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S. Mandal,
J. Gerl,
H. Geissel,
K Hauschild,
M Hellstrom,
Z. Janas,
I. Kojouharov,
Y Kopatch,
RC Lemmon,
P Mayet, Z Podolyak,
PH Regan,
H Schaffnre,
C Schlegel,
J Simpson,
HJ Wollersheim
[show abstract]
[hide abstract]
ABSTRACT: Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors (segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed.
Pramana 04/2012; · 0.57 Impact Factor
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N. Al-Dahan,
P. H. Regan, Z. Podolyak,
P. M. Walker,
N. Alkhomashi,
G. D. Dracoulis,
G. Farrelly,
J. Benlliure,
S. B. Pietri,
R. F. Casten, [......],
Z. Liu,
P. J. Mason,
C. Mihai,
F. Molina,
D. Mucher,
B. Rubio,
A. Tamii,
S. Tashenov,
J. J. Valiente-Dobon,
P. J. Woods
[show abstract]
[hide abstract]
ABSTRACT: beta decays from heavy, neutron-rich nuclei with A similar to 190 have been investigated following their production via the relativistic projectile fragmentation of an E/A = 1 GeV Pb-208 primary beam on a similar to 2.5 g/cm(2) Be-9 target. The reaction products were separated and identified using the GSI FRagment Separator (FRS) and stopped in the RISING active stopper. gamma decays were observed and correlated with these secondary ions on an event-by-event basis such that gamma-ray transitions following from both internal (isomeric) and beta decays were recorded. A number of discrete, beta-delayed gamma-ray transitions associated with beta decays from Re-194 to excited states in Os-194 have been observed, including previously reported decays from the yrast I-pi = (6(+)) state. Three previously unreported gamma-ray transitions with energies 194, 349, and 554 keV are also identified; these transitions are associated with decays from higher spin states in Os-194. The results of these investigations are compared with theoretical predictions from Nilsson multi-quasiparticle (MQP) calculations. Based on lifetime measurements and the observed feeding pattern to states in Os-194, it is concluded that there are three beta(-)-decaying states in Re-194.
Physical Review C 01/2012; 85:034301. · 3.31 Impact Factor
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C Nociforo,
F Farinon,
A Musumarra,
F Bosch,
D Boutin,
A Del Zoppo,
P Figuera,
M Fisichella,
H Geissel,
R Knöbel, [......],
V Scuderi,
B Sun,
T Suzuki,
D Torresi,
H Weick,
J S Winfield,
N Winckler,
M Winkler,
H J Wollersheim,
T Yamaguchi
Physica Scripta 01/2012; 2012(T150):014028. · 1.20 Impact Factor
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S. Akkoyun,
A. Algora,
B. Alikhani,
F. Ameil,
G. de Angelis,
L. Arnold,
A. Astier,
A. Ataç,
Y. Aubert,
C. Aufranc, [......],
D. Weisshaar,
D. Wells,
O. Wieland,
A. Wiens,
G. Wittwer,
H. J. Wollersheim,
F. Zocca,
N. V. Zamfir,
M. Ziȩbliński,
A. Zucchiatti
[show abstract]
[hide abstract]
ABSTRACT: The Advanced GAmma Tracking Array (AGATA) is a European project to develop
and operate the next generation gamma-ray spectrometer. AGATA is based on the
technique of gamma-ray energy tracking in electrically segmented high-purity
germanium crystals. This technique requires the accurate determination of the
energy, time and position of every interaction as a gamma ray deposits its
energy within the detector volume. Reconstruction of the full interaction path
results in a detector with very high efficiency and excellent spectral
response. The realization of gamma-ray tracking and AGATA is a result of many
technical advances. These include the development of encapsulated
highly-segmented germanium detectors assembled in a triple cluster detector
cryostat, an electronics system with fast digital sampling and a data
acquisition system to process the data at a high rate. The full
characterization of the crystals was measured and compared with
detector-response simulations. This enabled pulse-shape analysis algorithms, to
extract energy, time and position, to be employed. In addition, tracking
algorithms for event reconstruction were developed. The first phase of AGATA is
now complete and operational in its first physics campaign. In the future AGATA
will be moved between laboratories in Europe and operated in a series of
campaigns to take advantage of the different beams and facilities available to
