0000000000018088
AUTHOR
Johan Nyberg
showing 62 related works from this author
Response of AGATA segmented HPGe detectors to gamma rays up to 15.1MeV
2013
WOS: 000314826000009
Evidence for a spin-aligned neutron-proton paired phase from the level structure of (92)Pd
2011
4 páginas, 4 figuras.-- El Pdf es la versión pre-print.-- et al.
The role of the shape driving neutron orbital in 108Cd
1993
Abstract The nucleus 108Cd has been studied using a heavy-ion reaction and the NORDBALL multi-detector array. The yrast band has been extended to Ip = 24+, and nine quasi-rotational side bands have been identified. The n h 11 2 negative-parity orbital is found to play a dominant role both in the low-spin as well as in the high-spin structure of 108Cd. The first band crossing in the yrast band is caused by the h 11 2 neutrons. The 10+ state of the aligned n( h 11 2 ) 2 configuration decays strongly into a low-lying low-spin intruder-like positive-parity band. It is suggested that this intruder structure is dominated by a non-aligned n( h 11 2 ) 2 configuration. For the first time in this mas…
The distribution of the rotational transition strength in warm nuclei studied through γ-ray correlations
1995
Abstract The study of damping of rotational motion applying te rotational plane mapping (RPM) method is presented and discussed. The aim of this technique is to extract the distribution of the rotational transition strength from an analysis of the shape of the “central valley” of two- and three-dimensional γ-ray spectra. The method is applied to a triple γ-coincidence data set of 162,163Tm nuclei formed in 37Cl+130Te reactions. The rotational transition strength is obtained as a function of rotational frequency for selected regions of entry states, and the width is found to be rather constant and approximately equal to 80 keV. This value is significantly smaller than the value predicted the…
Position resolution of the prototype AGATA triple-cluster detector from an in-beam experiment
2009
AGATA belongs to a new generation of gamma-ray detector arrays for nuclear spectroscopy at present in its final stage of development. The detectors of these new arrays will be based on 36-fold electronically segmented coaxial germanium diodes operated in position sensitive mode. An in-beam test of the AGATA prototype triple cluster detector was carried out with the purpose of demonstrating the feasibility of such detectors and in order to measure the most sensitive parameters for their overall performance. An inverse kinematics reaction was performed, using a (48)Ti beam at an energy of 100MeV, impinging on a deuterated titanium tat-get. The results from the analysis of the experimental dat…
γ-ray linear polarization measurements and(g9/2)−3neutron alignment in91Ru
2013
The authors would like to thank the operators of the GANIL cyclotrons for providing the 36Ar beam. We would also like to thank the EXOGAM Collaboration for use of the clover Ge detector array, the DIAMANT Collaboration for use of the charged particle detector system, and the European gamma-ray Spectroscopy Pool for use of the neutron detector system. We acknowledge funding support from the French-Polish LEA COPIGAL and the IN2P3-Polish laboratories COPIN Agreement No. 06-122, from the UK STFC, from the Swedish Research Council (Contracts No. 2007-4067 and No. 2008-5793), from the Goran Gustafsson Foundation, from the OTKA under Contract No. K100835, and from the Bolyai Janos Foundation. AG …
Maximum spin aligned states in 98 47Ag51
1998
New excited states have been observed in the neutron deficient isotope Ag-98 following the Ni-58+Cr-50-->Te-108* heavy-ion reaction. One of these states may be interpreted as a maximum spin aligned state of the pi g(9/2)(-3) nu vg(7/2) configuration. Other possible interpretations within the nuclear shell model are discussed as well.
Studies of Inelastic Scattering of Fast Heavy Ions
2003
In the present experiment 250A MeV O-17 ions were melastically scattered front xenon and argon in the cluster-jet target of the CELSIUS storage ring. The magnetic lattice of the ring is such that the quadrant following the target can be used as a magnetic spectrometer with an acceptance cone of +/-0.6degrees, centred at 0degrees. A focal plane telescope, placed in the injection straight section. determined the excitation energy of the residual target nuclei. Data were taken for excitation energies between 15 and 35 MeV. The neutron decay was studied by the EDEN detector array positioned around the target, covering an angular range of 7-110degrees. In order to investigate a previously observ…
In-beam γ-ray spectroscopy of 56Co
1997
Excited states of Co-56 were studied in the reaction Al-27(S-32,2p1n) Co-56. The NORDBALL array with a Neutron Wall and a Silicon Ball was employed. The excited states were interpreted in terms of ...
