Department of Physics

IGISOL-4_2.png

IGISOL

The exotic nuclei and beams group studies properties of nuclei employing Penning-trap mass spectrometry as well as laser and decay spectroscopy at the IGISOL-4 facility.

Contact persons: , and

IMG_2073_Dima_Laetitia_James.JPG
JYFLTRAP - A part of IGISOL system.

The exotic nuclei and beams group, aka the IGISOL group is a part of the Center of Excellence (CoE) of the Academy of Finland. In 2016 the number of major nuclear physics experiments at the Jyväskylä Ion Guide Isotope Separator On-Line (IGISOL) facility was lower than usual; instead, a significant effort was invested into improving the ion beam transmission to and through the JYFLTRAP Penning trap, resulting in record-breaking transmissions of over 30 % from the IGISOL switchyard to the post-trap setup.

In addition to our home laboratory, our research takes place in number of other laboratories, such as the ISOLDE facility in CERN, GANIL and Helmholzzentrum GSI, the location of the future radioactive beam facility FAIR. We are also actively involved in work to support the development of international future facilities EURISOL and aforementioned FAIR, which we have done in close collaboration with HIP, the Helsinki Institute of Physics.

An important form of our international collaboration is also participation in research networks. Recently, our group has benefited from the EU FP7 and Horizon 2020 programs within ENSAR2, CHANDA and nuClock projects. The research at IGISOL is strongly supported by the Academy of Finland with two Academy Research Fellows and an Academy postdoctoral researcher working in the group. The Academy’s FIRI funding has been essential for renewing our research infrastructure.

The research at the IGISOL facility in Jyväskylä since early 1980's until 2010 has been pictured in a laboratory portrait: "Three decades of research at IGISOL", whose articles are published in special issues of European Physical Journal A and Hyperfine Interactions.


  • Technical developments
    • FIRI infrastructure funding »
    • Magneto-optical trapping of Cs atoms»
    • Post-trap decay spectroscopy »
  • Recent research
    • Laser resonance ionization studies of Pu and Th»
    • JYFLTRAP»
    • High-precision mass measurements for IMME at A = 52»
      According to the Isobaric Multiplet Mass Equation (IMME) [1], the masses of Isobaric Analoque States (IAS) in a mass multiplet with a mass number A and isospin T should lie on a parabola: M(A, T, TZ) = a(A, T) + b(A,T)TZ + c(A, T )TZ2 where a, b and c are interpreted as being the scalar, vector and tensor Coulomb energies. High precision mass measurements with Penning traps have offered new possibilities to investigate the validity of the IMME. Masses of 52Co, 52mCo, 52Fe, 52mFe, and 52Mn were determined with JYFLTRAP. 52Co and 52mCo were measured for the first time and were found more bound than predicted. The JYFLTRAP mass values were employed to study IMME for the T = 2 quintet at A = 52. No significant breakdown (beyond the 3σ level) of the quadratic form of the IMME was observed (χ2/n = 2.4). The excitation energies for the isomer and the T = 2 isobaric analogue state in 52Co were determined to be 374(13) keV and 2922(13) keV, respectively. The proton separation energies of 52Co and 53Ni relevant for the astrophysical rapid proton capture process were measured for the first time. [1] S. B. Weinberg, S. and Treiman, Phys. Rev. 116, 465 (1959).
  • Highlights of 2015
    • I-187 Collinear laser spectroscopy of long-lived Pu isotopes »
    • I-199: Quantum-state selective decay spectroscopy: Proton decay branch of 53Com »
    • I-207: Single and double beta decay Q-value of 96Zr »


      The neutrinoless double beta (0νββ) decay is currently of significant interest in nuclear and particle physics. An observation of this decay mode not only gives insight into the nature of the neutrino but also provides information about its absolute mass scale. The critical quantity which enters in theoretical model calculations is the nuclear matrix element [1]. It describes the underlying nuclear physics, and because of its complexity, neither the matrix elements nor the adequacy of the models can be easily assessed.

      We measured the single and double beta decay Q-value of 96Zr. This nucleus has the third largest ββ Q-value, topped only by 48Ca and 150Nd. Furthermore, it is also one of the two nuclides (the other is 48Ca) unstable against single β-decay. If single β-decay is observed in either of these systems, matrix element calculations can be directly tested for double beta decay. Presently, the matrix element is only theoretically determined. Its value has been calculated within the framework of the QRPA model by J. Suhonen’s group.

      Just prior to our work, the 96Zr double beta decay Q-value was measured with Michigan State University's LEBIT trap to be nearly 7 keV higher [2] than in the most recent atomic mass evaluation (AME2012 [3]). Whether this discrepancy would be manifest also in the single beta decay Q-value was still to be confirmed. The measurement imposed an experimental challenge since 96Zr and96Nb are separated by only about 1.8 parts per million in mass. Although challenging, the two were separated with the in-house developed Ramsey cleaning method [4].

      No discrepancy in the single β-decay Q-value was found. The precision of the value was, nevertheless, improved by 20-fold. The 7 keV discrepancy found by the LEBIT group in the ββ Q-value was confirmed.

      This project was done in collaboration with the University of Münster, Calgary, Bratislava and with JYFL J. Suhonen's theory group.

