Seminarium Fizyki Jądra Atomowego
2006/2007 | 2007/2008 | 2008/2009 | 2009/2010 | 2010/2011 | 2011/2012 | 2012/2013 | 2013/2014 | 2014/2015 | 2015/2016 | 2016/2017 | 2017/2018 | 2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024 | 2024/2025 | 2025/2026
2026-06-11 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15 
dr Gilles De France (GANIL, Caen, Francja)Nuclear structure at GANIL with a focus on gamma-ray spectroscopy
In this seminar, I will describe and discuss several recent experiments realized in the framework of a campaign at the LISE spectrometer using transfer reactions, the MUGAST campaign. In this experimental campaign we used the coupling of the charged particle MUGAST detector with the EXOGAM Ge array and the LISE spectrometer. Several aspects of nuclear structure have been addressed like pairing, clustering or the structure of nuclei around N=40. In addition, the use of a high energy neutron beam with EXOGAM to study nuclei around 56Ni in the spirit of an exploratory experiment will be presented. I will also briefly describe the GANIL facility and the on going developments which will shape its future.
2026-05-28 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
prof. Andreas Görgen (University of Oslo, Norwegia)Studies of nuclear shapes in neutron-rich fission fragments
Neutron-rich nuclei in the mass region around A=100-110 exhibit several interesting phenomena related to nuclear shapes: a rapid onset of deformation at neutron number N=60 for strontium and zirconium, coexistence of near spherical and well-deformed shapes in the transitional region and pronounced triaxiality for slightly heavier molybdenum and ruthenium isotopes. The richness of shape phenomena, and their sensitivity to small changes in proton and neutron numbers, excitation energy, and angular momentum, makes this mass region an ideal testing ground for theoretical nuclear models.
New experimental results will be presented with a focus on lifetime measurements for short-lived excited states for several nuclides in this mass region. Experiments were performed at GANIL using fusion-fission reactions in inverse kinematics, the VAMOS++ magnetic spectrometer for identification of fission fragments, the AGATA spectrometer for detection of gamma rays, and the recoil distance Doppler shift method to measure picosecond lifetimes. The comparison of the resulting electromagnetic transition strengths with both phenomenological and fully microscopical theoretical models provides new insights into the evolution of nuclear shapes throughout this mass region.
New experimental results will be presented with a focus on lifetime measurements for short-lived excited states for several nuclides in this mass region. Experiments were performed at GANIL using fusion-fission reactions in inverse kinematics, the VAMOS++ magnetic spectrometer for identification of fission fragments, the AGATA spectrometer for detection of gamma rays, and the recoil distance Doppler shift method to measure picosecond lifetimes. The comparison of the resulting electromagnetic transition strengths with both phenomenological and fully microscopical theoretical models provides new insights into the evolution of nuclear shapes throughout this mass region.
2026-05-21 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
dr hab. Michał Warda, prof. UMCS (Lublin)Cluster radioactivity: exotic process or dominant nuclear decay
Most heavy and super-heavy nuclei decay through fission or alpha emission, but other decay modes can also be noticed. In the 1980s, an exotic decay of cluster radioactivity was observed in actinides [1, 2, 3]. A light nucleus, but heavier than an alpha particle, is emitted in this process. The heavy mass residue is a doubly magic 208Pb in all observed decays of this type.
The theoretical description of this process as a very asymmetric fission has been successfully carried out in the HFB model [4]. The analysis of cluster radioactivity fission valley on the potential energy surface has been extended to heavier isotopes. It has been found that the analog process, with lead as one of the fragments, can be noticed even in super-heavy nuclei [5]. Moreover, the asymmetric fission of cluster radioactivity type plays a non-negligible role in this region. In some cases, in the region around 284Cn, it may be even the dominant fission channel.
We also delimit the region in the chart of nuclides where super-asymmetric fission paths exist and set the limits for the cluster radioactivity decay mode [6]. Selected isotopic and isotonic chains in the region of heavy and super-heavy nuclei will be investigated to find the evolution of the super-asymmetric fission valley with increasing number of protons and neutrons.
[1] H.J. Rose and G.A. Jones, Nature (London) 307, 245 (1984).
[2] A. Sandulescu, D.N. Poenaru, and W. Greiner, Sov. J. Part. Nucl. 11, 528 (1980).
[3] R. Bonetti and A. Guglielmetti, in Heavy Elements and Related Phenomena, Vol. II, edited by W. Greiner and R.K. Gupta (World Scientific, Singapore, 1999), p. 643.
[4] M. Warda, and L.M. Robledo, Physical Review C 84, 044608 (2011).
[5] M. Warda, A. Zdeb, and L.M. Robledo, Physical Review C 98, 041602 (2018).
[6] M. Warda, A. Zdeb, and R. Rodriguez-Guzman, Physical Review C 113, 034619 (2026).
