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288 results on '"K P, Rykaczewski"'

1. First observation of isomeric states in Zr111, Nb113 , and Mo115

Author

J. Wu, S. Nishimura, P.-A. Söderström, A. Algora, J. J. Liu, V. H. Phong, Y. Q. Wu, F. R. Xu, J. Agramunt, D. S. Ahn, T. A. Berry, C. G. Bruno, J. J. Bundgaard, R. Caballero-Folch, A. C. Dai, T. Davinson, I. Dillmann, A. Estrade, A. Fijałkowska, N. Fukuda, S. Go, R. K. Grzywacz, T. Isobe, S. Kubono, G. Lorusso, K. Matsui, A. I. Morales, N. Nepal, S. E. A. Orrigo, B. C. Rasco, K. P. Rykaczewski, H. Sakurai, Y. Shimizu, D. W. Stracener, T. Sumikama, H. Suzuki, J. L. Tain, H. Takeda, A. Tarifeño-Saldivia, A. Tolosa-Delgado, M. Wolińska-Cichocka, and R. Yokoyama

Published
2022

2. New isotope Mc286 produced in the Am243+Ca48 reaction

Author

Yu. Ts. Oganessian, V. K. Utyonkov, N. D. Kovrizhnykh, F. Sh. Abdullin, S. N. Dmitriev, A. A. Dzhioev, D. Ibadullayev, M. G. Itkis, A. V. Karpov, D. A. Kuznetsov, O. V. Petrushkin, A. V. Podshibiakin, A. N. Polyakov, A. G. Popeko, I. S. Rogov, R. N. Sagaidak, L. Schlattauer, V. D. Shubin, M. V. Shumeiko, D. I. Solovyev, Yu. S. Tsyganov, A. A. Voinov, V. G. Subbotin, A. Yu. Bodrov, A. V. Sabel'nikov, A. V. Khalkin, K. P. Rykaczewski, T. T. King, J. B. Roberto, N. T. Brewer, R. K. Grzywacz, Z. G. Gan, Z. Y. Zhang, M. H. Huang, and H. B. Yang

Published
2022

3. Demonstration of the neutron tracking capability of NEXT array in time-of-flight measurements to improve energy resolution

Author

S. Neupane, J. Heideman, R. Grzywacz, M. Cooper, J. Hooker, K. L. Jones, T. T. King, N. Kitamura, M. Madurga, K. Siegl, C. R. Thornsberry, P. Wagenknecht, Z. Y. Xu, L. H. Heilbronn, M. M. Rajabali, A. Chester, A. Richard, Y. Alberty-Jones, J. Derkin, T. N. Massey, D. Soltesz, N. T. Brewer, B. C. Rasco, K. P. Rykaczewski, M. Wolinska-Cichocka, J. Clark, D. Santiago-Gonzales, and G. Savard

Published
2022

4. β -Delayed One and Two Neutron Emission Probabilities Southeast of Sn132 and the Odd-Even Systematics in r -Process Nuclide Abundances

Author

V. H. Phong, S. Nishimura, G. Lorusso, T. Davinson, A. Estrade, O. Hall, T. Kawano, J. Liu, F. Montes, N. Nishimura, R. Grzywacz, K. P. Rykaczewski, J. Agramunt, D. S. Ahn, A. Algora, J. M. Allmond, H. Baba, S. Bae, N. T. Brewer, C. G. Bruno, R. Caballero-Folch, F. Calviño, P. J. Coleman-Smith, G. Cortes, I. Dillmann, C. Domingo-Pardo, A. Fijalkowska, N. Fukuda, S. Go, C. J. Griffin, J. Ha, L. J. Harkness-Brennan, T. Isobe, D. Kahl, L. H. Khiem, G. G. Kiss, A. Korgul, S. Kubono, M. Labiche, I. Lazarus, J. Liang, Z. Liu, K. Matsui, K. Miernik, B. Moon, A. I. Morales, P. Morrall, N. Nepal, R. D. Page, M. Piersa-Siłkowska, V. F. E. Pucknell, B. C. Rasco, B. Rubio, H. Sakurai, Y. Shimizu, D. W. Stracener, T. Sumikama, H. Suzuki, J. L. Tain, H. Takeda, A. Tarifeño-Saldivia, A. Tolosa-Delgado, M. Wolińska-Cichocka, P. J. Woods, and R. Yokoyama

Subjects
General Physics and Astronomy
Published
2022

5. β decay of neutron-rich Cu76 and the structure of Zn76

Author

U. Silwal, J. A. Winger, S. V. Ilyushkin, K. P. Rykaczewski, C. J. Gross, J. C. Batchelder, L. Cartegni, I. G. Darby, R. Grzywacz, A. Korgul, W. Królas, S. N. Liddick, C. Mazzocchi, A. J. Mendez, S. Padgett, M. M. Rajabali, D. P. Siwakoti, D. Shapira, D. W. Stracener, and E. F. Zganjar

Published
2022

6. First experiment at the Super Heavy Element Factory: High cross section of Mc288 in the Am243+Ca48 reaction and identification of the new isotope Lr264

Author

Yu. Ts. Oganessian, V. K. Utyonkov, N. D. Kovrizhnykh, F. Sh. Abdullin, S. N. Dmitriev, D. Ibadullayev, M. G. Itkis, D. A. Kuznetsov, O. V. Petrushkin, A. V. Podshibiakin, A. N. Polyakov, A. G. Popeko, R. N. Sagaidak, L. Schlattauer, I. V. Shirokovski, V. D. Shubin, M. V. Shumeiko, D. I. Solovyev, Yu. S. Tsyganov, A. A. Voinov, V. G. Subbotin, A. Yu. Bodrov, A. V. Sabel'nikov, A. V. Khalkin, V. B. Zlokazov, K. P. Rykaczewski, T. T. King, J. B. Roberto, N. T. Brewer, R. K. Grzywacz, Z. G. Gan, Z. Y. Zhang, M. H. Huang, and H. B. Yang

Published
2022

7. Investigation of Ca48 -induced reactions with Pu242 and U238 targets at the JINR Superheavy Element Factory

Author

Yu. Ts. Oganessian, V. K. Utyonkov, D. Ibadullayev, F. Sh. Abdullin, S. N. Dmitriev, M. G. Itkis, A. V. Karpov, N. D. Kovrizhnykh, D. A. Kuznetsov, O. V. Petrushkin, A. V. Podshibiakin, A. N. Polyakov, A. G. Popeko, R. N. Sagaidak, L. Schlattauer, V. D. Shubin, M. V. Shumeiko, D. I. Solovyev, Yu. S. Tsyganov, A. A. Voinov, V. G. Subbotin, A. Yu. Bodrov, A. V. Sabel'nikov, A. Lindner, K. P. Rykaczewski, T. T. King, J. B. Roberto, N. T. Brewer, R. K. Grzywacz, Z. G. Gan, Z. Y. Zhang, M. H. Huang, and H. B. Yang

Published
2022

8. Crossing N=28 Toward the Neutron Drip Line: First Measurement of Half-Lives at FRIB

Author

H. L. Crawford, V. Tripathi, J. M. Allmond, B. P. Crider, R. Grzywacz, S. N. Liddick, A. Andalib, E. Argo, C. Benetti, S. Bhattacharya, C. M. Campbell, M. P. Carpenter, J. Chan, A. Chester, J. Christie, B. R. Clark, I. Cox, A. A. Doetsch, J. Dopfer, J. G. Duarte, P. Fallon, A. Frotscher, T. Gaballah, T. J. Gray, J. T. Harke, J. Heideman, H. Heugen, R. Jain, T. T. King, N. Kitamura, K. Kolos, F. G. Kondev, A. Laminack, B. Longfellow, R. S. Lubna, S. Luitel, M. Madurga, R. Mahajan, M. J. Mogannam, C. Morse, S. Neupane, A. Nowicki, T. H. Ogunbeku, W.-J. Ong, C. Porzio, C. J. Prokop, B. C. Rasco, E. K. Ronning, E. Rubino, T. J. Ruland, K. P. Rykaczewski, L. Schaedig, D. Seweryniak, K. Siegl, M. Singh, S. L. Tabor, T. L. Tang, T. Wheeler, J. A. Winger, and Z. Xu

Subjects
General Physics and Astronomy
Abstract

New half-lives for exotic isotopes approaching the neutron drip-line in the vicinity of N∼28 for Z=12-15 were measured at the Facility for Rare Isotope Beams (FRIB) with the FRIB decay station initiator. The first experimental results are compared to the latest quasiparticle random phase approximation and shell-model calculations. Overall, the measured half-lives are consistent with the available theoretical descriptions and suggest a well-developed region of deformation below ^{48}Ca in the N=28 isotones. The erosion of the Z=14 subshell closure in Si is experimentally confirmed at N=28, and a reduction in the ^{38}Mg half-life is observed as compared with its isotopic neighbors, which does not seem to be predicted well based on the decay energy and deformation trends. This highlights the need for both additional data in this very exotic region, and for more advanced theoretical efforts.