      [1] J. Shone, et al., J. Phys. G: Nucl. Part. Phys. 39 (2012) 124005, doi:10.1088/0954-3899/39/12/124005
      [2] K. Gulyuz, et al., Phys. Rev. C 91, 055501 (2015), doi:10.1103/PhysRevC.91.055501
      [3] G. Audi, et al. , Chinese physics C 36(12) 1157 (2012).
      [4] T. Eronen, et al., Nuclear Instr. and Methods B 266 (2008) 4527–4531, doi:10.1016/j.nimb.2008.05.076.

    • I-200: The first Penning-trap mass measurement of the TZ=-3/2 nucleus 31Cl »
  • Recent publications
    • 30/2017. V. Guadilla, et al.: TAGS measurements of 100Nb ground and isomeric states 140Cs for neutrino physics with the new DTAS detector EPJ Web of Conferences 146, 10010 (2017) - DOI 10.1051/epjconf/201714610010 Submitted on 31 October 2016, published 13 September 2017
      Authors V. Guadilla, A. Algora, J.L. Tain, J. Agramunt, J. Äystö, J.A. Briz, A. Cucoanes, T. Eronen, M. Estienne, M. Fallot, L.M. Fraile, E. Ganioğlu, W. Gelletly, D. Gorelov, J. Hakala, A. Jokinen, D. Jordan, A. Kankainen, V. Kolhinen, J. Koponen, M. Lebois, T. Martinez, M. Monserrate, A. Montaner-Pizá, I. Moore, E. Nácher, S.E.A. Orrigo, H. Penttilä, I. Pohjalainen, A. Porta, J. Reinikainen, M. Reponen, S. Rinta-Antila, B. Rubio, K. Rytkönen, T. Shiba, V. Sonnenschein, A.A. Sonzogni, E. Valencia, V. Vedia, A. Voss, J.N. Wilson and A.-A. Zakari-Issoufou
      Abstract In this work we report on total absorption γ-ray spectroscopy measurements of the β decay of fission products that are important contributors to the antineutrino spectrum. The experiment was performed at IGISOL as a part of a campaign of measurements with the new DTAS spectrometer. Preliminary results of the analysis of the β decay of 100Nb, 100mNb and 140Cs are presented.
      Acknowledgements This work has been supported by the Spanish Ministerio de Econom´ıa y Competitividad under the FPA2011-24553, the AIC-A-2011-0696, the FPA2014-52823-C2-1-P and the SEV-2014-0398 Grants, by the European Commission under the FP7/EURATOM contract 605203, and by the Spanish Ministerio de Educaci´on under the FPU12/01527 Grant.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 29/2017. M. Fallot, et al.: Total absorption spectroscopy of fission fragments relevant for reactor antineutrino spectra EPJ Web of Conferences 146, 10002 (2017) - DOI 10.1051/epjconf/201714610002 - Submitted on 31 October 2016, published 13 September 2017
      Authors M. Fallot, A. Porta, L. Le Meur, J.A. Briz, A.-A. Zakari-Issoufou, V. Guadilla, A. Algora, J.-L. Taìn, E. Valencia, S. Rice, V.M. Bui, S. Cormon, M. Estienne, J. Agramunt, J. Äystö, L. Batist, M. Bowry, R. Caballero-Folch, D. Cano-Ott, A. Cucoanes, V.-V. Elomaa, T. Eronen, E. Estévez, G.F. Farrelly, L.M. Fraile, M. Fleming, E. Ganogliu, A.R. Garcia, W. Gelletly, M.B. Gomez-Hornillos, D. Gorelov, V. Gorlychev, J. Hakala, A. Jokinen, M.D. Jordan, A. Kankainen, P. Karvonen, V.S. Kolhinen, F.G. Kondev, J. Koponen, M. Lebois, T. Martinez, P. Mason, E. Mendoza, F. Molina, M. Monserrate, A. Montaner-Pizá, I. Moore, E. Nácher, S.E.A. Orrigo, H. Penttilä, A. Perez, Zs. Podolyák, I. Pohjalainen, P.H. Regan, J. Reinikainen, M. Reponen, S. Rinta-Antila, J. Rissanen, B. Rubio, T. Shiba, V. Sonnenschein, A.A. Sonzogni, J.-C. Sublet, V. Vedia, A. Voss, C. Weber, and J.N. Wilson
      Abstract The accurate determination of reactor antineutrino spectra remains a very active research topic for which new methods of study have emerged in recent years. Indeed, following the long-recognized reactor anomaly (measured antineutrino deficit in short baseline reactor experiments when compared with spectral predictions), the three international reactor neutrino experiments Double Chooz, Daya Bay and Reno have recently demonstrated the existence of spectral distortions in their measurements with respect to the same predictions. These spectral predictions were obtained through the conversion of integral beta-energy spectra obtained at the ILL research reactor. Several studies have shown that the underlying nuclear physics required for the conversion of these spectra into antineutrino spectra is not totally understood. An alternative to such converted spectra is a complementary approach that consists of determining the antineutrino spectrum by means of the measurement and processing of nuclear data. The beta properties of some key fission products suffer from the pandemonium effect which can be circumvented by the use of the Total Absorption Gammaray Spectroscopy technique (TAGS). The two main contributors to the PressurizedWater Reactor antineutrino spectrum in the region where the spectral distortion has been observed are 92Rb and 142Cs, which have been measured at the radioactive beam facility of the University of Jyväskylä in two TAGS experiments.We present the results of the analysis of the TAGS measurements of the β-decay properties of 92Rb along with preliminary results on 142Cs and report on the measurements already performed.
