Speaker
Description
The synthesis of elements heavier than iron occurs primarily through the (n,$\gamma$) reactions [1]. However, processes of the “rapid” ($r$-) and “slow” ($s$-) radiative neutron capture cannot produce 35 proton-rich stable nuclei known as the $p$-nuclei. The production of these chemical elements is referred to in astrophysics as the $p$-process [2]. The description of the $p$-process mechanism is crucial for explaining the discrepancy between observed and calculated abundances of chemical elements. A particularly large discrepancy is observed in the region of light $p$-nuclei, such as $^{92,94}$Mo and $^{96,98}$Ru. To explain these differences or eliminate them, it is crucial to consider all possible accumulation and decay channels of nuclei located near these $p$-nuclei. In this regard, information on proton-induced reactions on stable isotopes of Zr is very important. In the literature, information on measurements of cross sections for proton-induced reactions on $^{91,92,96}$Zr is scarce. In particular, $^{94}$Zr stands out as no information on proton-induced reactions on this isotope has been reported so far [3].
In this contribution, we will present the results of an experimental study of proton-induced reactions on stable $^{94}$Zr at astrophysically relevant energies. In the measurements, thin self-supporting $^{94}$Zr targets and the proton beam from the 6 MV Tandem accelerator of the Slovak University of Technology [4] are used. An array of the HPGe and BEGe detectors is used to detect the $\gamma$ rays emitted by the irradiated samples. Comparison of the measured cross sections with theoretical predictions obtained with the TALYS code [5] for various level density models, photon strength functions, and optical model potentials will also be presented and discussed.
Thus, for the first time, experimental data are obtained for the $^{94}$Zr(p,$\gamma$)$^{95}$Nb reaction cross section and isomer ratio for the reaction products $^{95\rm m,g}$Nb. These data are of great importance for nuclear astrophysics, especially for understanding the mechanism of the $p$-process and for developing modern, state-of-the-art theoretical models.
$ Acknowledgement$: “This work has received funding through the MSCA4Ukraine project, which is funded by the European Union. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union, the European Research Executive Agency, or the MSCA4Ukraine Consortium. Neither the European Union nor the European Research Executive Agency, nor the MSCA4Ukraine Consortium as a whole, nor any individual member institutions of the MSCA4Ukraine Consortium can be held responsible for them.
This work was also supported by the Slovak Research and Development Agency under Contract No. APVV-24-0516, and the Slovak grant agency VEGA (Contract No. 2/0175/24).”
[1] F. Käppeler, et al. Rev. Mod. Phys. 83 (2011) 157, doi.org/10.1103/RevModPhys.83.157.
[2] M. Arnould, et al. Phys. Rep. 450 (2007) 97, doi.org/10.1016/j.physrep.2007.06.002.
[3] N. Otuka, et al. Nucl. Data Sheets 120 (2014) 272, doi.org/10.1016/j.nds.2014.07.065.
[4] P. Noga, et al. Nucl. Instr. Meth. Phys. Res. B409 (2017) 264, dx.doi.org/10.1016/j.nimb.2017.04.051.
[5] A.J. Koning, et al. “TALYS-1.0,” EPJ Web Conf., 211 (2008). Proc. Int. Conf. on Nuclear Data for Science and Technology, 22 - 27 Apr., 2007, Nice, France.