Published
2022

9. β-Delayed One and Two Neutron Emission Probabilities Southeast of ^{132}Sn and the Odd-Even Systematics in r-Process Nuclide Abundances

Author

V H, Phong, S, Nishimura, G, Lorusso, T, Davinson, A, Estrade, O, Hall, T, Kawano, J, Liu, F, Montes, N, Nishimura, R, Grzywacz, K P, Rykaczewski, J, Agramunt, D S, Ahn, A, Algora, J M, Allmond, H, Baba, S, Bae, N T, Brewer, C G, Bruno, R, Caballero-Folch, F, Calviño, P J, Coleman-Smith, G, Cortes, I, Dillmann, C, Domingo-Pardo, A, Fijalkowska, N, Fukuda, S, Go, C J, Griffin, J, Ha, L J, Harkness-Brennan, T, Isobe, D, Kahl, L H, Khiem, G G, Kiss, A, Korgul, S, Kubono, M, Labiche, I, Lazarus, J, Liang, Z, Liu, K, Matsui, K, Miernik, B, Moon, A I, Morales, P, Morrall, N, Nepal, R D, Page, M, Piersa-Siłkowska, V F E, Pucknell, B C, Rasco, B, Rubio, H, Sakurai, Y, Shimizu, D W, Stracener, T, Sumikama, H, Suzuki, J L, Tain, H, Takeda, A, Tarifeño-Saldivia, A, Tolosa-Delgado, M, Wolińska-Cichocka, P J, Woods, and R, Yokoyama

Abstract

The β-delayed one- and two-neutron emission probabilities (P_{1n} and P_{2n}) of 20 neutron-rich nuclei with N≥82 have been measured at the RIBF facility of the RIKEN Nishina Center. P_{1n} of ^{130,131}Ag, ^{133,134}Cd, ^{135,136}In, and ^{138,139}Sn were determined for the first time, and stringent upper limits were placed on P_{2n} for nearly all cases. β-delayed two-neutron emission (β2n) was unambiguously identified in ^{133}Cd and ^{135,136}In, and their P_{2n} were measured. Weak β2n was also detected from ^{137,138}Sn. Our results highlight the effect of the N=82 and Z=50 shell closures on β-delayed neutron emission probability and provide stringent benchmarks for newly developed macroscopic-microscopic and self-consistent global models with the inclusion of a statistical treatment of neutron and γ emission. The impact of our measurements on r-process nucleosynthesis was studied in a neutron star merger scenario. Our P_{1n} and P_{2n} have a direct impact on the odd-even staggering of the final abundance, improving the agreement between calculated and observed Solar System abundances. The odd isotope fraction of Ba in r-process-enhanced (r-II) stars is also better reproduced using our new data.

Published
2022

10. Deciphering Nb98 β decay with the Modular Total Absorption Spectrometer at ORNL

Author

B. C. Rasco, K. P. Rykaczewski, A. Fijałkowska, M. Karny, M. Wolińska-Cichocka, R. K. Grzywacz, D. W. Stracener, E. F. Zganjar, J. C. Batchelder, J. C. Blackmon, N. T. Brewer, M. P. Cooper, K. C. Goetz, J. W. Johnson, T. King, A. Laminack, J. T. Matta, K. Miernik, M. Madurga, D. Miller, M. M. Rajabali, T. Ruland, P. Shuai, M. Stepaniuk, and J. Winger

Published
2022

11. Determination of β -decay feeding patterns of Rb88 and Kr88 using the Modular Total Absorption Spectrometer at ORNL HRIBF

Author

P. Shuai, B. C. Rasco, K. P. Rykaczewski, A. Fijałkowska, M. Karny, M. Wolińska-Cichocka, R. K. Grzywacz, C. J. Gross, D. W. Stracener, E. F. Zganjar, J. C. Batchelder, J. C. Blackmon, N. T. Brewer, S. Go, M. Cooper, K. C. Goetz, J. W. Johnson, C. U. Jost, T. T. King, J. T. Matta, J. H. Hamilton, A. Laminack, K. Miernik, M. Madurga, D. Miller, C. D. Nesaraja, S. Padgett, S. V. Paulauskas, M. M. Rajabali, T. Ruland, M. Stepaniuk, E. H. Wang, and J. A. Winger

Published
2022

12. Design of a new central module for the Modular Total Absorption Spectrometer

Author

michal Stepaniuk, K. P. Rykaczewski, M. Karny, Robert Grzywacz, A. Fijałkowska, and B.C. Rasco

Subjects
Nuclear and High Energy Physics, Full width at half maximum, Optics, Materials science, Low energy, Spectrometer, business.industry, Yield (chemistry), Modular design, business, Absorption (electromagnetic radiation), Instrumentation
Abstract

The design and expected performance of the new Central module for the Modular Total Absorption Spectrometer is discussed. Small losses ( ≈ 1%) in efficiency and small increase ( ≈ 10%) of the FWHM are expected due to the introduced dead layers for optical separation between segments. This however should not be significant for the future measurements, while the advantages of the increased segmentation should yield improved information about low energy gamma transitions.

Published
2020

13. Study of decay properties for Ba to Nd nuclei relevant for the formation of the r-process rare-earth peak (A∼160)

Author

M. Pallàs, A. Tarifeño-Saldivia, G. G. Kiss, J. L. Tain, A. Tolosa-Delgado, A. Vitéz-Sveiczer, F. Calviño, J. Agramunt, P. Aguilera, A. Algora, J. M. Allmond, H. Baba, N. T. Brewer, R. Caballero-Folch, P. J. Coleman-Smith, G. Cortes, T. Davinson, I. Dillmann, C. Domingo-Pardo, A. Estrade, N. Fukuda, S. Go, C. J. Griffin, R. K. Grzywacz, O. Hall, L. J. Harkness-Brennan, T. Isobe, D. Kahl, T. T. King, A. Korgul, S. Kovács, S. Kubono, M. Labiche, J. Liu, M. Madurga, K. Miernik, F. Molina, N. Mont-Geli, A. I. Morales, E. Nácher, A. Navarro, N. Nepal, S. Nishimura, M. Piersa-Silkowska, V. Phong, B. C. Rasco, J. Romero-Barrientos, B. Rubio, K. P. Rykaczewski, Y. Saito, H. Sakurai, Y. Shimizu, M. Singh, T. Sumikama, H. Suzuki, T. N. Szegedi, H. Takeda, K. Wang, M. Wolińska-Cichocka, P. J. Woods, and R. Yokoyama

Subjects
General Medicine
Abstract

At the RIKEN Nishina Center, exotic neutron-rich isotopes of Ba, La, Ce, Pr, and Nd were measured. This work reports their half-lives (T1/2) and β-delayed neutron-emission probabilities (Pxn). The setup consisted of the BigRIPS in-flight separator for particle identification, the Advanced Implantation Detector Array (AIDA) for ions and β detection, and the BRIKEN neutron counter for neutron detection. Using this arrangement, 4 new T1/2 and 14 new P1n were measured. Furthermore, 38 T1/2 and 2 P1n values were remeasured, decreasing the uncertainties for some of them. In addition to improving predictions of nucleosynthesis models that describe the production of the rare-earth peak at A ∼ 160 via the r-process, these additional experimental data should help to constrain theoretical models for calculations of T1/2 and Pxn in this region.

Published
2023

14. Levels in Cd125 populated by the β decay of Ag125m and Ag125

Author

Andrew Ratkiewicz, A. J. Mendez, S. Padgett, W. A. Peters, B. Manning, Carl J Gross, M. Madurga, K. Miernik, J. C. Batchelder, S. V. Paulauskas, M. Matos, K. P. Rykaczewski, E. H. Wang, C. Apgar, D. W. Stracener, Marzena Wolinska-Cichocka, N. T. Brewer, S. V. Ilyushkin, David Miller, J. A. Winger, D. W. Bardayan, B. C. Rasco, M. E. Howard, E. F. Zganjar, and Robert Grzywacz

Subjects
Physics, Decay scheme, Neutron emission, Center (category theory), Atomic physics, Nuclear Experiment, Ground state, Energy (signal processing), Intensity (heat transfer)
Abstract

The $\ensuremath{\beta}$ decay of $^{125m,125}\mathrm{Ag}$ into levels in $^{125}\mathrm{Cd}$ was investigated at the Holifield Radioactive Ion Beam Facility (HRIBF). Uranium-238 targets were bombarded with 50-MeV protons with an intensity of $15\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}$A, and the induced fission products were mass separated and deposited on a moving tape in the center of the VANDLE array consisting of $\ensuremath{\gamma}$ detectors and plastic scintillators. A partial decay scheme has been assigned for both $\ensuremath{\beta}$ decay of the (9/${2}^{+}$) ground state of $^{125}\mathrm{Ag}$ and its low-lying (1/${2}^{\ensuremath{-}}$) isomer, with the energy of the low-lying (11/${2}^{\ensuremath{-}}$) isomeric state in $^{125}\mathrm{Cd}$ assigned as 188.5 keV. In addition, $\ensuremath{\beta}$-delayed neutron emission probabilities were also determined to be 1.2(2)% for the (9/${2}^{+}$) $^{125}\mathrm{Ag}$ ground state and 4.6(10)% for the (1/${2}^{\ensuremath{-}}$) isomer, which are substantially lower than the previously reported value.