      Acknowledgements The authors acknowledge the nuclear data section of the IAEA and especially Paraskevi (Vivian) Dimitriou for fostering research in the field through the TAGS consultant meetings and the CRP about beta-delayed neutron emission. This work was supported by the CHANDA European project, the In2p3 institute of CNRS, and the NEEDS challenge through the NACRE project. This work was supported by the Academy of Finland under Project No. 213503, Nuclear and Accelerator-Based Physics Research at JYFL. This work was supported by Spanish Ministerio de Econom´ıa y Competitividad under grants FPA2008- 06419, FPA2010-17142 and FPA2011- 24553 and FPA2014-52823-C2-1-P, CPAN CSD-2007-00042 (Ingenio2010), and the program Severo Ochoa (SEV- 2014-0398) and by EPSRC and STFC (UK). Work at ANL was supported by the U.S Department of Energy under contract DE-AC02- 06CH11357.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 28/2017. A. Algora, et al.: Total absorption studies of high priority decays for reactor applications: 86Br and 91Rb EPJ Web of Conferences 146, 10001 (2017) - DOI 10.1051/epjconf/201714610001 - Submitted on 31 October 2016, published 13 September 2017
      Authors A. Algora, S. Rice, V. Guadilla, J.L. Tain, E. Valencia, A.-A. Zakari-Issoufou, J. Agramunt, J. Äystö, L. Batist, J.A. Briz, M. Bowry, V.M. Bui, R. Caballero-Folch, D. Cano-Ott, A. Cucoanes, T. Eronen, V.-V. Elomaa, E. Estevez, M. Estienne, M. Fallot, G.F. Farrelly, L.M. Fraile, M. Fleming, E. Ganioglu, A.R. Garcia, W.Gelletly, B. Gómez-Hornillos, D. Gorelov, V. Gorlychev, J. Hakala, A. Jokinen, D. Jordan, A. Kankainen, V.S. Kolhinen, F.G. Kondev, J. Koponen, M. Lebois, T. Martínez, P. Mason, E. Mendoza, M. Monserrate, A. Montaner-Pizá, I. Moore, E. Nacher, S. Orrigo, H. Penttilä, Zs. Podolyák, I. Pohjalainen, A. Porta, P. Regan, J. Reinikainen, M. Reponen, S. Rinta-Antila, J. Rissanen, B. Rubio, K. Rytkönen, T. Shiba, V. Sonnenschein, A.A. Sonzogni, J.-Ch. Sublet, V. Vedia, A. Voss, and J.N. Wilson
      Abstract Preliminary results from beta decay studies of nuclei that are important for reactor applications are presented. The beta decays have been studied using the total absorption technique (TAS) and the pure beams provided by the IGISOL facility of the University of Jyväskylä
      Acknowledgements This work was supported by Spanish Ministerio de Economía y Competitividad under grants FPA200806419, FPA2010-17142 and FPA2011-24553 and FPA2014-52823-C2-1-P, CPAN CSD-2007-00042 (Ingenio2010), and the program Severo Ochoa (SEV2014-0398) and by EPSRC and STFC (UK). Work at ANL was supported by the U.S Department of Energy under contract DE-AC02-06CH11357.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 27/2017. Vasileios Rakopoulos, et al.: Measurements of isomeric yield ratios of fission products from proton-induced fission on natU and 232Th via direct ion counting EPJ Web of Conferences 146, 04054 (2017) - DOI 10.1051/epjconf/201714604054- Submitted on 15 November 2016, accepted 7 March 2017, published 13 September 2017
      Authors Vasileios Rakopoulos, Mattias Lantz, Ali Al-Adili, Dmitry Gorelov, Ari Jokinen, Veli Kolhinen, Andrea Mattera, Iain D. Moore, Heikki Penttilä, Alexander V. Prokofiev, Andreas Solders and Stephan Pomp
      Abstract Independent isomeric yield ratios (IYR) of 81Ge, 96Y, 97Y, 97Nb, 128Sn and 130Sn have been determined in the 25 MeV proton-induced fission of natU and 232Th. The measurements were performed at the Ion Guide Isotope Separator On-Line (IGISOL) facility at the University of Jyväskylä. A direct ion counting measurement of the isomeric fission yield ratios was accomplished for the first time, registering the fission products in less than a second after their production. In addition, the IYRs of natU were measured by means of γ-spectroscopy in order to verify the consistency of the recently upgraded experimental setup. From the obtained results, indications of a dependence of the production rate on the fissioning system can be noticed. These data were compared with data available in the literature, whenever possible. Using the TALYS code and the experimentally obtained IYRs, we also deduced the average angular momentum of the fission fragments after scission.
      Acknowledgements The author would like to acknowledge the Swedish Radiation Safety Authority (SSM) and the Swedish Nuclear Fuel and Waste Management Company (SKB) for their financial support.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 26/2017. Andreas Solders, et al.: Simulations of the stopping efficiencies of fission ion guides EPJ Web of Conferences 146, 03025 (2017) - DOI 10.1051/epjconf/201714603025 - Submitted on 15 November 2016, accepted 7 March 2017, published 13 September 2017
      Authors Andreas Solders, Ali Al-Adili, Dmitry Gorelov, Kaj Jansson, Ari Jokinen, Veli Kolhinen, Mattias Lantz, Andrea Mattera, Ian Moore, Niklas Nilsson, Martin Norlin, Heikki Penttilä, Stephan Pomp, Alexander Prokofiev, Vasileios Rakopoulos, Sami Rinta-Antila, Vasily Simutkin, and the IGISOL group