Neutron detection and γ-ray suppression using artificial neural networks with the liquid scintillators BC-501A and BC-537
2019
Abstract In this work we present a comparison between the two liquid scintillators BC-501A and BC-537 in terms of their performance regarding the pulse-shape discrimination between neutrons and γ rays. Special emphasis is put on the application of artificial neural networks . The results show a systematically higher γ -ray rejection ratio for BC-501A compared to BC-537 applying the commonly used charge comparison method. Using the artificial neural network approach the discrimination quality was improved to more than 95% rejection efficiency of γ rays over the energy range 150 to 1000 keV for both BC-501A and BC-537. However, due to the larger light output of BC-501A compared to BC-537, neu…
Monte Carlo simulation of a single detector unit for the neutron detector array NEDA
2012
WOS: 000301813500009
Alignment processes in 119Cs, 121Cs and 123Cs
1992
Rotational band structures have been observed in the odd-A Cs isotopes 119Cs, 121Cs and 123Cs. The previously known bands have been extended to higher spin values and several new bands have been es ...
In-beam γ-ray spectroscopy of 102Cd
1997
Neutron deficient nuclei close to 100Sn have been studied using the NORDBALL Ge-detector array together with ancillary particle detectors. Evaporation residues from the compound nucleus 108Te were identified with charged particle and neutron detectors. In this paper a considerable extension of the level scheme of the nucleus 102Cd is presented. The strongest cascade of the new level scheme reveals an irregular sequence of dipole transitions above Iπ = 10+ extending up to spin 17. A strongly populated rather regular side band consisting of four quadrupole transitions ranging from spin 9 to spin 17 was also discovered. This band was tentatively assigned negative parity. Shell model calculatio…
Maximally aligned states in the proton drip line nucleus 106Sb
2005
High-spin states in Sb-106 have been investigated in the Fe-54(Ni-58, 1α 1p1n) reaction by in-beam γ-spectroscopic methods using the EUROBALL detector array equipped with charged particle and neutr ...
On the 2485 keV γ-ray line in208Pb
1995
The 2485 keV γ-ray line, which in a GSI experiment originally was suggested to decay from the 6+ state of the double octupole vibration in 208Pb, was in a later experiment in Berlin proposed to belong to 207Pb, populated in one-neutron transfer. It has been searched for in the present experiment using Coulomb excitation.
High-spin studies of the neutron deficient nuclei 103In, 105In, 107In, and 109In
1997
High-spin states of the isotopes In-103,In-105,In-107,In-109 have been investigated using in-beam gamma-ray spectroscopic methods. Results from three different experiments are presented. Targets of Fe-54, Cr-50, and Mo-92 were bombarded by a 270 and 261 MeV Ni-58 beam and by a 95 MeV F-19 beam, respectively. Reaction channel separation was achieved with a charged-particle detector array and in the first two experiments also with a 1 pi neutron detector system. As a result of these experiments the level schemes of In-103,In-105,In-107,In-109 were significantly extended. Excited states of these odd-A indium isotopes are discussed within the framework of the nuclear shell model and the hole-co…
In-beam γ-ray spectroscopy of 103Cd
1997
Excited states of Cd-103 were studied in the reaction Ni-58(Cr-50,4pn)Cd-103. The NORDBALL array with neutron and charged particle detectors was employed for the detection of gamma rays and light evaporated particles. The level scheme of Cd-103 was significantly extended. A strong cascade of E2 transitions connecting negative parity states was found, Shell model calculations were performed and positive parity excited states were interpreted in terms of neutron-particle and proton-hole excitations with respect to the doubly magic N = Z = 50 core. The negative parity band was well reproduced by the total routhian surface calculations. (C) 1997 Elsevier Science B.V.
