Welcome to the 'SUNFLOWER (Spectroscopy of Unstable Nuclei with Fast and sLOW beam Experiments at RIBF) Collaboration'. The SUNFLOWER collaboration is a framework to enhance the activity of the in-beam γ-ray spectroscopy at RI Beam Factory (RIBF) by coordinating experimentalists aspiring to reach the heart of the structure study of unstable nuclei with fast and decelerated RI beams by means of γ-ray measurements. Here, information on collaboration, research subjects, related publications, and experimental devices are introduced.

You are welcome to join the collaboration. If you wish to join, please visit the 'Collaboration' menu. When you consider experiments with local devices in RIBF, please visit the 'Proposing Exp.' menu, in which information on performing experiments in RIBF are described.


Apr. 2019 N. Paul, A. Obertelli, C.A Obertelli, et al., Phys.Rev.Lett., 122:162503, 2019.
'Prominence of Pairing in Inclusive (p,2p) and (p,pn) Cross Sections from Neutron-Rich Nuclei'
Apr. 2019 Baffled physicists label gamma-ray measurements of super-heavy magnesium “a mystery”
RIKEN Research Highlight
Apr. 2019 Neutron-rich magnesium undergoes unexpected transitions.
Physics Today, Volume 72, Issue 4 (2019).
Mar. 2019 V. Vaquero, A. Jungclaus, P. Doornenbal, et al., Phys.Rev.C, 99:034306, 2019.
'In-beam γ-ray spectroscopy of 136Te at relativistic energies'
Feb. 2019 H.N. Liu, A. Obertelli, P. Doornenbal, et al., Phys.Rev.Lett., 122:072502, 2019.
'How Robust is the N=34 Subshell Closure? First Spectroscopy of 52Ar'
Jan. 2019 H.L. Crawford, P. Fallon, A.O. Macchiavelli, et al., Phys.Rev.Lett., 122:052501, 2019.
'First Spectroscopy of the Near Drip-line Nucleus 40Mg'
Jan. 2019 Z. Elekes, A. Kripko, D. Sohler, et al., Phys.Rev.C, 99:014312, 2019.
'Nuclear structure of 76Ni from the (p,2p) reaction'
Jan. 2019 A Workshkop on High Resolution Gamma-Ray Spectroscopy at the RIBF will be held on April 10-12, 2019 in Darmstadt.
Jan. 2019 I. Murray, M. MacCormick, D. Bazin, et al., Phys.Rev.C, 99:011302(R), 2019.
'Spectroscopy of strongly deformed 32Ne by proton knockout reactions'
Dec. 2018 O. Wieland, A. Bracco, F. Camera, et al., Phys.Rev.C, 98:064313, 2018.
'Low-lying dipole response in the unstable 70Ni nucleus'
Sep. 2018 K. Wimmer, W. Korten, T. Arici, et al., Phys.Lett.B, 785:441, 2018.
'Shape coexistence and isospin symmetry in A = 70 nuclei: Spectroscopy of the Tz = -1 nucleus 70Kr'
Sep. 2018 X.Y. Liu, Z. Liu, B. Ding, et al., Phys.Lett.B, 784:392, 2018.
'Spectroscopy of 65,67Mn: Strong coupling in the N=40 “island of inversion”'
May 2018 Zs. Vajta, D. Sohler, Y. Shiga, et al., Phys.Lett.B, 782:99, 2018.
'Proton single particle energies next to 78Ni: Spectroscopy of 77Cu via single proton knock-out reaction'
Apr. 2018 The RIBF Week 2018 will be held from September 3 to 7, 2018 at RIKEN.
Apr. 2018 A. Corsi, A. Obertelli, P. Doornenbal, et al., Phys.Rev.C, 97:044321, 2018.
'Spectroscopy of nuclei around 100Sn populated via two-neutron knockout reactions'
Apr. 2018 M.L. Cortes, P. Doornenbal, M. Dupuis, et al., Phys.Rev.C, 97:044315, 2018.
'Inelastic scattering of neutron-rich Ni and Zn isotopes off a proton target'
Dec. 2017 D. Steppenbeck, S. Takeuchi, N. Aoi, et al., Phys.Rev.C, 96:064310, 2017.