      Abstract With the Ion Guide Isotope Separator On-Line (IGISOL) facility, located at the University of Jyväskylä, products of nuclear reactions are separated by mass. The high resolving power of the JYFLTRAP Penning trap, with full separation of individual nuclides, capacitates the study of nuclides far from the line of stability. For the production of neutron-rich medium-heavy nuclides, fissioning of actinides is a feasible reaction. This can be achieved with protons from an in-house accelerator or, alternatively, with neutrons through the addition of a newly developed Be(p,xn)-converter. The hereby-obtained fission products are used in nuclear data measurements, for example fission yields, nuclear masses, Q-values and decay spectroscopy. Prior to separation, the ionized reaction products are stopped in a helium-filled gas cell, referred to as the ion guide. In this work we present simulations of the stopping of fission products in an ion guide developed for neutron-induced fission. The production and extraction rates are evaluated and compared against experimental values.
      Acknowledgements We would like to acknowledge the Swedish Radiation Safety Authority (SSM) and the Swedish Nuclear Fuel and Waste Management Company (SKB) for their financial support.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 25/2017. R. Caballero-Folch, et al.: Measurement of the heaviest β-delayed 2-neutron emitter: 136Sb EPJ Web of Conferences 146, 01005 (2017) - DOI 10.1051/epjconf/201714601005 Submitted on 31 October 2016, published 13 September 2017
      Authors R. Caballero-Folch, I. Dillmann, J.L. Taín, J. Agramunt, C. Domingo-Pardo, A. Algora, J. Äysto, F. Calviño, L. Canete, G. Cortès, T. Eronen, E. Ganioglu, W. Gelletly, D. Gorelov, V. Guadilla, J. Hakala, A. Jokinen, A. Kankainen, V. Kolhinen, J. Koponen, M. Marta, E. Mendoza, A. Montaner-Pizá, I. Moore, Ch. Nobs, S. Orrigo, H. Penttilä, I. Pohjalainen, J. Reinikainen, A. Riego, S. Rinta-Antila, B. Rubio, P. Salvador-Castiñeira, V. Simutkin, and A. Voss
      Abstract The β-delayed neutron emission probability, Pn, of very exotic nuclei is crucial for the understanding of nuclear structure properties of many isotopes and astrophysical processes such as the rapid neutron capture process (r-process). In addition β-delayed neutrons are clue in a nuclear power reactor operated in a prompt sub-critical, delayed critical condition, as they contribute to the decay heat inducing fission reactions after a shut down. The study of neutron-rich isotopes, and the measurement of β-delayed one-neutron emitters (β1n) is possible thanks to the RIB facilities, where radioactive beams allow the production of exotic nuclei of interest, which can be studied and analyzed by using specific detection systems. This contribution reports two recent measurements of β-delayed neutron emitters which allowed to determine half-lives and the neutron branching ratio of isotopes in a region with masses above A=200 and N>126, and a second experiment which confirmed the 136Sb as the heaviest double neutron emitter (β2n) measured so far.
      Acknowledgements This work is supported by the Spanish Ministerio de Economía y Competitividad under grants CPAN CSD2007-00042 (Ingenio2010), FPA2008-04972-C03-03, FPA2008-06419, FPA2010-17142, FPA2011-28770C03-03, FPA2011-24553, FPA2014-52823-C2-1-P, FPA2014-52823-C2-2-P and the program Severo Ochoa (SEV-2014-0398). It is also supported by the Academy of Finland under Project No. 213503, Nuclear and Accelerator-Based Physics Research at JYFL, and by the European Commission under the FP7/EURATOM contract 605203. I.D. and M.M. acknowledge the support of the German Helmholtz Association via the Young Investigators Grant No. VH-NG 627. W.G. acknowledges the support of the UK Science Technology Faculties Council (STFC) under grant No. ST/F012012/1 and the University of Valencia. R.C.F. and I.D. are supported by the National Research Council of Canada (NSERC) Discovery Grants SAPIN-2014-00028 and RGPAS 462257-2014 at TRIUMF.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 24/2017. J. Agramunt, et al.: New accurate measurements of neutron emission probabilities for relevant fission products EPJ Web of Conferences 146, 01004 (2017) - DOI 10.1051/epjconf/201714601004 Submitted on 31 October 2016, published 13 September 2017
      Authors J. Agramunt, J.L. Tain, F. Albiol, A. Algora, R. Caballero-Folch, F. Calviño, G. Cortes, I. Dillmann, T. Eronen, A.R. Garcia, E. Ganioglu, W. Gelletly, D. Gorelov, V. Guadilla, H. Hakala, A. Jokinen, A. Kankainen, A. Montaner, M. Marta, E. Mendoza, I. Moore, C. Nobs, S. Orrigo, H. Penttila, M. Reponen, S. Rinta-Antila, A. Riego, B. Rubio, A. Saastamoinen, P. Salvador-Castiñeira, A. Tarifeño-Saldivia, A. Tolosa and E. Valencia