Published
2021

15. Measuring the β-decay Properties of Neutron-rich Exotic Pm, Sm, Eu, and Gd Isotopes to Constrain the Nucleosynthesis Yields in the Rare-earth Region

Author

G. G. Kiss, A. Vitéz-Sveiczer, Y. Saito, A. Tarifeño-Saldivia, M. Pallas, J. L. Tain, I. Dillmann, J. Agramunt, A. Algora, C. Domingo-Pardo, A. Estrade, C. Appleton, J. M. Allmond, P. Aguilera, H. Baba, N. T. Brewer, C. Bruno, R. Caballero-Folch, F. Calvino, P. J. Coleman-Smith, G. Cortes, T. Davinson, N. Fukuda, Z. Ge, S. Go, C. J. Griffin, R. K. Grzywacz, O. Hall, A. Horváth, J. Ha, L. J. Harkness-Brennan, T. Isobe, D. Kahl, T. T. King, A. Korgul, S. Kovács, R. Krücken, S. Kubono, M. Labiche, J. Liu, J. Liang, M. Madurga, K. Miernik, F. Molina, A. I. Morales, M. R. Mumpower, E. Nacher, A. Navarro, N. Nepal, S. Nishimura, M. Piersa-Siłkowska, V. Phong, B. C. Rasco, B. Rubio, K. P. Rykaczewski, J. Romero-Barrientos, H. Sakurai, L. Sexton, Y. Shimizu, M. Singh, T. Sprouse, T. Sumikama, R. Surman, H. Suzuki, T. N. Szegedi, H. Takeda, A. Tolosa, K. Wang, M. Wolinska-Cichocka, P. Woods, R. Yokoyama, Z. Xu, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. Doctorat en Enginyeria Nuclear i de les Radiacions Ionitzants, and Universitat Politècnica de Catalunya. ANT - Advanced Nuclear Technologies Research Group

Subjects
Física [Àrees temàtiques de la UPC], Space and Planetary Science, Astronomy and Astrophysics, Stars, Nucleosynthesis, Estels, Nucleosíntesi
Abstract

The β-delayed neutron-emission probabilities of 28 exotic neutron-rich isotopes of Pm, Sm, Eu, and Gd were measured for the first time at RIKEN Nishina Center using the Advanced Implantation Detector Array (AIDA) and the BRIKEN neutron detector array. The existing β-decay half-life (T 1/2) database was significantly increased toward more neutron-rich isotopes, and uncertainties for previously measured values were decreased. The new data not only constrain the theoretical predictions of half-lives and β-delayed neutron-emission probabilities, but also allow for probing the mechanisms of formation of the high-mass wing of the rare-earth peak located at A ≈ 160 in the r-process abundance distribution through astrophysical reaction network calculations. An uncertainty quantification of the calculated abundance patterns with the new data shows a reduction of the uncertainty in the rare-earth peak region. The newly introduced variance-based sensitivity analysis method offers valuable insight into the influence of important nuclear physics inputs on the calculated abundance patterns. The analysis has identified the half-lives of 168Sm and of several gadolinium isotopes as some of the key variables among the current experimental data to understand the remaining abundance uncertainty at A = 167–172.

Published
2022

16. β-delayed neutron emission of r-process nuclei at the N = 82 shell closure

Author

K. Matsui, Shintaro Go, G. G. Kiss, M. Labiche, C. J. Griffin, A. Estrade, Iris Dillmann, B. Rubio, Carlo Bruno, Robert Grzywacz, H. Baba, V. H. Phong, J. Ha, V. F. E. Pucknell, C. Domingo-Pardo, J. Agramunt, N. Nepal, A. Korgul, Shunji Nishimura, R. Yokoyama, P. J. Coleman-Smith, G. Cortes, H. Suzuki, J. L. Tain, L. J. Harkness-Brennan, D. W. Stracener, J. Liu, J. Liang, H. Takeda, Zi Hong Liu, D. S. Ahn, M. Wolińska-Cichocka, Y. Shimizu, A. I. Morales, Ariel Tarifeño-Saldivia, T. Davinson, L. H. Khiem, M. Piersa, N. Fukuda, P. J. Woods, Shigeru Kubono, F. Calviño, R. Caballero-Folch, K. Miernik, K. P. Rykaczewski, Alejandro Algora, A. Tolosa-Delgado, Hiroyoshi Sakurai, B. Moon, Fernando Montes, B.C. Rasco, A. Fijalkowska, T. Isobe, I.H. Lazarus, P.S. Morrall, Giuseppe Lorusso, D. Kahl, J. M. Allmond, S. Bae, N. T. Brewer, R. D. Page, Toshiyuki Sumikama, Matthew Mumpower, O. Hall, Universitat Politècnica de Catalunya. Departament de Física, and Universitat Politècnica de Catalunya. ANT - Advanced Nuclear Technologies Research Group

Subjects
Nuclear and High Energy Physics, National security, QC1-999, ß-delayed, Nuclear physics, Library science, Neutrons--Captura, β-delayed neutron emission, 7. Clean energy, 01 natural sciences, Neutrons--Capture, Astrophysical, 0103 physical sciences, European commission, r-processimportant, 010306 general physics, China, Nuclear Experiment, Neutron emissionr-process, Physics, Física [Àrees temàtiques de la UPC], 010308 nuclear & particles physics, business.industry, r-process, Chinese academy of sciences, beta-delayed neutron emission, Research council, Christian ministry, Física nuclear, National laboratory, business, Administration (government)
Abstract

This experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. O.H, T.D, P.J.W, C.G.B, C.J.G and D.K would like to thank STFC, UK for support. This research was sponsored in part by the Office of Nuclear Physics, U.S. Department of Energy under Award No. DE-FG02-96ER40983 (UTK) and DEAC05-00OR22725 (ORNL), and by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DENA0002132. This work was supported by National Science Foundation under Grants No. PHY-1430152 (JINA Center for the Evolution of the Elements), No. PHY-1565546 (NSCL), and No. PHY-1714153 (Central Michigan University). This work was supported by the Polish National Science Center under Contracts No. UMO-2015/18/E/ST2/00217, No. 2017/01/X/ST2/01144, No. 2019/33/N/ST2/03023 and No. 2020/36/T/ST2/00547. This work was also supported by JSPS KAKENHI (Grants No. 14F04808, No. 17H06090, No. 25247045, and No. 19340074). This work was also supported by Spanish Ministerio de Economia y Competitividad grants (FPA2011-06419, FPA2011-28770-C03-03, FPA2014-52823-C2-1-P, FPA2014-52823-C2-2-P, SEV-2014-0398, IJCI-2014-19172), by European Commission FP7/EURATOM Contract No. 605203, by the UK Science and Technology Facilities Council Grant No. ST/N00244X/1, by the National Research Foundation (NRF) in South Korea (No. 2016K1A3A7A09005575, No. 2015H1A2A1030275) and by the Natural Sciences and Engineering Research Council of Canada (NSERC) via the Discovery Grants SAPIN-2014-00028 and RGPAS 462257-2014. TRIUMF receives federal funding via a contribution agreement with the National Research Council Canada. This work was also supported by NKFIH (NN128072), and by the UNKP-20-5-DE-2 New National Excellence Program of the Ministry of Human Capacities of Hungary. G.G.K. acknowledges support from the Janos Bolyai research fellowship of the Hungarian Academy of Sciences. M.W.-C. acknowledges support from the Polish NCN project Miniatura No. 2017/01/X/ST2/01144. Z.L was supported by the National Key Research and Development Program of China (Contract No. 2018YFA0404402), the National Natural Science Foundation of China (Grants No. 11961141004, No. 11735017, No. 11675225 and No. 11635003) and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB34000000). M.R.M. performed this work under the auspice of the U.S. Department of Energy at Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001).

Published
2021

17. Long-lived isomeric states and quasiparticle band structures in neutron-rich Gd162,164 nuclei from β decay

Author

Marzena Wolinska-Cichocka, Stan Paulauskas, S. W. Padgett, J. A. Winger, M. Karny, A. V. Ramayya, C. Jost, Yuan Liu, D. W. Stracener, N. T. Brewer, J. C. Batchelder, A. Fijałkowska, E. F. Zganjar, Robert Grzywacz, B. M. Musangu, C. J. Gross, C. J. Zachary, M. Madurga, Yu Sun, J. M. Eldridge, S. V. Ilyushkin, K. Miernik, K. P. Rykaczewski, J. H. Hamilton, A. J. Mendez, D.W. Miller, C. Brown, S. H. Liu, and E. H. Wang

Subjects
Physics, Nuclear physics, Quasiparticle, Neutron
Published
2021

18. Search for elements 119 and 120

Author

Michael Block, Mahananda Dasgupta, S. Minami, Susanta Lahiri, M. Wegrzecki, N. Kurz, Rose A. Boll, Andreas Türler, J. V. Kratz, R-D Herzberg, Daniel Cox, James B. Roberto, Claes Fahlander, Jadambaa Khuyagbaatar, Dirk Rudolph, K. P. Rykaczewski, A. Hübner, G. K. Pang, K. Miernik, N. Gharibyan, B. Schausten, J. Hoffmann, L.-L. Andersson, Bettina Lommel, Luis Sarmiento, U. Forsberg, Matthias Schädel, J. H. Hamilton, Juha Uusitalo, Kenneth E. Gregorich, Heino Nitsche, H. Brand, Julia Even, Moumita Maiti, J. M. Gates, David Hinde, Philippos Papadakis, M. Laatiaoui, Norbert Wiehl, Klaus Eberhardt, W. Hartmann, J. Runke, D. A. Shaughnessy, Dieter Ackermann, Petra Thörle-Pospiech, K. Tinschert, R. Lang, C. Mokry, Birgit Kindler, Jon Petter Omtvedt, Ch. E. Düllmann, S. M. Van Cleve, J. Steiner, D. Renisch, A. K. Mistry, M. Asai, Maurits Evers, Alexander Yakushev, Patrick Steinegger, A. Semchenkov, Pavel Golubev, V. Yakusheva, X. Derkx, Evgeny E. Tereshatov, J. Krier, Norbert Trautmann, T. Torres De Heidenreich, A. Di Nitto, F. P. Heßberger, R. Hollinger, Egon Jäger, Khuyagbaatar, J., Yakushev, A., Düllmann, Ch. E., Ackermann, D., Andersson, L. -L., Asai, M., Block, M., Boll, R. A., Brand, H., Cox, D. M., Dasgupta, M., Derkx, X., Di Nitto, A., Eberhardt, K., Even, J., Evers, M., Fahlander, C., Forsberg, U., Gates, J. M., Gharibyan, N., Golubev, P., Gregorich, K. E., Hamilton, J. H., Hartmann, W., Herzberg, R. -D., Heßberger, F. P., Hinde, D. J., Hoffmann, J., Hollinger, R., Hübner, A., Jäger, E., Kindler, B., Kratz, J. V., Krier, J., Kurz, N., Laatiaoui, M., Lahiri, S., Lang, R., Lommel, B., Maiti, M., Miernik, K., Minami, S., Mistry, A. K., Mokry, C., Nitsche, H., Omtvedt, J. P., Pang, G. K., Papadakis, P., Renisch, D., Roberto, J. B., Rudolph, D., Runke, J., Rykaczewski, K. P., Sarmiento, L. G., Schädel, M., Schausten, B., Semchenkov, A., Shaughnessy, D. A., Steinegger, P., Steiner, J., Tereshatov, E. E., Thörle-Pospiech, P., Tinschert, K., Torres De Heidenreich, T., Trautmann, N., Türler, A., Uusitalo, J., Wegrzecki, M., Wiehl, N., Van Cleve, S. M., Yakusheva, V., and Van Swinderen Institute for Particle Physics and G