'Structure of 55Sc and development of the N = 34 subshell closure'
Nov. 2017 L. Olivier, S. Franchoo, M. Niikura, et al., Phys.Rev.Lett, 119:192501, 2017.
'Persistence of the Z = 28 Shell Gap Around 78Ni: First Spectroscopy of 79Cu'
Oct. 2017 C.M. Shand, Zs. Podolyak, M. Gorska, et al., Phys.Lett.B, 773:492, 2017.
'Shell evolution beyond Z = 28 and N = 50: Spectroscopy of 81,82,83,84Zn'
Sep. 2017 S. Momiyama, P. Doornenbal, H. Scheit, et al., Phys.Rev.C, 96:034328, 2017.
'In-beam gamma-ray spectroscopy of 35Mg via knockout reactions at intermediate energies'
Jul. 2017 M. Lettmann, V. Werner, N. Pietralla, et al., Phys.Rev.C, 96:011301, 2017.
'Triaxiality of neutron-rich 84,86,88Ge from low-energy nuclear spectra'
Jun. 2017 F. Flavigny, P. Doornenbal, A. Obertelli, et al., Phys.Rev.Lett, 118:242501, 2017.
'Shape Evolution in Neutron-Rich Krypton Isotopes Beyond N = 60: First Spectroscopy of 98,100Kr'
May 2017 6th SUNFLOWER Workshop will be held on 11th-15th September 2017 in Oslo.
May 2017 V. Vaquero, A. Jungclaus, P. Doornenbal, et al., Phys.Rev.Lett, 118:202502, 2017.
'Gamma Decay of Unbound Neutron-Hole States in 133Sn'
Apr. 2017 S. Chen, P. Doornenbal, A. Obertelli, et al., Phys.Rev.C, 95:041302(R), 2017.
'Low-lying structure and shape evolution in neutron-rich Se isotopes'
Apr. 2017 P. Doornenbal, H. Scheit, S. Takeuchi, et al., Phys.Rev.C, 95:041301(R), 2017.
'Low-Z shore of the "island of inversion" and the reduced neutron magicity toward 28O'
Mar. 2017 N. Nakatsuka, H. Baba, T. Aumann, et al., Phys.Lett.B, 768:387, 2017.
'Observation of isoscaler and isovector dipole excitations in neutron-rich 20O'
Jan. 2017 H. N. Liu, J. Lee, P. Doornenbal, et al., Phys.Lett.B, 767:58, 2017.
'Intruder configurations in the ground state of 30Ne'
Jan. 2017 N. Paul, A. Corsi, A. Obertelli, et al., Phys.Rev.Lett., 118:032501, 2017.
'Are There Signatures of Harmonic Oscillator Shells Far from Stability? First Spectroscopy of 110Zr'
Oct. 2016 H. Wang, N. Aoi, S. Takeuchi, et al., Phys.Rev.C, 94:051301(R), 2016.
'First spectroscopic information from even-even nuclei in the region "southeast" of 132Sn: Neutron-excitation dominance of the 2+1 state in 132Cd'
Aug. 2016 J. Lee, H. Liu, P. Doornenbal, et al., Prog.Theor.Exp.Phys., 2016:083D01, 2016.
'Asymmetry dependence of reduction factors from signle-neutron knockout of 30Ne at ~ 230 MeV/nucleon'
May 2016 5th SUNFLOWER Workshop will be held on 18th-20th September 2016.
Apr. 2016 P. Doornenbal, H. Scheit, S. Takeuchi, et al., Phys.Rev.C, 93:044306, 2016.
'Mapping the deformation in the "island of inversion": Inelastic scattering of 30Ne and 36Mg at intermediate energies'
Feb. 2016 Y. Shiga, K. Yoneda, D. Steppenbeck, et al., Phys.Rev.C, 93:024320, 2016.
'Investigating nuclear shell structure in the vicinity of 78Ni: Low-lying excited states in the neutron-rich istopes 80,82Zn.'
Jan. 2016 N. Kobayashi, T. Nakamura, Y. Kondo, et al., Phys.Rev.C, 93:014613, 2016.
'One-neutron removal from 29Ne: Defining the lower limits of the island of inversion'
Nov. 2015 C. Santamaria, C. Louchart, A. Obertelli, et al., Phys.Rev.Lett., 115:192501, 2015.