      Abstract We have performed new accurate measurements of the beta-delayed neutron emission probability for ten isotopes of the elements Y, Sb, Te and I. These are fission products that either have a significant contribution to the fraction of delayed neutrons in reactors or are relatively close to the path of the astrophysical r process. The measurements were performed with isotopically pure radioactive beams using a constant and high efficiency neutron counter and a low noise beta detector. Preliminary results are presented for six of the isotopes and compared with previous measurements and theoretical calculations.
      Acknowledgements This work was supported by Spanish Ministerio de Economia y Competitividad under grant numbers FPA2011-24553, FPA 2011-28770-C03-03, FPA2014-52823-C2-1-P/-2-P, CPAN CSD- 2007-00042 (Ingenio2010) and the program Severo Ochoa (SEV- 2014–0398). Work supported by the European Commission under the FP7/EURATOM contract 605203 (CHANDA). Work supported by the Finnish Centre of Excellence Programme 2012–2017 (Project No. 21350). Work partially done within IAEA-CRP for Beta Delayed Neutron Data.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 23/2017. J.L.Tain, et al.: Strong γ-ray emission from neutron unbound states populated in β-decay: Impact on (n,γ) cross-section estimates EPJ Web of Conferences 146, 01002 (2017) - DOI 10.1051/epjconf/201714601002 Submitted on 31 October 2016, published 13 September 2017
      Authors J.L. Tain, V. Guadilla, E. Valencia, A. Algora, A.-A. Zakari-Issoufou, S. Rice, J. Agramunt, J. Äystö, L. Batist, M. Bowry, J.A. Briz, V.M. Bui, R. Caballero-Folch, D. Cano-Ott, A. Cucoanes, V.-V. Elomaa, T. Eronen, E. Estevez, M. Estienne, M. Fallot, G.F. Farrelly, L.M. Fraile, E. Ganioglu, A.R. Garcia, W. Gelletly, B. Gómez-Hornillos, D. Gorelov, V. Gorlychev, J. Hakala, A. Jokinen, M.D. Jordan, A. Kankainen, V.S. Kolhinen, F.G. Kondev, J. Koponen, M. Lebois, L. Le Meur, T. Martínez, P. Mason, E. Mendoza, M. Monserrate, A. Montaner-Pizá, I. Moore, E. Nacher, S.E.A. Orrigo, H. Penttilä, Zs. Podolyák, I. Pohjalainen, A. Porta, P. Regan, J. Reinikainen, M. Reponen, S. Rinta-Antila, J. Rissanen, B. Rubio, K. Rytkönen, T. Shiba, V. Sonnenschein, A.A. Sonzogni, V. Vedia, A. Voss, and J.N. Wilson
      Abstract Total absorption gamma-ray spectroscopy is used to measure accurately the intensity of γ emission from neutron-unbound states populated in the β-decay of delayed-neutron emitters. From the comparison of this intensity with the intensity of neutron emission one can deduce information on the (n,γ ) cross section for unstable neutron-rich nuclei of interest in r process abundance calculations. A surprisingly large γ branching was observed for a number of isotopes. The results are compared with Hauser-Feshbach calculations and discussed.
      Acknowledgements This work was supported by Spanish Ministerio de Economía y Competitividad under grants FPA200806419, FPA2010-17142, FPA2011-24553, FPA201452823-C2-1-P, CPAN CSD-2007-00042 (Ingenio2010) and the program Severo Ochoa (SEV-2014-0398). WG would like to thank the University of Valencia for support. This work was supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2012-2017 (Project No. 21350). Work supported by EPSRC(UK) and STFC(UK). Work supported by the European Commission under the FP7/EURATOM contract 605203. FGK acknowledges support from the U.S. Department of Energy, under contract number DE-AC0206CH11357.
      Other Proceedings of the International Conference on Nuclear Data for Science and Industry (ND2016) , 11–16 September 2016, Bruges, Belgium.
    • 22/2017. A. Mattera, et al.: A neutron source for IGISOL-JYFLTRAP: Design and characterisation Eur. Phys. J. A (2017) 53: 173 - DOI 10.1140/epja/i2017-12362-x Submitted on 14 May 2017, published 30 August 2017
      Authors A. Mattera, S. Pomp, M. Lantz, V. Rakopoulos, A. Solders, A. Al-Adili, E. Passoth, A. V. Prokofiev, P. Andersson, A. Hjalmarsson, R. Bedogni, D. Bortot, A. Esposito, A. Gentile, J. M. Gómez-Ros, M. V. Introini, A. Pola, D. Gorelov, H. Penttilä, I. D. Moore, S. Rinta-Antila, V. S. Kolhinen, T. Eronen
      Abstract Abstract. A white neutron source based on the Be(p, nx) reaction for fission studies at the IGISOLJYFLTRAP facility has been designed and tested. 30MeV protons impinge on a 5mm thick water-cooled beryllium disc. The source was designed to produce at least 1012 fast neutrons/s on a secondary fission target, in order to reach competitive production rates of fission products far from the valley of stability. The Monte Carlo codes MCNPX and FLUKA were used in the design phase to simulate the neutron energy spectra. Two experiments to characterise the neutron field were performed: the first was carried out at The Svedberg Laboratory in Uppsala (SE), using an Extended-Range Bonner Sphere Spectrometer and a liquid scintillator which used the time-of-flight (TOF) method to determine the energy of the neutrons; the second employed Thin-Film Breakdown Counters for the measurement of the TOF, and activation foils, at the IGISOL facility in Jyväskylä (FI). Design considerations and the results of the two characterisation measurements are presented, providing benchmarks for the simulations.