Collective and broken pair states of65,67Ga
1999
Excited states of 65Ga and 67Ga nuclei were populated through the 12C(58Ni,αp) and 12C(58Ni,3p) reactions, respectively, and investigated by in-beam γ-ray spectroscopic methods. The NORDBALL array equipped with a charged particle ball and 11 neutron detectors was used to detect the evaporated particles and γ rays. The level schemes of 65,67Ga were constructed on the basis of γγ-coincidence relations up to 8.6 and 10 MeV excitation energy, and Iπ=27/2 and 33/2+ spin and parity, respectively. The structure of 65,67Ga nuclei was described in the interacting boson-fermion plus broken pair model, including quasiproton, quasiproton-two-quasineutron, and three-quasiproton fermion configurations in…
In-beam study of 102In, 104In and 106In
1995
Proton-rich odd-odd In isotopes have been investigated by in-beam spectroscopic methods using the NORDBALL detector array. A Ni-58 beam with an energy of 270 MeV was used to bombard a Fe-54 target. ...
Neutron Excitations Across the N=50 Shell Gap in 102In
2002
The structure of In-102 has been investigated by in-beam gamma-spectroscopic methods. Knowledge on the excited states of this nucleus has significantly been extended. Three cascades of transitions were observed to exceed the spin-energy domain spanned by the pig(9/2)(-1)v(d(5/2),g(7/2))(3) configurations. The new high spin states at similar to 4 MeV excitation energy could be assigned to the pig(9/2)(-1)v(d(5/2), g(7/2))(2)h (11/2) configuration, while at least those at 4.733, 5.192 and 5.853 MeV most likely arise from the vg(9/2) --> vd(5/2), g(7/2) one-particle-one-hole excitation across the N = 50 shell closure.
Structure of high-spin states in Pd
2001
High-spin states of the neutron deficient (100)pd nucleus have been investigated via the Cr-50(Ni-58, 4p alpha) and Zn-70(S-36,6n) heavy-ion induced reactions. For the detection of evaporated particles and gamma rays the NORDBALL array equipped with ancillary detectors and the EUROGAM II detector system were utilized. By the use of in-beam spectroscopic methods 89 transitions belonging to (100)pd have been observed, 49 of which were identified for the first time. The level scheme has been extended up to E-X approximate to 16 MeV excitation energy and I approximate to 25h. The experimental results were compared with the predictions of cranked shell model calculations. Maximal spin alignments…
Excited states of111I and the observation of a 21 ns isomer
1994
Proton rich nuclei close to 100 Sn have been investigated inbeam using the NORDBALL detector array. A beam of 270 MeV58 Ni was used to bombard a 54 Fe target. Reaction channel separation was achieved with a 4π charged particle multi-detector set-up together with a 1π neutron detector wall placed in the forward direction. Gamma-ray transitions belonging to the 111 I nucleus were identified for the first time. A level scheme constructed from γ-γ-particle-coincidence analysis is proposed. The level structure is discussed within the framework of the shell model and the systematics of the heavier odd iodine nuclei.
Lifetime measurement of neutron-rich even-even molybdenum isotopes
2017
D. Ralet et al. -- 11 pags., 10 figs., 3 tabs.
Lifetime measurements in Ti52,54 to study shell evolution toward N=32
2019
Lifetimes of the excited states in the neutron-rich Ti-52,Ti-54 nuclei, produced in a multinucleon-transfer reaction, were measured by employing the Cologne plunger device and the recoil-distance D ...
Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy.
2021
Summary Background Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligib…
In-beam?-ray spectroscopy of102In
1993
Neutron deficient nuclei close to100Snhave been investigated in-beam by γ-ray spectroscopic methods using the NORDBALL detector array. A beam of 270 MeV58Niwas used to bombard a target of54Fe.Reaction channel separation was achieved with a 4π charged particle multidetector setup together with a 1π neutron detector wall placed in the forward direction. Excited states of102Inwere identified for the first time. The level scheme constructed from γ-γ-particle-coincidence and γ-γ-angular correlation analysis is presented. The structure of102In is discussed and compared to neighboring nuclei in the framework of the nuclear shell-model.
Level Scheme of 102In first observed
2019
Neutron deficient nuclei close to 100Sn have been investigated in-beam by particle and γ -ray spectroscopic methods using the NORDBALL detector array following the bombartment of a 54Fe target with a beam of 270 MeV 58Ni. Protons and α particles were identified with a 4 π ΔE -type Si-multidetector and neutrons with a 1π liquid-scintillator-detectorassembly placed in the forward derection. Excited states of 102 In were identified for the first time. The level scheme constructed from γ - γ -particle-coincidence and γ angular correlations is discussed and compared to the structure of neighboring nuclei in the framework of the nuclear shell model.
