Study of nuclear equation of state in collisions of tin isotopes

Polazište ovog rada je eksperiment izveden na institutu RIKEN u Japanu u kojem je proučavana nuklearna jednadžba stanja u sudarima izotopa kositra. Energijske distribucije i njihovi omjeri za izospinske parove poput para proton-neutron primjeri su opservabla koje mogu pokazivati osjetljivost na energiju simetrije - najmanje poznat član u nuklearnoj jednadžbi stanja, a u ovakvim sudarima one se nastoje izmjeriti. Cilj rada bio je rekonstruirati ove opservable energije simetrije iz mjerenja neutronskog detektora NeuLAND i vidjeti može li se iz njih zaključiti nešto o parametru γ u potencijalnom članu energije simetrije. Napravljene su simulacije eksperimenta u softverskom okruženju R3BRoot pomoću simulacijskog paketa GEANT4 i pomoću njih je određena efikasnost detekcije protona i neutrona u ovisnosti o energiji što je omogućilo rekonstrukciju distribucija za sustave 132Sn + 124Sn te 124Sn + 112Sn. Distribucije su uspoređene s rezultatima UrQMD transportnog modela za dvije parametrizacije energije simetrije: γ = 0.5 i γ = 1.5. Konačno, raspravljena je mogućnost izbora jedne od njih kao preferirajuće parametrizacije energije simetrije.Starting point of this work is the experiment conducted at RIKEN institute in Japan the focus of the which was the study of nuclear equation of state in collisions of tin isotopes. Energy distributions of isospin pairs like proton-neutron pair and their ratio are examples of observables which can show sensitivity to the symmetry energy - the least known part of nuclear equation of state. Purpose of mentioned collisions is to measure them. Hence, the aim of this work was to reconstruct these observables from measurements made by neutron detector NeuLAND and from them possibly conclude something about the parameter γ in potential part of the symmetry energy. Simulations of the experiment were made using software framework R3BRoot with transport machine GEANT4. Using simulations, proton and neutron efficiencies depending on particle energy were calculated which enabled reconstruction of energy distributions for systems 132Sn + 124Sn and 124Sn + 112Sn. These distributions were compared to UrQMD model results for two parametrizations of symmetry energy, namely γ = 0.5 and γ = 1.5. Work finishes with the discussion weather preference could be given to any of the two as the possible parametrization of symmetry energy

Study of nuclear equation of state in collisions of tin isotopes

Polazište ovog rada je eksperiment izveden na institutu RIKEN u Japanu u kojem je proučavana nuklearna jednadžba stanja u sudarima izotopa kositra. Energijske distribucije i njihovi omjeri za izospinske parove poput para proton-neutron primjeri su opservabla koje mogu pokazivati osjetljivost na energiju simetrije - najmanje poznat član u nuklearnoj jednadžbi stanja, a u ovakvim sudarima one se nastoje izmjeriti. Cilj rada bio je rekonstruirati ove opservable energije simetrije iz mjerenja neutronskog detektora NeuLAND i vidjeti može li se iz njih zaključiti nešto o parametru γ u potencijalnom članu energije simetrije. Napravljene su simulacije eksperimenta u softverskom okruženju R3BRoot pomoću simulacijskog paketa GEANT4 i pomoću njih je određena efikasnost detekcije protona i neutrona u ovisnosti o energiji što je omogućilo rekonstrukciju distribucija za sustave 132Sn + 124Sn te 124Sn + 112Sn. Distribucije su uspoređene s rezultatima UrQMD transportnog modela za dvije parametrizacije energije simetrije: γ = 0.5 i γ = 1.5. Konačno, raspravljena je mogućnost izbora jedne od njih kao preferirajuće parametrizacije energije simetrije.Starting point of this work is the experiment conducted at RIKEN institute in Japan the focus of the which was the study of nuclear equation of state in collisions of tin isotopes. Energy distributions of isospin pairs like proton-neutron pair and their ratio are examples of observables which can show sensitivity to the symmetry energy - the least known part of nuclear equation of state. Purpose of mentioned collisions is to measure them. Hence, the aim of this work was to reconstruct these observables from measurements made by neutron detector NeuLAND and from them possibly conclude something about the parameter γ in potential part of the symmetry energy. Simulations of the experiment were made using software framework R3BRoot with transport machine GEANT4. Using simulations, proton and neutron efficiencies depending on particle energy were calculated which enabled reconstruction of energy distributions for systems 132Sn + 124Sn and 124Sn + 112Sn. These distributions were compared to UrQMD model results for two parametrizations of symmetry energy, namely γ = 0.5 and γ = 1.5. Work finishes with the discussion weather preference could be given to any of the two as the possible parametrization of symmetry energy

