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1. Direct Evidence of Octupole Deformation in Neutron-Rich Ba144

Author

Bucher, B, Zhu, S, Wu, CY, Janssens, RVF, Cline, D, Hayes, AB, Albers, M, Ayangeakaa, AD, Butler, PA, Campbell, CM, Carpenter, MP, Chiara, CJ, Clark, JA, Crawford, HL, Cromaz, M, David, HM, Dickerson, C, Gregor, ET, Harker, J, Hoffman, CR, Kay, BP, Kondev, FG, Korichi, A, Lauritsen, T, Macchiavelli, AO, Pardo, RC, Richard, A, Riley, MA, Savard, G, Scheck, M, Seweryniak, D, Smith, MK, Vondrasek, R, and Wiens, A

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, nucl-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5  s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34)  W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

Published
2016

2. Direct Evidence of Octupole Deformation in Neutron-Rich ^{144}Ba.

Author

Bucher, B, Zhu, S, Wu, CY, Janssens, RVF, Cline, D, Hayes, AB, Albers, M, Ayangeakaa, AD, Butler, PA, Campbell, CM, Carpenter, MP, Chiara, CJ, Clark, JA, Crawford, HL, Cromaz, M, David, HM, Dickerson, C, Gregor, ET, Harker, J, Hoffman, CR, Kay, BP, Kondev, FG, Korichi, A, Lauritsen, T, Macchiavelli, AO, Pardo, RC, Richard, A, Riley, MA, Savard, G, Scheck, M, Seweryniak, D, Smith, MK, Vondrasek, R, and Wiens, A

Subjects
nucl-ex, General Physics, Physical Sciences
Abstract

The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5  s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34)  W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

Published
2016

3. Single-particle states and parity doublets in odd-Z Ac-221 and Pa-225 from alpha-decay spectroscopy

Author

Parr, E, Smith, JF, Greenlees, PT, Butler, PA, Auranen, K, Chapman, R, Cox, DM, Cullen, DM, Gaffney, LP, Grahn, T, Gregor, ET, Grocutt, L, Herzan, A, Herzberg, R-D, Hodge, D, Jakobsson, U, Julin, R, Juutinen, S, Keatings, JM, Konki, J, Leino, M, McKee, PP, McPeake, C, Mengoni, D, Mistry, AK, Singh, BS Nara, O'Neill, GG, Pakarinen, J, Papadakis, P, Partanen, J, Peura, P, Rahkila, P, Ruotsalainen, P, Sandzelius, M, Saren, J, Scheck, M, Scholey, C, Siciliano, M, Smolen, M, Sorri, J, Spagnoletti, P, Spohr, KM, Stolze, S, Taylor, MJ, and Uusitalo, J

Published
2022

4. The observation of vibrating pear-shapes in radon nuclei (vol 10, 2473, 2019)

Author

Butler, PA, Gaffney, LP, Spagnoletti, P, Konki, J, Scheck, M, Smith, JF, Abrahams, K, Bowry, M, Cederkaell, J, Chupp, T, de Angelis, G, De Witte, H, Garrett, PE, Goldkuhle, A, Henrich, C, Illana, A, Johnston, K, Joss, DT, Keatings, JM, Kelly, NA, Komorowska, M, Kroell, T, Lozano, M, Singh, BS Nara, O'Donnell, D, Ojala, J, Page, RD, Pedersen, LG, Raison, C, Reiter, P, Rodriguez, JA, Rosiak, D, Rothe, S, Shneidman, TM, Siebeck, B, Seidlitz, M, Sinclair, J, Stryjczyk, M, Van Duppen, P, Vinals, S, Virtanen, V, Warr, N, Wrzosek-Lipska, K, and Zielinska, M

Published
2020

7. The observation of vibrating pear-shapes in radon nuclei (vol 10, pg 2473, 2020)

Author

Butler, PA, Gaffney, LP, Spagnoletti, P, Konki, J, Scheck, M, Smith, JF, Abrahams, K, Bowry, M, Cederkaell, J, Chupp, T, de Angelis, G, De Witte, H, Garrett, PE, Goldkuhle, A, Henrich, C, Illana, A, Johnston, K, Joss, DT, Keatings, JM, Kelly, NA, Komorowska, M, Kroell, T, Lozano, M, Singh, BS Nara, O'Donnell, D, Ojala, J, Page, RD, Pedersen, LG, Raison, C, Reiter, P, Rodriguez, JA, Rosiak, D, Rothe, S, Shneidman, TM, Siebeck, B, Seidlitz, M, Sinclair, J, Stryjczyk, M, Van Duppen, P, Vinals, S, Virtanen, V, Warr, N, Wrzosek-Lipska, K, and Zielinska, M