The theoretical description of this process as a very asymmetric fission has been successfully carried out in the HFB model [4]. The analysis of cluster radioactivity fission valley on the potential energy surface has been extended to heavier isotopes. It has been found that the analog process, with lead as one of the fragments, can be noticed even in super-heavy nuclei [5]. Moreover, the asymmetric fission of cluster radioactivity type plays a non-negligible role in this region. In some cases, in the region around 284Cn, it may be even the dominant fission channel.
We also delimit the region in the chart of nuclides where super-asymmetric fission paths exist and set the limits for the cluster radioactivity decay mode [6]. Selected isotopic and isotonic chains in the region of heavy and super-heavy nuclei will be investigated to find the evolution of the super-asymmetric fission valley with increasing number of protons and neutrons.
[1] H.J. Rose and G.A. Jones, Nature (London) 307, 245 (1984).
[2] A. Sandulescu, D.N. Poenaru, and W. Greiner, Sov. J. Part. Nucl. 11, 528 (1980).
[3] R. Bonetti and A. Guglielmetti, in Heavy Elements and Related Phenomena, Vol. II, edited by W. Greiner and R.K. Gupta (World Scientific, Singapore, 1999), p. 643.
[4] M. Warda, and L.M. Robledo, Physical Review C 84, 044608 (2011).
[5] M. Warda, A. Zdeb, and L.M. Robledo, Physical Review C 98, 041602 (2018).
[6] M. Warda, A. Zdeb, and R. Rodriguez-Guzman, Physical Review C 113, 034619 (2026).
2026-05-14 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
mgr inż. Anna Władyszewska (Uniwersytet Jagielloński, Kraków)Λ(1405) 'golden channel' measured in p+p at HADES
The nature of the Λ(1405) hyperon remains one of the longstanding open questions in hadron physics. Since its prediction and discovery in the 1960s, its structure is still widely debated. With a mass located below the KN threshold, it cannot be explained within the constituent quark model. Furthermore, its lineshape deviates from a Breit–Wigner distribution and depends on the production and decay channels. Interpretations of Λ(1405) include a quasi-bound state KN and a dynamically generated meson–baryonmolecule with a two-pole structure. The exclusive channel pK+Λ(1405) → (Σ0(→ Λ(→ pπ−)γ)π0(→ γγ)) has been investigated using the HADES detector in proton–proton collisions at a beam energy of 4.5 GeV. The reconstructed invariant mass spectrum of Σ0π0 shows clear contributions from the Λ(1405) and Λ(1520) resonances, as well as an enhancement near the masses of Λ(1600), Λ(1670), and Λ(1690). Production of these states has been studied in function of the four-momentum transfer between the initial proton and the outgoing K+. The obtained Λ(1405) → Σ0π0 mass distribution can be analyzed together with the pK− invariant mass distribution, which shows an enhancement near the KN threshold. Potential for this study using a K-matrix formalism within a coupled-channel model will also be presented.
2026-05-07 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
Dr hab. Krzysztof Piasecki (Zakład Fizyki Jądrowej IFD UW)Precyzyjna i wielowymiarowa eksploracja materii QCD spektrometrem CBM
Zderzenia jądrowe przy energiach kilku GeV/nukleon dają nam wgląd w intrygujący światgorącego i gęstego obszaru diagramu materii QCD. W regionie tym podstawowe własności hadronów, takiejak masa czy stosunki rozgałęzień rozpadów cząstek, mogą być zmodyfikowane względem ich wartości wpróżni. Wraz z narastającą energią wiązki, produkcja wielu hadronów narasta z rzadkiej ku obfitej.Produkowane są również hadrony (wielo-)dziwne, rezonanse hadronów dziwnych, hiperjądra, a być może teżhadrony z kwarkiem powabnym. Pozwala to na uzyskanie złożonego obrazu materii wytworzonej w tychekstremalnych warunkach. Zderzenia są również źródłem par leptonowych (tzw. dileptonów), których pomiarpozwala na dedukcję m.in. temperatury materii w fazach przed wymrożeniem hadronów.
Układ badawczy Compressed Baryonic Matter (CBM) powstaje obecnie przy budowanym ośrodku FAIR wDarmstadt. Jest on zaprojektowany z myślą o wysokoprecyzyjnych pomiarach szerokiej gamy typów cząstekemitowanych ze zderzeń ciężkich jonów. Planowane intensywności reakcji, dochodzące do 10 MHz, nie mająprzed CBM precedensu. Układ eksperymentalny zaprojektowano tak, aby detektory cechowała wysokaodporność na promieniowanie, elektronika była szybka, a system zbierania danych działał w trybiestrumieniowym. W celu testowania tych komponentów, rozwijane jest stanowisko mCBM (mini-CBM). Wniniejszym referacie przedstawię wyniki testów mCBM na wiązce SIS18.