High spin band structures in104Cd
1995
High spin states in Cd-104 have been investigated by means of heavy ion induced reactions using the Nordball detector array. The level scheme constructed from yy-coincidences is dominated by three ...
Determination of the intrinsic quadrupole moment of the superdeformed band in 143Eu
1995
The intrinsic quadrupole moment, Q0, of the superdeformed band in 143Eu has been extracted from nuclear lifetimes, measured in a Doppler shift attenuation method experiment. Data were collected with the NORDBALL gamma-ray spectrometer following the reaction 110Pd (37Cl, 4n) 143Eu at a beam energy of 160 MeV. A centroid shift analysis of the data was carried out, using the Braune stopping powers to model the slowing down of the recoil nuclei in the target and backing materials. This gave a value of Q0 = 13.0 ± 1.5 eb for the band. The result is in good agreement with the theoretical prediction of Total Routhian Surface calculations, and supports the assigned single particle configuration, in…
In-beam spectroscopy of 110Te
1994
The neutron-deficient nucleus Te-110 has been investigated by in-beam spectroscopic methods using the NORDBALL multi-detector array. Except for the energy of one level observed in alpha-decay, exci ...
In-beam spectroscopy at the proton-drip line. First observation of excited states in 106Sb and 107Sb
1994
Neutron deficient nuclei close to Sn-100 have been investigated in-beam using the NORDBALL detector array. A target of Fe-54 was bombarded with a beam of Ni-58 at 270 MeV. Evaporation residues were identified by detecting protons and alpha particles in a 4 pi charged particle multi-detector set-up and neutrons in a 1 pi neutron detector wall in coincidence with gamma rays. Excited states of the proton drip line nucleus Sb-106 and of Sb-107 were identified for the first time. The yrast level schemes constructed from gamma-gamma-particle coincidence and gamma-gamma angular correlation analysis are presented and discussed within the framework of the nuclear shell model.
A New Front-End High-Resolution Sampling Board for the New-Generation Electronics of EXOGAM2 and NEDA Detectors
2015
19th Real Time Conference (RT) -- MAY 26-30, 2014 -- Nara, JAPAN WOS: 000356458000028 This paper presents the final design and results of the FADC Mezzanine for the EXOGAM (EXOtic GAMma array spectrometer) and NEDA (Neutron Detector Array) detectors. The measurements performed include those of studying the effective number of bits, the energy resolution using HP-Ge detectors, as well as timing histograms and discrimination performance. Finally, the conclusion shows how a common digitizing device has been integrated in the experimental environment of two very different detectors which combine both low-noise acquisition and fast sampling rates. Not only the integration fulfilled the expected …
Structure of 68As studied via the 12C(58Ni,pn) reaction
1998
Excited states of As-68 nucleus were populated through the C-12(Ni-58,pn) reaction and investigated by in-beam gamma-spectroscopic methods. The NORDBALL detector array equipped with charged particle and neutron detectors was used to detect the evaporated particles and gamma-rays. The level scheme of As-68 was constructed on the basis of gamma gamma-coincidence relations up to 6 MeV excitation energy and J(pi) = (15(+)). The structure of the nucleus is discussed in the framework of the interacting boson-fermion-fermion model. The states below 2.3 MeV are described as members of proton-neutron-phonon multiplets. (C) 1998 Elsevier Science B.V.
Digital pulse-timing technique for the neutron detector array NEDA
2015
WOS: 000348040900011
Single-step link from yrast SD band in 143Eu
1997
A discrete γ-ray transition from the yrast SD band to the region of near-yrast discrete normal-deformed states has been identified in 143Eu. It has an energy of 3360.6 keV and an intensity corresponding to 3.2% of the full intensity of the SD band and feeds a nearly-spherical state above spin 352(+) and Ex=4947 keV. This agrees well with the picture of the decay out of the SD band gained previously from two-step links. The angular distribution analysis favours a stretched dipole character for the transition. Due to the complicated structure of the level scheme in the region of interest it has not been possible to place the transition exactly.
