Multi-Nucleon Transfer (MNT) reactions have been used for decades as a reaction mechanism, in order to populate excited states in nuclei far from stability and to perform nuclear structure studies. ...Nevertheless, the development of set-ups involving high acceptance tracking magnetic spectrometers (mainly existing in Europe), coupled with the Advanced GAmma Tracking Array (AGATA) opens new possibilities, especially if they are used in conjunction with high-intensity stable beams or ISOL RIBs. In this article, we will discuss the capabilities of such set-ups aiming at different goals, including complete information in high-resolution spectroscopy as well as lifetime measurements.
Abstract
Spectroscopic information on exotic Br and Nb nuclei, with odd and even masses around A=100, respectively, was obtained by analyzing fission fragments data collected with AGATA+VAMOS++ at ...GANIL and the FIPPS spectrometer at ILL. The complementarity of these two state-of-the art setups has been used, for the first time, to investigate the structure of these neutron-rich fission fragments via gamma-ray spectroscopy. Details on the two fission experiments will be given, as well as examples of high-resolution gamma-ray spectra used for the reconstruction of the level schemes. The active fission target, used in the neutron-induced fission experiment at ILL, allowed for high-statistics prompt-delayed coincidences for the analysis of a new isomeric state in
100
Nb. Evidence for a spherical isomeric state in
100
Nb will be shown and discussed within the systematic of neighbouring nuclei.
A complete-spectroscopy investigation of low-lying, low-spin states in the one-proton-hole and one-neutron-hole nucleus 206Tl has been performed by using thermal neutron capture and γ-coincidence ...technique with the FIPPS Ge array at ILL Grenoble. The new experimental results, together with data for the one-proton-particle and one-neutron-particle nucleus 210Bi (taken from a previous study done at ILL in the EXILL campaign), allowed for an extensive comparison with predictions of shell-model calculations performed with realistic interactions. No phenomenological adjustments were introduced in the calculations. In 210Bi, state energies, transition multipolarities and decay branchings agree well with theory for the three well separated multiplets of states which dominate the low-lying excitations. On the contrary, in 206Tl significant discrepancies are observed: in the same energy region, six multiplets were identified, with a significant mixing among them being predicted, as a consequence of the smaller energy separation between the active orbitals. The discrepancies in 206Tl are attributed to the larger uncertainties in the determination of the off-diagonal matrix elements of the realistic shell-model interaction with respect to the calculated diagonal matrix elements, the only ones playing a major role in the case of 210Bi. The work points to the need of more advanced approaches in the construction of the realistic interactions.
Abstract
The structure of the
11
/
2
1
+
state in
131
Sb was investigated at the LOHENGRIN spectrometer of Institut Laue-Langevin via neutron-induced fission of
235
U and lifetime measurements, ...yielding
T
1
/
2
=
3
(
2
)
, at the edge of the sensitivity of the experimental method. This first result for the
11
/
2
1
+
state half-life in neutron-rich Sb isotopes provides a quadrupole reduced transition probability to the ground state of
B
(
E
2
)
=
1.4
−
0.6
+
1.5
W.u., very close to the
B
(
E
2
;
2
1
+
→
0
1
+
)
in
130
Sn. Realistic shell-model calculations reproduce well both the experimental level scheme of
131
Sb and the
B
(
E
2
;
11
/
2
1
+
→
7
/
2
1
+
)
value, indicting a dominant
2
+
(
130
Sn
)
⊗
π
g
7
/
2
core-proton coupled configuration for the
11
/
2
1
+
state.
Tetragonal FeSe, a prototype iron-chalcogenide superconductor, shows signatures of a strange incoherent normal state. Motivated thereby, we use LDA+DMFT to show how multi-band correlations generate a ...low-energy pseudogap in the normal state, giving an incoherent metal in good semi-quantitative agreement with observations. Anomalous responses in the normal state, including orbital-dependent effective mass enhancement and photoemission lineshape, are consistently understood.