Subjects
Physics, element 119, 010308 nuclear & particles physics, element 120, Superheavy Elements, 01 natural sciences, Island of stability, Recoil separator, Nuclear physics, superheavy elements, Production cross section, Subatomic Physics, 0103 physical sciences, 540 Chemistry, 570 Life sciences, biology, low and intermediate energy heavy-ion reactions, Atomic number, Irradiation, Sensitivity (control systems), ydinfysiikka, 010306 general physics, Beam energy
Abstract

A search for production of the superheavy elements with atomic numbers 119 and 120 was performed in the 50Ti+249Bk and 50Ti+249Cf fusion-evaporation reactions, respectively, at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. Over four months of irradiation, the 249Bk target partially decayed into 249Cf, which allowed for a simultaneous search for both elements. Neither was detected at cross-section sensitivity levels of 65 and 200 fb for the 50Ti+249Bk and 50Ti+249Cf reactions, respectively, at a midtarget beam energy of Elab=281.5 MeV. The nonobservation of elements 119 and 120 is discussed within the concept of fusion-evaporation reactions including various theoretical predictions on the fission-barrier heights of superheavy nuclei in the region of the island of stability. peerReviewed

Published
2020

19. Mapping of fragmented νf5/2→πf7/2 transitions in the Co73→Ni73 decay

Author

K. P. Rykaczewski, K. Kolos, Carl J Gross, J. C. Batchelder, C. J. Prokop, Mustafa Rajabali, A. A. Ciemny, Sean Liddick, T. N. Ginter, S. Taylor, Y. Xiao, S. V. Paulauskas, Shintaro Go, Thomas Baumann, Robert Grzywacz, C. Mazzocchi, M. Al-Shudifat, and A. Korgul

Subjects
Physics, 010308 nuclear & particles physics, Branching fraction, State (functional analysis), 7. Clean energy, 01 natural sciences, Superconducting cyclotron, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Energy (signal processing), Excitation
Abstract

Excited states in ${}^{73,75}\mathrm{Ni}$ were investigated through the $\ensuremath{\beta}$ decay of ${}^{73,75}\mathrm{Co}$ in an experiment performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). The experimental results extended the level scheme of $^{73}\mathrm{Ni}$ to 3.2-MeV excitation energy and provided the experimental information on excited states in $^{75}\mathrm{Ni}$. The $\ensuremath{\beta}$-delayed neutron branching ratio for $^{73}\mathrm{Co}$ was obtained. The experimental results are discussed in comparison with shell-model calculations.

Published
2020

20. New transitions and levels for Tb163 obtained from β -decay studies

Author

C. Jost, D. W. Stracener, A. V. Ramayya, B. M. Musangu, S. H. Liu, S. W. Padgett, A. J. Mendez, N. T. Brewer, J. C. Batchelder, Robert Grzywacz, J. M. Eldridge, K. Miernik, K. P. Rykaczewski, A. C. Dai, C. J. Gross, J. H. Hamilton, M. Madurga, A. Fijałkowska, E. F. Zganjar, Furong Xu, Marzena Wolinska-Cichocka, E. H. Wang, S. V. Ilyushkin, Stan Paulauskas, M. Karny, C. J. Zachary, D.W. Miller, and J. A. Winger

Subjects
Physics, Atomic physics
Published
2020

21. Identification of new transitions and levels in Gd163 from β -decay studies

Author

K. P. Rykaczewski, K. Miernik, C. Jost, A. V. Ramayya, D. W. Stracener, Marzena Wolinska-Cichocka, J. H. Hamilton, Furong Xu, M. Madurga, B. M. Musangu, Stan Paulauskas, E. H. Wang, N. T. Brewer, M. Karny, S. H. Liu, S. V. Ilyushkin, Yuan Liu, D.W. Miller, A. Fijałkowska, S. W. Padgett, J. C. Batchelder, J. A. Winger, A. C. Dai, E. F. Zganjar, A. J. Mendez, C. J. Zachary, J. M. Eldridge, Yu Sun, Robert Grzywacz, and C. J. Gross

Subjects
Physics, Ion beam, 010308 nuclear & particles physics, SHELL model, Nuclear structure, Scintillator, Oak Ridge National Laboratory, 01 natural sciences, Nuclear physics, 0103 physical sciences, Potential energy surface, Nuclear force, Neutron, 010306 general physics
Abstract

Background: Neutron-rich nuclei in the mass region around A=160 have been and will continue to be of interest for the study of nuclear structure because of the rapid onset of deformation between 88 and 90 neutrons. The observation of detailed changes in nuclear structures within this mass region has provided and will continue to provide insight into the nuclear force. Purpose: Investigations of γ rays emitted following Eu163 β-decay to Gd163 have been performed for evaluation of the nuclear structure of Gd163. Method: Data were collected at the LeRIBSS station of the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory with an array of four Clover HPGe detectors for γ-rays and two plastic scintillators for β detection. The γ rays were identified as belonging to Gd163 via mass selection and γ-γ-β, x-ray-γ, or γ-γ coincidences. Results: In total 107 new γ-ray transitions were observed in Gd163 from 53 newly identified levels. Conclusions: The structure of Gd163 has been identified for the first time. This structure has been evaluated in comparison to projected shell model, and potential energy surface calculations with good agreement.

Published
2020

22. First identification of Zn58 β -delayed proton emission

Author

Robert Grzywacz, K. Kolos, A. Korgul, T. Rogiński, Y. Xiao, C. Mazzocchi, Pedro Sarriguren, Hendrik Schatz, E. Kwan, M. Cwiok, T. N. Ginter, A. A. Bezbakh, Thomas Baumann, M. Pomorski, A. A. Ciemny, G. Kaminski, J. Pereira, M. Kuich, S. V. Paulauskas, Benjamin P. Crider, M. Pfützner, K. P. Rykaczewski, Z. Janas, Shintaro Go, Chandana Sumithrarachchi, W. Dominik, D. Bazin, K. Miernik, and Sean Liddick

Subjects
Physics, Analytical chemistry, Identification (biology), Proton emission
Published
2020

23. Study of Neutron-Deficient Nuclei in the 239,240Pu+48Ca Reactions

Author

F. Sh. Abdullin, K. P. Rykaczewski, Robert Grzywacz, J. H. Hamilton, A. I. Svirikhin, A. A. Voinov, Zibao Gan, N. T. Brewer, Yu. Ts. Oganessian, M. V. Shumeiko, I. V. Shirokovsky, R. N. Sagaidak, A. G. Popeko, Lanqing Ma, A. M. Sukhov, V. G. Subbotin, James B. Roberto, A. V. Karpov, Yu. S. Tsyganov, V. K. Utyonkov, M. G. Itkis, K. Miernik, A. N. Polyakov, A. V. Sabelnikov, M. A. Stoyer, L. Schlattauer, S. N. Dmitriev, N. D. Kovrizhnykh, W. Huang, and Grigory K. Vostokin

Subjects
Materials science, Radiochemistry, Neutron
Published
2019

24. Experimental Study of the 249-251Cf + 48Ca Reactions: Toward the Magic Neutron Number N=184

Author

S. M. Van Cleve, M. G. Itkis, Grigory K. Vostokin, S. N. Dmitriev, Robert Grzywacz, D. C. McInturff, G. D. Owen, M. A. Stoyer, A. G. Popeko, James B. Roberto, A. I. Svirikhin, V. G. Subbotin, E. H. Smith, Rose A. Boll, R. N. Sagaidak, C. S. White, Yu. Ts. Oganessian, A. M. Sukhov, A. A. Voinov, N. T. Brewer, K. Miernik, A. N. Polyakov, K. P. Rykaczewski, Julie G. Ezold, J. H. Hamilton, Nathan J. Sims, N. D. Kovrizhnykh, D. J. Dean, V. K. Utyonkov, L. K. Felker, M. V. Shumeiko, Yu. S. Tsyganov, F. Sh. Abdullin, A. V. Sabelnikov, and I. V. Shirokovsky

Subjects
Physics, Nuclear physics, Neutron number, Magic (programming)
Published
2019

25. A novel experimental system for the KDK measurement of the 40K decay scheme relevant for rare event searches

Author

Jelena Ninkovic, P. Lechner, K.C. Goetz, K. Dering, Eric Lukosi, P. Squillari, H. Davis, Charles L. Melcher, Jouni Suhonen, N. T. Brewer, A. Fijałkowska, D. W. Stracener, P. Di Stefano, Z. Gai, Itay Yavin, B. C. Rasco, K. P. Rykaczewski, F. Petricca, P. Davis, Luis Stand, M. Constable, Robert Grzywacz, L. Hariasz, M. Mancuso, Christopher M. Rouleau, M. Stukel, Yuan Liu, Marzena Wolinska-Cichocka, and Joel Kostensalo