'Extension of the N = 40 island of inverstion towards N = 50: Spectroscopy of 66Cr, 70,72Fe.'
Jul. 2015 K. Li, Y. Ye, T. Motobayashi, et al., Phys.Rev.C, 92:014608, 2015.
'Relativistic Coulomb excitation in 32Mg near 200 MeV/nucleon with a thick target'
Jun. 2015 D. Steppenbeck, S. Takeuchi, N. Aoi, et al., JPS Conf. Proc., 6:020019, 2015.
'In-Beam γ-Ray Spectroscopy of Very Neutron-Rich N=32 and 34 Nuclei'
Jun. 2015 Zs. Vajta, Zs. Dombràdi, Z. Elekes, et al., Phys.Rev.C, 91:064315, 2015.
'γ-ray spectroscopy of 19C via the single-neutron knock-out reaction'
Jun. 2015 D. Steppenbeck, S. Takeuchi, N. Aoi, et al., Phys.Rev.Lett., 114:252501, 2015.
'Low-Lying Structure of 50Ar and the N=32 Subshell Closure'
Jun. 2015 Frontier of gamma-ray spectroscopy (Gamma15) will be held from 1st to 3rd October 2015.
Jun. 2015 4th SUNFLOWER Workshop will be held on 30th September 2015.
Mar. 2015 A. Corsi, S. Boissinot, A. Obertelli, et al., Phys.Lett.B, 743:451, 2015.
'Neutron-driven collectivity in light tin isotopes: Proton inelastic scattering from 104Sn'
Dec. 2014 P. Doonenbal, S. Takeuchi, N. Aoi, et al., Phys.Rev.C, 90:061302(R), 2014.
'Intermediate-energy Coulomb excitation of 104Sn: Moderate E2 strength decrease approaching 100Sn'
Aug. 2014 S. Takeuchi, T. Motobayashi, Y. Togano, et al., Nucl. Instrum. and Methods in Phys. Res. Sect. A, 763:596, 2014.
'DALI2: A NaI(Tl) detector array for measurements of γ rays from fast nuclei'
Jul. 2014 3rd SUNFLOWER Workshop will be held on 15th and 16th September 2014.
Jun. 2014 N. Kobayashi, T. Nakamura, Y. Kondo, et al., Phys.Rev.Lett., 112:242501, 2014.
'Observation of a p-Wave One-Neutron Halo Configuration in 37Mg'
May. 2014 P. Doornenbal, H. Scheit, S. Takeuchi, et al., Prog.Theor.Exp.Phys., 2014:053D01, 2014.
'Rotational level structure of sodium isotopes inside the "island of inversion"'
May. 2014 S. Michimasa, Y. Yanagisawa, K. Inafuku, et al., Phys.Rev.C, 89:054307, 2014.
'Quadrupole collectivity in island-of-inversion nuclei 28,30Ne and 34,36Mg'
Apr. 2014 H. L. Crawford, P. Fallon, A. O. Macchiavelli, et al., Phys.Rev.C, 89:041303(R), 2014.
'Shell and shape evolution at N=28: The 40Mg ground state'
Apr. 2014 T. Nakamura, N. Kobayashi, Y. Kondo, et al., Phys.Rev.Lett., 112:142501, 2014.
'Deformation-Driven p-Wave Halos at the Drip Line: 31Ne'
Feb. 2014 H. Wang, N. Aoi, S. Takeuchi, et al., Prog.Theor.Exp.Phys., 2014:023D02, 2014.
'Structure of 136Sn and the Z=50 magicity'
Nov. 2013 H. Wang, N. Aoi, S. Takeuchi, et al., Phys.Rev.C, 88:054318, 2013.
'Collectivity evolution in the neutron-rich Pd isotopes toward the N=82 shell closure'
Nov. 2013 P. Doornenbal, H. Scheit, S. Takeuchi, et al., Phys.Rev.Lett., 111:212502, 2013.
'In-Beam γ-Ray Spectroscopy of 34,36,38Mg: Merging the N=20 and N=28 Shell Quenching'
Oct. 2013 L. Audirac, A. Obertelli, P. Doornenbal, et al., Phys.Rev.C, 88:041602, 2013.
'Evaporation-cost dependence in heavy-ion fragmentation'
Oct. 2013 D. Steppenbeck, S. Takeuchi, N. Aoi, et al., Nature, 502:207, 2013.