Coexistence of collective and quasiparticle structures in 106Sn and 108Sn
1997
New levels in the neutron deficient nuclei 106Sn and 108Sn have been investigated by using the NORDBALL detector array combined with charged particle and neutron detectors. The excited structures are discussed in terms of collectivity and the shell model. The excitations are interpreted to be based on d52, g72 and h112 both for protons and neutrons and g92 for protons. The systematical behaviour of the specific states in the Sn isotopes is studied in the mass range of A = 106–118.
Spectroscopy of the neutron-deficientN=50nucleusRh95
2014
The neutron-deficient semimagic (neutron number N = 50) Rh-95 nucleus has been produced at high spins using the projectile-target system Ca-40 + Ni-58 at 125 MeV beam energy. The gamma-decays of le ...
Evidence of octupole-phonons at high spin in 207Pb
2019
A lifetime measurement of the 19/2 state in Pb has been performed using the Recoil Distance Doppler-Shift (RDDS) method. The nuclei of interest were produced in multi-nucleon transfer reactions induced by a Pb beam impinging on a Mo enriched target. The beam-like nuclei were detected and identified in terms of their atomic mass number in the VAMOS++ spectrometer while the prompt γ rays were detected by the AGATA tracking array. The measured large reduced transition probability B(E3,19/2→13/2)=40(8) W.u. is the first indication of the octupole phonon at high spin in Pb. An analysis in terms of a particle-octupole-vibration coupling model indicates that the measured B(E3) value in Pb is compa…
Pulse pile-up identification and reconstruction for liquid scintillator based neutron detectors
2018
WOS: 000433206800010 The issue of pulse pile-up is frequently encountered in nuclear experiments involving high counting rates, which will distort the pulse shapes and the energy spectra. A digital method of off-line processing of pile-up pulses is presented. The pile-up pulses were firstly identified by detecting the downward-going zero-crossings in the first-order derivative of the original signal, and then the constituent pulses were reconstructed based on comparing the pile-up pulse with four models that are generated by combining pairs of neutron and.. standard pulses together with a controllable time interval. The accuracy of this method in resolving the pile-up events was investigate…
A finite number of regular rotational bands in the superdeformed well of 143Eu
1995
Abstract The number of excited superdeformed bands in 143 Eu is measured by use of the Fluctuation Analysis Method. Between 10 and 40 rotational bands, displaying typical rotational energy correlations over two consecutive transitions, are populated within a rather narrow range in transition energy, E γ ≈ 1300–1500 keV. These numbers are close to the values found for normally deformed nuclei and agree with microscopic cranking + band mixing calculations for the specific superdeformed nucleus, which predict the onset of rotational damping to occur at the excitation energy U 0 = 1.3–1.6 MeV above the yrast line.
Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in 106,108Sn
2020
The lifetimes of the low-lying excited states 2(+) and 4(+) have been directly measured in the neutron-deficient Sn-106,Sn-108 isotopes. the nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. the emitted gamma rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2; 2(1)(+) -> 0(g.s)(+)) values and it describes well the experimental pattern for Sn104-114 ; the B…
Maximally aligned states in $^{99}$Ag
2003
Excited states of Ag-99 were populated via the Cr-50 + Ni-58 (261 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron. detector systems for reaction channel separation. On the basis of the measured gammagamma-coincidence relations and angular distribution ratios a significantly extended level scheme has been constructed up to E-x similar to 7.8 MeV and I = 35/2. The experimental results were described within the framework of the shell model. Candidates for states fully aligned in the pig(9/2)(-3)nu(d(5/2),g(7/2))(2) valence configuration space were found at 4109 and 6265 keV.
