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Author (up) BRIKEN Collaboration (Tarifeño-Saldivia, A. et al); Tain, J.L.; Domingo-Pardo, C.; Agramunt, J.; Algora, A.; Morales, A.I.; Rubio, B.; Tolosa, A.
Title Conceptual design of a hybrid neutron-gamma detector for study of beta-delayed neutrons at the RIB facility of RIKEN Type Journal Article
Year 2017 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.
Volume 12 Issue Pages P04006 - 22pp
Keywords Detector modelling and simulations I (interaction of radiation with matter, interaction; of photons with matter, interaction of hadrons with matter, etc); Instrumentation for radioactive beams (fragmentation devices; fragment and isotope, separators incl. ISOL; isobar separators; ion and atom traps; weak-beam diagnostics; radioactive-beam ion sources); Neutron detectors (cold, thermal, fast neutrons)
Abstract BRIKEN is a complex detection system to be installed at the RIB-facility of the RIKEN Nishina Center. It is aimed at the detection of heavy-ion implants, β-particles, γ-rays and β-delayed neutrons. The whole detection setup involves the Advanced Implantation Detection Array (AIDA), two HPGe Clover detectors and a large set of 166 counters of 3He embedded in a high-density polyethylene matrix. This article reports on a novel methodology developed for the conceptual design and optimisation of the 3He-tubes array, aiming at the best possible performance in terms of neutron detection. The algorithm is based on a geometric representation of two selected parameters of merit, namely, average neutron detection efficiency and efficiency flatness, as a function of a reduced number of geometric variables. The response of the detection system itself, for each configuration, is obtained from a systematic MC-simulation implemented realistically in Geant4. This approach has been found to be particularly useful. On the one hand, due to the different types and large number of 3He-tubes involved and, on the other hand, due to the additional constraints introduced by the ancillary detectors for charged particles and gamma-rays. Empowered by the robustness of the algorithm, we have been able to design a versatile detection system, which can be easily re-arranged into a compact mode in order to maximize the neutron detection performance, at the cost of the gamma-ray sensitivity. In summary, we have designed a system which shows, for neutron energies up to 1(5) MeV, a rather flat and high average efficiency of 68.6%(64%) and 75.7%(71%) for the hybrid and compact modes, respectively. The performance of the BRIKEN system has been also quantified realistically by means of MC-simulations made with different neutron energy distributions.
Address [Tarifeno-Saldivia, A.] UPC, Barcelona, Spain, Email: ariel.esteban.tarifeno@upc.edu
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1748-0221 ISBN Medium
Area Expedition Conference
Notes WOS:000405067800006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3209
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Author (up) BRIKEN Collaboration (Tolosa-Delgado, A. et al); Agramunt, J.; Tain, J.L.; Algora, A.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.
Title Commissioning of the BRIKEN detector for the measurement of very exotic beta-delayed neutron emitters Type Journal Article
Year 2019 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 925 Issue Pages 133-147
Keywords Beta-delayed neutrons; Neutron and beta counters; Analysis methodology; Background correction
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 gamma-ray detectors. We describe here the setup, the commissioning experiment and some selected results demonstrating its performance for the measurement of half-lives and beta-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.
Address [Tolosa-Delgado, A.; Agramunt, J.; Tain, J. L.; Algora, A.; Domingo-Pardo, C.; Morales, A., I; Rubio, B.] CSIC, Inst Fis Corpuscular, E-46980 Paterna, Spain, Email: tain@ific.uv.es
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000460539400018 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3939
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Author (up) Briz, J.A.; Borge, M.J.G.; Rubio, B.; Agramunt, J.; Algora, A.; Deo, A.Y.; Estevez Aguado, M.E.; Farrelly, G.; Fraile, L.M.; Gelletly, W.; Maira, A.; Nacher, E.; Perea, A.; Podolyak, Z.; Poves, A.; Sarriguren, P.; Tengblad, O.
