theoretical mass models needed for r-process simulations Erler et al., Nature 486 (2012) 509
Mass models for the r process? Deviations to FRDM2012 for different mass models Z=45 (Rh) to Z=55 (Cs) T. Eronen, A. Kankainen and J. Äystö, submitted to PPNP The r-process: connecting FRIB with the cosmos, June 8 2016 20
Post-trap spectroscopy: pure beams for beta-decay studies DTAS@IGISOL BELEN@IGISOL TAS on 87,88 Br and 94 Rb: observed gamma decays above S n! J. L. Tain et al., PRL 115 (2015) 062502 Beta-delayed neutrons with BELEN J. Agramunt et al., NIMA 807(2016) 69 A.-A. Zakari-Issoufou et al., PRL 115 (2015) 102503 The r-process: connecting FRIB with the cosmos, June 8 2016 21
FAIR MONSTER demonstrator to IGISOL? Possibility to have the demonstrator at IGISOL (not yet confirmed) Modular Neutron Time of Flight Spectrometer Array of 100 scintillator cells Different geometries possible Gamma-neutron separation from pulse shape Cross talk minimized; β-2n detection possible Possible to couple with other detector arrays (gamma detectors) Part of the array can be used as a detector itself The r-process: connecting FRIB with the cosmos, June 8 2016 22
Yields at IGISOL-4 Typical isotope yield at IGISOL-4 switchyard, 10µA beam intensity Courtesy of Heikki Penttilä The r-process: connecting FRIB with the cosmos, June 8 2016 23
Neutron-induced fission to boost the yields? 135 Sn measured at JYFLTRAP Independent isotopic fission yields of p-induced fission on U and Th studied thoroughly at IGISOL H. Penttilä et al., Eur. Phys. J. A 44 (2010) 147 H. Penttilä et al., Nucl. Data Sheets 119 (2014) 334 H. Penttilä et al., Eur. Phys. J. A 52 (2016) 104 Independent yield E p =25 MeV E d =15 MeV E n =10 MeV x + 238 U A Sn Sn x 300! Mass number, A Calculations by Valery Rubchenya The r-process: connecting FRIB with the cosmos, June 8 2016 24
Ongoing developments at IGISOL: neutron converter D. Gorelov et al., NIM B 376 (2016) 46 The r-process: connecting FRIB with the cosmos, June 8 2016 25
Ongoing developments at JYFLTRAP MR-TOF PI-ICR Octupolar resonances Off-line ion sources The r-process: connecting FRIB with the cosmos, June 8 2016 26
Acknowledgements JYFLTRAP&IGISOL L. Canete T. Eronen D. Gorelov J. Hakala A. Jokinen V.S. Kolhinen J. Koponen I. D. Moore D. Nesterenko H. Penttilä I. Pohjalainen J. Reinikainen S. Rinta-Antila M. Vilén A. Voss J. Äystö The r-process: connecting FRIB with the cosmos, June 8 2016 27