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.


Jul. 2024 P.J. Li, J. Lee, P. Doornenbal et al., Phys.Lett. B, 855:138828, 2024.
'Spectroscopy of deeply bound orbitals in neutron-rich Ca isotopes'
Mar. 2024 B.D. Linh, A. Corsi, A. Gillibert et al., Phys.Rev. C, 109:034312, 2024.
'Onset of collectivity for argon isotopes close to N=32'
Mar. 2024 A. Jungclaus, P. Doornenbal, J. Acosta et al., Phys.Lett. B, 851:138561, 2024.
'Position of the single-particle 3/2 state in 135Sn and the N=90 subshell closure'
Nov. 2023 K. Wimmer, P. Ruotsalainen, S.M. Lenzi et al., Phys.Lett. B, 847:138249, 2023.
'Isospin symmetry in the T = 1,A = 62 triplet'
Jun. 2023 S. Chen, F. Browne, P. Doornenbal et al., Phys.Lett. B, 843:138025, 2023.
'Level structures of 56,58Ca cast doubt on a doubly magic 60Ca'
Jun. 2023 H. Wang, M. Yasuda, Y. Kondo et al., Phys.Lett. B, 843:138038, 2023.
'Intruder configurations in 29Ne at the transition into the island of inversion: Detailed structure study of 28Ne'
Jun. 2023 9th SUNFLOWER Workshop will be held on July 28 2023 in York, UK.
Apr. 2023 Symposium on 10 years of nuclear structure studies with LH2 targets at the RIBF.
Held from 31 July 2023 to 4 August 2023, York, UK
Dec. 2022 M. Enciu, H.N. Liu, A. Obertelli et al., Phys.Rev.Lett., 129:262501, 2022.
'Extended p3/2 Neutron Orbital and the N = 32 Shell Closure in 52Ca'
Dec. 2022 Z. Elekes, M.M. Juhasz, D. Sohler et al., Phys.Rev. C, 106:064321, 2022.
'"Southwestern" boundary of the N = 40 island of inversion: First study of low-lying bound excited states in 59V and 61V'
Feb. 2022 T. Koiwai, K. Wimmer, P. Doornenbal et al., Phys.Lett. B, 827:136953, 2022.
'A first glimpse at the shell structure beyond 54Ca: Spectroscopy of 55K, 55Ca, and 57Ca'
Feb. 2022 R.-B. Gerst, A. Blazhev, K. Moschner et al., Phys.Rev. C, 105:024302, 2022.
'γ-ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich 94,95,96Kr'
Jan. 2022 見たい!知りたい! 原子核サイエンス最前線
Nov. 2021 A. Fernández, A. Jungclaus, P. Doornenbal et al., Phys.Lett. B, 823:136784, 2021.
'Mirror energy differences above the 0f7/2 shell: First γ-ray spectroscopy of the Tz = −2 nucleus 56Zn'
Oct. 2021 B.D. Linh, A. Corsi, A. Gillibert et al., Phys.Rev. C, 104:04431, 2021.
'Investigation of the ground-state spin inversion in the neutron-rich 47,49Cl isotopes'
Aug. 2021 S.Y. Jin, S.T. Wang, J. Lee et al., Phys.Rev. C, 104:024302, 2021.
'Spectroscopy of 98Cd by two-nucleon removal from 100In'
Jun. 2021 F. Browne, S. Chen, P. Doornenbal et al., Phys.Rev.Lett., 126:252501, 2021.
'Pairing Forces Govern Population of Doubly Magic 54Ca from Direct Reactions'
Jun. 2021 D. Bazin, N. Aoi, H. Baba et al., Phys.Rev. C, 103:064318, 2021.
'Spectroscopy of 33Mg with knockout reactions'
Jun. 2021 M.M. Juhasz, Z. Elekes, D. Sohler et al., Phys.Rev. C, 103:064308, 2021.
'First spectroscopic study of 63V at the N = 40 island of inversion'
Jan. 2021 K. Wimmer, W. Korten, P. Doornenbal et al., Phys.Rev.Lett., 126:072501, 2021.
'Shape Changes in the Mirror Nuclei 70Kr and 70Se'
Jan. 2021 M.M. Juhasz, Z. Elekes, D. Sohler et al., Phys.Lett. B, 814:136108, 2021.