Title Clarifying the structure of low-lying states in Br-72 Type Journal Article
Year 2022 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 105 Issue 1 Pages 014323 - 17pp
Keywords
Abstract The spins and parities of low-lying states in 72Br populated in the beta decay of 72Kr have been studied via conversion electron spectroscopy. The measurements were carried out at ISOLDE using a miniorange spectrometer with Si(Li) and HPGe detectors for electrons and gamma ray detection. Results of the conversion coefficients corresponding to transitions deexciting 12 levels in 72Br are reported. The multipolarities of the transitions are deduced and the spins and parities of the levels involved are discussed. From the multipolarities of the most intense transitions to the ground state, the spin and parity of the 72Br ground state have been definitely established as 1+. The spin of the 101.2-keV isomeric state is determined to be 3-. The level scheme is compared with mean-field and shell-model calculations and oblate deformation for the 72Br ground state is deduced. No E0 transitions have been found in 72Br. E0 transitions in the neighboring isobaric nuclei, 72Se and 72Ge, have also been studied.
Address [Briz, J. A.; Borge, M. J. G.; Maira, A.; Perea, A.; Sarriguren, P.; Tengblad, O.] CSIC, Inst Estruct Mat, Serrano 113 Bis, E-28006 Madrid, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000748401900005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5092
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Author (up) Briz, J.A.; Nacher, E.; Borge, M.J.G.; Algora, A.; Rubio, B.; Dessagne, P.; Maira, A.; Cano-Ott, D.; Courtin, S.; Escrig, D.; Fraile, L.M.; Gelletly, W.; Jungclaus, A.; Le Scornet, G.; Marechal, F.; Miehe, C.; Poirier, E.; Poves, A.; Sarriguren, P.; Tain, J.L.; Tengblad, O.
Title Shape study of the N = Z nucleus Kr-72 via beta decay Type Journal Article
Year 2015 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 92 Issue 5 Pages 054326 - 10pp
Keywords
Abstract The beta decay of the N = Z nucleus Kr-72 has been studied with the total absorption spectroscopy technique at ISOLDE (CERN). A total B(GT) = 0.79(4)g(A)(2)/4 pi has been found up to an excitation energy of 2.7 MeV. The B(GT) distribution obtained is compared with predictions from state-of-the-art theoretical calculations to learn about the ground state deformation of Kr-72. Although a dominant oblate deformation is suggested by direct comparison with quasiparticle random phase approximation (QRPA) calculations, beyond-mean-field and shell-model calculations favor a large oblate-prolate mixing in the ground state.
Address [Briz, J. A.; Nacher, E.; Borge, M. J. G.; Maira, A.; Escrig, D.; Jungclaus, A.; Sarriguren, P.; Tengblad, O.] CSIC, Inst Estruct Mat, E-28006 Madrid, Spain, Email: jose.briz@subatech.in2p3.fr
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000365867500002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2486
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Author (up) Caballero, L.; Rubio, B.; Kleinheinz, P.; Yates, S.W.; Algora, A.; Dewald, A.; Fitzler, A.; Gadea, A.; Jolie, J.; Julin, R.; Linnemann, A.; Lunardi, S.; Menegazzo, R.; Moller, O.; Nacher, E.; Piiparinen, M.; Blomqvist, J.
Title Two-phonon octupole excitation in Gd-146 Type Journal Article
Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 81 Issue 3 Pages 031301 - 4pp
Keywords
Abstract Based on experimental evidence from the Sm-144(alpha,2n) reaction, the 3484.7- keV 6(+) state in Gd-146 is identified as the highest-spin member of the 3(-) circle times 3(-) two-phonon octupole quartet. A previously unknown gamma line of 1905.8 keV and E3 character feeding the 3(-) octupole state has been observed. These results represent the first observation of a 6(+) -> 3(-) -> 0(+) cascade of two E3 transitions in an even-even nucleus and provide strong support for the interpretation of the 6(+) state as a two-phonon octupole excitation.
Address [Caballero, L.; Rubio, B.; Algora, A.; Gadea, A.; Nacher, E.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: Berta.Rubio@ific.uv.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes ISI:000276769400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 468
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Author (up) Caballero-Folch, R. et al; Agramunt, J.; Tain, J.L.; Algora, A.; Domingo-Pardo, C.; Guadilla, V.; Montaner-Piza, A.; Orrigo, S.E.A.; Rubio, B.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A.