      Acknowledgements This work was supported by the European Commission within the Seventh Framework Programme through Fission-2010-ERINDA (project no. 269499) and Fission-2013-CHANDA (project no. 605203), by the NESCOFI@BTF project (INFN— CSN V, Italy), by the Swedish Radiation Safety Authority (SSM), and by the Swedish Nuclear Fuel and Waste Management Co. (SKB).
    • 21/2017. S. Rice, et al.: Total Absorption Spectroscopy Study of the Beta Decay of 86Br and 91Rb Phys. Rev. C 96, 014320 - DOI 10.1103/PhysRevC.96.014320 Submitted 6 April 2017, accepted on 21 June 2017, Published 27 July 2017
      Authors S. Rice, A. Algora, J. L. Tain, E. Valencia, J. Agramunt, B. Rubio, W. Gelletly, P.H. Regan, A.-A. Zakari-Issoufou, M. Fallot, A. Porta, J. Rissanen, T. Eronen, J. Äystö, L. Batist, M. Bowry, V. M. Bui, R. Caballero-Folch, D. Cano-Ott, V.-V. Elomaa, E. Estevez, G. F. Farrelly, A. R. Garcia, B. Gomez-Hornillos, V. Gorlychev, J. Hakala, M. D. Jordan, A. Jokinen, F. G. Kondev, T. Martínez, P. Mason, E. Mendoza, I. Moore, H. Penttilä, Zs. Podolyák, M. Reponen, V. Sonnenschein, A. A. Sonzogni, P. Sarriguren
      Abstract The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the IGISOL facility in Jyväskylä and further purified using the JYFLTRAP. 86Br and 91Rb are considered to be major contributors to the decay heat in reactors. In addition 91Rb was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decay was well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renormalized. The relative impact of the studied decays in the prediction of the decay heat and antineutrino spectrum from reactors has been evaluated.
      Acknowledgements AA acknowledges useful discussions with Prof. A Garcia and Dr. S Sjue during the preparation of the experimental proposal. This work has been supported by the Spanish Ministerio de Econom´ıa y Competitividad under Grants No. FPA2011-24553, No. AIC-A-2011-0696, No. FPA2014-52823-C2-1-P, No. FPA2015-65035-P, No. FPI/BES-2014-068222 and the program Severo Ochoa (SEV-2014-0398), by the Spanish Ministerio de Educaci´on under the FPU12/01527 Grant, by the European Commission under the FP7/EURATOM contract 605203 and the FP7/ENSAR contract 262010, and by the Junta para la Ampliaci´on de Estudios Programme (CSIC JAE-Doc contract) co-financed by FSE. This work has been partially supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2012-2017 (Project No. 213503, Nuclear and Accelerator Based Programme at JYFL). WG was supported by the UK Science and Technology Facilities Council (STFC) Grant ST/F012012/1 and by the University of Valencia.
    • 20/2017. V. Guadilla, et al.: Study of the β-decay of 100Tc with Total Absorption γ-Ray Spectroscopy Phys. Rev. C 96, 014319 - DOI 10.1103/PhysRevC.96.014319 Submitted 3 April 2017, accepted on 21 June 2017, Published 27 July 2017
      Authors V. Guadilla, A. Algora, J.L. Tain, J. Agramunt, D. Jordan, A. Montaner-Pizá, S.E.A. Orrigo, B. Rubio, E. Valencia, J. Suhonen, O. Civitarese, J. Äystö, J.A. Briz, A. Cucoanes, T. Eronen, M. Estienne, M. Fallot, L.M. Fraile, E. Ganioglu, W. Gelletly, D. Gorelov, J. Hakala, A. Jokinen, A. Kankainen, V. Kolhinen, J. Koponen, M. Lebois, T. Martinez, M. Monserrate, I. Moore, E. Nácher, H. Penttilä, I. Pohjalainen, A. Porta, J. Reinikainen, M. Reponen, S. Rinta-Antila, K. Rytkönen, T. Shiba, V. Sonnenschein, A.A. Sonzogni, V. Vedia, A. Voss, J.N. Wilson, A.-A. Zakari-Issoufou
      Abstract The β-decay of 100Tc has been studied using the Total Absorption γ-Ray Spectroscopy technique at IGISOL. In this work the new DTAS spectrometer in coincidence with a cylindrical plastic β-detector has been employed. The β-intensity to the ground state obtained from the analysis is in good agreement with previous high-resolution measurements. However, differences in the feeding to the first excited state as well as weak feeding to a new level at high excitation energy have been deduced from this experiment. Theoretical calculations performed in the quasiparticle random- phase approximation (QRPA) framework are also reported. Comparison of these calculations with our measurement serves as a benchmark for calculations of the double β-decay of 100Mo.
      Acknowledgements AA acknowledges useful discussions with Prof. A Garcia and Dr. S Sjue during the preparation of the experimental proposal. This work has been supported by the Spanish Ministerio de Econom´ıa y Competitividad under Grants No. FPA2011-24553, No. AIC-A-2011-0696, No. FPA2014-52823-C2-1-P, No. FPA2015-65035-P, No. FPI/BES-2014-068222 and the program Severo Ochoa (SEV-2014-0398), by the Spanish Ministerio de Educaci´on under the FPU12/01527 Grant, by the European Commission under the FP7/EURATOM contract 605203 and the FP7/ENSAR contract 262010, and by the Junta para la Ampliaci´on de Estudios Programme (CSIC JAE-Doc contract) co-financed by FSE. This work has been partially supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2012-2017 (Project No. 213503, Nuclear and Accelerator Based Programme at JYFL). WG was supported by the UK Science and Technology Facilities Council (STFC) Grant ST/F012012/1 and by the University of Valencia.