'Evidence for a new nuclear ‘magic number’ from the level structure of 54Ca'
Aug. 2013 H. Suzuki, N. Aoi, E. Takeshita, et al., Phys.Rev.C, 88:024326, 2013.
'Collectivity of neutron-rich Ti isotopes'
Jul. 2013 SUNFLOWER Workshop will be held on 10th and 11th September 2013.
May. 2013 The RIBF Users Meering will be held on 26th and 27th June 2013.
Apr. 2013 H. Wang, N. Aoi, S. Takeuchi, et al., Chinese Phys.Lett., 30:042501, 2013.
'Observation of New Isotope 131Ag via the Two-Step Fragmentation Technique'
Dec. 2012 SUNFLOWER Workshop will be held on 20th and 21st Feb. 2013.
Nov. 2012 S. Takeuchi, M. Matsushita, N. Aoi, et al., Phys.Rev.Lett., 109:182501, 2012.
'Well Developed Deformation in 42Si'
Oct. 2012 K. -A.Li, Y. -L.Ye, H. Scheit, et al., Chinese Phys.Lett., 29:102301, 2012.
'Inelastic Scattering of 32Mg at 190 MeV/Nucleon from a Thick Proton Target'
Oct. 2012 RCNP International Workshop: Clover12 will be held on 7th and 8th Dec. 2012.
Jul. 2012 K. Tshoo, Y. Satou, H. Bhang, et al., Phys.Rev.Lett., 109:222501, 2012.
'N=16 Spherical Shell Closure in 24O'
Jun. 2012 RIBF Users Meeting 2012
Jun. 2012 SUNFLOWER Meeting 2012
May 2012 Y. Togano, Y. Yamada, N. Iwasa, et al., Phys.Rev.Lett., 108:222501, 2012.
'Hindered Proton Collectivity in 2816S12: Possible Magic Number at Z=16'
Mar. 2011 Y. Satou, T. Nakamura, Y. Kondo, et al., Phys.Lett. B, 697:459, 2011.
'14Be(p,n)14B reaction at 69 MeV in inverse kinematics'
Aug. 2010 N. Aoi, S. Kanno, S. Takeuchi, et al., Phys.Lett. B, 692:302, 2010.
'Enhanced collectivity in 74Ni'
Aug. 2010 Z. Elekes, Zs. Vajta, Zs. Dombradi, et al., Phys.Rev. C, 82:027305, 2010.
'Nuclear structure study of 19,21N nuclei by γ spectroscopy'
Jun. 2010 E. Yu. Nikolskii, A. A. Korsheninnikov, H. Otsu, et al., Phys.Rev. C, 81:064606, 2010.
'Search for 7H in 2H+8He collisions'
Jun. 2010 Y. Kondo, T. Nakamura, Y. Satou, et al., Phys.Lett. B, 690:245, 2010.
'Low-lying intruder state of the unbound nucleus 13Be'
Apr. 2010 P. Doornenbal, H. Scheit, N. Kobayashi, et al., Phys.Rev. C, 81:041305(R), 2010.
'Exploring the "island of inversion" by in-beam γ-ray spectropscopy of the neutron-rich sodium isotopes 31,32,33Na'
Feb. 2010 K. Tanaka, T. Yamaguchi, T. Suzuki, et al., Phys.Rev.Lett., 104:062701, 2010.
'Observation of a Large Reaction Cross Section in the Drip-Line Nucleus 22C.'
Jan. 2010 Physics Update in Physics Today, "A carbon halo"
Jul. 2009 Press Release, "Discovery of large deformation of very neutron-rich 32Ne nucleus."
Jul. 2009 P. Doornenbal, H. Scheit, N. Aoi, et al., Phys.Rev.Lett., 103:032501, 2009.
'Spectroscopy of 32Ne and the "Island of Inversion".'
May 2009 S. Takeuchi, N. Aoi, T. Motobayashi, et al., Phys.Rev. C, 79:054319, 2009.
'Low-lying states in 32Mg studied by proton inelastic scattering.'
Jan. 2009 N. Aoi, E. Takeshita, H. Suzuki, et al., Phys.Rev.Lett., 102:012502, 2009.
'Development of Large Deformation in 62Cr.'