Title First determination of beta-delayed multiple neutron emission beyond A=100 through direct neutron measurement: The P-2n value of Sb-136 Type Journal Article
Year 2018 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 98 Issue 3 Pages 034310 - 10pp
Keywords
Abstract Background: beta-delayed multiple neutron emission has been observed for some nuclei with A <= 100 being the Rb-100 the heaviest beta 2n emitter measured to date. So far only 25 P-2n values have been determined for the approximate to 300 nuclei that may decay in this way. Accordingly it is of interest to measure P-2n values for the other possible multiple neutron emitters throughout the chart of the nuclides. It is of particular interest to make such a measurement for nuclei with A > 100 to test the predictions of theoretical models and simulation tools for the decays of heavy nuclei in the region of very neutron-rich nuclei. In addition the decay properties of these nuclei are fundamental for the understanding of astrophysical nucleosynthesis processes such as the r-process and safety inputs for nuclear reactors. Purpose: To determine for the first time the two-neutron branching ratio the P-2n value for Sb-136 through a direct neutron measurement and to provide precise P-1n values for Sb-136 and Te-136. Method: A pure beam of each isotope of interest was provided by the JYFLTRAP Penning trap at the Ion Guide Isotope Separator On-Line (IGISOL) facility of the University of Jyvaskyla Finland. The purified ions were implanted into a moving tape at the end of the beam line. The detection setup consisted of a plastic scintillator placed right behind the implantation point after the tape to register the beta decays and the BELEN detector based on neutron counters embedded in a polyethylene matrix. The analysis was based on the study of the beta- and neutron-growth-and-decay curves and the beta-one-neutron and beta-two-neutron time correlations which allowed us the determination of the neutron branching ratios. Results: The P-2n value of Sb-136 was found to be 0.14(3)% and the measured P-1n values for Sb-136 and Te-136 were found to be 32.2(15)% and 1.47(6)% respectively. Conclusions: The measured P-2n value is a factor 44 smaller than predicted by the finite-range droplet model plus the quasiparticle random-phase approximation (FRDM+QRPA) model used for r-process calculations.
Address [Caballero-Folch, R.; Dillmann, I] TRIUMF, Vancouver, BC V6T 2A3, Canada, Email: rcaballero-folch@triumf.ca
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000444207600003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3728
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Author (up) Caballero-Folch, R. et al; Domingo-Pardo, C.; Agramunt, J.; Algora, A.; Rubio, B.; Tain, J.L.
Title beta-decay half-lives and beta-delayed neutron emission probabilities for several isotopes of Au, Hg, Tl, Pb, and Bi, beyond N=126 Type Journal Article
Year 2017 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 95 Issue 6 Pages 064322 - 16pp
Keywords
Abstract Background: There have been measurements on roughly 230 nuclei that are beta-delayed neutron emitters. They range from He-8 up to La-150. Apart from 210Tl, with a branching ratio of only 0.007%, no other neutron emitter has been measured beyond A = 150. Therefore, new data are needed, particularly in the region of heavy nuclei around N = 126, in order to guide theoretical models and help understand the formation of the third r-process peak at A similar to 195. Purpose: To measure both beta-decay half-lives and neutron branching ratios of several neutron-rich Au, Hg, Tl, Pb, and Bi isotopes beyond N = 126. Method: Ions of interest were produced by fragmentation of a U-238 beam, selected and identified via the GSI-FRS fragment separator. A stack of segmented silicon detectors (SIMBA) was used to measure ion implants and beta decays. An array of 30 He-3 tubes embedded in a polyethylene matrix (BELEN) was used to detect neutrons with high efficiency and selectivity. A self-triggered digital system is employed to acquire data and to enable time correlations. The latter were analyzed with an analytical model and results for the half-lives and neutron-branching ratios were derived by using the binned maximum-likelihood method. Results: Twenty new beta-decay half-lives are reported for Au204-206, Hg208-211, Tl211-216, Pb215-218, and Bi218-220, nine of them for the first time. Neutron emission probabilities are reported for Hg-210,Hg-211 and Tl211-216. Conclusions: The new beta-decay half-lives are in good agreement with previous measurements on nuclei in this region. The measured neutron emission probabilities are comparable to or smaller than values predicted by global models such as relativistic Hartree Bogoliubov plus the relativistic quasi-particle random phase approximation (RHB + RQRPA).