Published
2020

8. Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive $^{222}$Ra and $^{228}$Ra Beams

Author

Butler, PA, Gaffney, LP, Spagnoletti, P, Abrahams, K, Bowry, M, Cederkäll, J, de Angelis, G, De Witte, H, Garrett, PE, Goldkuhle, A, Henrich, C, Illana, A, Johnston, K, Joss, DT, Keatings, JM, Kelly, NA, Komorowska, M, Konki, J, Kröll, T, Lozano, M, Nara Singh, BS, O’Donnell, D, Ojala, J, Page, RD, Pedersen, LG, Raison, C, Reiter, P, Rodriguez, JA, Rosiak, D, Rothe, S, Scheck, M, Seidlitz, M, Shneidman, TM, Siebeck, B, Sinclair, J, Smith, JF, Stryjczyk, M, Van Duppen, P, Vinals, S, Virtanen, V, Warr, N, Wrzosek-Lipska, K, and Zielińska, M

Subjects
Nuclear Theory, Atomic Physics (physics.atom-ph), FOS: Physical sciences, nuclear structure and decays, Physics - Atomic Physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), electromagnetic transitions, Physics::Accelerator Physics, collective levels, Physics::Atomic Physics, Nuclear Experiment (nucl-ex), ydinfysiikka, Nuclear Experiment
Abstract

There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in $^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing $^{222}$Ra as pear-shaped with stable octupole deformation, while $^{228}$Ra behaves like an octupole vibrator., Comment: to be published in Physical Review Letters

Published
2020
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9. alpha-decay spectroscopy of the N=130 isotones Ra-218 and Th-220: Mitigation of alpha-particle energy summing with implanted nuclei

Author

Parr, E, Smith, JF, Greenlees, PT, Auranen, K, Butler, PA, Chapman, R, Cox, DM, Cullen, DM, Gaffney, LP, Grahn, T, Gregor, ET, Grocutt, L, Herzan, A, Herzberg, R-D, Hodge, D, Jakobsson, U, Julin, R, Asztalos, S, Keatings, J, Konki, J, Leino, M, McKee, PP, McPeake, C, Mengoni, D, Mistry, AK, Mulholland, KF, Singh, BS Nara, O'Neill, GG, Pakarinen, J, Papadakis, P, Partanen, J, Peura, P, Rahkila, P, Ruotsalainen, P, Sandzelius, M, Saren, J, Scheck, M, Scholey, C, Siciliano, M, Smolen, M, Sorri, J, Spagnoletti, P, Spohr, KM, Stolze, S, Taylor, MJ, and Uusitalo, J

Published
2019

10. α -decay spectroscopy of the N=130 isotones Ra 218 and Th 220: Mitigation of α -particle energy summing with implanted nuclei

Author

Parr, E, Smith, JF, Greenlees, PT, Auranen, K, Butler, PA, Chapman, R, Cox, DM, Cullen, DM, Gaffney, LP, Grahn, T, Gregor, ET, Grocutt, L, Herzáň, A, Herzberg, RD, Hodge, D, Jakobsson, U, Julin, R, Juutinen, S, Keatings, J, Konki, J, Leino, M, McKee, PP, McPeake, C, Mengoni, D, Mistry, AK, Mulholland, KF, Nara Singh, BS, O'Neill, GG, Pakarinen, J, Papadakis, P, Partanen, J, Peura, P, Rahkila, P, Ruotsalainen, P, Sandzelius, M, Sarén, J, Scheck, M, Scholey, C, Siciliano, M, Smolen, M, Sorri, J, Spagnoletti, P, Spohr, KM, Stolze, S, Taylor, MJ, and Uusitalo, J