'First spectroscopic study of 51Ar by the (p,2p) reaction'
Dec. 2020 M.L. Cortes, W. Rodriguez, P. Doornenbal et al., Phys.Rev. C, 102:064320, 2020.
'N = 32 shell closure below calcium: Low-lying structure of 50Ar'
Dec. 2020 Photograph of HiCARI on Cover of RIKEN NEWS
RIKEN News No. 474
Jul. 2020 A. Gottardo, G. de Angelis, P. Doornenbal et al., Phys.Rev. C, 102:014323, 2020.
'Transition strengths in the neutron-rich 73,74,75Ni isotopes'
Jun. 2020 A. Frotscher, M. Gomez-Ramos, A. Obertelli et al., Phys.Rev.Lett., 125:012501, 2020.
'Sequential Nature of (p,3p) Two-Proton Knockout from Neutron-Rich Nuclei'
Jun. 2020 S. Bagchi, R. Kanungo, Y.K. Tanaka et al., Phys.Rev.Lett., 124:222504, 2020.
'Two-Neutron Halo is Unveiled in 29F'
Jun. 2020 K. Wimmer, T. Arici, W. Korten et al., Eur.Phys.J. A, 56:159, 2020.
'Shape coexistence revealed in the N=Z isotope 72Kr through inelastic scattering'
Jun. 2020 C. Lizarazo, P.-A. Söderström, V. Werner et al., Phys.Rev.Lett., 124:222501, 2020.
'Metastable States of 92,94Se: Identification of an Oblate K Isomer of 94Se and the Ground- State Shape Transition between N = 58 and 60'
May 2020 K.J. Cook, T. Nakamura, Y. Kondo et al., Phys.Rev.Lett., 124:212503, 2020.
'Halo Structure of the Neutron-Dripline Nucleus 19B'
Mar. 2020 Doubly Magic 54Ca on the YouTube RIKEN Channel
Mar. 2020 T. Lokotko, S. Leblond, J. Lee et al., Phys.Rev. C, 101:034314, 2020.
'Shell structure of the neutron-rich isotopes 69,71,73Co'
Jan. 2020 Y.L. Sun, A. Obertelli, P. Doornenbal et al., Phys.Lett. B, 802:135215, 2020.
'Restoration of the natural E(1/2+1-3/2+1) energy splitting in odd-K isotopes towards N = 40'
Jan. 2020 V. Vaquero, A. Jungclaus, T. Aumann et al., Phys.Rev.Lett., 124:022501, 2020.
'Fragmentation of Single-Particle Strength around the Doubly Magic Nucleus 132Sn and the Position of the 0f5/2 Proton-Hole State in 131In'
Nov. 2019 M.L. Cortes, W. Rodriguez, P. Doornenbal et al., Phys.Lett. B, 800:135071, 2020.
'Shell Evolution of N = 40 isotones towards 60Ca: First Spectroscopy of 62Ti'
Sep. 2019 S. Chen, J. Lee, P. Doornenbal et al., Phys.Rev.Lett., 123:142501, 2019.
'Quasifree Neutron Knockout from 54Ca Corroborates Arising N = 34 Neutron Magic Number'
Aug. 2019 A. Corsi, Y. Kubota, J. Casal et al., Phys.Lett. B, 797:134843, 2019.
'Structure of 13Be probed via quasi-fre scattering'
Jun. 2019 8th SUNFLOWER Workshop will be held on August 26-28 2019 in Osaka.
Jun. 2019 V. Vaquero, A. Jungclaus, J.L. Rodriguez et al., Phys.Lett. B, 795:356, 2019.
'Inclusive cross sections for one- and multi-nucleon removal from Sn, Sb, and Te projectiles beyond the N=82 shell closure'
Jun. 2019 K. Wimmer, P. Doornenbal, W. Korten et al., Phys.Lett. B, 795:266, 2019.
'Discovery of 68Br in secondary reactions of radioactive beams'
May 2019 R. Taniuchi, C. Santamaria, P. Doornenbal et al., Nature, 569:53, 2019.
'78Ni revealed as a doubly magic stronghold against nuclear deformation'
Apr. 2019 N. Paul, A. Obertelli, C.A. Bertulani 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.'