maximize its science output. The paper reviews all the achievements made in the
AGATA project including all the necessary infrastructure to operate and support
the spectrometer.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 11/2011; 668:26. · 1.21 Impact Factor
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D.D. DiJulio,
J. Cederkall,
C. Fahlander,
A. Ekstr¨om,
P. Golubev,
K. Mattsson,
D. Rudolph,
G. de Angelis,
S. Aydin,
A. Y. Deo, [......],
P. Reiter,
E. Sahin,
J. Smith,
P.A. S¨oderstr¨om,
D.A. Torres,
G.M. Tveten,
C.A. Ur,
J.J. Valiente-Dob´on,
A. Wendt,
M. Zieli´nska
[show abstract]
[hide abstract]
ABSTRACT: Excited states of the nucleus 170Er have been studied by Coulomb excitation using the GASP γ -ray detector system at the Laboratori Nazionali di Legnaro. The ground-state band along with a low-lying \ensuremathKπ=0+ band and γ -vibrational band were populated during the experiment. Based on the measured γ -ray yields, a set of interband and intraband matrix elements has been extracted using the Coulomb excitation code GOSIA. The resulting E2 matrix elements are compared to collective model predictions.
European Physical Journal A 02/2011; 47(1):25. · 2.19 Impact Factor
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J. A. Briz,
M. J. G. Borge,
A. Maira,
A. Perea,
O. Tengblad,
J. Agramunt,
A. Algora,
E. Estevez,
E. Nacher,
B. Rubio,
L. M. Fraile,
A. Deo,
G. Farrelly,
W. Gelletly, Z. Podolyak
[show abstract]
[hide abstract]
ABSTRACT: In order to determine the Gamow‐Teller strength distribution for the N = Z nucleus 72Kr an experiment was performed with a Total Absorption Gamma Spectrometer. To fully accomplish this task it is crucial to determine the multipolarity of the low energy transitions as the spin‐parity of the daughter ground state has been debated. This is done by experimental determination of the conversion coefficients. Preliminary results for the multipolarity and conversion coefficients of the transition connecting the isomeric state at 101 keV with the 72Br ground state are presented.
AIP Conference Proceedings. 04/2010; 1231(1):203-204.
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L Chen,
W. R. Plaß,
H. Geissel,
R. Knöbel,
C. Kozhuharov,
Yuri A. Litvinov,
Z. Patyk,
C. Scheidenberger,
K Siegien-Iwaniuk,
B Sun, [......],
T Saito,
M Shindo,
M. Steck,
P. Ugorowski,
P. M. Walker,
S Williams,
M Winkler,
H J Wollersheim,
T. Yamaguchio,
I. J. Cullen
Physics Letters B 03/2010; 691:234-237. · 3.95 Impact Factor
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N. Braun,
A. Atac,
L. Bettermann,
A. Blazhev,
P. Boutachkov,
T. Brock,
L. Caceres,
C. Domingo,
T. Engert,
K. Eppinger, [......],
P. Reiter,
S. Rinta-Antila,
D. Rudolph,
C. Scholl,
P.-A. Soderstrom,
S. Steer,
R. Wadsworth,
N. Warr,
H.-J. Wollersheim,
P. Woods
DPG Verhandlungen 2009; 01/2009
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L Chen,
Y A Litvinov,
W R Plass,
K Beckert,
P Beller,
F Bosch,
D Boutin,
L Caceres,
R B Cakirli,
J J Carroll, [......],
C Scheidenberger,
M Shindo,
M Steck,
P Ugorowski,
P M Walker,
S Williams,
H Weick,
M Winkler,
H J Wollersheim,
T Yamaguchi
Physical Review Letters 01/2009; 102(13). · 7.37 Impact Factor
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N. Al-Dahan, Z. Podolyak,
P. H. Regan,
S. J. Steer,
N. Alkhomashi,
A. M. D. Bacelar,
M. Gorska,
S. B. Pietri,
W. Gelletly,
P. M. Walker, [......],
R. Nicolini,
D. R. Napoli,
C. Nociforo,
B. Rubio,
A. Prochazka,
D. Rudolph,
P. Strmen,
I. Szarka,
J. J. Valiente-Dobon,
H. Weick
[show abstract]
[hide abstract]
ABSTRACT: The nuclear structure of neutron-rich N >= 126 nuclei have been investigated following their production via relativistic projectile fragmentation of a E/A=1 GeV (238)U beam on a Be target. The cocktail of secondary beam products were separated and identified using the GSI FRagment Separator (FRS). The nuclei of interest were implanted in a high-granularity active stopper detector set-up consisting of 6 double sided silicon strip detectors. The associated gammaray transitions were detected with the RISING array, consisting of 15 Euroball cluster Ge-detectors. Time-correlated gamma decays from individually identified nuclear species have been recorded, allowing the clean identification of isomeric decays.