    • 19/2017. Caballero-Folch R, et al.: First evidence of multiple β-delayed neutron emission for isotopes with A>100 Acta Physica Polonica B, 48 (3), 529-532 - DOI: 10.5506/APhysPolB.48.529 Submitted on 14 December 2016 , published March 2017
      Authors R. Caballero-Folch, I. Dillmann, J. Agramunt, J.L. Taín, C. Domingo-Pardo, A. Algora, J. Äysto, F. Calvino,L. Canete, G. Cortès, T. Eronen, E. Ganioglu, W. Gelletly, D. Gorelov, V. Guadilla, J. Hakala, A. Jokinen, A. Kankainen, V. Kolhinen, J. Koponen, M. Marta, E. Mendoza, A. Montaner-Pizá, I. Moore, Ch. Nobs, S. Orrigo, H. Penttilä, I. Pohjalainen, J. Reinikainen, A. Riego, S. Rinta-Antila, B. Rubio, P. Salvador-Castineira, V. Simutkin, A. Voss
      Abstract The β-delayed neutron emission probability, Pn, of very neutron-rich nuclei allows us to achieve a better understanding of the nuclear structure above the neutron separation energy, Sn. The emission of neutrons can become the dominant decay process in neutron-rich astrophysical phenomena such as the rapid neutron capture process (r-process). There are around 600 accessible isotopes for which β-delayed one-neutron emission (β1n) is energetically allowed, but the branching ratio has only been determined for about one third of them. β1n decays have been experimentally measured up to the mass A ∼ 150, plus a single measurement of 210Tl. Concerning two-neutron emitters (β2n), ∼ 300 isotopes are accessible and only 24 have been measured so far up to the mass A = 100. In this contribution, we report recent experiments which allowed the measurement of β1n emitters for masses beyond A > 200 and N > 126 and identified the heaviest β2n emitter measured so far, 136Sb.
      Acknowledgements This work is supported by the Spanish Ministerio de Economía y Com- petitividad under grants: CPAN CSD-2007-00042 (Ingenio2010), FPA2008- 04972-C03-03, FPA2008-06419, FPA2010-17142, FPA2011-28770-C03-03, FPA2011-24553, FPA2014-52823-C2-1-P, FPA2014-52823-C2-2-P and the program Severo Ochoa (SEV-2014-0398). It is also supported by the Academy of Finland under Project No. 213503, Nuclear and Accelerator- Based Physics Research at JYFL, and by the European Commission un- der the FP7/EURATOM contract 605203. I.D. and M.M. acknowledge the support of the German Helmholtz Association via the Young Investigators Grant No. VH-NG 627. W.G. acknowledges the support of the UK Science Technology Faculties Council (STFC) under grant No. ST/F012012/1 and the University of Valencia. R.C.F. and I.D. are supported by the National Research Council of Canada (NSERC) Discovery Grants SAPIN-2014-00028 and RGPAS 462257-2014 at TRIUMF.
    • 18/2017. V. Guadilla, et al.: Study of the β decay of fission products with the DTAS detector Acta Physica Polonica B, 48 (3), 517-522 - DOI: 10.5506/APhysPolB.48.517 Submitted on 14 December 2016 , published March 2017
      Authors V. Guadilla, A. Algora, J.L. Tain, J. Agramunt, J. Äystö J.A. Briz, A. Cucoanes, T. Eronen, M. Estienne, M. Fallot, L.M. Fraile, E. Ganioğlu, W. Gelletly, D. Gorelov, J. Hakala, A. Jokinen, D. Jordan, A. Kankainen, V. Kolhinen, J. Koponen, M. Lebois, T. Martinez, M. Monserrate, A. Montaner-Pizá, I. Moore, E. Nácher, S.E.A. Orrigo, H. Penttilä, I. Pohjalainen, A. Porta, J. Reinikainen, M. Reponen, S. Rinta-Antila, B. Rubio, K. Rytkönen, T. Shiba, V. Sonnenschein, A.A. Sonzogni, E. Valencia, V. Vedia, A. Voss, J.N. Wilson, A.-A. Zakari-Issoufou.
      Abstract Total Absorption Spectroscopy measurements of the β decay of 103Mo and 103Tc, important contributors to the decay heat summation calculation in reactors, are reported in this work. The analysis of the experiment, performed at IGISOL with the new DTAS detector, show new β intensity that was not detected in previous measurements with Ge detectors.
      Acknowledgements This work has been supported by the Spanish Ministerio de Economía y Competitividad under the FPA2011-24553, the AIC-A-2011-0696, the FPA 2014-52823-C2-1-P and the SEV-2014-0398 grants, and by the Spanish Min- isterio de Educación under the FPU12/01527 grant.
    • 17/2017. C. Magron, et al.: Precise measurements of half-lives and branching ratios for the β decay of two mirror nuclei, 23Mg and 27Si European Physical Journal A 53: 77 (2017) - DOI: 10.1140/epja/i2017-12271-0 - Submitted on 4 December 2016, accepted 4 April 2017, published 24 April 2017
      Authors C. Magron, A. Alfaurt, B. Blank, L. Daudin, T. Eronen, M. Gerbaux, J. Giovinazzo, D. Gorelov, H. Guérin, J. Hakala, V. Kolhinen, J. Koponen, T. Kurtukian Nieto, I. Moore, H. Penttilä, I. Pohjalainen, J. Reinikainen, M. Reponen, S. Rinta-Antila, M. Roche, A. de Roubin, N. Smirnova, B. Thomas, A. Voss, and L. Xayavong