Subjects
Physics, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Decay scheme, Silicon drift detector, Spectrometer, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Electron capture, Branching fraction, Detector, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Scintillator, 7. Clean energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Instrumentation, Event (particle physics)
Abstract

Potassium-40 ($^{40}$K) is a long-lived, naturally occurring radioactive isotope. The decay products are prominent backgrounds for many rare event searches, including those involving NaI-based scintillators. $^{40}$K also plays a role in geochronological dating techniques. The branching ratio of the electron capture directly to the ground state of argon-40 has never been measured, which can cause difficulty in interpreting certain results or can lead to lack of precision depending on the field and analysis technique. The KDK (Potassium (K) Decay (DK)) collaboration is measuring this decay. A composite method has a silicon drift detector with an enriched, thermally deposited $^{40}$K source inside the Modular Total Absorption Spectrometer. This setup has been characterized in terms of energy calibration, gamma tagging efficiency, live time and false negatives and positives. A complementary, homogeneous, method is also discussed; it employs a KSr$_2$I$_5$:Eu scintillator as source and detector., Comment: 20 pages, 24 figures, Submitted to NIM A

Published
2021

26. Discovery of element 117: Super-heavy elements and the 'island of stability'*

Author

K. P. Rykaczewski and J. B. Roberto

Subjects
010308 nuclear & particles physics, Process Chemistry and Technology, General Chemical Engineering, chemistry.chemical_element, Transactinide element, Mineralogy, Filtration and Separation, General Chemistry, Actinide, Oak Ridge National Laboratory, 01 natural sciences, Island of stability, Nuclear physics, Berkelium, chemistry, 0103 physical sciences, 010306 general physics, Joint (geology)
Abstract

Element 117 (tennessine) joined the periodic table in November 2016. Two tennessine isotopes were synthesized by bombarding 249Bk from Oak Ridge National Laboratory with 48Ca ions at the Joint Inst...

Published
2017

27. Modular total absorption spectrometer

Author

Robert Grzywacz, K.C. Goetz, E.F. Zganjar, Bertis Rasco, Marzena Wolinska-Cichocka, K. P. Rykaczewski, M. Karny, David Miller, and A. Fijałkowska

Subjects
High peak, Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, business.industry, Detector, Analytical chemistry, Modular design, Oak Ridge National Laboratory, Modular construction, 01 natural sciences, Nuclear magnetic resonance, 0103 physical sciences, 010306 general physics, Absorption (electromagnetic radiation), business, Instrumentation, Delayed neutron
Abstract

The design and performance of the Modular Total Absorption Spectrometer built and commissioned at the Oak Ridge National Laboratory is presented. The active volume of the detector is approximately one ton of NaI(Tl), which results in very high full γ energy peak efficiency of 71% at 6 MeV and nearly flat efficiency of around 81.5% for low energy γ -rays between 300 keV and 1 MeV. In addition to the high peak efficiency, the modular construction of the detector permits the use of a γ -coincidence technique in data analysis as well as β -delayed neutron observation.

Published
2016

28. Strong one-neutron emission from two-neutron unbound states in β decays of the r -process nuclei Ga86,87

Author

G. Cortes, L. J. Harkness-Brennan, X. X. Xu, Robert Grzywacz, K. Matsui, G. G. Kiss, A. Algora, C. Domingo-Pardo, H. Takeda, D. S. Ahn, K. P. Rykaczewski, Mustafa Rajabali, J. Simpson, C. J. Griffin, M. Singh, Y. Saito, K. Miernik, P. J. Woods, Shigeru Kubono, Le Hong Khiem, D. W. Stracener, Jun Liang, M. Karny, N. Nepal, A. Korgul, R. Caballero-Folch, T. Isobe, M. Wolińska-Cichocka, Hiroyoshi Sakurai, P. J. Coleman-Smith, H. Baba, V. H. Phong, A. I. Morales, T. T. King, S.L. Thomas, Toshiyuki Sumikama, Fernando Montes, Joseph Heideman, Ariel Tarifeño-Saldivia, M. Prydderch, I.H. Lazarus, J. Ha, A. Estrade, H. Suzuki, M. Piersa, N. Fukuda, F. Calviño, Jorge Agramunt, R. Yokoyama, B. C. Rasco, Shintaro Go, J. M. Allmond, J. L. Tain, Rebecca Surman, Giuseppe Lorusso, S. Bae, D. Kahl, Berta Rubio, O. Hall, M. Madurga, Toshihiko Kawano, P. Morrall, N. T. Brewer, R. D. Page, M. Labiche, JJ Liu, V. F. E. Pucknell, A. Tolosa-Delgado, Y. Shimizu, Shunji Nishimura, Iris Dillmann, T. Davinson, and C. G. Bruno

Subjects
Physics, Nuclear physics, 010308 nuclear & particles physics, Neutron emission, 0103 physical sciences, Nuclear structure, r-process, Neutron, 010306 general physics, 01 natural sciences, Delayed neutron, Beta decay, 3. Good health
Abstract

Aquesta es una copia de la versio author’s final draft d'un article publicat a la revista [Physical Review C ]. URL d'aquest document a UPCommons E-prints: http://hdl.handle.net/2117/174873

Published
2019

29. Observation of a μs isomer in In8549134 : Proton-neutron coupling 'southeast' of Sn8250132

Author

M. Wolińska-Cichocka, Ana Isabel Morales, J. M. Allmond, Y. Shimizu, V. H. Phong, Shunji Nishimura, L. H. Khiem, G. G. Kiss, P. J. Woods, Shigeru Kubono, T. Isobe, Alfredo Estrade, Hiroyoshi Sakurai, A. Jungclaus, Z. Y. Xu, T. Davinson, Bertis Rasco, D. W. Stacener, Giuseppe Lorusso, G. Cortes, L. J. Harkness-Brennan, A. Boso, N. T. Brewer, Carlo Bruno, Iris Dillmann, P. H. Regan, D. Kahl, Toshiyuki Sumikama, F. Calviño, Alejandro Algora, Ariel Tarifeño-Saldivia, H. Suzuki, R. Caballero-Folch, K. Miernik, Cenxi Yuan, H. Takeda, D. S. Ahn, Robert Grzywacz, J. L. Tain, J. Liu, H. Baba, Shintaro Go, César Domingo Pardo, K. Matsui, C. J. Griffin, Fernando Montes, Jorge Agramunt, Victor Vaquero, N. Nepal, A. Korgul, K. P. Rykaczewski, A. Gargano, M. Piersa, R. Shearman, R. Yokoyama, O. Hall, Zs. Podolyák, and A. Tolosa-Delgado

Subjects
Physics, Coupling, Proton, 010308 nuclear & particles physics, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, 01 natural sciences
Published
2019

30. A new reference database for beta-delayed neutrons

Author

K. P. Rykaczewski, G. Mukherjee, Jose-Luis Tain, Alejandro Sonzogni, Iris Dillmann, Xiaolong Huang, Bertis-Charlie Rasco, Ivan Borzov, Tomislav Marketin, D. Cano-Ott, Muriel Fallot, Vladimir M. Piksaikin, Balraj Singh, Alejandro Algora, Satoshi Chiba, Futoshi Minato, Daniela Foligno, Kaushik Banerjee, Marco Verpelli, Robert Grzywacz, P. Dimitriou, Laboratoire de physique subatomique et des technologies associées (SUBATECH), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique)

Subjects
Physics, 010308 nuclear & particles physics, QC1-999, Experimental data, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Decay curve, Nuclear physics, 0103 physical sciences, Reference database, Neutron, Beta (velocity), Nuclear Experiment, 010306 general physics, Delayed neutron
Abstract

International audience; A new database containing all available experimental and evaluated β-delayed neutron data is presented in this paper. The database is the product of an international effort coordinated by the International Atomic Energy Agency. It comprises a microscopic section including all available experimental data on beta-decay half-lives, β-delayed neutron emission probabilities and spectra, as well as new systematics and global theoretical calculations for comparison. The beta-delayed neutron data for individual precursors have been benchmarked against available data on macroscopic properties such as total delayed-neutron yields and spectra, delayed-neutron decay curves and time-dependent group parameters using the summation method. All available measured macroscopic data have also been compiled in the macroscopic section of the database. The dedicated database is available online on the IAEA server (URL:http://www-nds.iaea.org/beta-delayed-neutron/database.html).

Published
2019

31. Fusion reaction Ca48+Bk249 leading to formation of the element Ts ( Z=117 )

Author

Rose A. Boll, G. K. Pang, Daniel Cox, Susanta Lahiri, F. P. Heßberger, J. Hoffmann, Daniel Ward, Evgeny E. Tereshatov, M. Wegrzecki, K. Tinschert, R. Lang, Andreas Türler, J. Krier, Claes Fahlander, C. Mokry, Julia Even, T. Torres De Heidenreich, Egon Jäger, D. Renisch, J. V. Kratz, D. A. Shaughnessy, H. Brand, R. Hollinger, J. M. Gates, Jon Petter Omtvedt, X. Derkx, S. M. Van Cleve, L.-L. Andersson, Philippos Papadakis, S. Minami, Klaus Eberhardt, U. Forsberg, W. Hartmann, A. Di Nitto, Norbert Trautmann, James B. Roberto, N. Kurz, V. Yakusheva, J. Runke, Bettina Lommel, Mahananda Dasgupta, A. Hübner, Alexander Yakushev, Matthias Schädel, Kenneth E. Gregorich, Patrick Steinegger, B. Schausten, H. Nitsche, Birgit Kindler, Luis Sarmiento, Juha Uusitalo, Maurits Evers, Dirk Rudolph, K. Miernik, R.-D. Herzberg, Ch. E. Düllmann, N. Gharibyan, A. Semchenkov, Pavel Golubev, Dieter Ackermann, Petra Thörle-Pospiech, J. Steiner, A. K. Mistry, M. Asai, David Hinde, Michael Block, M. Laatiaoui, Norbert Wiehl, K. P. Rykaczewski, J. H. Hamilton, Jadambaa Khuyagbaatar, and Moumita Maiti

Subjects
Physics, Nuclear physics, Nuclear Theory, Nuclear fusion, Decay chain, Alpha decay, Actinide, Superheavy Elements, Nuclear Experiment, Recoil separator
Abstract

The heaviest currently known nuclei, which have up to 118 protons, have been produced in 48Ca induced reactions with actinide targets. Among them, the element tennessine (Ts), which has 117 protons, has been synthesized by fusing 48Ca with the radioactive target 249Bk, which has a half-life of 327 d. The experiment was performed at the gas-filled recoil separator TASCA. Two long and two short α decay chains were observed. The long chains were attributed to the decay of 294Ts. The possible origin of the short-decay chains is discussed in comparison with the known experimental data. They are found to fit with the decay chain patterns attributed to 293Ts. The present experimental results confirm the previous findings at the Dubna Gas-Filled Recoil Separator on the decay chains originating from the nuclei assigned to Ts.