Na seminarium ukażę również wyniki testów rozkładów fizycznych cząstek emitowanych ze zderzeń.Obejmują one m.in. rozkłady kinematyczne (wielo-)dziwnych hadronów i hiperjąder, rozkłady pływuazymutalnego i fluktuacji rozkładów krotności. Przedstawione zostaną też testy rozkładów dileptonów orazanaliz femtoskopowych.
Układ badawczy Compressed Baryonic Matter (CBM) powstaje obecnie przy budowanym ośrodku FAIR wDarmstadt. Jest on zaprojektowany z myślą o wysokoprecyzyjnych pomiarach szerokiej gamy typów cząstekemitowanych ze zderzeń ciężkich jonów. Planowane intensywności reakcji, dochodzące do 10 MHz, nie mająprzed CBM precedensu. Układ eksperymentalny zaprojektowano tak, aby detektory cechowała wysokaodporność na promieniowanie, elektronika była szybka, a system zbierania danych działał w trybiestrumieniowym. W celu testowania tych komponentów, rozwijane jest stanowisko mCBM (mini-CBM). Wniniejszym referacie przedstawię wyniki testów mCBM na wiązce SIS18.
Na seminarium ukażę również wyniki testów rozkładów fizycznych cząstek emitowanych ze zderzeń.Obejmują one m.in. rozkłady kinematyczne (wielo-)dziwnych hadronów i hiperjąder, rozkłady pływuazymutalnego i fluktuacji rozkładów krotności. Przedstawione zostaną też testy rozkładów dileptonów orazanaliz femtoskopowych.
2026-04-23 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
Dr Gagandeep Singh (National Centre for Nuclear Research)Low and medium mass neutron halos
The nuclear chart is full of phenomena hitherto unexplained. Of the roughly estimated 7000 nuclear species to exist in nature, only about 10% are known and studied. Owing to the Coulomb barrier, most of these lie on the neutron rich side of the valley of stability. Halos are a special class of these exotic nuclei where one or two nucleons decouple from a composite core and penetrate the classically forbidden region. They are weakly bound nuclei, with the continuum playing a major role in their description. I discuss the three-body Borromean system 31F, which is the last known isotope of the Fluorine chain and has been deemed as a p-wave halo, using a pseudostate approach with a transformed harmonic oscillator (THO) basis. Similarly, 34Na, analyzed using the post form finite range distorted wave Born approximation (FRDWBA) theory is a vital p-wave halo like 31F, but is a one-neutron halo candidate whose formation rate is crucial to 35Na, the most abundant neutron rich isotope of the Sodium chain. With the same basis discretizing the intermediate continuum as 31F, I then discuss two-neutron transfer reactions with 6He as an ideal candidate to understand the reaction mechanism due to the pairing interactions in the final nucleus. I weigh up scattering of the Cooper pair of the nucleons via the different states of the intermediate continuum through comparisons with a hypothetical bound case of 5He. Extending the possibilities for astrophysical applications, reaction rates for radiative neutron capture (n,γ) reactions involving some of these exotic nuclei would also be discussed.
2026-04-16 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
dr hab. Michał Kowal, prof. NCBJ (NCBJ)A Question of Shape: New Mechanism Governing Superheavy Nuclei Survival
We demonstrate that hot superheavy nuclei do not retain spherical shapes, as traditionally assumed, but instead equilibrate in deformed —often oblate or triaxial— configurations at finite excitation energy. This behavior arises from a mechanism analogous to the Jahn--Teller effect: spherical systems exhibit high single-particle degeneracy near the Fermi surface, causing their shell corrections to damp out significantly faster with temperature than those of deformed shapes. Using a finite-temperature framework, we reveal a thermally induced inversion of the potential-energy landscape in the Z=118-120 region, where deformed minima become energetically favored at U ~= 30-50 MeV. This shape inversion fundamentally alters the competition between neutron evaporation and fission. We derive a deformation-dependent correction to the survival probability, revealing a systematic bias in estimates based on spherical ground-state properties. Our results identify a finite-temperature structure effect that calls for a revision of current models of superheavy nucleus synthesis and decay.
2026-04-09 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
dr Marco Rocchini (INFN - Istituto Nazionale di Fisica Nucleare, Division of Florence, Italy)Spherical-oblate shape coexistence in 94Zr and the SPIDER Coulomb-excitation campaign at LNL
Low-energy Coulomb excitation is a powerful tool for studying collective properties and shape evolution in atomic nuclei. At the INFN Legnaro National Laboratories (LNL), we have been conducting a long-term experimental campaign using the SPIDER detector, an array of segmented silicon detectors specifically designed for Coulomb-excitation experiments. SPIDER has been used in combination with both the GALILEO gamma-ray spectrometer and, more recently, the AGATA gamma-tracking array.