Abstract

An analysis technique has been developed in order to mitigate energy summing due to sequential short-lived α decays from nuclei implanted into a silicon detector. Using this technique, α-decay spectroscopy of the N=130 isotones Ra218 (Z=88) and Th220 (Z=90) has been performed. The energies of the α particles emitted in the Ra218→Rn214 and Th220→Ra216 ground-state-to-ground-state decays have been measured to be 8381(4) keV and 8818(13) keV, respectively. The half-lives of the ground states of Ra218 and Th220 have been measured to be 25.99(10) μs and 10.4(4) μs, respectively. The half-lives of the ground states of the α-decay daughters, Rn214 and Ra216, have been measured to be 259(3) ns and 161(11) ns, respectively. Fine structure in the α decay of Ra218 has been observed for the first time, populating the 695-keV 21+ state in Rn214. The fine-structure α decay has an α-particle energy of 7715(40) keV and branching ratio bα=0.123(11)%.

Published
2019

11. In-beam study of No-253 using the SAGE spectrometer

Author

Mistry, AK, Herzberg, R-D, Greenlees, PT, Papadakis, P, Auranen, K, Butler, PA, Cox, DM, Garnsworthy, AB, Grahn, T, Hauschild, K, Jakobsson, U, Joss, DT, Julin, R, Ketelhut, S, Konki, J, Leino, M, Lopez-Martens, A, Page, RD, Pakarinen, J, Peura, P, Rahkila, P, Sandzelius, M, Scholey, C, Simpson, J, Seddon, D, Sorri, J, Stolze, S, Thornhill, J, Uusitalo, J, and Wells, D

Published
2017

12. STUDY OF OCTUPOLE COLLECTIVITY IN Nd-146 AND Sm-148 USING THE NEW COULOMB EXCITATION SET-UP AT ALTO

Author

Komorowska, M, Zielinska, M, Napiorkowski, P, Doherty, T, Wrzosek-Lipska, Kasia, Butler, PA, Prochniak, L, Korten, W, Briselet, R, De Witte, Hilde, Gaffney, Liam, Georgiev, G, Goasduff, A, Gorgen, A, Gottardo, A, Gregor, ET, Hadynska-Klek, K, Hess, H, Klintefjord, M, Konstantinopoulos, T, Ljungvall, J, Lutter, R, Matea, I, Matuszczak, P, O'Neill, GG, Piatek, W, Reiter, P, Rosiak, D, Scheck, M, Seidlitz, M, Siebeck, B, Thuerauf, M, and Warr, N

Subjects
Nuclear Theory
Abstract

For certain combinations of protons and neutrons in atomic nuclei, a rise of a reflection asymmetry is expected. Experimental E3 strengths, which as a function of the neutron number peak at around N ≈ 88 and N ≈ 134, indicate enhanced octupole correlations as predicted by theory. Low-energy Coulomb excitation is a highly successful method for establishing the evolution of nuclear shapes, through the measurement of cross sections, to populate excited states that can be directly related to the static and dynamic moments of the charge distribution of the nucleus. A Coulomb excitation experiment at the ALTO facility, Orsay was performed recently to study collective properties of 146Nd and 148Sm. In particular, the strengths of the ⟨3−||E3||0+⟩ and ⟨1−||E3||4+⟩ matrix elements will provide a clear distinction between octupole vibration and rigid deformation. ispartof: Acta Physica Polonica B vol:47 issue:3 pages:923-928 status: published

Published
2016

13. Low-energy Coulomb excitation of Sr-96,Sr-98 beams

Author

Clement, E, Zielinska, M, Peru, S, Goutte, H, Hilaire, S, Gorgen, A, Korten, W, Doherty, DT, Bastin, B, Bauer, C, Blazhev, A, Bree, Nick, Bruyneel, B, Butler, PA, Butterworth, J, Cederkall, J, Delahaye, P, Dijon, A, Ekstrom, A, Fitzpatrick, C, Fransen, C, Georgiev, G, Gernhauser, R, Hess, H, Iwanicki, J, Jenkins, DG, Larsen, AC, Ljungvall, J, Lutter, R, Marley, P, Moschner, K, Napiorkowski, PJ, Pakarinen, J, Petts, A, Reiter, P, Renstrom, T, Seidlitz, M, Siebeck, B, Siem, S, Sotty, C, Srebrny, J, Stefanescu, Irina, Tveten, GM, Van de Walle, J, Vermeulen, M, Voulot, D, Warr, N, Wenander, F, Wiens, A, De Witte, Hilde, and Wrzosek-Lipska, Kasia

