Search

Your search keyword '"Savran, D"' showing total 17 results
Start Over Author "Savran, D" Publisher elsevier
17 results on '"Savran, D"'

1. Unveiling the two-proton halo character of Ne: Exclusive measurement of quasi-free proton-knockout reactions

Author

Lehr, C., Wamers, F., Aksouh, F., Aksyutina, Yu., Álvarez-Pol, H., Atar, L., Aumann, T., Beceiro-Novo, S., Bertulani, C.A., Boretzky, K., Borge, M.J.G., Caesar, C., Chartier, M., Chatillon, A., Chulkov, L.V., Cortina-Gil, D., Díaz Fernández, P., Emling, H., Ershova, O., Fraile, L.M., Fynbo, H.O.U., Galaviz, D., Geissel, H., Heil, M., Heine, M., Hoffmann, D.H.H., Holl, M., Johansson, H.T., Jonson, B., Karagiannis, C., Kiselev, O.A., Kratz, J.V., Kulessa, R., Kurz, N., Langer, C., Lantz, M., Le Bleis, T., Lemmon, R., Litvinov, Yu.A., Löher, B., Mahata, K., Marganiec-Galązka, J., Müntz, C., Nilsson, T., Nociforo, C., Ott, W., Panin, V., Paschalis, S., Perea, A., Plag, R., Reifarth, R., Richter, A., Riisager, K., Rodriguez-Tajes, C., Rossi, D., Savran, D., Scheit, H., Schrieder, G., Schrock, P., Simon, H., Stroth, J., Sümmerer, K., Tengblad, O., Weick, H., and Wimmer, C.

Abstract

The proton drip-line nucleus $^{17}$Ne is investigated experimentally in order to determine its two-proton halo character. A fully exclusive measurement of the $^{17}$Ne(p,2p)16F→15⁎O+p quasi-free one-proton knockout reaction has been performed at GSI at around 500 MeV/nucleon beam energy. All particles resulting from the scattering process have been detected. The relevant reconstructed quantities are the angles of the two protons scattered in quasi-elastic kinematics, the decay of $^{16}$F into $^{15}$O (including γ decays from excited states) and a proton, as well as the $^{15}$O+p relative-energy spectrum and the $^{16}$F momentum distributions. The latter two quantities allow an independent and consistent determination of the fractions of l=0 and l=2 motion of the valence protons in $^{17}$Ne. With a resulting relatively small l=0 component of only around 35(3)%, it is concluded that $^{17}$Ne exhibits a rather modest halo character only. The quantitative agreement of the two values deduced from the energy spectrum and the momentum distributions supports the theoretical treatment of the calculation of momentum distributions after quasi-free knockout reactions at high energies by taking into account distortions based on the Glauber theory. Moreover, the experimental data allow the separation of valence-proton knockout and knockout from the $^{15}$O core. The latter process contributes with 11.8(3.1) mb around 40% to the total proton-knockout cross section of 30.3(2.3) mb, which explains previously reported contradicting conclusions derived from inclusive cross sections.

Published
2022

2. Unveiling the Two-Proton Halo Character of 17Ne: Exclusive Measurement of Quasi-free Proton-Knockout Reactions

Author

Federal Ministry of Education and Research (Germany), Helmholtz International Center for FAIR, Technische Universität Darmstadt, Swedish Research Council, Russian Foundation for Basic Research, Ministerio de Ciencia e Innovación (España), Department of Energy (US), National Science Foundation (US), Aumann, T. [0000-0003-1660-9294], Lehr, C., Wamers, F., Aksouh, F., Aksyutina, Yu., Alvarez-Pol, H., Atar, L., Aumann, T., Beceiro-Novo, S., Bertulani, C.A., Boretzky, K., García Borge, María José, Caesar, C., Chartier, M., Chatillon, A., Chulkov, L.V., Cortina-Gil, D., Diaz Fernandez, P., Emling, H., Ershova, O., Fraile, Luis M., Fynbo, H.O.U., Galaviz, D., Geissel, H., Heil, M., Heine, M., Hoffmann, D.H.H., Holl, M., Johansson, H.T., Jonson, B., Karagiannis, C., Kiselev, O. A., Kratz, J. V., Kulessa, R., Kurz, N., Langer, C., Lantz, M., Bleis, T. Le, Lemmon, R., Litvinov, Yu. A., Loeher, B., Mahata, K., Marganiec-Galazka, J., Muentz, C., Nilsson, T., Nociforo, C., Ott, W., Panin, V., Paschalis, S., Perea, Ángel, Plag, R., Reifarth, R., Richter, A., Riisager, K., Rodriguez-Tajes, C., Rossi, D., Savran, D., Scheit, H., Schrieder, G., Schrock, R., Simon, H., Stroth, J., Suemmerer, K., Tengblad, Olof, Weick, H., Wimmer, C., Federal Ministry of Education and Research (Germany), Helmholtz International Center for FAIR, Technische Universität Darmstadt, Swedish Research Council, Russian Foundation for Basic Research, Ministerio de Ciencia e Innovación (España), Department of Energy (US), National Science Foundation (US), Aumann, T. [0000-0003-1660-9294], Lehr, C., Wamers, F., Aksouh, F., Aksyutina, Yu., Alvarez-Pol, H., Atar, L., Aumann, T., Beceiro-Novo, S., Bertulani, C.A., Boretzky, K., García Borge, María José, Caesar, C., Chartier, M., Chatillon, A., Chulkov, L.V., Cortina-Gil, D., Diaz Fernandez, P., Emling, H., Ershova, O., Fraile, Luis M., Fynbo, H.O.U., Galaviz, D., Geissel, H., Heil, M., Heine, M., Hoffmann, D.H.H., Holl, M., Johansson, H.T., Jonson, B., Karagiannis, C., Kiselev, O. A., Kratz, J. V., Kulessa, R., Kurz, N., Langer, C., Lantz, M., Bleis, T. Le, Lemmon, R., Litvinov, Yu. A., Loeher, B., Mahata, K., Marganiec-Galazka, J., Muentz, C., Nilsson, T., Nociforo, C., Ott, W., Panin, V., Paschalis, S., Perea, Ángel, Plag, R., Reifarth, R., Richter, A., Riisager, K., Rodriguez-Tajes, C., Rossi, D., Savran, D., Scheit, H., Schrieder, G., Schrock, R., Simon, H., Stroth, J., Suemmerer, K., Tengblad, Olof, Weick, H., and Wimmer, C.