Performance of the Advanced GAmma Tracking Array at GANIL
2020
The performance of the Advanced GAmma Tracking Array (AGATA) at GANIL is discussed, on the basis of the analysis of source and in-beam data taken with up to 30 segmented crystals. Data processing is described in detail. The performance of individual detectors are shown. The efficiency of the individual detectors as well as the efficiency after $\gamma$-ray tracking are discussed. Recent developments of $\gamma$-ray tracking are also presented. The experimentally achieved peak-to-total is compared with simulations showing the impact of back-scattered $\gamma$ rays on the peak-to-total in a $\gamma$-ray tracking array. An estimate of the achieved position resolution using the Doppler broadeni…
Isospin dependence of electromagnetic transition strengths among an isobaric triplet
2019
*Aydın, Sezgin ( Aksaray, Yazar )
Collectivity in ‘‘spherical’’Eu143,144nuclei
1995
Long cascades of stretched E2 transitions have been observed in $^{143}\mathrm{Eu}$ and $^{144}\mathrm{Eu}$ nuclei which at low excitation exhibit spherical shape. Lifetime experiments demonstrate high collectivity values up to B(E2)\ensuremath{\approxeq}100 W.u. among these E2 cascades. The total Routhian surface calculations indicate many crossing rotational bands of the nucleus with triaxial shape at ${\mathrm{\ensuremath{\beta}}}_{2}$\ensuremath{\approxeq}0.25 and \ensuremath{\gamma}\ensuremath{\approxeq}30\ifmmode^\circ\else\textdegree\fi{}. The E2 cascades in $^{143}\mathrm{Eu}$ are proposed to represent the \ensuremath{\nu}${\mathit{h}}_{11/2}^{2}$\ensuremath{\pi}${\mathit{h}}_{11/2}…
Band-terminating states in 101Ag
2004
Excited states of the neutron deficient Ag-101 nucleus have been investigated via the Cr-50(Ni-58, 3rho1alpha) heavy-ion induced reaction at 261 meV by use of in-beam spectroscopic methods. On the basis of the measured gammagamma-cincidence relations and angular distribution ratios high-spin bands have been extended up to I-pi = 35/2(+), 45/2((-)) and (49/2(-)). The negative parity states at the highest energy have been interpreted as terminating non-collective oblate states in the framework of the Nilsson-Strutinsky cranking formalism.
Superallowed Gamow-Teller decay of the doubly magic nucleus $^{100}$Sn
2012
Expérience au GSI; The shell structure of atomic nuclei is associated with 'magic numbers' and originates in the nearly independent motion of neutrons and protons in a mean potential generated by all nucleons. During b1-decay, a proton transforms into a neutron in a previously not fully occupied orbital, emitting a positron-neutrino pair with either parallel or antiparallel spins, in a Gamow-Teller or Fermi transition, respectively. The transition probability, or strength, of a Gamow-Teller transition depends sensitively on the underlying shell structure and is usually distributed among many states in the neighbouring nucleus. Here we report measurements of the half-life and decay energy fo…
Coexistence of collective and quasiparticle structures in 106, 108Sn nuclei
1995
New revels in two neutron deficient nuclei Sn-106.108 have been found by using the Nordball detector array extended with the arrangements of charged particle and neutron detectors. The excited stru ...
Character of particle-hole excitations in94Ru deduced fromγ-ray angular correlation and linear polarization measurements
2014
Linear polarization and angular correlations of gamma-rays depopulating excited states in the neutron-deficient nucleus Ru-94(44)50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1, and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spin parity 12(1)(-) rather than 12(3)(+) as proposed in previous works. The presence of a 12(1)(-) state is interp…
Test of digital neutron-gamma discrimination with four different photomultiplier tubes for the NEutron Detector Array (NEDA)
2014
WOS: 000344994600012
First evidence for excited states inIn101
1996
The first evidence for excited states in In-101 is presented. In-101 is the lightest In isotope observed in an in-beam experiment. Two gamma-ray transitions at 1309 and 341 keV, respectively, are s ...
Low-lying electric dipole gamma-continuum for the unstable Fe-62,64 nuclei : Strength evolution with neutron number
2020
6 pags., 4 figs.
Interaction position resolution simulations and in-beam measurements of the AGATA HPGe detectors
2011
WOS: 000290082600015
Sn108studied with intermediate-energy Coulomb excitation
2005
The unstable neutron-deficient Sn-108 isotope has been studied in inverse kinematics by intermediate-energy Coulomb excitation using the RISING/FRS experimental setup at GSI. This is the highest Z nucleus studied so far with this method. Its reduced transition probability B (E2;0(g.s.)(+)-> 2(1)(+)) has been measured for the first time. The extracted B(E2) value of 0.230(57)e(2) b(2) has been determined relative to the known value in the stable Sn-112 isotope. The result is discussed in the framework of recent large-scale shell model calculations performed with realistic effective interactions. The roles of particle-hole excitations of the Sn-100 core and of the Z=50 shell gap for the E2 po…
Stability ofS50100n50Deduced from Excited States inC4899d51
1996
Excited states of neutron deficient nuclei close to Sn-100 were investigated in an in-beam spectroscopic experiment using the NORDBALL detector array. Excited states in Cd-99 were identified for the first time. The measured half-life of an isomeric state in Cd-99 indicates that the stability with respect to quadrupole shape changes is as large in Sn-100 as for other heavy doubly magic nuclei.
High-spin studies near 100Sn with NORDBALL: New results on 102In, 104In and 108Sb
1993
The NORDBALL detector array has been used in a gamma-ray spectroscopic study of neutron deficient nuclei close to 100Sn. A beam of 270 MeV 58Ni ions was used to bombard a target of Fe-54. Reaction channel separation was achieved with a 4pi charged particle Si-ball together with a 1pi neutron detector wall. Altogether 29 final nuclei were identified and excited states were observed for the first time in 8 of them. The weakest identified channel was 100Cd which represented 4.10(-3) % of the observed total yield. Level schemes Of 102In, 104In and 108Sb constructed from gamma-gamma-particle-coincidence and gamma-gamma-angular correlation analyses are presented. The observed structures are discu…
Identification and spectroscopy of the108Te nucleus
1994
Excited states of 108 Te were populated in the 54 Fe + 58 Ni (270 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron detector systems for reaction channel separation. Gamma rays belonging to the neutron deficient nucleus 108 Te were identified for the first time. On the basis of γγ-coincidence and angular correlation relations a level scheme was constructed with tentative spin and parity assignments. The structure of the nucleus is discussed in the framework of systematics of heavier Te nuclei.
Neutron Skin Effects in Mirror Energy Differences: The Case of Mg23−Na23
2018
Energy differences between analogue states in the T=1/2 Mg23-Na23 mirror nuclei have been measured along the rotational yrast bands. This allows us to search for effects arising from isospin-symmetry-breaking interactions (ISB) and/or shape changes. Data are interpreted in the shell model framework following the method successfully applied to nuclei in the f7/2 shell. It is shown that the introduction of a schematic ISB interaction of the same type of that used in the f7/2 shell is needed to reproduce the data. An alternative novel description, applied here for the first time, relies on the use of an effective interaction deduced from a realistic charge-dependent chiral nucleon-nucleon pote…
Four independent decay properties in the super-deformed well of 143Eu
1997
Abstract The flow of γ-transitions through the superdeformed minimum of 143Eu is investigated by studying the intensities of four different types of γ-rays of superdeformed origin, obtained with a variety of gating conditions. They can all be explained rather well by schematic simulation calculations assuming only well known statistical properties. Information on level density, competition between E1 and E2 strengths and rotational damping width in the SD well is obtained, yielding a rather complete picture of the feeding mechanism into different regions of the second minimum.
First observation of excited states in 108Sb
1995
A spectroscopic study of Sb-108 has been carried out as a part of a larger experiment where in total twenty-nine different residual nuclei were identified. This study gives the first information on excited levels in this nucleus. A low-lying two-quasi-particle multiplet together with some of the higher lying levels are discussed within the framework of the nuclear shell model. A rotational, strongly coupled, band is identified as, most likely, being built on the deformed pig9/2(-1) nuh11/2 configuration in accordance with total routhian surface calculations. Tentative spins and parities are presented as well as B(M1)/B(E2) ratios for some of the transitions in the strongly coupled band.
AGATA-Advanced GAmma Tracking Array
2012
WOS: 000300864200005
Isospin Properties of Nuclear Pair Correlations from the Level Structure of the Self-Conjugate Nucleus Ru88
2020
The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N = Z) nuclide 88 44Ru44 has been measured using the combination of the Advanced Gamma Tracking Array (AGATA) spectrometer, the NEDA and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in 88Ru were populated via the 54Fe(36Ar; 2n )88Ru fusion-evaporation reaction at the Grand Acc�el�erateur National d'Ions Lourds (GANIL) accelerator complex. The observed -ray cascade is assigned to 88Ru using clean prompt - -2-neutron coincidences in anti-coincidence with the detection of charged particles, con�rming and extending the previously assigned sequence of low-lyin…