Capture Gamma-Ray Spectroscopy and Related Topics. 01/2009; 1090:145-148.
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N. Al-Dahan, Z. Podolyak,
P. H. Regan,
S. J. Steer,
A. M. D. Bacelar,
N. Alkhomashi,
M. Gorska,
J. Gerl,
H. J. Wollersheim,
S. B. Pietri, [......],
B. Rubio,
D. Rudolph,
H. Schaffner,
P. Strmen,
I. Szarka,
T. Swan,
J. J. Valiente-Dobon,
S. Verma,
P. M. Walker,
H. Weick
[show abstract]
[hide abstract]
ABSTRACT: The nuclear structure of neutron-rich N > 126 nuclei has been investigated following their production via relativistic projectile fragmentation of a E/A = 1 GeV U-238 beam on a Be target. The preliminary analysis indicates the presence of previously unreported isomeric states in the N = 128 isotones Hg-208 and Tl-209.
Acta Physica Polonica Series B 01/2009; 40:871-874. · 0.90 Impact Factor
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A. I. Morales,
J. Benlliure,
P. H. Regan, Z. Podolyak,
M. Gorska,
N. Alkhomashi,
S. Pietri,
R. Kumar,
E. Casarejos,
J. Agramunt, [......],
B. Rubio,
H. Schapffner,
S. J. Steer,
A. Tamii,
S. Tashenov,
J. J. V. Dobon,
S. Verma,
P. M. Walker,
H. J. Wollersheim,
P. J. Woods
[show abstract]
[hide abstract]
ABSTRACT: Relativistic projectile fragmentation of a (208)Pb primary beam has been used to produce neutron-rich nuclei with proton-holes relative to the Z = 82 shell closure, i.e., "south" of Pb. beta-delayed gamma-ray spectroscopy allows to investigate the structural properties of such nuclei with A similar to 195 -> 205. The current work presents transitions de-exciting excited states in (204)Au, which are the first spectroscopic information on this N = 125 isotone.
Acta Physica Polonica Series B 01/2009; 40:867-870. · 0.90 Impact Factor
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A Musumarra,
F Farinon,
C Nociforo,
H Geissel,
G Baur,
K -H Behr,
A Bonasera,
F Bosch,
D Boutin,
A Brunle, [......],
P Strmen,
B Sun,
T Suzuki,
I Szarka,
D Torresi,
H Weick,
J S Winfield,
M Winkler,
H J Wollersheim,
T Yamaguchi
Proc.Intern.Conf.on Nuclear Structure and Dynamics; 01/2009
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R L Lozeva,
G.S. Simpson,
H. Grawe,
G. Neyens,
L A Atanasova,
D L Balabanski,
D. Bazzacco,
F. Becker,
P. Bednarczyk,
G. Benzoni, [......],
H. Schaffner,
R. Schwengner,
S. Tashenov,
K Turzo,
J J Valiente-Dobon,
N. Vermeulen,
J Walker,
E. Werner-Malento,
O. Wieland,
H J Wollersheim
[show abstract]
[hide abstract]
ABSTRACT: New sub-mu s isomers have been observed in the neutron-rich Sn isotopes. Sn-125,Sn-127,Sn-129 nuclei have been produced in a relativistic fission reaction of U-238 on a Be-9 target at 750 A.MeV and by the fragmentation of Xe-136 at 600 A.MeV populating high-spin yrast states. In addition to the already known mu s isomers, three new ones with sub-mu s half-lives have been observed. These yrast isomers are the high-spin members of the nu(d(3/2)(-1)h(11/2)(-2)) and nu h(11/2)(-n), seniority v = 3 multiplets leading to isomeric (23/2(+)) and (27/2(-)) states, respectively. Added to the already known 19/2(+)mu s isomers in this region the current work completes the systematic information of neutron-hole excitations toward the filling of the last h(11/2) orbital at N = 82. The results are discussed in the framework of state-of-the-art shell-model calculations using realistic interactions.
Physical Review C 05/2008; 77:064313. · 3.31 Impact Factor
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Y Fujita,
B Rubio,
T Adachi,
F. Molina,
A. Algora,
G.P.A. Berg,
P. von Brentano,
J. Buscher,
T. Cocolios,
D. De Frenne, [......],
Y. Shimbara,
Y Shimizu,
T. Shizuma,
T Tameshige,
A. Tamii,
P. Van den Bergh,
J. Van de Walle,
P. Van Duppen,
M. Yosoi,
K O Zell
[show abstract]
[hide abstract]
ABSTRACT: Gamow–Teller (GT) transitions starting from unstable pf -shell nuclei are of interest not only in nuclear physics, but also in astrophysics, e.g. in violent neutrino induced reactions at the core-collapse stage of type II supernovae. In the β-decay study of these pf -shell nuclei, half-lives can be measured rather accurately. On the other hand, in high-resolution (3He, t) charge-exchange reactions at 0◦, individual GT transitions up to high excitations can be studied. Assuming the isospin symmetry for the strengths of Tz = ±1 → 0 analogous GT transitions, we present a unique ‘merged analysis’ for the determination of absolute B(GT) values.
Journal of Physics G Nuclear and Particle Physics 01/2008; 35(1):014041. · 4.18 Impact Factor
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A Jungclaus,
L Cáceres,
M Górska,
M Pfützner,
S Pietri,
E Werner-Malento,
H Grawe,
K Langanke,
G Martínez-Pinedo,
F Nowacki, [......],
M Kmiecik,
R Kumar,
A Maj,
S Mandal,
F Montes,
S Myalski,
G S Simpson,
S J Steer,
S Tashenov,
O Wieland
[show abstract]
[hide abstract]
ABSTRACT: The gamma decay of excited states in the waiting-point nucleus (130)Cd(82) has been observed for the first time. An 8(+) two-quasiparticle isomer has been populated both in the fragmentation of a (136)Xe beam as well as in projectile fission of 238U, making (130)Cd the most neutron-rich N = 82 isotone for which information about excited states is available. The results, interpreted using state-of-the-art nuclear shell-model calculations, show no evidence of an N = 82 shell quenching at Z = 48. They allow us to follow nuclear isomerism throughout a full major neutron shell from (98)Cd(50) to (130)Cd(82) and reveal, in comparison with (76)Ni(48) one major proton shell below, an apparently abnormal scaling of nuclear two-body interactions.
Physical Review Letters 10/2007; 99(13):132501. · 7.37 Impact Factor
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A. Jungclaus,
L. Caceres,
M Gorska,
M. Pfutzner,
S. Pietri,
E. Werner-Malento,
H. Grawe,
K. Langanke,
G. Martinez-Pinedo,
F. Nowacki, [......],
M. Kmiecik,
R Kumar,
A. Maj,
S. Mandal,
F. Montes,
S. Myalski,
G.S. Simpson,
S.J. Steer,
S. Tashenov,
O. Wieland
[show abstract]
[hide abstract]
ABSTRACT: The gamma decay of excited states in the waiting-point nucleus Cd-130(82) has been observed for the first time. An 8(+) two-quasiparticle isomer has been populated both in the fragmentation of a Xe-136 beam as well as in projectile fission of U-238, making Cd-130 the most neutron-rich N=82 isotone for which information about excited states is available. The results, interpreted using state-of-the-art nuclear shell-model calculations, show no evidence of an N=82 shell quenching at Z=48. They allow us to follow nuclear isomerism throughout a full major neutron shell from Cd-98(50) to Cd-130(82) and reveal, in comparison with Ni-76(48) one major proton shell below, an apparently abnormal scaling of nuclear two-body interactions.