Abstract

The proton drip-line nucleus 17Ne is investigated experimentally in order to determine its two-proton halo character. A fully exclusive measurement of the 17Ne(p,2p)16F->15O+p quasi-free one-proton knockout reaction has been performed at GSI at around 500 MeV/nucleon beam energy. All particles resulting from the scattering process have been detected. The relevant reconstructed quantities are the angles of the two protons scattered in quasi-elastic kinematics, the decay of 16F into 15O (including gamma decays from excited states) and a proton, as well as the 15O+p relative-energy spectrum and the 16F momentum distributions. The latter two quantities allow an independent and consistent determination of the ratio of l=0 and l=2 motion of the valence protons in 17Ne. With a resulting relatively small l=0 component of only around 35(3)%, it is concluded that 17Ne exhibits a rather modest halo character only. The quantitative agreement of the two values deduced from the energy spectrum and the momentum distributions supports the theoretical treatment of the calculation of momentum distributions after quasi-free knockout reactions at high energies by taking into account distortions based on the Glauber theory. Moreover, the experimental data allow the separation of valence-proton knockout and knockout from the 15O core. The latter process contributes with 11.8(3.1) mb around 40% to the total proton-knockout cross section of 30.3(2.3) mb, which explains previously reported contradicting conclusions derived from inclusive cross sections.

Published
2022

3. Unveiling the two-proton halo character of 17Ne: Exclusive measurement of quasi-free proton-knockout reactions

Author

Lehr, C., Wamers, F., Aksouh, F., Aksyutina, Yu., ��lvarez-Pol, H., Atar, Leyla, Aumann, Thomas, Beceiro-Novo, S., Bertulani, C. A., Boretzky, K., Borge, M. J. G., Caesar, C., Chartier, M., Chatillon, A., Chulkov, L. V., Cortina-Gil, D., D��az Fern��ndez, P., Emling, Hans, Ershova, Olga, Fraile, L. M., Fynbo, H. O. U., Galaviz, D., Geissel, H., Heil, M., Heine, M., Hoffmann, D. H. H., Holl, M., Johansson, H. T., Jonson, B., Karagiannis, C., Kiselev, O. A., Kratz, J. V., Kulessa, R., Kurz, N., Langer, Christoph, Lantz, M., Le Bleis, T., Lemmon, R., Litvinov, Yu. A., L��her, B., Mahata, K., Marganiec-Gal��zka, J., M��ntz, C., Nilsson, T., Nociforo, C., Ott, W., Panin, V., Paschalis, S., Perea, A., Plag, Ralf, Reifarth, Rene, Richter, A., Riisager, K., Rodriguez-Tajes, C., Rossi, D., Savran, D., Scheit, H., Schrieder, G., Schrock, P., Simon, H., Stroth, J., S��mmerer, K., Tengblad, O., Weick, H., Wimmer, C., Federal Ministry of Education and Research (Germany), Helmholtz International Center for FAIR, Technische Universität Darmstadt, Swedish Research Council, Russian Foundation for Basic Research, Ministerio de Ciencia e Innovación (España), Department of Energy (US), National Science Foundation (US), Aumann, T. [0000-0003-1660-9294], and Aumann, T.

Subjects
Subatomär fysik, Nuclear and High Energy Physics, Física-Modelos matemáticos, Subatomic Physics, Nuclear Theory, Partículas, FOS: Physical sciences, ddc:530, Nuclear Experiment (nucl-ex), Nuclear experiment, Nuclear Experiment
Abstract

7 pags., 5 figs., The proton drip-line nucleus 17Ne is investigated experimentally in order to determine its two-proton halo character. A fully exclusive measurement of the 17Ne(p,2p)16F->15O+p quasi-free one-proton knockout reaction has been performed at GSI at around 500 MeV/nucleon beam energy. All particles resulting from the scattering process have been detected. The relevant reconstructed quantities are the angles of the two protons scattered in quasi-elastic kinematics, the decay of 16F into 15O (including gamma decays from excited states) and a proton, as well as the 15O+p relative-energy spectrum and the 16F momentum distributions. The latter two quantities allow an independent and consistent determination of the ratio of l=0 and l=2 motion of the valence protons in 17Ne. With a resulting relatively small l=0 component of only around 35(3)%, it is concluded that 17Ne exhibits a rather modest halo character only. The quantitative agreement of the two values deduced from the energy spectrum and the momentum distributions supports the theoretical treatment of the calculation of momentum distributions after quasi-free knockout reactions at high energies by taking into account distortions based on the Glauber theory. Moreover, the experimental data allow the separation of valence-proton knockout and knockout from the 15O core. The latter process contributes with 11.8(3.1) mb around 40% to the total proton-knockout cross section of 30.3(2.3) mb, which explains previously reported contradicting conclusions derived from inclusive cross sections., This work is supported by the German Federal Ministry for Education and Research (BMBF) under contract No. 05P15RDFN1, the ExtreMe Matter Institute (EMMI), HIC for FAIR, and the GSI- TU Darmstadt cooperation agreement. Financial support from the Swedish Research Council, from the Russian Foundation for Ba- sic Research (RFBR Grant 12-02-01115-a), and from the Spanish grants from MICINN AEI FPA2017-87568-P, PGC2018-0099746-B- C21, FPA2015-64969-P, PID2019-104390GB-I00, RTI2018-098868- B-100, and Maria de Maeztu Units of excellence MDM-2016-0692 are also acknowledged. One of us (B. J.) is a Helmholtz Interna- tional Fellow. C.A.B. acknowledges support by the U.S. DOE grant DE-FG02-08ER41533 and the U.S. NSF Grant No. 1415656