Study of nuclear equation of state in collisions of tin isotopes

Polazište ovog rada je eksperiment izveden na institutu RIKEN u Japanu u kojem je proučavana nuklearna jednadžba stanja u sudarima izotopa kositra. Energijske distribucije i njihovi omjeri za izospinske parove poput para proton-neutron primjeri su opservabla koje mogu pokazivati osjetljivost na energiju simetrije - najmanje poznat član u nuklearnoj jednadžbi stanja, a u ovakvim sudarima one se nastoje izmjeriti. Cilj rada bio je rekonstruirati ove opservable energije simetrije iz mjerenja neutronskog detektora NeuLAND i vidjeti može li se iz njih zaključiti nešto o parametru γ u potencijalnom članu energije simetrije. Napravljene su simulacije eksperimenta u softverskom okruženju R3BRoot pomoću simulacijskog paketa GEANT4 i pomoću njih je određena efikasnost detekcije protona i neutrona u ovisnosti o energiji što je omogućilo rekonstrukciju distribucija za sustave 132Sn + 124Sn te 124Sn + 112Sn. Distribucije su uspoređene s rezultatima UrQMD transportnog modela za dvije parametrizacije energije simetrije: γ = 0.5 i γ = 1.5. Konačno, raspravljena je mogućnost izbora jedne od njih kao preferirajuće parametrizacije energije simetrije.Starting point of this work is the experiment conducted at RIKEN institute in Japan the focus of the which was the study of nuclear equation of state in collisions of tin isotopes. Energy distributions of isospin pairs like proton-neutron pair and their ratio are examples of observables which can show sensitivity to the symmetry energy - the least known part of nuclear equation of state. Purpose of mentioned collisions is to measure them. Hence, the aim of this work was to reconstruct these observables from measurements made by neutron detector NeuLAND and from them possibly conclude something about the parameter γ in potential part of the symmetry energy. Simulations of the experiment were made using software framework R3BRoot with transport machine GEANT4. Using simulations, proton and neutron efficiencies depending on particle energy were calculated which enabled reconstruction of energy distributions for systems 132Sn + 124Sn and 124Sn + 112Sn. These distributions were compared to UrQMD model results for two parametrizations of symmetry energy, namely γ = 0.5 and γ = 1.5. Work finishes with the discussion weather preference could be given to any of the two as the possible parametrization of symmetry energy

Ograničavanje nuklearne energije simetrije koristeći kulonsko pobuđenje izotopa kositra bogatih neutronima pri relativističkim energijama