Address [Caballero-Folch, R.; Calvino, F.; Cortes, G.; Gomez-Hornillos, M. B.; Riego, A.] Univ Politecn Cataluna, DFEN, INTE, E-08028 Barcelona, Spain, Email: rcaballero-folch@triumf.ca
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000404022100001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3176
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Author (up) Caballero-Folch, R. et al; Domingo-Pardo, C.; Agramunt, J.; Algora, A.; Rubio, B.; Tain, J.L.
Title First Measurement of Several beta-Delayed Neutron Emitting Isotopes Beyond N=126 Type Journal Article
Year 2016 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 117 Issue 1 Pages 012501 - 6pp
Keywords
Abstract The beta-delayed neutron emission probabilities of neutron rich Hg and Tl nuclei have been measured together with beta-decay half-lives for 20 isotopes of Au, Hg, Tl, Pb, and Bi in the mass region N greater than or similar to 126. These are the heaviest species where neutron emission has been observed so far. These measurements provide key information to evaluate the performance of nuclear microscopic and phenomenological models in reproducing the high-energy part of the beta-decay strength distribution. This provides important constraints on global theoretical models currently used in r-process nucleosynthesis.
Address [Caballero-Folch, R.; Algora, A.; Calvino, F.; Cortes, G.; Gomez-Hornillos, M. B.; Riego, A.] Univ Politecn Cataluna, INTE DFEN, E-08028 Barcelona, Spain, Email: domingo@ific.uv.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000378879000008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2742
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Author (up) Caballero-Folch, R. et al; Domingo-Pardo, C.; Tain, J.L.; Agramunt, J.; Algora, A.; Rubio, B.
Title beta-decay and beta-delayed Neutron Emission Measurements at GSI-FRS Beyond N=126, for r-process Nucleosynthesis Type Journal Article
Year 2014 Publication Nuclear Data Sheets Abbreviated Journal Nucl. Data Sheets
Volume 120 Issue Pages 81-83
Keywords
Abstract New measurements of very exotic nuclei in the neutron-rich region beyond N=126 have been performed at the GSI facility with the fragment separator (FRS). The aim of the experiment is to determine half-lives and beta-delayed neutron emission branching ratios of isotopes of Hg, Tl and Pb in this region. This contribution summarizes final counting statistics for identification and for implantation, as well as the present status of the data analysis of the half-lives. In summary, isotopes of Pt, Au, Hg, Ti, Pb, Bi, Po, At, Rn and Fr were clearly identified and several of them (Hg208-211, Tl211-215, Pb214-218) were implanted with enough statistics to determine their half-lives. About half of them are expected to be neutron emitters, in such cases it will become possible to obtain the neutron emission probabilities, P-n.
Address [Caballero-Folch, R.; Cortes, G.; Calvino, F.; Gomez-Hornillos, M. B.; Riego, A.] Univ Politecn Cataluna, Dept Fis Enginyeria Nucl, E-08028 Barcelona, Spain, Email: roger.caballero@upc.edu
Corporate Author Thesis
Publisher Academic Press Inc Elsevier Science Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0090-3752 ISBN Medium
Area Expedition Conference
Notes WOS:000339860100022 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1873
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Author (up) Catford, W.N. et al; Caballero, L.; Rubio, B.
Title Migration of Nuclear Shell Gaps Studied in the d(Ne-24, p gamma)Ne-25 Reaction Type Journal Article
Year 2010 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 104 Issue 19 Pages 192501 - 4pp
Keywords
Abstract The transfer of neutrons onto Ne-24 has been measured using a reaccelerated radioactive beam of Ne-24 to study the (d, p) reaction in inverse kinematics. The unusual raising of the first 3/2(+) level in Ne-25 and its significance in terms of the migration of the neutron magic number from N = 20 to N = 16 is put on a firm footing by confirmation of this state's identity. The raised 3/2(+) level is observed simultaneously with the intruder negative parity 7/2(-) and 3/2(-) levels, providing evidence for the reduction in the N = 20 gap. The coincident gamma-ray decays allowed the assignment of spins as well as the transferred orbital angular momentum. The excitation energy of the 3/2(+) state shows that the established USD shell model breaks down well within the sd model space and requires a revised treatment of the proton-neutron monopole interaction.
Address [Catford, W. N.; Timis, C. N.; Baldwin, T. D.; Gelletly, W.; Pain, S. D.] Univ Surrey, Dept Phys, Guildford GU2 5XH, Surrey, England
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes ISI:000277699600014 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 452
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