Published
2022
Full Text
View/download PDF

4. The structure of low-lying 1 States in Zr from ( , ′ ) and ( , ′ ) Reactions

Author

Crespi, F.C.L., Bracco, A., Lanza, E.G., Tamii, A., Blasi, N., Camera, F., Wieland, O., Aoi, N., Balabanski, D.L., Bassauer, S., Brown, A.S., Carpenter, M.P., Carroll, J.J., Ciemała, M., Czeszumska, A., Davies, P.J., Derya, V., Donaldson, L.M., Fang, Y.D., Fujita, H., Gey, G., Ha, H.T., Harakeh, M.N., Hashimoto, T., Ichige, N., Ideguchi, E., Inoue, A., Isaak, J., Iwamoto, C., Jenkins, D.G., Klaus, T., Kobayashi, N., Koike, T., Krzysiek, M., Raju, M.K., Liu, M., Maj, A., Morris, L., von Neumann Cosel, P., Noji, S., Ong, H.J., Pickstone, S.G., Pietralla, N., Savran, D., Schmitt, J.M., Spieker, M., Steinhilber, G., Sullivan, C., Wasilewska, B., Weinert, M., Werner, V., Yamamoto, Y., Yamamoto, T., Zegers, R.G.T., Zhou, X., Zhu, S., and Zilges, A.

Abstract

The low-lying dipole strength in the $^{90,94}$Zr nuclei was investigated via (p,p′γ) at 80 MeV and (α,α′γ) at 130 MeV. The experiments, made at RCNP, used the magnetic spectrometer Grand Raiden for the scattered particles and the array CAGRA with HPGe detectors for the γ-decay. For $^{94}$Zr these are the first data for both reactions and for $^{90}$Zr these are the first data with (p,p′γ) and the first ones at high resolution for (α,α′γ). The comparison of the present results for the two nuclei with existing (γ,γ′) data shows that both nuclear probes produce an excitation pattern different than that of the electromagnetic probes.DWBA calculations were made using form factors deduced from transition densities, based on RPA calculations, characterized by a strong neutron component at the nuclear surface. A combined analysis of the two reactions was performed for the first time to investigate the isoscalar character of the 1$^{−}$ states in $^{90,94}$Zr. The (p,p′γ) cross section was calculated using values for the isoscalar electric dipole energy-weighted sum rule (E1 ISEWSR) obtained from the (α,α′γ) data. The isoscalar strength for $^{90}$Zr was found to exhaust 20 ± 2.5% of the EWSR in the energy range up to 12 MeV. In case of $^{94}$Zr, a strength of 9 ± 1.1% of the EWSR was found in the range up to 8.5 MeV.Although an overall general description was obtained in the studied energy intervals, not all proton cross sections were well reproduced using the isoscalar strength from (α,α′γ). This might suggest mixing of isoscalar and isovector components and that this mixing and the degree of collectivity are not the same for all the 1$^{−}$ states below the particle binding energy.

Published
2021

5. Structure of high-lying levels populated in the Y-96 -> Zr-96 beta decay

Author

Mashtakov, KR, Ponomarevc, V Yu, Scheck, M, Finch, SW, Isaak, J, Zweidinger, M, Agar, O, Bathia, C, Beck, T, Beller, J, Bowrya, M, Chapman, R, Chishti, MMR, Friman-Gayer, U, Gaffney, LP, Garrett, PE, Gregor, ET, Keatings, JM, Koster, U, Loher, B, MacLean, AD, O'Donnell, D, Pai, H, Pietralla, N, Rainovski, G, Ramdhane, M, Romig, C, Rusev, G, Savran, D, Simpson, GS, Sinclair, J, Sonnabend, K, Spagnoletti, P, Tonchev, AP, and Tornow, W

Subjects
Science & Technology, Physics, Nuclear, Reactor antineutrino anomaly, NUCLEAR-DATA SHEETS, Quasi-particle phonon model, Physics, Physical Sciences, High resolution gamma-ray spectroscopy, Pygmy dipole resonance, Astronomy & Astrophysics, Physics, Particles & Fields
Abstract

ispartof: PHYSICS LETTERS B vol:820 status: published

Published
2021

6. Structure of high-lying levels populated in the Y → Zr Decay

Author

Mashtakov, K.R., Ponomarev, V.Yu., Scheck, M., Finch, S.W., Isaak, J., Zweidinger, M., Agar, O., Bathia, C., Beck, T., Beller, J., Bowry, M., Chapman, R., Chishti, M.M.R., Friman-Gayer, U., Gaffney, L.P., Garrett, P.E., Gregor, E.T., Keatings, J.M., Köster, U., Löher, B., MacLean, A.D., O'Donnell, D., Pai, H., Pietralla, N., Rainovski, G., Ramdhane, M., Romig, C., Rusev, G., Savran, D., Simpson, G.S., Sinclair, J., Sonnabend, K., Spagnoletti, P., Tonchev, A.P., and Tornow, W.

Abstract

The nature of the high-lying final levels of the $^{96}$Y$_{gs}$ β decay, one of the three most important contributors to the high-energy reactor antineutrino spectrum, has been investigated in high-resolution γ-ray spectroscopy following the β decay as well as in a campaign of inelastic photon scattering experiments. The comprehensive approach establishes 1$^{−}$ levels associated with the Pygmy Dipole Resonance as high-lying final levels in the β decay. Branching ratios extracted from β decay complement photon scattering and allow the absolute E1 excitation strength to be determined for levels populated in both reactions. The combined data represents a comprehensive approach to the wavefunction of the 1− levels below the Qβ value, which are investigated in the Quasiparticle Phonon Model. The calculations reveal that the components populated in β decay contribute only with small amplitudes to the complex wavefunction of these 1$^{−}$ levels. A comparison of the β decay results to data from total absorption γ-ray spectroscopy demonstrates a good agreement between both measurements.

Published
2021

7. The structure of low-lying 1(-) states in Zr-90,Zr-94 from (alpha, alpha 'gamma) and (p, p 'gamma) reactions

Author

Crespi, F. C. L., Bracco, A., Lanza, E. G., Tamii, A., Blasi, N., Camera, F., Wieland, O., Aoi, N., Balabanski, D. L., Bassauer, S., Brown, A. S., Carpenter, M. P., Carroll, J. J., Ciemata, M., Czeszumska, A., Davies, P. J., Derya, V., Donaldson, L. M., Fang, Y. D., Fujita, H., Gey, G., Ha, H. T., Harakeh, M. N., Hashimoto, T., Ichige, N., Ideguchi, E., Inoue, A., Isaak, J., Iwamoto, C., Jenkins, D. G., Klaus, T., Kobayashi, N., Koike, T., Krzysiek, M., Raju, M. K., Liu, M., Maj, A., Morris, L., Cosel, P. von Neumann, Noji, S., Ong, H. J., Pickstone, S. G., Pietralla, N., Savran, D., Schmitt, J. M., Spieker, M., Steinhilber, G., Sullivan, C., Wasilewska, B., Weinert, M., Werner, V., Yamamoto, Y., Yamamoto, T., Zegers, R. G. T., Zhou, X., Zhu, S., Zilges, A., Crespi, F. C. L., Bracco, A., Lanza, E. G., Tamii, A., Blasi, N., Camera, F., Wieland, O., Aoi, N., Balabanski, D. L., Bassauer, S., Brown, A. S., Carpenter, M. P., Carroll, J. J., Ciemata, M., Czeszumska, A., Davies, P. J., Derya, V., Donaldson, L. M., Fang, Y. D., Fujita, H., Gey, G., Ha, H. T., Harakeh, M. N., Hashimoto, T., Ichige, N., Ideguchi, E., Inoue, A., Isaak, J., Iwamoto, C., Jenkins, D. G., Klaus, T., Kobayashi, N., Koike, T., Krzysiek, M., Raju, M. K., Liu, M., Maj, A., Morris, L., Cosel, P. von Neumann, Noji, S., Ong, H. J., Pickstone, S. G., Pietralla, N., Savran, D., Schmitt, J. M., Spieker, M., Steinhilber, G., Sullivan, C., Wasilewska, B., Weinert, M., Werner, V., Yamamoto, Y., Yamamoto, T., Zegers, R. G. T., Zhou, X., Zhu, S., and Zilges, A.

Abstract

The low-lying dipole strength in the Zr-90,Zr-94 nuclei was investigated via (p, p'gamma) at 80 MeV and (alpha, alpha'gamma) at 130 MeV. The experiments, made at RCNP, used the magnetic spectrometer Grand Raiden for the scattered particles and the array CAGRA with HPGe detectors for the gamma-decay. For Zr-94 these are the first data for both reactions and for Zr-90 these are the first data with (p, p'gamma) and the first ones at high resolution for (alpha, alpha'gamma). The comparison of the present results for the two nuclei with existing (gamma, gamma') data shows that both nuclear probes produce an excitation pattern different than that of the electromagnetic probes. DWBA calculations were made using form factors deduced from transition densities, based on RPA calculations, characterized by a strong neutron component at the nuclear surface. A combined analysis of the two reactions was performed for the first time to investigate the isoscalar character of the 1(-) states in Zr-90,Zr-94. The (p, p'gamma) cross section was calculated using values for the isoscalar electric dipole energy-weighted sum rule (E1 ISEWSR) obtained from the (alpha, alpha'gamma) data. The isoscalar strength for Zr-90 was found to exhaust 20 +/- 2.5% of the EWSR in the energy range up to 12 MeV. In case of Zr-94, a strength of 9 +/- 1.1% of the EWSR was found in the range up to 8.5 MeV. Although an overall general description was obtained in the studied energy intervals, not all proton cross sections were well reproduced using the isoscalar strength from (alpha, alpha'gamma). This might suggest mixing of isoscalar and isovector components and that this mixing and the degree of collectivity are not the same for all the 1(-) states below the particle binding energy. (C) 2021 The Authors. Published by Elsevier B.V.