Relativistic Coulomb excitation of neutron-rich nuclei can be utilized to study the symmetry energy - a crucial yet still fairly enigmatic ingredient of the nuclear equation of state. Projectile nuclei are accelerated to relativistic velocities in inverse kinematics towards the Coulomb field of a high-Z target. Collective Coulomb excitations arise in projectile nuclei, whereby neutron and proton densities are displaced with respect to each other. An isospin imbalance forms in the system, which makes a suitable environment to probe the slope of the symmetry energy L, i.e., the linear coefficient in the expansion of the symmetry energy around the saturation density. An experiment aiming to constrain the parameter L was carried out using the large acceptance spectrometer R⌃3B-GLAD at the GSI accelerator facility, as a part of the FAIR Phase-0 campaign. Tin isotopes in the mass range A = 124 − 134 were produced as a secondary beam via fragmentation and fission reactions at energies close to 1 GeV/u and impinged onto the lead target to induce Coulomb excitations. After the deexcitation process, during which neutrons and γ-rays are emitted, the outgoing particles – including the residual fragment – were detected using the R⌃3B setup. This allowed for the measurement of the Coulomb-excitation cross section σ_C above the one-neutron separation threshold. In this work, an approach to constrain the slope of the symmetry energy, first suggested by A. Horvat and collaborators at GSI, was studied. Namely, σ_C of neutron-rich nuclei at relativistic energies correlates with the dipole polarizability α_D, owing to their similar functional dependence on excitation energy. Through the established correlation between α_D and L, measurement of the said cross section enables placing constraints on the slope of the symmetry energy via comparison with theoretical calculations. Coulomb-excitation cross sections were determined for the tin isotopes 124⌃Sn, 130⌃Sn and 132⌃Sn. The dipole response, characterized by the transition strengths B(E1) and B(E2), was computed using the Quasiparticle Random Phase Approximation with a variety of energy density functionals. Based on these inputs, Coulomb-excitation cross sections were subsequently evaluated using both first-order perturbation theory and the coupled-channel approach. A comparison between theoretical predictions and experimental measurements revealed a systematic discrepancy, with the theoretical calculations consistently overestimating the observed cross sections. Potential sources of this discrepancy are discussed in detail. It is concluded that resolving this inconsistency is necessary to give a reliable constraint on L. This will require close and continued collaboration between theoretical and experimental efforts.Relativisticko kulonsko pobuđenje jezgara bogatih neutronima može se koristiti u svrhu proučavanja energije simetrije – ključne, ali još uvijek nedovoljno poznate komponente nuklearne jednadžbe stanja. Takvi eksperimentalni uvjeti zahtijevaju korištenje inverzne kinematike. Nestabilne jezgre akceleriraju se do relativističkih brzina kao projektili i sudaraju s metom velikog atomskog broja Z. Dolazi do kulonskog pobuđenja projektila prilikom kojeg se u dotičnoj jezgri razdvajaju protonska i neutronska gustoća. Drugim riječima, u sustavu nastaje izospinska neravnoteža, što predstavlja pogodno okruženje za ispitivanje nagiba energije simetrije L, odnosno linearnog koeficijenta u Taylorovom razvoju energije simetrije oko gustoće saturacije. U svrhu proučavanja nuklearne jednadžbe stanja, proveden je eksperiment koristeći postav R⌃3B-GLAD na akceleratorskom postrojenju GSI, u sklopu kampanje FAIR Phase-0. Izotopi kositra u masenom rasponu A = 124 − 134 proizvedeni su kao sekundarni snop putem fragmentacijskih i fisijskih reakcija pri energijama oko 1 GeV/u. Kulonska pobuđenja inducirana su u električnom polju olovne mete, a izlazne čestice detektirane su pomoću postava R⌃3B-GLAD, što je omogućilo mjerenje udarnog presjeka kulonskih pobuđenja iznad energije separacije jednog neutrona. U ovom radu istraživan je pristup ograničavanja nagiba energije simetrije preko korelacije s udarnim presjekom kulonskih pobuđenja σ_C koji su prvi put predložili A. Horvat i kolaboratori na institutu GSI. Naime, σ_C u jezgrama bogatim neutronima pri relativističkim energijama korelira s dipolnom polarizabilnošću α_D , što proizlazi iz njihove slične funkcijske ovisnosti o energiji pobuđenja. Uzevši u obzir dobro poznatu korelaciju između α_D i parametra L, očekivana je korelacija između σ_C i L što omogućuje ograničavanje spomenutog parametra usporedbom mjerenja udarnog presjeka i teorijskih izračuna. Udarni presjeci kulonskih pobuđenja izmjereni su za izotope kositra 124⌃Sn, 130⌃Sn i 132⌃Sn. Dipolni odziv, opisan reduciranim vjerojatnostima prijelaza B(E1) i B(E2), izračunat je koristeći aproksimaciju nasumičnih faza uz primjenu različitih energijskih funkcionala gustoće. Zatim su udarni presjeci kulonskih pobuđenja, koristeći dobivene B(E1,E2) vrijednosti, izračunati pomoću prvog reda računa smetnje te metodom vezanih kanala. Između teorijskih predviđanja i izmjerenih udarnih presjeka za sva tri proučavana izotopa uočeno je značajno odstupanje pri čemu teorijski izračuni sustavno precjenjuju mjerenja. Mogući uzroci tog odstupanja detaljno i su diskutirani. Zaključeno je da, uz ovakvo neslaganje eksperimentalnih mjerenja i teorijskih izračuna, nije moguće pouzdano ograničavanje nagiba energije simetrije. Bliska i kontinuirana suradnja između teorijskih i eksperimentalnih istraživanja neophodna je za pronalaženje uzroka ovom neslaganju

Ograničavanje nuklearne energije simetrije koristeći kulonsko pobuđenje izotopa kositra bogatih neutronima pri relativističkim energijama

Relativistic Coulomb excitation of neutron-rich nuclei can be utilized to study the symmetry energy - a crucial yet still fairly enigmatic ingredient of the nuclear equation of state. Projectile nuclei are accelerated to relativistic velocities in inverse kinematics towards the Coulomb field of a high-Z target. Collective Coulomb excitations arise in projectile nuclei, whereby neutron and proton densities are displaced with respect to each other. An isospin imbalance forms in the system, which makes a suitable environment to probe the slope of the symmetry energy L, i.e., the linear coefficient in the expansion of the symmetry energy around the saturation density. An experiment aiming to constrain the parameter L was carried out using the large acceptance spectrometer R⌃3B-GLAD at the GSI accelerator facility, as a part of the FAIR Phase-0 campaign. Tin isotopes in the mass range A = 124 − 134 were produced as a secondary beam via fragmentation and fission reactions at energies close to 1 GeV/u and impinged onto the lead target to induce Coulomb excitations. After the deexcitation process, during which neutrons and γ-rays are emitted, the outgoing particles – including the residual fragment – were detected using the R⌃3B setup. This allowed for the measurement of the Coulomb-excitation cross section σ_C above the one-neutron separation threshold. In this work, an approach to constrain the slope of the symmetry energy, first suggested by A. Horvat and collaborators at GSI, was studied. Namely, σ_C of neutron-rich nuclei at relativistic energies correlates with the dipole polarizability α_D, owing to their similar functional dependence on excitation energy. Through the established correlation between α_D and L, measurement of the said cross section enables placing constraints on the slope of the symmetry energy via comparison with theoretical calculations. Coulomb-excitation cross sections were determined for the tin isotopes 124⌃Sn, 130⌃Sn and 132⌃Sn. The dipole response, characterized by the transition strengths B(E1) and B(E2), was computed using the Quasiparticle Random Phase Approximation with a variety of energy density functionals. Based on these inputs, Coulomb-excitation cross sections were subsequently evaluated using both first-order perturbation theory and the coupled-channel approach. A comparison between theoretical predictions and experimental measurements revealed a systematic discrepancy, with the theoretical calculations consistently overestimating the observed cross sections. Potential sources of this discrepancy are discussed in detail. It is concluded that resolving this inconsistency is necessary to give a reliable constraint on L. This will require close and continued collaboration between theoretical and experimental efforts.Relativisticko kulonsko pobuđenje jezgara bogatih neutronima može se koristiti u svrhu proučavanja energije simetrije – ključne, ali još uvijek nedovoljno poznate komponente nuklearne jednadžbe stanja. Takvi eksperimentalni uvjeti zahtijevaju korištenje inverzne kinematike. Nestabilne jezgre akceleriraju se do relativističkih brzina kao projektili i sudaraju s metom velikog atomskog broja Z. Dolazi do kulonskog pobuđenja projektila prilikom kojeg se u dotičnoj jezgri razdvajaju protonska i neutronska gustoća. Drugim riječima, u sustavu nastaje izospinska neravnoteža, što predstavlja pogodno okruženje za ispitivanje nagiba energije simetrije L, odnosno linearnog koeficijenta u Taylorovom razvoju energije simetrije oko gustoće saturacije. U svrhu proučavanja nuklearne jednadžbe stanja, proveden je eksperiment koristeći postav R⌃3B-GLAD na akceleratorskom postrojenju GSI, u sklopu kampanje FAIR Phase-0. Izotopi kositra u masenom rasponu A = 124 − 134 proizvedeni su kao sekundarni snop putem fragmentacijskih i fisijskih reakcija pri energijama oko 1 GeV/u. Kulonska pobuđenja inducirana su u električnom polju olovne mete, a izlazne čestice detektirane su pomoću postava R⌃3B-GLAD, što je omogućilo mjerenje udarnog presjeka kulonskih pobuđenja iznad energije separacije jednog neutrona. U ovom radu istraživan je pristup ograničavanja nagiba energije simetrije preko korelacije s udarnim presjekom kulonskih pobuđenja σ_C koji su prvi put predložili A. Horvat i kolaboratori na institutu GSI. Naime, σ_C u jezgrama bogatim neutronima pri relativističkim energijama korelira s dipolnom polarizabilnošću α_D , što proizlazi iz njihove slične funkcijske ovisnosti o energiji pobuđenja. Uzevši u obzir dobro poznatu korelaciju između α_D i parametra L, očekivana je korelacija između σ_C i L što omogućuje ograničavanje spomenutog parametra usporedbom mjerenja udarnog presjeka i teorijskih izračuna. Udarni presjeci kulonskih pobuđenja izmjereni su za izotope kositra 124⌃Sn, 130⌃Sn i 132⌃Sn. Dipolni odziv, opisan reduciranim vjerojatnostima prijelaza B(E1) i B(E2), izračunat je koristeći aproksimaciju nasumičnih faza uz primjenu različitih energijskih funkcionala gustoće. Zatim su udarni presjeci kulonskih pobuđenja, koristeći dobivene B(E1,E2) vrijednosti, izračunati pomoću prvog reda računa smetnje te metodom vezanih kanala. Između teorijskih predviđanja i izmjerenih udarnih presjeka za sva tri proučavana izotopa uočeno je značajno odstupanje pri čemu teorijski izračuni sustavno precjenjuju mjerenja. Mogući uzroci tog odstupanja detaljno i su diskutirani. Zaključeno je da, uz ovakvo neslaganje eksperimentalnih mjerenja i teorijskih izračuna, nije moguće pouzdano ograničavanje nagiba energije simetrije. Bliska i kontinuirana suradnja između teorijskih i eksperimentalnih istraživanja neophodna je za pronalaženje uzroka ovom neslaganju