Published
2019

32. Improving Nuclear Data Input for r-Process Calculations Around A $$\sim $$ 80

Author

A. Tolosa-Delgado, J. Agramunt, D. S. Ahn, A. Algora, H. Baba, S. Bae, N. T. Brewer, C. Bruno, R. Caballero Folch, F. Calviño, P. J. Coleman-Smith, G. Cortés, T. Davinson, I. Dillmann, C. Domingo-Pardo, A. Estrade, N. Fukuda, S. Go, C. J. Griffin, R. Grzywacz, J. Ha, O. Hall, L. Harkness-Brennan, T. Isobe, D. Kahl, M. Karny, L. H. Khiem, G. G. Kiss, M. Kogimtzis, S. Kubono, M. Labiche, I. Lazarus, J. Lee, J. Liang, J. Liu, G. Lorusso, K. Matsui, K. Miernik, F. Montes, B. Moon, A. I. Morales, N. Nepal, S. Nishimura, R. D. Page, V. H. Phong, Z. Podolyak, V. F. E. Pucknell, B. C. Rasco, P. Regan, A. Riego, B. Rubio, K. P. Rykaczewski, Y. Saito, H. Sakurai, Y. Shimizu, J. Simpson, P.-A. Söderström, D. W. Stracener, T. Sumikama, H. Suzuki, J. L. Tain, M. Takechi, H. Takeda, A. Tarifeño-Saldivia, S. L. Thomas, P. J. Woods, X. X. Xu, and R. Yokoyama

Subjects
Nuclear physics, Physics, Abundance (ecology), Neutron emission, r-process, Nuclear data, Measure (mathematics)
Abstract

© 2019, Springer Nature Switzerland AG. We made an experiment to measure half-lives T1/2 and neutron emission probabilities Pxn of nuclei around mass 80, aiming to improve r-process abundance calculations around the first abundance peak with a new dedicated experimental setup at RIKEN. Details of the experiment and a few preliminary results are presented.

Published
2019

33. Recoil-α-fission and recoil-α–α-fission events observed in the reaction 48Ca + 243Am

Author

Carl J Gross, Julia Even, J. Krier, Witold Nazarewicz, T. Torres, Alexander Yakushev, K. P. Rykaczewski, I. Kojouharov, Matthias Schädel, Dirk Rudolph, Birgit Kindler, Ch. E. Düllmann, N. Kurz, Daniel Cox, F. P. Heßberger, Egon Jäger, Ingemar Ragnarsson, Klaus Eberhardt, Michael Block, J. P. Omtvedt, C. Mokry, Dieter Ackermann, Jacek Dobaczewski, Petra Thörle-Pospiech, H. Schaffner, A. Ward, Sven Åberg, J. V. Kratz, Daniel Ward, A. K. Mistry, Andreas Türler, Philippos Papadakis, Heino Nitsche, Kenneth E. Gregorich, Norbert Wiehl, Claes Fahlander, U. Forsberg, X. Derkx, Jadambaa Khuyagbaatar, H. Brand, Bettina Lommel, J. Gerl, A. Di Nitto, Yue Shi, Jörg Runke, B. G. Carlsson, J. M. Gates, L.-L. Andersson, B. Schausten, Luis Sarmiento, Norbert Trautmann, R.-D. Herzberg, Pavel Golubev, T. Traut, Forsberg, U., Rudolph, D., Andersson, L. -L., Di Nitto, A., Dullmann, C. E., Fahlander, C., Gates, J. M., Golubev, P., Gregorich, K. E., Gross, C. J., Herzberg, R. -D., Hessberger, F. P., Khuyagbaatar, J., Kratz, J. V., Rykaczewski, K., Sarmiento, L. G., Schadel, M., Yakushev, A., Aberg, S., Ackermann, D., Block, M., Brand, H., Carlsson, B. G., Cox, D., Derkx, X., Dobaczewski, J., Eberhardt, K., Even, J., Gerl, J., Jager, E., Kindler, B., Krier, J., Kojouharov, I., Kurz, N., Lommel, B., Mistry, A., Mokry, C., Nazarewicz, W., Nitsche, H., Omtvedt, J. P., Papadakis, P., Ragnarsson, I., Runke, J., Schaffner, H., Schausten, B., Shi, Y., Thorle-Pospiech, P., Torres, T., Traut, T., Trautmann, N., Turler, A., Ward, A., Ward, D. E., and Wiehl, N.

Subjects
Nuclear and High Energy Physics, alpha decay, Fission, Superheavy elements, chemistry.chemical_element, Superheavy Elements, nucl-ex, Atomic, 01 natural sciences, 7. Clean energy, Nuclear physics, Particle and Plasma Physics, Recoil, 0103 physical sciences, Nuclear, Element 115, α decay, Nuclear Experiment, 010306 general physics, Ununpentium, Spontaneous fission, Physics, Quantum Physics, Uup, 010308 nuclear & particles physics, Molecular, Nuclear & Particles Physics, Superheavy element, chemistry, Decay chain, Alpha decay, Astronomical and Space Sciences, Excitation
Abstract

Products of the fusion-evaporation reaction 48Ca + 243Am were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. Amongst the detected thirty correlated α-decay chains associated with the production of element Z=115, two recoil-α-fission and five recoil-α-α-fission events were observed. The latter five chains are similar to four such events reported from experiments performed at the Dubna gas-filled separator, and three such events reported from an experiment at the Berkeley gas-filled separator. The four chains observed at the Dubna gas-filled separator were assigned to start from the 2n-evaporation channel 289115 due to the fact that these recoil-α-α-fission events were observed only at low excitation energies. Contrary to this interpretation, we suggest that some of these recoil-α-α-fission decay chains, as well as some of the recoil-α-α-fission and recoil-α-fission decay chains reported from Berkeley and in this article, start from the 3n-evaporation channel 288115.

Published
2016

34. Actinide targets for the synthesis of super-heavy elements

Author

Susan L. Hogle, K. P. Rykaczewski, Rose A. Boll, Julie G. Ezold, L. K. Felker, James B. Roberto, Jonathan D. Burns, and C.W. Alexander

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Berkelium, chemistry, business.industry, Einsteinium, chemistry.chemical_element, Transactinide element, Californium, Actinide, Process engineering, business
Abstract

Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of 48Ca beams on actinide targets. These target materials, including 242Pu, 244Pu, 243Am, 245Cm, 248Cm, 249Cf, and 249Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including 249Bk, 251Cf, and 254Es are described.

Published
2015
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35. The KDK (potassium decay) experiment

Author

Charles L. Melcher, K. P. Rykaczewski, N. T. Brewer, K.C. Goetz, M. WoliĔska-Cichocka, Christopher M. Rouleau, Daniel Hamm, P. Lechner, Eric Lukosi, P. Squillari, Jelena Ninkovic, M. Stukel, I. Yavin, Z. Gai, A. Fijałkowska, Yuan Liu, M. Mancuso, A. C. Rasco, Luis Stand, D. W. Stracener, Robert Grzywacz, P. Di Stefano, and F. Petricca

Subjects
History, Materials science, Spectrometer, Branching fraction, Potassium, Dark matter, Analytical chemistry, X-ray detector, chemistry.chemical_element, Computer Science Applications, Education, chemistry, Ground state, Absorption (electromagnetic radiation)
Abstract

Potassium-40 (40K) is a background in many rare-event searches and may well play a role in interpreting results from the DAMA dark-matter search. The electron-capture decay of 40K to the ground state of 40 Ar has never been measured and contributes an unknown amount of background. The KDK (potassium decay) collaboration will measure this branching ratio using a 40K source, an X-ray detector, and the Modular Total Absorption Spectrometer at Oak Ridge National Laboratory.