Published
2021

8. NeuLAND: The high-resolution neutron time-of-flight spectrometer for (RB)-B-3 at FAIR

Author

Boretzky, K., Gasparic, I, Heil, M., Mayer, J., Heinz, A., Caesar, C., Kresan, D., Simon, H., Toernqvist, H. T., Koerper, D., Alkhazov, G., Atar, L., Aumann, T., Bemmerer, D., Bondarev, S., V, Bott, L. T., Chakraborty, S., Cherciu, M., I, Chulkov, L., V, Ciobanu, M., Datta, U., De Filippo, E., Douma, C. A., Dreyer, J., Elekes, Z., Enders, J., Galaviz, D., Geraci, E., Gnoffo, B., Goebel, K., Golovtsov, V. L., Diaz, D. Gonzalez, Gruzinsky, N., Heftrich, T., Heggen, H., Hehner, J., Hensel, T., Hoemann, E., Holl, M., Horvat, A., Horvath, A., Ickert, G., Malenica, D. Jelavic, Johansson, H. T., Jonson, B., Kahlbow, J., Kalantar-Nayestanaki, N., Kelic-Heil, A., Kempe, M., Koch, K., Kozlenko, N. G., Krivshich, A. G., Kurz, N., Kuznetsov, V, Langer, C., Leifels, Y., Lihtar, I, Loeher, B., Machado, J., Martorana, N. S., Miki, K., Nilsson, T., Orischin, E. M., Pagano, E., V, Pirrone, S., Politi, G., Potlog, P. M., Rahaman, A., Reifarth, R., Rigollet, C., Roeder, M., Rossi, D. M., Russotto, P., Savran, D., Scheit, H., Schindler, F., Stach, D., Stan, E., Gill, J. Stomvall, Teubig, P., Trimarchi, M., Uvarov, L., Volknandt, M., Volkov, S., Wagner, A., Wagner, V, Wranne, S., Yakorev, D., Zanetti, L., Zilges, A., Zuber, K., Boretzky, K., Gasparic, I, Heil, M., Mayer, J., Heinz, A., Caesar, C., Kresan, D., Simon, H., Toernqvist, H. T., Koerper, D., Alkhazov, G., Atar, L., Aumann, T., Bemmerer, D., Bondarev, S., V, Bott, L. T., Chakraborty, S., Cherciu, M., I, Chulkov, L., V, Ciobanu, M., Datta, U., De Filippo, E., Douma, C. A., Dreyer, J., Elekes, Z., Enders, J., Galaviz, D., Geraci, E., Gnoffo, B., Goebel, K., Golovtsov, V. L., Diaz, D. Gonzalez, Gruzinsky, N., Heftrich, T., Heggen, H., Hehner, J., Hensel, T., Hoemann, E., Holl, M., Horvat, A., Horvath, A., Ickert, G., Malenica, D. Jelavic, Johansson, H. T., Jonson, B., Kahlbow, J., Kalantar-Nayestanaki, N., Kelic-Heil, A., Kempe, M., Koch, K., Kozlenko, N. G., Krivshich, A. G., Kurz, N., Kuznetsov, V, Langer, C., Leifels, Y., Lihtar, I, Loeher, B., Machado, J., Martorana, N. S., Miki, K., Nilsson, T., Orischin, E. M., Pagano, E., V, Pirrone, S., Politi, G., Potlog, P. M., Rahaman, A., Reifarth, R., Rigollet, C., Roeder, M., Rossi, D. M., Russotto, P., Savran, D., Scheit, H., Schindler, F., Stach, D., Stan, E., Gill, J. Stomvall, Teubig, P., Trimarchi, M., Uvarov, L., Volknandt, M., Volkov, S., Wagner, A., Wagner, V, Wranne, S., Yakorev, D., Zanetti, L., Zilges, A., and Zuber, K.

Abstract

NeuLAND (New Large-Area Neutron Detector) is the next-generation neutron detector for the (RB)-B-3 (Reactions with Relativistic Radioactive Beams) experiment at FAIR (Facility for Antiproton and Ion Research). NeuLAND detects neutrons with energies from 100 to 1000 MeV, featuring a high detection efficiency, a high spatial and time resolution, and a large multi-neutron reconstruction efficiency. This is achieved by a highly granular design of organic scintillators: 3000 individual submodules with a size of 5 x 5 x 250 cm(3) are arranged in 30 double planes with 100 submodules each, providing an active area of 250 x 250 cm(2) and a total depth of 3 m. The spatial resolution due to the granularity together with a time resolution of sigma(t) <= 150 ps ensures highresolution capabilities. In conjunction with calorimetric properties, a multi-neutron reconstruction efficiency of 50% to 70% for four-neutron events will be achieved, depending on both the emission scenario and the boundary conditions allowed for the reconstruction method. We present in this paper the final design of the detector as well as results from test measurements and simulations on which this design is based.

Published
2021

9. Probing the Z=6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions

Author

Syndikus, I, Petri, M., Macchiavelli, A. O., Paschalis, S., Bertulani, C. A., Aumann, T., Alvarez-Pol, H., Atar, L., Beceiro-Novo, S., Benlliure, J., Boillos, J. M., Boretzky, K., Borge, M. J. G., Brown, B. A., Caamano, M., Caesar, C., Casarejos, E., Catford, W., Cederkall, J., Chakraborty, S., Chulkov, L., V, Cortina-Gil, D., Cravo, E., Crespo, R., Pramanik, U. Datta, Dillmann, I, Fernandez, P. Diaz, Elekes, Z., Enders, J., Farinon, F., Fraile, L. M., Galaviz, D., Geissel, H., Gernhaeuser, R., Golubev, P., Goebel, K., Heil, M., Heine, M., Heinz, A., Henriques, A., Holl, M., Johansson, H. T., Jonson, B., Kalantar-Nayestanaki, N., Kanungo, R., Kelic-Heil, A., Kroll, T., Kurz, N., Langer, C., Le Bleis, T., Machado, J., Marganiec-Galazka, J., Nacher, E., Nilsson, T., Nociforo, C., Panin, V, Perea, A., Pietri, S. B., Plag, R., Rahaman, A., Reifarth, R., Revel, A., Ribeiro, G., Rigollet, C., Rossi, D. M., Savran, D., Scheit, H., Simon, H., Sorlin, O., Tengblad, O., Togano, Y., Vandebrouck, M., Volkov, V., Wamers, F., Wheldon, C., Wilson, G. L., Winfield, J. S., Weick, H., Woods, P., Yakorev, D., Zhukov, M., Zilges, A., Zuber, K., Syndikus, I, Petri, M., Macchiavelli, A. O., Paschalis, S., Bertulani, C. A., Aumann, T., Alvarez-Pol, H., Atar, L., Beceiro-Novo, S., Benlliure, J., Boillos, J. M., Boretzky, K., Borge, M. J. G., Brown, B. A., Caamano, M., Caesar, C., Casarejos, E., Catford, W., Cederkall, J., Chakraborty, S., Chulkov, L., V, Cortina-Gil, D., Cravo, E., Crespo, R., Pramanik, U. Datta, Dillmann, I, Fernandez, P. Diaz, Elekes, Z., Enders, J., Farinon, F., Fraile, L. M., Galaviz, D., Geissel, H., Gernhaeuser, R., Golubev, P., Goebel, K., Heil, M., Heine, M., Heinz, A., Henriques, A., Holl, M., Johansson, H. T., Jonson, B., Kalantar-Nayestanaki, N., Kanungo, R., Kelic-Heil, A., Kroll, T., Kurz, N., Langer, C., Le Bleis, T., Machado, J., Marganiec-Galazka, J., Nacher, E., Nilsson, T., Nociforo, C., Panin, V, Perea, A., Pietri, S. B., Plag, R., Rahaman, A., Reifarth, R., Revel, A., Ribeiro, G., Rigollet, C., Rossi, D. M., Savran, D., Scheit, H., Simon, H., Sorlin, O., Tengblad, O., Togano, Y., Vandebrouck, M., Volkov, V., Wamers, F., Wheldon, C., Wilson, G. L., Winfield, J. S., Weick, H., Woods, P., Yakorev, D., Zhukov, M., Zilges, A., and Zuber, K.

Abstract

The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z = 6 spin-orbit shell gap towards the neutron dripline. To do so, we employed N-A(p,2p)CA-1 quasi-free scattering reactions to measure the proton component of the 2(1)(+) state of C-16,C-18,C-20. The experimental findings support the notion of a moderate reduction of the proton 1p(1/2) - 1p(3/2) spin-orbit splitting, at variance to recent claims for a prevalent Z = 6 magic number towards the neutron dripline. (C) 2020 The Authors. Published by Elsevier B.V.

Published
2020

10. The concept of nuclear photon strength functions: A model-independent approach via ((gamma)over-right-arrow, gamma ' gamma ') reactions

Author

Isaak, J., Savran, D., Loher, B., Beck, T., Bhike, M., Gayer, U., Pietralla, N., Scheck, M., Tornow, W., Werner, V., Zilges, A., Zweidinger, M., Isaak, J., Savran, D., Loher, B., Beck, T., Bhike, M., Gayer, U., Pietralla, N., Scheck, M., Tornow, W., Werner, V., Zilges, A., and Zweidinger, M.

Abstract

Most theoretical approaches used in nuclear astrophysics to model the nucleosynthesis of heavy elements incorporate the so-called statistical model in order to describe the excitation and decay properties of atomic nuclei. One of the basic assumptions of this model is the validity of the Brink-Axel hypothesis and the related concept of so-called photon strength functions to describe gamma-ray transition probabilities. We present a novel experimental approach that allows for the first time to experimentally determine the photon strength function simultaneously in two independent ways by a unique combination of quasimonochromatic photon beams and a newly implemented gamma-gamma coincidence setup. This technique does not assume a priori the validity of the Brink-Axel hypothesis and sets a benchmark in terms of the detection sensitivity for measuring decay properties of photo-excited states below the neutron separation energy. The data for the spherical off-shell nucleus Te-128 were obtained for y-ray beam-energy settings between 3 MeV and 9 MeV in steps of 130 keV for the lower beam energies and in steps of up to 280 keV for the highest beam settings. We present a quantitative analysis on the consistency of the derived photon strength function with the Brink-Axel hypothesis. The data clearly demonstrate a discrepancy of up to a factor of two between the photon strength functions extracted from the photoabsorption and photon emission process, respectively. In addition, we observe that the photon strength functions are not independent of the excitation energy, as usually assumed. Thus, we conclude, that the Brink-Axel hypothesis is not strictly fulfilled in the excitation-energy region below the neutron separation threshold S-n= 8.78 MeV) for the studied case of Te-128. (C) 2018 The Authors. Published by Elsevier B.V.

Published
2019

11. Multi-messenger investigation of the Pygmy Dipole Resonance in Ce

Author

Savran, D., Derya, V., Bagchi, S., Endres, J., Harakeh, M.N., Isaak, J., Kalantar-Nayestanaki, N., Lanza, E.G., Löher, B., Najafi, A., Pascu, S., Pickstone, S.G., Pietralla, N., Ponomarev, V.Yu., Rigollet, C., Romig, C., Spieker, M., Vitturi, A., and Zilges, A.

Abstract

We report on the first (p,p′γ) experiments at Ep=80 MeV to investigate the Pygmy Dipole Resonance (PDR) in the semi-magic nucleus $^{140}$Ce. This experiment is the latest in a series of experiments to investigate the PDR with different complementary probes to provide a multi-messenger data set on the properties of the PDR in $^{140}$Ce. In addition, calculations within the Quasi-particle Phonon Model (QPM) have been performed. Cross sections have been calculated for proton- as well as α-scattering reactions based on the transition densities obtained from the QPM, not only at the RPA level, but including the full model space of up to 3p–3h configurations. This allows for the first time to compare the calculations to the experimental results on an absolute scale for single excitations. Agreement between QPM and experiment is observed, which proves the high accuracy of the calculated transition densities for individual PDR states.