Investigating nuclei produced in 9Li +11B reaction

In this contribution, a preliminary analysis of the first part of the experiment S2012 conducted at the ISAC-II facility of Canada’s particle accelerator center TRIUMF in Vancouver will be presented. The experiment aims to study highly clustered structures of nuclei created in multi-nucleon transfer reactions of 9Li radioactive beam on natural boron target (11B and 10B). The main objective of the experiment is to study exotic structures created in neutron-rich 16C nucleus in the range of higher excitation energies. The analysis presented here probes the existence of exotic cluster configurations and the quality of detected results using the invariant mass techniques

Investigating nuclei produced in

In this contribution, a preliminary analysis of the first part of the experiment S2012 conducted at the ISAC-II facility of Canada’s particle accelerator center TRIUMF in Vancouver will be presented. The experiment aims to study highly clustered structures of nuclei created in multi-nucleon transfer reactions of 9Li radioactive beam on natural boron target (11B and 10B). The main objective of the experiment is to study exotic structures created in neutron-rich 16C nucleus in the range of higher excitation energies. The analysis presented here probes the existence of exotic cluster configurations and the quality of detected results using the invariant mass techniques

NeuLAND: The high-resolution neutron time-of-flight spectrometer for R3B at FAIR

NeuLAND (New Large-Area Neutron Detector) is the next-generation neutron detector for the R3B (Reactions with Relativistic Radioactive Beams) experiment at FAIR (Facility for Antiproton and Ion Research). NeuLAND detects neutrons with energies from 100 to 1000 MeV, featuring a high detection efficiency, a high spatial and time resolution, and a large multi-neutron reconstruction efficiency. This is achieved by a highly granular design of organic scintillators: 3000 individual submodules with a size of 5 × 5 × 250 cm3 are arranged in 30 double planes with 100 submodules each, providing an active area of 250 × 250 cm2 and a total depth of 3 m. The spatial resolution due to the granularity together with a time resolution of 150 ps ensures high-resolution capabilities. In conjunction with calorimetric properties, a multi-neutron reconstruction efficiency of 50% to 70% for four-neutron events will be achieved, depending on both the emission scenario and the boundary conditions allowed for the reconstruction method. We present in this paper the final design of the detector as well as results from test measurements and simulations on which this design is based

A new Time-of-flight detector for the R 3 B setup

© 2022, The Author(s).We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R3B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision σΔE/ ΔE of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.11Nsciescopu