Published
2020

36. Low-lying states in Ra219 and Rn215 : Sampling microsecond α -decaying nuclei

Author

Alexander Yakushev, Ingemar Ragnarsson, N. Kurz, Julia Even, K. P. Rykaczewski, T. Torres, Carl J Gross, I. Kojouharov, Andreas Türler, R.-D. Herzberg, Dirk Rudolph, J. P. Omtvedt, Jörg Runke, B. Schausten, Luis Sarmiento, J. Krier, F. P. Heßberger, Pavel Golubev, Ch. E. Düllmann, J. M. Gates, Birgit Kindler, L.-L. Andersson, Michael Block, J. V. Kratz, B. G. Carlsson, Norbert Wiehl, Bettina Lommel, Klaus Eberhardt, Dieter Ackermann, Petra Thörle-Pospiech, Norbert Trautmann, Egon Jäger, H. Schaffner, Claes Fahlander, Kenneth E. Gregorich, J. Gerl, Matthias Schädel, A. Di Nitto, A. Ward, U. Forsberg, C. Mokry, J Ljungberg, A. Såmark-Roth, Philippos Papadakis, H. Brand, A. K. Mistry, Jadambaa Khuyagbaatar, and Daniel Cox

Subjects
Physics, 010308 nuclear & particles physics, Nuclear shell model, Half-life, 01 natural sciences, Nuclear physics, Microsecond, 0103 physical sciences, Atomic nucleus, Gamma spectroscopy, Alpha decay, Decay chain, Nuclide, 010306 general physics
Abstract

Short-lived α-decaying nuclei "northeast" of 208Pb in the chart of nuclides were studied using the reaction 48Ca+243Am with the decay station TASISpec at TASCA, GSI Darmstadt. Decay energies and times from pile-up events were extracted with a tailor-made pulse-shape analysis routine and specific α-decay chains were identified in a correlation analysis. Decay chains starting with the even-even 220Ra and its odd-A neighbors, 219Fr, and 219,221Ra, with a focus on the 219Ra→215Rn decay, were studied by means of α-γ spectroscopy. A revised α-decay scheme of 219Ra is proposed, including a new decay branch from a previously not considered isomeric state at 17 keV excitation energy. Conclusions on nuclear structure are drawn from the experimental data, aided by Geant4 simulations and a discussion on theoretical calculations. (Less)

Published
2018

37. Updated β -decay measurement of neutron-rich Cu74

Author

E. F. Zganjar, Carl J Gross, Mustafa Rajabali, A. J. Mendez, Robert Grzywacz, Durga Siwakoti, M. Madurga, Lucia Cartegni, K. Miernik, Umesh Silwal, S. W. Padgett, Marzena Wolinska-Cichocka, C. R. Bingham, C. Jost, D. W. Stracener, J. C. Batchelder, C. Mazzocchi, Yuan Liu, W. Krolas, A. A. Ciemny, N. T. Brewer, K. P. Rykaczewski, D.W. Miller, K. Kolos, J. L. Tracy, A. Korgul, A. Fijałkowska, Bertis Rasco, Stan Paulauskas, M. Karny, and J. A. Winger

Subjects
Nuclear physics, Physics, 010308 nuclear & particles physics, 0103 physical sciences, Neutron, 010306 general physics, 01 natural sciences
Published
2018

38. Search for the heaviest atomic nuclei among the products from reactions of mixed-Cf with a Ca48 beam

Author

Robert Grzywacz, I. V. Shirokovsky, A. V. Sabelnikov, M. G. Itkis, A. A. Voinov, S. N. Dmitriev, N. T. Brewer, K. Miernik, F. Sh. Abdullin, A. N. Polyakov, Nathan J. Sims, K. P. Rykaczewski, Julie G. Ezold, S. M. Van Cleve, J. H. Hamilton, G. D. Owen, R. N. Sagaidak, M. V. Shumeiko, A. I. Svirikhin, A. M. Sukhov, E. H. Smith, L. K. Felker, N. D. Kovrizhnykh, V. G. Subbotin, Rose A. Boll, A. G. Popeko, Yu. S. Tsyganov, D. J. Dean, V. K. Utyonkov, C. S. White, Yu. Ts. Oganessian, James B. Roberto, M. A. Stoyer, Grigory K. Vostokin, and D. C. McInturff

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Detector, chemistry.chemical_element, Californium, 01 natural sciences, Recoil separator, Nuclear physics, chemistry, 0103 physical sciences, Atomic nucleus, Irradiation, Decay chain, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract

The search for new decay chains of oganesson isotopes is presented. The experiment utilized the Dubna Gas Filled Recoil Separator and a highly segmented recoil-decay detection system. The signals from all detectors were analyzed in parallel by digital and analog data acquisition systems. For the first time, a target of mixed californium (51% Cf249, 13% Cf250, and 36% Cf251) recovered from decayed Cf252 sources was produced and irradiated with an intense Ca48 beam. The observation of a new decay chain of Og294 is reported. The prospects for reaching new isotopes Og295,296 are discussed.

Published
2018

39. The ORNL Analysis Technique for Extracting $\beta$-Delayed Multi-Neutron Branching Ratios with BRIKEN

Author

Shunji Nishimura, C. J. Griffin, G. G. Kiss, K. P. Rykaczewski, A. Estrade, V. H. Phong, A. Algora, O. Hall, Thomas Davinson, Jorge Agramunt, Robert Grzywacz, B. C. Rasco, R. Yokoyama, J. Liu, A. Tolosa-Delgado, J. L. Tain, N. Nepal, and N. T. Brewer

Subjects
Physics, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Branching (polymer chemistry), nucl-ex, 01 natural sciences, Coincidence, Nuclear physics, 0103 physical sciences, Neutron detection, Neutron, 010306 general physics, Nuclear Experiment, Instrumentation, physics.ins-det, Radioactive decay
Abstract

Many choices are available in order to evaluate large radioactive decay networks. %multi-particle decay data. There are many parameters that influence the calculated $\beta$-decay delayed single and multi-neutron emission branching fractions. We describe assumptions about the decay model, background, and other parameters and their influence on $\beta$-decay delayed multi-neutron emission analysis. An analysis technique, the ORNL BRIKEN analysis procedure, for determining $\beta$-delayed multi-neutron branching ratios in $\beta$-neutron precursors produced by means of heavy-ion fragmentation is presented. The technique is based on estimating the initial activities of zero, one, and two neutrons occurring in coincidence with an ion-implant and $\beta$ trigger. The technique allows one to extract $\beta$-delayed multi-neutron decay branching ratios measured with the hybrid \textsuperscript{3}He BRIKEN neutron counter. As an example, two analyses of the $\beta$-neutron emitter \textsuperscript{77}Cu based on different {\it a priori} assumptions are presented along with comparisons to literature values., Comment: 21 pages, 10 figures

Published
2018

40. β -delayed neutron emission from Ga85

Author

K. P. Rykaczewski, David Miller, D. W. Stracener, Carl J Gross, E. F. Zganjar, A. J. Mendez, Yuan Liu, J. A. Winger, C. Mazzocchi, Robert Grzywacz, Marzena Wolinska-Cichocka, J. C. Batchelder, N. T. Brewer, M. Madurga, K. Miernik, A. Korgul, and S. V. Paulauskas

Subjects
Physics, Decay scheme, Ion beam, 010308 nuclear & particles physics, Neutron emission, Astrophysics::High Energy Astrophysical Phenomena, 01 natural sciences, Ion source, 0103 physical sciences, Beta (velocity), Atomic physics, 010306 general physics, Spectroscopy, Delayed neutron, Beam (structure)
Abstract

Decay of $^{85}\mathrm{Ga}$ was studied by means of $\ensuremath{\beta}$-neutron-$\ensuremath{\gamma}$ spectroscopy. A pure beam of $^{85}\mathrm{Ga}$ was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and a high-resolution electromagnetic separator. The $\ensuremath{\beta}$-delayed neutron emission probability was measured for the first time, yielding 70(5)%. An upper limit of 0.1% for $\ensuremath{\beta}$-delayed two-neutron emission was also experimentally established for the first time. A detailed decay scheme including absolute $\ensuremath{\gamma}$-ray intensities was obtained. Results are compared with theoretical $\ensuremath{\beta}$-delayed emission models.

Published
2018

41. Neutron-deficient superheavy nuclei obtained in the Pu240+Ca48 reaction

Author

F. Sh. Abdullin, Lanqing Ma, Grigory K. Vostokin, R. N. Sagaidak, S. N. Dmitriev, A. I. Svirikhin, K. P. Rykaczewski, A. M. Sukhov, M. A. Stoyer, M. V. Shumeiko, L. Schlattauer, Robert Grzywacz, J. H. Hamilton, Yu. S. Tsyganov, A. V. Sabelnikov, A. V. Karpov, Zibao Gan, I. V. Shirokovsky, V. K. Utyonkov, K. Miernik, A. G. Popeko, A. N. Polyakov, M. G. Itkis, A. A. Voinov, V. G. Subbotin, N. T. Brewer, N. D. Kovrizhnykh, Yu. Ts. Oganessian, Wenxue Huang, and James B. Roberto

Subjects
Physics, Nuclear physics, 010308 nuclear & particles physics, 0103 physical sciences, Neutron, 010306 general physics, 01 natural sciences
Published
2018

42. Commissioning of the BRIKEN detector for the measurement of very exotic beta-delayed neutron emitters

Author

P. J. Coleman-Smith, T. T. King, B. Rubio, Shigeru Kubono, C. G. Bruno, K. P. Rykaczewski, K. Matsui, Robert Grzywacz, J. Ha, J. M. Allmond, H. Baba, J. Liu, V. H. Phong, A. I. Morales, Mark L. Prydderch, Shunji Nishimura, B. Moon, S. Bae, D. W. Stracener, A. Estrade, Giuseppe Lorusso, J. Simpson, V. F. E. Pucknell, Philip Woods, Y. Shimizu, H. Suzuki, A. Tolosa-Delgado, Y. Saito, N. T. Brewer, R. D. Page, D. Kahl, Ariel Tarifeño-Saldivia, Iris Dillmann, N. Nepal, S.L. Thomas, Toshiyuki Sumikama, Maya Takechi, Shintaro Go, F. Calviño, C. J. Griffin, N. Fukuda, R. Caballero-Folch, R. Yokoyama, C. Domingo-Pardo, M. Singh, O. Hall, H. Takeda, D. S. Ahn, M. Labiche, M. Madurga, G. G. Kiss, A. Algora, Jun Liang, Thomas Davinson, Jorge Agramunt, J. L. Tain, P. A. Söderström, Fernando Montes, Hiroyoshi Sakurai, Bertis Rasco, I.H. Lazarus, G. Cortes, L. J. Harkness-Brennan, T. Isobe, P.S. Morrall, Ministerio de Economía y Competitividad (España), Universitat Politècnica de Catalunya. Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya. Departament de Física, and Universitat Politècnica de Catalunya. ANT - Advanced Nuclear Technologies Research Group

Subjects
Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Nuclear physics, Beta-delayed neutrons, FOS: Physical sciences, Analysis methodology, 01 natural sciences, Ion, Neutron and beta counters, 0103 physical sciences, Dosimetry, Neutron, 010306 general physics, Nuclear Experiment, Instrumentation, Physics, Neutrons, Energies::Energia nuclear [Àrees temàtiques de la UPC], Física [Àrees temàtiques de la UPC], 010308 nuclear & particles physics, Detector, technology, industry, and agriculture, Instrumentation and Detectors (physics.ins-det), Background Correction, biological sciences, Física nuclear, Background correction, Delayed neutron
Abstract

A new detection system has been installed at the RIKEN Nishina Center (Japan) to investigate decay properties of very neutron-rich nuclei. The setup consists of three main parts: a moderated neutron counter , a detection system sensitive to the implantation and decay of radioactive ions, and γ -ray detectors. We describe here the setup, the commissioning experiment and some selected results demonstrating its performance for the measurement of half-lives and β -delayed neutron emission probabilities. The methodology followed in the analysis of the data is described in detail. Particular emphasis is placed on the correction of the accidental neutron background.

Published
2018
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43. A beachhead on the island of stability

Author

K. P. Rykaczewski and Yuri Oganessian

Subjects
Periodic system, Theoretical physics, Isotope, Chart, General Physics and Astronomy, Geometry, Nuclide, Stability (probability), Geology, Island of stability
Abstract

Recent experiments to synthesize the heaviest elements have dramatically expanded the periodic table and the Segre chart of nuclides.

Published
2015

44. The nonlinear light output of NaI(Tl) detectors in the Modular Total Absorption Spectrometer

Author

K. P. Rykaczewski, Bertis Rasco, Robert Grzywacz, M. Karny, A. Fijałkowska, K.C. Goetz, and Marzena Wolinska-Cichocka

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Fission products, Full width at half maximum, Ion beam, Spectrometer, Resolution (electron density), Detector, Absorption (electromagnetic radiation), Instrumentation, Spectral line
Abstract

A new detector array, the Modular Total Absorption Spectrometer (MTAS), was commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Lab (ORNL). Total absorption gamma spectra measured with MTAS are expected to improve beta-feeding patterns and beta strength functions in fission products. MTAS is constructed out of hexagonal NaI(Tl) detectors with a unique central module surrounded by 18 identical crystals assembled in three rings. The total NaI(Tl) mass of MTAS is over 1000 kg. The response of the central and other 18 MTAS modules to γ-radiation was simulated using the GEANT4 toolkit modified to analyze the nonlinear light output of NaI(Tl). A detailed description of the GEANT4 modifications made is discussed. Simulated energy resolution of MTAS modules is found to agree well with the measurements for single γ transitions of 662 keV (137Cs) with 8.2% full width half maximum (FWHM), 835 keV (54Mn) with FWHM of 7.5% FWHM, and 1115 keV (65Zn) with FWHM of 6.5%. Simulations of single and multiple γ-rays from 60Co are also discussed.

Published
2015
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45. Fission Barriers of Super-Heavy Nuclei and Search for Element 120

Author

D. A. Shaughnessy, J. Maurer, R. Mann, H. J. Schött, K. P. Rykaczewski, Roger Henderson, Jörg Runke, R. Grzywacz, A. G. Popeko, K. Tinschert, R. Lang, I. Kojouharov, S. Saro, H. G. Burkhard, Ken Moody, C. Scheidenberger, J. H. Hamilton, S. Heinz, Bettina Lommel, A. V. Yeremin, S. Hofmann, D. Miller, G. Münzenberg, James B. Roberto, Norbert Trautmann, J. M. Kenneally, Juha Uusitalo, Katsuhisa Nishio, Birgit Kindler, S. Antalic, Klaus Eberhardt, M. A. Stoyer, K. Miernik, K. Morita, L. Dahl, Petra Thörle-Pospiech, and W. Barth

Subjects
High probability, Physics, ta114, fission barriers, Isotope, Fission, super-heavy nuclei, Nuclear physics, fissio, Chain (algebraic topology), Decay chain, Element (category theory), ydinfysiikka, cross-sections, Nuclear Experiment
Abstract

After a successful production of isotopes of element 116 in the reaction 48Ca + 248Cm, the reaction 54Cr + 248Cm → 302120* was investigated at the velocity filter SHIP at GSI, Darmstadt, aiming to search for isotopes of element 120. One chain of events was observed, which is not created by chance with high probability. Parts of the chain agree with model predictions and measured data from a decay chain which could start at the isotope 299120. In a complementary study, model dependent shell-correction energies and related heights of fission barriers were deduced from measured Qα values. The results are compared with predictions of macroscopic-microscopic models. The consequences for calculations of crosssections are discussed.

Published
2017

46. Decays of the Three Top Contributors to the Reactor V¯e High-Energy Spectrum, 92Rb, 96gsY, and 142Cs, Studied with Total Absorption Spectroscopy

Author

E. F. Zganjar, C. J. Zachary, J. C. Blackmon, B. Heffron, C. D. Nesaraja, Shintaro Go, D. W. Stracener, J. T. Matta, Thomas King, R. K. Grzywacz, K. Miernik, A. Fijałkowska, Marzena Wolinska-Cichocka, C. J. Gross, B. C. Rasco, K. C. Goetz, M. M. Rajabali, Y. Xiao, E. H. Wang, Stan Paulauskas, M. Karny, K. P. Rykaczewski, N. T. Brewer, J. C. Batchelder, and J. A. Winger

Subjects
High energy, Materials science, Total absorption spectroscopy, Spectrum (functional analysis), Analytical chemistry
Published
2017

47. Discovery of Elements 113–118

Author

James B. Roberto, V. K. Utyonkov, K. J. Moody, Yu. Ts. Oganessian, M. A. Stoyer, D. A. Shaughnessy, S. N. Dmitriev, M. G. Itkis, K. P. Rykaczewski, and J. H. Hamilton

Subjects
Nuclear physics, Physics, Superheavy Elements
Published
2017

48. Beta-Delayed Neutron Measurements near 132Sn with CARIBU

Author

C J Gross, K. Kolos, K. P. Rykaczewski, W. A. Peters, J M Allmond, S. V. Paulauskas, T King, M. Al-Shudifat, S. Taylor, M. Madurga, R. Grzywacz, and Marzena Wolinska-Cichocka

Subjects
Materials science, Radiochemistry, Beta (finance), Delayed neutron
Published
2017

49. Impact of Modular Total Absorption Spectrometer measurements ofβdecay of fission products on the decay heat and reactorν¯eflux calculation

Author

K.C. Goetz, J.W. Johnson, B. C. Rasco, K. Miernik, S. V. Paulauskas, K. P. Rykaczewski, C. Jost, J. H. Hamilton, D. W. Stracener, Marzena Wolinska-Cichocka, Robert Grzywacz, M. Karny, M. Madurga, E. F. Zganjar, David Miller, W. Bielewski, S. Padgett, A. V. Ramayya, Carl J Gross, A. Fijałkowska, and R. Goans

Subjects
Physics, Fission products, 010308 nuclear & particles physics, Fission, Xenon-135, Analytical chemistry, General Physics and Astronomy, 01 natural sciences, Ion, Nuclear physics, Excited state, 0103 physical sciences, Absorption (logic), Decay heat, 010306 general physics, Energy (signal processing)
Abstract

We report the results of a β-decay study of fission products ^{86}Br, ^{89}Kr, ^{89}Rb, ^{90gs}Rb, ^{90m}Rb, ^{90}Kr, ^{92}Rb, ^{139}Xe, and ^{142}Cs performed with the Modular Total Absorption Spectrometer (MTAS) and on-line mass-separated ion beams. These radioactivities were assessed by the Nuclear Energy Agency as having high priority for decay heat analysis during a nuclear fuel cycle. We observe a substantial increase in β feeding to high excited states in all daughter isotopes in comparison to earlier data. This increases the average γ-ray energy emitted by the decay of fission fragments during the first 10 000 s after fission of ^{235}U and ^{239}Pu by approximately 2% and 1%, respectively, improving agreement between results of calculations and direct observations. New MTAS results reduce the reference reactor ν[over ¯]_{e} flux used to analyze reactor ν[over ¯]_{e} interaction with detector matter. The reduction determined by the ab initio method for the four nuclear fuel components, ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu, amounts to 0.976, 0.986, 0.983, and 0.984, respectively.

Published
2017

50. EXPERIMENTS ON SYNTHESIS OF SUPERHEAVY NUCLEI 284Fl AND 285Fl IN THE 239,240Pu + 48Ca REACTIONS

Author

Robert Grzywacz, V. K. Utyonkov, K. Miernik, A. N. Polyakov, Grigory K. Vostokin, K. P. Rykaczewski, M. G. Itkis, V. G. Subbotin, A. A. Voinov, N. T. Brewer, J. H. Hamilton, M. A. Stoyer, Yu. S. Tsyganov, James B. Roberto, M. V. Shumeiko, I. V. Shirokovsky, F. Sh. Abdullin, S. Y. Strauss, S. N. Dmitriev, A. V. Sabelnikov, Yu. Ts. Oganessian, R. N. Sagaidak, and A. M. Sukhov

Published
2017

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