Published
2018

12. Separation of the 1+/1− parity doublet in 20 Ne

Author

Beller, J., Stumpf, C., Scheck, M., Pietralla, N., Deleanu, D., Filipescu, D.M., Glodariu, T., Haxton, W., Idini, A., Kelley, J.H., Kwan, E., Martinez-Pinedo, G., Raut, R., Romig, C., Roth, R., Rusev, G., Savran, D., Tonchev, A.P., Tornow, W., Wagner, J., Weller, H.R., Zamfir, N.V., and Zweidinger, M.

Subjects
High Energy Physics::Phenomenology, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The (J,T)=(1,1) parity doublet in 20 Ne at 11.26 MeV is a good candidate to study parity violation in nuclei. However, its energy splitting is known with insufficient accuracy for quantitative estimates of parity violating effects. To improve on this unsatisfactory situation, nuclear resonance fluorescence experiments using linearly and circularly polarized γ -ray beams were used to determine the energy difference of the parity doublet ΔE=E(1−)−E(1+)=−3.2(±0.7)stat(−1.2+0.6)sys keV and the ratio of their integrated cross sections Is,0(+)/Is,0(−)=29(±3)stat(−7+14)sys . Shell-model calculations predict a parity-violating matrix element having a value in the range 0.46–0.83 eV for the parity doublet. The small energy difference of the parity doublet makes 20 Ne an excellent candidate to study parity violation in nuclear excitations.

Published
2014

13. Coulomb and nuclear excitations of narrow resonances in 17Ne

Author

Universidade de Santiago de Compostela. Departamento de Física de Partículas, Marganiec, J., Wamers, F., Aksouh, F., Aksyutina, Y., Álvarez Pol, Héctor, Aumann, T., Beceiro Novo, Saúl, Bertulani, C. A., Boretzky, K., Borge, M. J. G., Chartier, M., Chatillon, A., Chulkov, L. V., Cortina Gil, María Dolores, Emling, H., Ershova, O., Fraile, L. M., Fynbo, H. O. U., Galaviz, D., Geissel, H., Heil, M., Hoffmann, D. H. H., Hoffmann, J., Johansson, H. T., Jonson, B., Karagiannis, C., Kiselev, O. A., Kratz, J. V., Kulessa, R., Kurz, N., Langer, C., Lantz, M., Le Bleis, T., Lemmon, R., Litvinov, Yu. A., Mahata, K., Müntz, C., Nilsson, T., Nociforo, C., Nyman, G., Ott, W., Panin, V., Paschalis, S., Perea, A., Plag, R., Reifarth, R., Richter, A., Rodríguez Tajes, Carme, Rossi, D., Riisager, K., Savran, D., Schrieder, G., Simon, H., Stroth, J., Sümmerer, K., Tengblad, O., Typel, S., Weick, H., Wiescher, M., Wimmer, C., Universidade de Santiago de Compostela. Departamento de Física de Partículas, Marganiec, J., Wamers, F., Aksouh, F., Aksyutina, Y., Álvarez Pol, Héctor, Aumann, T., Beceiro Novo, Saúl, Bertulani, C. A., Boretzky, K., Borge, M. J. G., Chartier, M., Chatillon, A., Chulkov, L. V., Cortina Gil, María Dolores, Emling, H., Ershova, O., Fraile, L. M., Fynbo, H. O. U., Galaviz, D., Geissel, H., Heil, M., Hoffmann, D. H. H., Hoffmann, J., Johansson, H. T., Jonson, B., Karagiannis, C., Kiselev, O. A., Kratz, J. V., Kulessa, R., Kurz, N., Langer, C., Lantz, M., Le Bleis, T., Lemmon, R., Litvinov, Yu. A., Mahata, K., Müntz, C., Nilsson, T., Nociforo, C., Nyman, G., Ott, W., Panin, V., Paschalis, S., Perea, A., Plag, R., Reifarth, R., Richter, A., Rodríguez Tajes, Carme, Rossi, D., Riisager, K., Savran, D., Schrieder, G., Simon, H., Stroth, J., Sümmerer, K., Tengblad, O., Typel, S., Weick, H., Wiescher, M., and Wimmer, C.

Abstract

New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the 15O +p +pthree-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.

Published
2016

14. Isospin properties of electric dipole excitations in Ca-48

Author

Derya, V., Savran, D., Endres, J., Harakeh, M. N., Hergert, H., Kelley, J. H., Papakonstantinou, P., Pietralla, N., Ponomarev, V. Yu., Roth, R., Rusev, G., Tonchev, A. P., Tornow, W., Wortche, H. J., Zilges, A., Derya, V., Savran, D., Endres, J., Harakeh, M. N., Hergert, H., Kelley, J. H., Papakonstantinou, P., Pietralla, N., Ponomarev, V. Yu., Roth, R., Rusev, G., Tonchev, A. P., Tornow, W., Wortche, H. J., and Zilges, A.

Abstract

Two different experimental approaches were combined to study the electric dipole strength in the doubly-magic nucleus Ca-48 below the neutron threshold. Real-photon scattering experiments using bremsstrahlung up to 9.9 MeV and nearly mono-energetic linearly polarized photons with energies between 6.6 and 9.51 MeV provided strength distribution and parities, and an (alpha, alpha'gamma) experiment at E-alpha = 136 MeV gave cross sections for an isoscalar probe. The unexpected difference observed in the dipole response is compared to calculations using the first-order random-phase approximation and points to an energy-dependent isospiu character. A strong isoscalar state at 7.6 MeV was identified for the first time supporting a recent theoretical prediction. (C) 2014 The Authors. Published by Elsevier B.V.