      Abstract Half-lives and branching ratios for the two mirror β decays of 23Mg and 27Si have been measured at the University of Jyvaskyla with the IGISOL facility. The results obtained, T1/2 = 11.303(3) s and T1/2 = 4.112(2) s for the half-lives of 23Mg and 27Si, respectively, are 7 and 9 times more precise than the averages of previous measurements. The values obtained for the superallowed branching ratios of 23Mg and 27Si are B.R. = 92.18(8)% and B.R. = 99.79(3)%, respectively. The result for 23Mg is three times more precise than the average of the previous measurements, while for 27Si the precision has not been improved, the average of the previous measurements being already very precise. Isospin breaking corrections have been calculated for the two nuclei to determine the corrected Ft value.
      Acknowledgements The authors would like to acknowledge the continuous effort of the whole Jyvaskyla accelerator laboratory staff for ensuring a smooth running of the experiment. This work was supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2012-2017 (Project No. 213503, Nuclear and Accelerator-Based Physics Research at JYFL), by the Conseil Régional d’Aquitaine, and by the European Community FP7 - Capacities - Integrated Infrastructure Initiative - contract ENSAR nO 262010. by the European Union 7th Framework Programme ”Integrated Infrastructure Initiative - Transnational Access”, ENSAR.
    • 16/2017. A. Voss, et al.: High-resolution laser spectroscopy of long-lived plutonium isotopes Physical Review A 95, 032506 (2017) - DOI: 10.1103/PhysRevA.95.032506 - Submitted on 8 December 2016, published 24 March 2017
      Authors A. Voss, V. Sonnenschein, P. Campbell, B. Cheal, T. Kron, I.D. Moore, I. Pohjalainen, S. Raeder, N. Trautmann, K. Wendt
      Abstract Long-lived isotopes of plutonium were studied using two complementary techniques, high-resolution resonance ionisation spectroscopy (HR-RIS) and collinear laser spectroscopy (CLS). Isotope shifts have been measured on the 5f6 7s2 7F0 → 5f5 6d2 7s (J=1) and 5f6 7s2 7F1 → 5f6 7s 7p (J=2) atomic transitions using the HR-RIS method and the hyperfine factors have been extracted for the odd mass nuclei 239,241Pu. Collinear laser spectroscopy was performed on the 5f6 7s 8F 1/2 →J=1/2(27523.61cm−1 ) ionic transition with the hyperfine A factors measured for 239Pu. Changes in mean-squared charge radii have been extracted and show a good agreement with previous non-optical methods, with an uncertainty improvement by approximately one order of magnitude. Plutonium represents the heaviest element studied to date using collinear laser spectroscopy.
      Acknowledgements We thank P. Thörle-Pospiech and J. Runke for preparing the Pu filaments. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 654002, the Academy of Finland under the Finnish Centre of Excellence Programme 2012–2017 (Project No. 251353, Nuclear and Accelerator-Based Physics Research at Jyfl), the Sciences and Technology Facilities Council (Stfc) of the United Kingdom, the Fwo-Vlaanderen (Belgium), Goa/2010/010 (Bof KU Leuven), the Iap Belgian Science Policy (BriX network P7/12) and a Grant from the European Research Council (Erc-2011-Adg-291561-Helios).
    • 15/2017. D. A. Nesterenko, et al.: High-precision mass measurements for the isobaric multiplet mass equation at A = 52 Journal of Physics G: Nuclear and Particle Physics 44 065103 (2017) - DOI: 10.1088/1361-6471/aa67ae - Accepted 20 March 2017, Published 19 April 2017, Available online 20 March 2017
      Authors D.A. Nesterenko, A. Kankainen, L. Canete, M. Block, D. Cox, T. Eronen, C. Fahlander, U. Forsberg, J. Gerl, P. Golubev, J. Hakala, A. Jokinen, V.S. Kolhinen, J. Koponen, N. Lalovic, Ch. Lorenz, I.D. Moore, P. Papadakis, J. Reinikainen, S. Rinta-Antila, D. Rudolph, L.G. Sarmiento, A. Voss, and J. Äystö
      Abstract Masses of 52Co, 52Com, 52Fe, 52Fem, and 52Mn have been measured with the JYFLTRAP double Penning trap mass spectrometer. Of these, 52Co and 52Com have been experimentally determined for the first time and found to be more bound than predicted by extrapolations. The isobaric multiplet mass equation for the T = 2 quintet at A = 52 has been studied employing the new mass values. No significant breakdown (beyond the 3σ level) of the quadratic form of the IMME was observed (χ2/n = 2.4). The cubic coefficient was 6.0(32) keV (χ2/n = 1.1). The excitation energies for the isomer and the T = 2 isobaric analogue state in 52Co have been determined to be 374(13) keV and 2922(13) keV, respectively. The Q value for the proton decay from the 19/2 isomer in 53Co has been determined with an unprecedented precision, Qp = 1558.8(17) keV. The proton separation energies of 52Co and 53Ni relevant for the astrophysical rapid proton capture process have been experimentally determined for the first time.
      Acknowledgements This work has been supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2012 - 2017 (Nuclear and Accelerator Based Physics Research at JYFL) and the Swedish Research Council (VR 2013-4271). A.K., D.N., and L.C. acknowledge support from the Academy of Finland under grant No. 275389.
    • MORE...