Physical Review Letters 05/2007; 99:132501. · 7.37 Impact Factor
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P. H. Regan,
A. B. Gamsworthy,
S. J. Steer,
S. Pletri, Z. Podolyak,
D. Rudolph,
M. Gorska,
L. Caceres,
E. Wemer-Malento,
J. Gerl, [......],
G. Kondev,
S. Lalkovski,
Z. Liu,
A. Maj,
S. Myalski,
S. Schwertel,
T. Shizuma,
A. J. Simons,
P. M. Walker,
O. Wieland
[show abstract]
[hide abstract]
ABSTRACT: The first results from the Stopped Beam RISING experimental campaign performed at the GSI laboratory in Darmstadt, Germany, are presented. RISING (Rare ISotope INvestigations at GSI) constitutes a major new experimental program in European nuclear structure physics research aimed at using relativistic-energy, projectile-fragmentation reactions to study nuclei with exotic proton-to-neutron ratios. This paper introduces the physics aims of the Stopped RISING collaboration and presents some technical details and initial results from experiments using the RISING array to study decays from metastable nuclear states in both proton and neutron-rich nuclei.
Six International Conference of the Balkan Physical Union. 01/2007; 899:19-22.
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AB Garnsworthy,
NJ Thompson, Z Podolyak,
PM Walker,
SJ Williams,
GD Dracoulis,
G France,
GJ Lane,
K Andgren,
AM Bruce, [......],
B Cederwall,
GA Jones,
B McGuirk,
S Mandal,
ES Paul,
V Pucknell,
N Redon,
B Rosse,
RJ Senior,
G Sletten
[show abstract]
[hide abstract]
ABSTRACT: A beam of 28 MeV He-8 particles with an average intensity 2 x 10(5) ions s(-1), produced by the SPIRAL facility at GANIL, was used to initiate fusion-evaporation reactions in thick targets of Pb-201 and Bi-209. Excited states of Po-212 and At-213 were populated in (He-8,4n) reactions. The emitted gamma-rays were detected using the EXOGAM array composed of four Compton suppressed germanium Clover detectors in a close geometry configuration. Preliminary results show that Po-212 has been populated to high spin (I similar or equal to 14) with a significantly increased yield compared with our previous He-8 beam experiment. An apparently increased relative population of states up to 12(+) was observed compared with published results from a Pb-208(Be-9,alpha n)(212) Po reaction at 48 MeV. Evidence is presented for a previously unreported de-excitation pathway: 69 keV (13(-) -> 12(+)). States up to I-pi = (39/2(-)) have also been observed in At-213.
Journal of Physics G Nuclear and Particle Physics 10/2005; 31(10, SI):S1851-S1854. · 4.18 Impact Factor
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M Caamano,
P M Walker,
P H Regan,
M Pfutzner, Z Podolyak,
J Gerl,
M Hellstrom,
P Mayet,
M N Mineva,
A Aprahamian, [......],
K H Schmidt,
P D Stevenson,
C Theisen,
F Vives,
D D Warner,
C Wheldon,
H J Wollersheim,
S Wooding,
F Xu,
O Yordanov
[show abstract]
[hide abstract]
ABSTRACT: Relativistic projectile fragmentation of Pb-208 has been used to produce isomers in neutron-rich, A approximate to 190 nuclides. A forward-focusing spectrometer provided ion-by-ion mass and charge identification. The detection of gamma-rays emitted by stopped ions has led to the assignment of isomers in Ta-188, W-190, Re-192, Re-193, Os-195, Ir-197, Ir-198, Pt-200, Pt-201, Pt-202 and Au-203, with half-lives ranging from approximately 10 ns to 1 ms. Tentative isomer information has been found also for Er-174, Er-175, Hf-185, Re-191, Re-194 and Ir-199. In most cases, time-correlated, singles gamma-ray events provided the first spectroscopic data on excited states for each nuclide. In Pt-200 and Pt-201. the assignments are supported by gamma-gamma coincidences. Isomeric ratios provide additional information, such as half-life and transition energy constraints in particular cases. The level structures of the platinum isotopes are discussed, and comparisons are made with isomer systematics.
European Physical Journal A. 01/2005; 23(2):201-215.