Subjects
Physics::Accelerator Physics, Nuclear Experiment
Abstract

The structure of neutron-rich 96,98Sr nuclei was investigated by low-energy safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN, with the MINIBALL spectrometer. A rich set of transitional and diagonal E2 matrix elements, including those for non-yrast structures, has been extracted from the differential Coulomb-excitation cross sections. The results support the scenario of a shape transition at N=60, giving rise to the coexistence of a highly deformed prolate and a spherical configuration in 98Sr, and are compared to predictions from several theoretical calculations. The experimental data suggest a significant contribution of the triaxal degree of freedom in the ground state of both isotopes. In addition, experimental information on low-lying states in 98Rb has been obtained. ispartof: Physical Review C vol:94 issue:5 status: published

Published
2016

14. Collective 2(1)(+) excitations in Po-206 and Rn-208,Rn-210

Author

Grahn, T, Pakarinen, J, Jokiniemi, L, Albers, M, Auranen, K, Bauer, C, Bernards, C, Blazhev, A, Butler, PA, Boenig, S, Damyanova, A, De Coster, T, De Witte, H, Elseviers, J, Gaffney, LP, Huyse, M, Herzan, A, Jakobsson, U, Julin, R, Kesteloot, N, Konki, J, Kroell, Th, Lewandowski, L, Moschner, K, Peura, P, Pfeiffer, M, Radeck, D, Rahkila, P, Rapisarda, E, Reiter, P, Reynders, K, Rudiger, M, Salsac, M-D, Sambi, S, Scheck, M, Seidlitz, M, Siebeck, B, Steinbach, T, Stolze, S, Suhonen, J, Thoele, P, Thuerauf, M, Warr, N, Van Duppen, P, Venhart, M, Vermeulen, MJ, Werner, V, Veselsky, M, Vogt, A, Wrzosek-Lipska, K, and Zielinska, M

Subjects
Nuclear Theory, Physics::Accelerator Physics, Nuclear Experiment
Abstract

In the present study, values have been measured in the 208,210Rn and 206Po nuclei through Coulomb excitation of re-accelerated radioactive beams in inverse kinematics at CERN-ISOLDE. These nuclei have been proposed to lie in, or at the boundary of the region where the seniority scheme should persist. However, contributions from collective excitations are likely to be present when moving away from the N=126 closed shell. Such an effect is confirmed by the observed increased collectivity of the transitions. Experimental results have been interpreted with the aid of theoretical studies carried out within the BCS-based QRPA framework. ispartof: European Physical Journal A, Hadrons and Nuclei vol:52 issue:11 status: published

Published
2016

15. High-sensitivity study of levels in Al-30 following beta decay of Mg-30

Author

Olaizola, B, Mach, H, Fraile, LM, Benito, J, Borge, MJG, Boutami, R, Butler, PA, Dlouhy, Z, Fynbo, HOU, Hoff, P, Hyldegaard, S, Jeppesen, HB, Jokinen, A, Jollet, C, Korgul, A, Koster, U, Kroell, Th, Kurcewicz, W, Marechal, F, Mrazek, J, Nilsson, T, Plociennik, WA, Ruchowska, E, Schuber, R, Schwerdtfeger, W, Sewtz, M, Simpson, GS, Stanoiu, M, Tengblad, O, Thirolf, PG, Yordanov, Deyan, and Helsinki Institute of Physics

Subjects
NUCLEAR-DATA SHEETS, MOMENTS, Physical Sciences, Fysik, PICOSECOND LIFETIME MEASUREMENTS, NEUTRON, DESCENDANTS, RICH SODIUM ISOTOPES, 114 Physical sciences, REGION
Abstract