To assess the impact of different vascular patterns at contrast-enhanced ultrasound (CEUS) on the characterization of small liver nodules (10-30 mm) in cirrhosis and to determine whether primary ...nodules and recurrent nodules (after a previously treated hepatocellular carcinoma) display variations in enhancement pattern.
A total of 135 cirrhotic patients were evaluated. A diagnosis of hepatocellular carcinoma (HCC) was established according to AASLD Guidelines, based on imaging (computed tomography and/or magnetic resonance) or liver biopsy. All patients underwent CEUS. Different CEUS patterns were evaluated in terms of diagnostic accuracy: HYPER-HYPO: Arterial hyperenhancement followed by washout (hypoechoic appearance compared with surrounding parenchyma) in late phase; HYPER-ISO: Arterial hyperenhancement followed by isoenhancement (isoechoic appearance) in late phase; ISO-ISO: Isoenhancement in all vascular phases.
A total of 155 consecutive primary (n = 90) or recurrent (n = 65) nodules were detected. HCC was diagnosed in 127 nodules (71 primary, 56 recurrent). A characteristic HYPER-HYPO CEUS pattern was revealed in 52/127 (40.9%) HCCs (31 primary, 21 recurrent) giving a positive predictive value (PPV) of 98% (97% primary, 100% recurrent) and an accuracy of 51% (54% primary, 46% recurrent). A HYPER-ISO pattern was noted in 46 HCCs (31 primary, 15 recurrent). Assuming this pattern to also be indicative of HCC, the PPV and accuracy were 94% (93% primary, 97% recurrent) and 77% (84% primary, 68% recurrent), respectively. An ISO-ISO pattern was present in 29 HCCs (9 primary, 20 recurrent) and 22 non-HCCs (14 primary, 8 recurrent).
These data confirm that the HYPER-HYPO pattern at CEUS is definitely diagnostic for HCC in cirrhosis and that the HYPER-ISO pattern has a similar PPV, indicating that this pattern is highly suspicious for HCC. The ISO-ISO pattern was found in > 50% of recurrent nodules and indicates a high risk of HCC.
The collective nuclear rotation, at high spins and as a function of temperature T, is investigated in the transition region between the regular ordered motion at T=0 and the chaotic compound nucleus ...regime around the particle binding energy. The experimental analysis, based on statistical techniques, is carried out in nuclear systems characterized by specific quantum numbers (such as K) and deformation (as for example superdeformed nuclei). Data from high statistics EUROBALL experiments are discussed, focusing on nuclear structure effects at the onset of the chaotic regime. The experimental findings are compared to prediction from a Montecarlo simulation of the γ-decay flow based on microscopic cranked shell model calculations at finite temperature.
Lifetime measurements in 131Sb at LOHENGRIN Bottoni, S.; Gamba, E. R.; De Gregorio, G. ...
Journal of physics. Conference series,
09/2023, Letnik:
2586, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The neutron-rich 131Sb nucleus was studied at Institut Laue-Langevin, with the LOHENGRIN spectrometer, via neutron-induced fission of 235U and lifetime measurements using LaBr3(Ce) detectors. The ...lifetimes of the 11/21+ and 19/21+ states were measured with the generalized centroid difference and the decay slope methods, yielding T½=3(2) ps and T½=1347(171) ps, respectively. The measured value for the 11/21+ is at the limit of the fast-timing technique. The level scheme of 131Sb and the decay properties of the 11/21+ state were described by realistic shell-model calculations, which reproduce well both the experimental spin and energy sequences of 131Sb and the measured B(E2; 11/21+→7/21+) value, pointing to an almost pure 2+(130Sn) ⊗ πg7/2, core-proton coupled configuration for the 11/21+ state.
Investigation of the properties of a 1″×1″ LaBr3:Ce scintillator Nicolini, R.; Camera, F.; Blasi, N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2007, Letnik:
582, Številka:
2
Journal Article
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