Published
2014

15. Performance analysis for the CALIFA Barrel calorimeter of the R3B experiment

Author

Álvarez-Pol, H., Ashwood, N., Aumann, T., Bertini, D., Cabanelas, P., Casarejos, E., Cederkall, J., Cortina-Gil, D., Díaz Fernández, P., Durán, Ignacio, Fiori, E., Galaviz, D., Labiche, M., Nácher, Enrique, Pietras, B., Savran, D., Tengblad, Olof, Teubig, P., Álvarez-Pol, H., Ashwood, N., Aumann, T., Bertini, D., Cabanelas, P., Casarejos, E., Cederkall, J., Cortina-Gil, D., Díaz Fernández, P., Durán, Ignacio, Fiori, E., Galaviz, D., Labiche, M., Nácher, Enrique, Pietras, B., Savran, D., Tengblad, Olof, and Teubig, P.

Abstract

© 2014 Elsevier B.V. All rights reserved. The CALIFA calorimeter is an advanced detector for gamma rays and light charged particles, accordingly optimized for the demanding requirements of the physics programme proposed for the R3B facility at FAIR. The multipurpose character of CALIFA is required to fulfil challenging demands in energy resolution (5-6% at 1 MeV for gamma rays) and efficiency. Charged particles, e.g. protons of energies up to 320 MeV in the Barrel section, should also be identified with an energy resolution better to 1%. CALIFA is divided into two well-separated sections: a >Forward EndCap> and a cylindrical >Barrel> covering an angular range from 43.2°to 140.3°. The Barrel section, based on long CsI(Tl) pyramidal frustum crystals coupled to large area avalanche photodiodes (LAAPDs), attains the requested high efficiency for calorimetric purposes. The construction of the CALIFA Demonstrator, comprising 20% of the total detector, has already been initiated, and commissioning experiments are expected for 2014. The assessment of the capabilities and expected performance of the detector elements is a crucial step in their design, along with the prototypes evaluation. For this purpose, the Barrel geometry has been carefully implemented in the simulation package R3BRoot, including easily variable thicknesses of crystal wrapping and carbon fibre supports. A complete characterization of the calorimeter response (including efficiency, resolution, evaluation of energy and reconstruction losses) under different working conditions, with several physics cases selected to probe the detector performance over a wide range of applications, has been undertaken. Prototypes of different sections of the CALIFA Barrel have been modeled and their responses have been evaluated and compared with the experimental results. The present paper summarizes the outcome of the simulation campaign for the entire Barrel section and for the corresponding prototypes tested at different

Published
2014

16. The high-efficiency gamma-ray spectroscopy setup gamma(3) at HI gamma S

Author

Loeher, B., Derya, V., Aumann, T., Beller, J., Cooper, N., Duchene, M., Endres, J., Fiori, E., Isaak, J., Kelley, J., Knoerzer, M., Pietralla, N., Romig, C., Savran, D., Scheck, M., Scheit, H., Silva, J., Tonchev, A., Tornow, W., Weller, H., Werner, V., Zilges, A., Loeher, B., Derya, V., Aumann, T., Beller, J., Cooper, N., Duchene, M., Endres, J., Fiori, E., Isaak, J., Kelley, J., Knoerzer, M., Pietralla, N., Romig, C., Savran, D., Scheck, M., Scheit, H., Silva, J., Tonchev, A., Tornow, W., Weller, H., Werner, V., and Zilges, A.

Abstract

The existing Nuclear Resonance Fluorescence (NRF) setup at the HI gamma S facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform gamma-gamma coincidence experiments. The new setup combines large volume LaBr3:Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient gamma-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HI gamma S provides a worldwide unique experimental facility to investigate the gamma-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus S-32 at 8.125 MeV beam energy. The relative gamma-decay branching ratio from the 1(+) level at 8125.4 keV to the first excited 2(+) state was determined to 15.7(3)%. (C) 2013 Elsevier B.V. All rights reserved.

Published
2013

17. Cryo-EM Structure of the Full-length hnRNPA1 Amyloid Fibril.

Author

Sharma K, Banerjee S, Savran D, Rajes C, Wiese S, Girdhar A, Schwierz N, Lee C, Shorter J, Schmidt M, Guo L, and Fändrich M

Subjects
Cryoelectron Microscopy methods, Mutation, Prions chemistry, Protein Domains, Amyloid chemistry, Heterogeneous Nuclear Ribonucleoprotein A1 chemistry
Abstract

Heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) is a multifunctional RNA-binding protein that is associated with neurodegenerative diseases, such as amyotrophic lateral sclerosis and multisystem proteinopathy. In this study, we have used cryo-electron microscopy to investigate the three-dimensional structure of amyloid fibrils from full-length hnRNPA1 protein. We find that the fibril core is formed by a 45-residue segment of the prion-like low-complexity domain of the protein, whereas the remaining parts of the protein (275 residues) form a fuzzy coat around the fibril core. The fibril consists of two fibril protein stacks that are arranged into a pseudo-2 1 screw symmetry. The ordered core harbors several of the positions that are known to be affected by disease-associated mutations, but does not encompass the most aggregation-prone segments of the protein. These data indicate that the structures of amyloid fibrils from full-length proteins may be more complex than anticipated by current theories on protein misfolding., Competing Interests: Declaration of Competing Interest All authors except J.S. declare no conflict of interest. J.S. is a consultant for Dewpoint Therapeutics, ADRx, and Neumora. J.S. is an advisor and shareholder for Confluence Therapeutics., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results