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Author Cederwall, B. et al; Algora, A.; Gadea, A.
Title Evidence for a spin-aligned neutron-proton paired phase from the level structure of Pd-92 Type Journal Article
Year 2011 Publication Nature Abbreviated Journal Nature
Volume 469 Issue 7328 Pages (up) 68-71
Keywords
Abstract Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.
Address [Cederwall, B.; Moradi, F. Ghazi; Back, T.; Johnson, A.; Blomqvist, J.; Andgren, K.; Lagergren, K.; Liotta, R.; Qi, C.; Hadinia, B.; Khaplanov, A.; Persson, A.; Sandzelius, M.] Royal Inst Technol, Dept Phys, SE-10691 Stockholm, Sweden, Email: cederwall@nuclear.kth.se
Corporate Author Thesis
Publisher Nature Publishing Group Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-0836 ISBN Medium
Area Expedition Conference
Notes ISI:000285921600032 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 588
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Author Modamio, V.; Valiente-Dobon, J.J.; Jaworski, G.; Huyuk, T.; Triossi, A.; Egea, J.; Di Nitto, A.; Soderstrom, P.A.; Ros, J.A.; de Angelis, G.; de France, G.; Erduran, M.N.; Erturk, S.; Gadea, A.; Gonzalez, V.; Kownacki, J.; Moszynski, M.; Nyberg, J.; Palacz, M.; Sanchis, E.; Wadsworthm, R.
Title Digital pulse-timing technique for the neutron detector array NEDA Type Journal Article
Year 2015 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 775 Issue Pages (up) 71-76
Keywords Digital timing; Constant fraction discriminator; Liquid scintillator; BC501A; Neutron detector; NEDA
Abstract A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in by 5 in BC501A liquict scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CM algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes.
Address [Modamio, V.; Valiente-Dobon, J. J.; Triossi, A.; de Angelis, G.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy, Email: victor.modamio@lnl.infn.it
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:000348040900011 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2093
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Author Valiente-Dobon, J.J. et al; Egea, J.; Huyuk, T.; Gadea, A.; Aliaga, R.; Jurado-Gomez, M.L.; Perez-Vidal, R.M.
Title NEDA-NEutron Detector Array Type Journal Article
Year 2019 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 927 Issue Pages (up) 81-86
Keywords NEDA; Nuclear structure; Gamma-ray spectroscopy; Neutron detector; Liquid scintillator; Digital electronics; Neutron-gamma discrimination
Abstract The NEutron Detector Array, NEDA, will form the next generation neutron detection system that has been designed to be operated in conjunction with gamma-ray arrays, such as the tracking-array AGATA, to aid nuclear spectroscopy studies. NEDA has been designed to be a versatile device, with high-detection efficiency, excellent neutron-gamma discrimination, and high rate capabilities. It will be employed in physics campaigns in order to maximise the scientific output, making use of the different stable and radioactive ion beams available in Europe. The first implementation of the neutron detector array NEDA with AGATA 1 pi was realised at GANIL. This manuscript reviews the various aspects of NEDA.
Address [Valiente-Dobon, J. J.; Jaworski, G.; Goasduff, A.; Egea, J.; Modamio, V; de Angelis, G.; Bissiato, E.; Carturan, S.; Cocconi, P.; Conventi, D.; Deltoro, J. M.; Hadynska-Klekn, K.; Illan, A.; Raggio, A.; Siciliano, M.; Zanon, I] Ist Nazl Fis Nucl, Lab Nazl Legnaro, Legnaro, Italy, Email: valiente@lnl.infn.it
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:000462142700010 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3956
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Author Luo, X.L. et al; Agramunt, J.; Egea, F.J.; Gadea, A.; Huyuk, T.
Title Test of digital neutron-gamma discrimination with four different photomultiplier tubes for the NEutron Detector Array (NEDA) Type Journal Article
Year 2014 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 767 Issue Pages (up) 83-91
Keywords Digital neutron-gamma discrimination; Liquid scintillator; Photomultiplier tube; Charge Comparison; Integrated rise-time; Time-of-flight; NEDA
Abstract A comparative study of the neutron-gamma discrimination performance of a liquid scintillator detector BC501A coupled to four different 5 in photomultiplier tubes (ET9390kb, R11833-100, XP4512 and R4144) was carried out Both the Charge Comparison method and the Integrated Rise-Time method were implemented digitally to discriminate between neutrons and gamma rays emitted by a Cf-252 source. In both methods, the neutron-gamma discrimination capabilities of the four photomultiplier tubes were quantitatively compared by evaluating their figure-of-merit values at different energy regions between 50 keVee and 1000 keVee. Additionally, the results were further verified qualitatively using time-of-flight to distinguish gamma rays and neutrons. The results consistently show that photomultiplier tubes R11833-100 and ET9390kb generally perform best regarding neutron-gamma discrimination with only slight differences in figure-of-merit values. This superiority can be explained by their relatively higher photoelectron yield, which indicates that a scintillator detector coupled to a photomultiplier tube with higher photoelectron yield tends to result in better neutron-gamma discrimination performance. The results of this work will provide reference for the choice of photomultiplier tubes for future neutron detector arrays like NEDA.
Address [Luo, X. L.] Natl Univ Def Technol, Coll Mechatron & Automat, Dept Instrument Sci & Technol, Changsha, Hunan, Peoples R China, Email: luo.xiaoliang@physics.uu.se
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:000344994600012 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2011
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Author AGATA and PRISMA Collaborations (Gadea, A. et al)
Title Conceptual design and infrastructure for the installation of the first AGATA sub-array at LNL Type Journal Article
Year 2011 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 654 Issue 1 Pages (up) 88-96
Keywords AGATA; PRISMA spectrometer; DANTE heavy-ion detector; HELENA multiplicity filter; Cologne plunger; TRACE Si detector
Abstract The first implementation of the AGATA spectrometer consisting of five triple germanium detector clusters has been installed at Laboratori Nazionali di Legnaro, INFN. This setup has two major goals, the first one is to validate the gamma-tracking concept and the second is to perform an experimental physics program using the stable beams delivered by the Tandem-PIAVE-ALPI accelerator complex. A large variety of physics topics will be addressed during this campaign, aiming to investigate both neutron and proton-rich nuclei. The setup has been designed to be coupled with the large-acceptance magnetic-spectrometer PRISMA. Therefore, the in-beam prompt gamma rays detected with AGATA will be measured in coincidence with the products of multinucleon-transfer and deep-inelastic reactions measured by PRISMA. Moreover, the setup is versatile enough to host ancillary detectors, including the heavy-ion detector DANTE, the gamma-ray detector array HELENA, the Cologne plunger for lifetime measurements and the Si-pad telescope TRACE. In this paper the design; characteristics and performance figures of the setup will be described.
Address [Gadea, A] Univ Valencia, CSIC, IFIC, Inst Fis Corpuscular IFIC, E-46003 Valencia, Spain, Email: gadea@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:000295765100014 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 791
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