In this talk, I will briefly introduce the SPIDER detector and provide an overview of the Coulomb-excitation measurements performed at LNL with the GALILEO and AGATA setups. I will then focus on the specific case of 94Zr, which represents our most recently completed analysis. This study marked the first application of the quadrupole sum rules method in the Zr isotopic chain and provided clear evidence of spherical-oblate shape coexistence in 94Zr. The experimental results will be discussed in the context of state-of-the-art nuclear models and quantum phase transitions.
In this talk, I will briefly introduce the SPIDER detector and provide an overview of the Coulomb-excitation measurements performed at LNL with the GALILEO and AGATA setups. I will then focus on the specific case of 94Zr, which represents our most recently completed analysis. This study marked the first application of the quadrupole sum rules method in the Zr isotopic chain and provided clear evidence of spherical-oblate shape coexistence in 94Zr. The experimental results will be discussed in the context of state-of-the-art nuclear models and quantum phase transitions.
2026-03-26 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
prof. Thomas Elias Cocolios (KU Leuven, Belgia)Getting NSHAPE: combining laser spectroscopy with muonic atoms of exotic nuclei to reveal exciting features of the nuclear landscape
Nuclear charge radii are known to be impactful to further our understanding of the nuclear landscape, from kinks at magic numbers to onset of deformation or the dramatic odd-even staggering in the neutron-deficient mercury isotopes. Recent developments at CERN ISOLDE, like the Perpendicularly-Illuminated Laser Ion Source & Trap (PI-LIST) has enabled the study of neutron-rich polonium and actinium isotopes, helping delineate the region of octupole deformation north-east of 208Pb.
While laser spectroscopy gives access to changes in charge radii across long chains of isotopes, those measurements rely on atomic parameters which determination from large-scale atomic calculations result in large systematic uncertainties, often obscuring the nuclear information. It is possible to benchmark those laser spectroscopy data against absolute charge radii, when those are available. However, given that none of the odd-Z elements nor any element beyond Pb have more than 2 stable isotopes, none of those have so far such data available.
At the Paul Scherrer Institute in Villigen, Switzerland, the muX collaboration has developed an approach to study muonic x rays for samples as small as 10 µg. This has enabled a new program, named ReferenceRadii, exploring absolute charge radii from aluminium to curium.
Recent highlights from PI-LIST and ReferenceRadii, and their impact will be presented.
While laser spectroscopy gives access to changes in charge radii across long chains of isotopes, those measurements rely on atomic parameters which determination from large-scale atomic calculations result in large systematic uncertainties, often obscuring the nuclear information. It is possible to benchmark those laser spectroscopy data against absolute charge radii, when those are available. However, given that none of the odd-Z elements nor any element beyond Pb have more than 2 stable isotopes, none of those have so far such data available.
At the Paul Scherrer Institute in Villigen, Switzerland, the muX collaboration has developed an approach to study muonic x rays for samples as small as 10 µg. This has enabled a new program, named ReferenceRadii, exploring absolute charge radii from aluminium to curium.
Recent highlights from PI-LIST and ReferenceRadii, and their impact will be presented.
2026-03-19 (Czwartek)
Zapraszamy do sali 1.01, ul. Pasteura 5 o godzinie 10:15
Dr Aafke Kraan (University of Pisa, Włochy)Nuclear Fragmentation Measurements for Particle Therapy and Beyond
FOOT (FragmentatiOn Of Target) is an experimental program in applied nuclear physics focused on the understanding of nuclear fragmentation processes. Understanding these fragmentation processes is important in two major contexts: improving cancer treatments that use hadron beams and assessing radiation risks for astronauts during space missions. The FOOT physics program foresees a set of measurements conducted in both direct and inverse kinematics, employing particle beams and targets relevant to particle therapy and radiation protection in space. The principal objective is to determine double-differential cross sections—measured as functions of the emission angle and the energy of the produced fragments—in the energy interval from about 100 to 800 MeV per nucleon. The experiment aims to reach a measurement accuracy better than approximately 5%. For this purpose, the FOOT collaboration has developed two experimental setups. One setup uses nuclear emulsion detectors and is optimized for identifying fragments with charge Z≤3. The second setup relies on electronic detector systems and is intended primarily for detecting lighter fragments with charge Z≥2.
In this seminar the physics motivations of the experiment will be discussed, followed by an overview of the apparatus. Several preliminary and recent results will be presented, focusing on topics such as fragment charge identification, new measurements obtained with helium beams, and recent determinations of fragmentation cross sections. Future plans will also be discussed.
In this seminar the physics motivations of the experiment will be discussed, followed by an overview of the apparatus. Several preliminary and recent results will be presented, focusing on topics such as fragment charge identification, new measurements obtained with helium beams, and recent determinations of fragmentation cross sections. Future plans will also be discussed.
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