Találati lista | Tudóstér

001-es BibID:	BIBFORM113363
035-os BibID:	(cikkazonosító)025803 (Scopus)85149633449 (WOS)000933015400001
Első szerző:	Gyürky György
Cím:	Cross section measurement of the 144Sm(α,n)147Gd reaction for studying the alpha-nucleus optical potential at astrophysical energies / Gy. Gyürky, P. Mohr, A Angyal, Z. Halász, G. Kiss, Zs Mátyus,T. N. Szegedi,T. Szücs, Zs. Fülöp
Dátum:	2023
ISSN:	2469-9985 2469-9993
Megjegyzések:	Background: Nuclear reactions involving alpha particles play an important role in various astrophysical processes such as the gamma process of heavy element nucleosynthesis. The poorly known low-energy alpha-nucleus optical potential is a key parameter to estimate the rates of these reactions.Purpose: The alpha-nucleus optical potential can be tested by measuring the cross section of alpha scattering as well as alpha-induced reactions. Low energy elastic alpha scattering on 144Sm has recently been measured with high precision. The aim of the present work was to complement that work by measuring the (alpha, n) cross sections on 144Sm at low energies. The experimental data shall be used to constrain the alpha-nucleus optical model potential. From this potential the 144Sm(alpha, gamma) 148Gd reaction rate can be derived with reduced uncertainties.Method: The 144Sm(alpha, n)147Gd reaction was studied by bombarding Sm targets with alpha beams provided by the cyclotron accelerator of Atomki. The cross section was determined using the activation method. The gamma radiation following the decay of the 147Gd reaction product was measured with a high-purity germanium (HPGe) detector. The experimental data are analyzed within the statistical model.Results: The cross section was measured in the alpha-energy range between 13 and 20 MeV in 1 MeV steps, i.e., from close above the (alpha, n) threshold. The results were compared with statistical model calculations using various approaches and parametrizations for the alpha-nucleus optical potential, and excellent agreement was obtained for two recent potentials. However, these potentials cannot reproduce literature data for the 144Sm(alpha, gamma) 148Gd reaction with the same accuracy.Conclusions: Constraints for the alpha-nucleus potential were derived from an analysis of the new 144Sm(alpha, n)147Gd data and literature data for 144Sm(alpha, gamma) 148Gd. These constraints enable a determination of the re-action rate of the 144Sm(alpha, gamma)148Gd reaction with significantly reduced uncertainties of less than a factor of 2.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Physical Review C. - 107 : 2 (2023), p. 1-8 (cikkazonosító)025803. -
További szerzők:	Mohr, P. Angyal Anikó (1984-) (környezetkutató fizikus geográfus) Halász Zoltán (1975-) (fizikus) Kiss Gábor Gyula (1979-) (kísérleti fizikus) Mátyus Zsolt Szegedi Tibor Norbert (1992-) (okleveles fizikus) Szücs Tamás (1984-) (fizikus) Fülöp Zsolt
Pályázati támogatás:	NN128072 Egyéb K134197 Egyéb GINOP-2.3.3-15-2016-00005 GINOP ÚNKP-22-5-DE-428 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM116201
035-os BibID:	(cikkazonosító)025802 (WoS)001052953200003 (Scopus)85168011413
Első szerző:	Tóth Ákos
Cím:	Experimental determination of the 3He(α, γ) 'Be reaction cross section above the 'Be proton separation thresholdd / Á. Tóth, T. Szücs, T. N. Szegedi, Gy. Gyürky, Z. Halász, G. G. Kiss, Zs. Fülöp
Dátum:	2023
ISSN:	2469-9985 2469-9993
Megjegyzések:	Background: The 3He(& alpha;, & gamma; ) 7Be reaction plays a major role both in the big bang nucleosynthesis producing the majority of the primordial 7Li, and in the pp chain of solar hydrogen burning, where it is the branching point between the pp-I and pp-II,-III chains. As a few-nucleon system, this reaction is often used to validate ab initio theoretical calculations and/or test R-matrix theory and code implementations. For the latter, experimental data in an extended energy range is of crucial importance to test the fit and extrapolation capabilities of the different codes.Purpose: The 3He(& alpha;, & gamma; ) 7Be reaction cross section has been measured by several groups up to the first resonance (Ec.m. & AP; 3 MeV) in the reaction. However, only one data set exists above the 7Be proton separation threshold measured in a narrow energy range (Ec.m. = 4.0-4.4 MeV). In this work we extend the available experimental capture cross section database to the energy range of known 7Be levels, where only particle scattering experiments are available for testing the models.Method: The activation method was used for the 3He(& alpha;, & gamma; ) 7Be reaction cross section determination. The experiment was performed using a thin-window gas cell with two high-purity Al foils as entrance and exit windows. The activity of the 7Be nuclei implanted in the exit/catcher foil was measured by detecting the yield of the emitted & gamma; rays using shielded high-purity germanium detectors.Results: New experimental 3He(& alpha;, & gamma; ) 7Be reaction cross section data were obtained for the first time in the Ec.m. = 4.3-8.3 MeV energy region, corresponding to Ex = 5.8-10 MeV excitation energies of 7Be. The new data set with about 0.2 MeV step covers the energy range of known levels and particle separation thresholds. No prominent structures are observer around the 7Be levels.Conclusions: The measured reaction cross section is slowly increasing with increasing energy in the range of Ex = 6-8 MeV from 10 & mu;b to 13 & mu;b. Above the 6Li +p1 threshold, a decrease starts in the cross section trend and reaches a value of about 8 & mu;b around Ex = 10 MeV. The overall structure of the cross section suggest a broad resonance peaking around Ex = 7.5 MeV 7Be excitation energy, with a width of 8 MeV.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Physical Review C. - 108 : 2 (2023), p. 1-8. -
További szerzők:	Szücs Tamás (1984-) (fizikus) Szegedi Tibor Norbert (1992-) (okleveles fizikus) Gyürky György Halász Zoltán (1975-) (fizikus) Kiss Gábor Gyula (1979-) (kísérleti fizikus) Fülöp Zsolt
Pályázati támogatás:	OTKA FK134845 OTKA OTKA K134197 OTKA ÚNKP-22-3-II-DE-31 egyéb ÚNKP-22-5-DE-428 egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: