Half-lives of the low-lying yrast states of 212Po have been measured using the delayed coincidence fast-timing method. We report on the first measurement of the 41+ half-life, as well as a new ...measurement of the 61+ half-life with improved accuracy compared to previous studies. The extracted lifetime of the 41+ and 61+ state have been determined to be 100(14) ps and 1.66(28) ns respectively. With these measurements, precise values are now available for the reduced transition strengths B(E2) of all ground state band levels in 212Po up to the first 8+ state, in particular B(E2; 41+→21+) = 9.4(13) W.u. and B(E2;61+→41+) = 8.7(15) W.u. Comparison of the new available data with an α-clustering model calculation provides evidence that the inclusion of the α-cluster degree of freedom significantly improves agreement with experimental data compared to earlier shell model calculations.
The OECD-NEA High Priority Request List (HPRL) is a point of reference to guide and stimulate the improvement of nuclear data for nuclear energy and other applications, and a tool to bridge the gap ...between data users and producers. The HPRL is application-driven and the requests are submitted by nuclear data users or representatives of the user’s communities. A panel of international experts reviews and monitors the requests in the framework of an Expert Group mandated by the NEA Nuclear Science Committee Working Party on International Nuclear Data Evaluation Cooperation (WPEC). After approval, individual requests are classified to three categories: high priority requests, general requests, and special purpose requests (e.g., dosimetry, standards). The HPRL is hosted by the NEA in the form of a relational database publicly available on the web. This paper provides an overview of HPRL entries, status and outlook. Examples of requests successfully completed are given and new requests are described with emphasis on updated nuclear data needs in the fields of nuclear energy, neutron standards and dosimetry.
The paper represents an overview of the measurements performed using GAINS at GELINA (JRC-Geel, Belgium). While undergoing continuous upgrades, the setup produced highly precise cross sections. Our ...measurements are primarily driven by technological needs with an emphasis on structural materials used in the development of nuclear facilities. However, most cases offered the opportunity to investigate various reaction mechanism and/or nuclear structure issues. We concentrate on several specific experiments describing the particular difficulties we met and the solutions we adopted to infer reliable data and to draw significant conclusions.
Pygmy Dipole Response in Samarium isotopes Jivan, H; Pellegri, L; Adsley, P. ...
Journal of physics. Conference series,
09/2023, Letnik:
2586, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
The influence of nuclear shape deformation on the Pygmy Dipole Response (PDR) was investigated using (α,α′γ) scattering on
144
Sm and
154
Sm. Experiments were conducted at iThemba LABS, ...coupling for the first time the K600 magnetic spectrometer with the BaGeL (Ball of Germanium and LaBr detectors) array. Preliminary results showcasing the efficacy of the facility and set-up for performing these 0° scattering experiments to investigate the PDR region are presented.
.
A fast-timing method to determine lifetimes of nuclear states in the sub-nanosecond domain is presented. It is based on in-beam measurements of triple-gamma coincidences in heavy-ion ...fusion-evaporation reactions, performed with an array of HPGe and LaBr
3
:Ce detectors. The high-energy resolution HPGe detectors are used to define de-exciting cascades, while the fast LaBr
3
:Ce detectors are used to determine the decay time spectra of selected levels fed by these cascades. A special method to treat the time information of an array of fast detectors is employed in order to fully use the efficiency of the array. Two measurements are presented to illustrate the method: a re-determination of the known half-life
ns of the
keV,
level in
107
Cd (test experiment), and the determination of a half-life
ps for the
keV,
state of
199
Tl .
The gamma efficiency of the GAINS spectrometer Deleanu, D.; Borcea, C.; Dessagne, Ph ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2010, Letnik:
624, Številka:
1
Journal Article
Recenzirano
The GAINS (Germanium Array for Inelastic Neutron Scattering) setup was recently installed at the GELINA (Geel Linear Accelerator) neutron source of EC-JRC-IRMM. In order to produce reliable neutron ...inelastic cross-section data the setup requires a precise efficiency calibration for each sample under investigation. These samples represent extended sources in non-standard orientations and with significant self-attenuation of gamma rays. We present in detail the efficiency calibration procedure performed with two Monte Carlo simulations using MCNP and GEANT4. A good agreement is found between the two independent approaches. The general features of the simulations are discussed together with an in-depth description of the various factors influencing the efficiency.
Neutron inelastic scattering on 54Fe Olacel, A.; Borcea, C.; Boromiza, M. ...
The European physical journal. A, Hadrons and nuclei,
2018/10, Letnik:
54, Številka:
10
Journal Article
Recenzirano
.
A neutron inelastic scattering experiment was performed at the Geel Electron Linear Accelerator neutron source using an enriched
54
Fe sample. The
γ
rays produced in the reaction were detected ...using the Gamma Array for Inelastic Neutron Scattering spectrometer. For each observed transition we determined the
γ
-production cross section for incident energies ranging from the inelastic threshold (
≈
1
.
434
MeV) up to 18 MeV. Using these primary data we also calculated the cross section of the first excited level and the total inelastic cross section. Our experimental results are compared with previous reported values, evaluated nuclear data libraries and theoretical calculations performed with the TALYS 1.9 code. A careful tuning of the optical model parameters allowed significant improvements in the description of the experimental results leading to interesting conclusions regarding the interaction of the
54
Fe nucleus with neutrons.
208Po populated through EC/β+ decay Brunet, M.; Berry, T.A.; Podolyák, Zs ...
Journal of physics. Conference series,
12/2020, Letnik:
1643, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The structure of 208Po resulting from the EC/β+ decay of 208At was studied at CERN's ISOLDE Decay Station (IDS). The high statistics afforded by the high yield of 208At and the high efficiency HPGe ...clusters at the IDS allowed for greater insight into lower intensity transitions and thus significant expansion of the 208Po level scheme. Furthermore, investigation into the isomeric state yielded a new half life 377(9) ns in addition to uncovering new transitions populating the state.
Study of exotic decay of Cs isotope close to the proton drip line Das, P.; Dattaf, Ushasi; Chakraborty, S. ...
27th International Nuclear Physics Conference, INPC 2019,Glasgow, United Kingdom,2019-07-29 - 2019-08-02,
12/2020, Letnik:
1643, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The neutron-deficient 115Cs was produced at ISOLDE, CERN by spallation reaction using 1.4 GeV proton on LaC2 target. The exotic decay modes were studied by using a charged particle array (DSSD and ...pad detectors) and a γ-detector array (four Clovers) at the ISOLDE decay station (IDS). In this report, results on observed β-delayed particle emission from 115Cs, a nucleus close to proton drip line, is presented. By measuring the time distribution in the delayed proton spectrum, the half-life of the ground state of 115Cs was extracted. The obtained half-life is in agreement with previous reported value. For the first time, the p-unbound states of 115Xe, obtained by measuring beta-delayed protons from 115Cs is reported.
The Zirconium isotopes across the N=56,58 neutron subshell closures have been of special interest since years, sparked by the near doubly-magic features of
96
Zr and the subsequent rapid onset of ...collectivity with a deformed ground-state structure already in
100
Zr. Recent state-of-the-art shell model approaches did not only correctly describe this shape-phase transition in the Zr isotopic chain, but alsothe coexistence of non-collective structures and pronounced collectivity especially
in
96,98
Zr. Theisotope
98
Zr is located on the transition from spherical to deformed ground state structures. We summarize recent experimental work to obtain the B(E2) excitation strengths of the first 2
+
state of
98
Zr, including a new experiment employing the recoil-distance Doppler-shift method following a two-neutron transfer reaction.
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