γ -ray and fast-timing spectroscopy were used to study levels in 30Al populated following the β− decay of 30Mg. Five new transitions and three new levels were located in 30Al. A search was made to identify the third 1+ state expected at an excitation energy of ∼2.5 MeV. Two new levels were found, at 3163.9 and 3362.5 keV, that are firm candidates for this state. Using the advanced time-delayed (ATD) βγγ (t) method we have measured the lifetime of the 243.8-keV state to be T1/2 = 15(4) ps, which implies that the 243.8-keV transition is mainly of M1 character. Its fast B(M1; 2+ → 3+) value of 0.10(3) W.u. is in very good agreement with the USD shell-model prediction of 0.090 W.u. The 1801.5-keV level is the only level observed in this study that could be a candidate for the second excited 2+ state. ispartof: Physical Review C vol:94 issue:5 pages:1-7 status: published

Published
2016

16. Direct Evidence of Octupole Deformation in Neutron-Rich Ba 144

Author

Bucher, B, Zhu, S, Wu, CY, Janssens, RVF, Cline, D, Hayes, AB, Albers, M, Ayangeakaa, AD, Butler, PA, Campbell, CM, Carpenter, MP, Chiara, CJ, Clark, JA, Crawford, HL, Cromaz, M, David, HM, Dickerson, C, Gregor, ET, Harker, J, Hoffman, CR, Kay, BP, Kondev, FG, Korichi, A, Lauritsen, T, Macchiavelli, AO, Pardo, RC, Richard, A, Riley, MA, Savard, G, Scheck, M, Seweryniak, D, Smith, MK, Vondrasek, R, and Wiens, A

Abstract

©=0.65(+17-23) eb3/2, corresponds to a reduced B(E3) transition probability of 48(+25-34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation. © 2016 American Physical Society. The neutron-rich nucleus Ba144 (t1/2=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV Ba144 beam on a 1.0-mg/cm2 Pb208 target. The measured value of the matrix element, 31-M(E3)01+

Published
2016
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17. Do nuclei go pear-shaped? Coulomb excitation of Rn-220 and Ra-224 at REX-ISOLDE (CERN)

Author

Scheck, M, Gaffney, Liam, Butler, PA, Hayes, AB, Wenander, F, Albers, M, Bastin, Beyhan, Bauer, C, Blazhev, A, Boenig, S, Bree, Nick, Cederkall, J, Chupp, T, Cline, D, Cocolios, Thomas Elias, Davinson, T, De Witte, Hilde, Diriken, Jan, Grahn, T, Herzan, A, Huyse, Mark, Jenkins, DG, Joss, DT, Kesteloot, Nele, Konki, J, Kowalczyk, M, Kroell, Th, Kwan, E, Lutter, R, Moschner, K, Napiorkowski, P, Pakarinen, J, Pfeiffer, M, Radeck, D, Reiter, P, Reynders, Kobe, Rigby, SV, Robledo, LM, Rudigier, M, Sambi, Sara, Seidlitz, M, Siebeck, B, Stora, T, Thoele, P, Van Duppen, Piet, Vermeulen, MJ, von Schmid, M, Voulot, D, Warr, N, Wimmer, K, Wrzosek-Lipska, Kasia, Wu, CY, Zielinska, M, Helsinki Institute of Physics, Schwengner, R, and Zuber, K

Subjects
MOMENTS, Coulomb excitation, Physics::Accelerator Physics, 114 Physical sciences
Abstract

The IS475 collaboration conducted Coulomb-excitation experiments with post-accelerated radioactive 220Rn and 224Ra beams at the REX-ISOLDE facility. The beam particles (Ebeam: 2.83 MeV/u) were Coulomb excited using 60Ni, 114Cd, and 120Sn scattering targets. De-excitation γ-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured γ-ray yields. The extracted ‹3−||E3||0+› matrix element allows for the conclusion that, while 220Rn represents an octupole vibrational system, 224Ra has already substantial octupole correlations in its ground state. This finding has implications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei. ispartof: EPJ Web of Conferences vol:93 ispartof: 15th International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (CGS) location:Dresden: GERMANY date:25 Aug - 29 Aug 2014 status: published

Published
2015

21. Foreword

Author

Butler, Paul

Published
2020

23. Contents

Author

Butler, Paul

Published
2020

40. Index

Author

Butler, Paul

Published
2020

45. Index

Author

Butler, Paula

Published
2015

50. Notes

Author

Butler, Paula

Published
2015

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