Nuclear-matter radius studies fromNi58(α,α)experiments at the GSI Experimental Storage Ring with the EXL facility

Abstract

A novel method for measuring nuclear reactions in inverse kinematics with stored ion beams was successfully used to extract the nuclear-matter radius of 58 Ni. The experiment was performed at the experimental heavy-ion storage ring at the GSI facility using a stored 58 Ni beam at energies of 100 and 150 MeV/u and an internal helium gas-jet target. Elastically scattered α-recoils at low momentum transfers were measured with an in-ring detector system compatible with ultrahigh vacuum. Experimental angular distributions were fitted using density-dependent optical model potentials within the eikonal approximation. This permitted the extraction of the point-matter root-mean-square radius of 58 Ni with an average value of 3.70(7) fm. Results from this work are in good agreement with several experiments performed in the past in normal kinematics. This pioneering experiment demonstrates a major breakthrough towards future investigations with far-from-stability stored beams using the present technique.

Erratum: Measurement of Ni58(p,p)Ni58 elastic scattering at low momentum transfer by using the HIRFL-CSR heavy-ion storage ring

“…In order to compare with our result, these values need to be converted into point-matter radii. In this Erratum to our paper, the point-matter radius was obtained via r [13], Alkhazov et al [44], and Lombard et al [45]. The finite size of the nucleon has been corrected.…”

“…5, of our original article, the nuclear matter radii data of 58 Ni from Refs. [13,44,45] contain the finite size of the nucleon. In order to compare with our result, these values need to be converted into point-matter radii.…”

Employing $p+^{58}$Ni elastic scattering for determination of $K$-shell ionization cross section of $^{58}$Ni$^{19+}$ in collisions with hydrogen gas target at 95 MeV/u

“…Thus, the ionization cross sections known with high precision are important for in-ring nuclear reaction experiments to normalize nuclear reaction cross sections induced by light ions [20]. Such elastic scattering reactions have already been used to study nuclear matter distribution [17,18,34] and will continue in the future addressing, e.g., neutron skin thicknesses of heavy nuclei, that can be related to radius of neutron star [35].…”

“…Thus, theoretical atomic cross sections are often used to normalize less-accurately known nuclear reaction cross sections in nuclear reaction experiments [14,16]. Many in-ring nuclear reaction experiments have been performed at the ESR ring [14,16,17,18,19]. In a pilot in-ring 58 Ni(p, p) 58 Ni elastic scattering experiment at the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou (HIRFL-CSR) [20], in order to show a potential for extracting optical model potentials (OMPs) of unstable nuclei, a theoretical K-shell ionization cross section was applied to determine the reaction luminosity.…”

Progress on internal gas-jet target nuclear reaction at the HIRFL-CSR

“…EXL合作 组发展出了重离子储存环适用的硅探测器 [19] , 利用硅 探测器进行了超高真空差分隔离 [20] , 发展了储存环气 体内靶核反应实验技术 [18] . 在这些技术支撑下, 开展了 广泛的实验研究, 例如, 利用质子和α两种轻粒子的弹 性散射开展了原子核核物质密度分布半径的测量实 验 [21,22] , 基于α粒子在原子核上的非弹性散射研究了巨 共振 [10] , 在低能区直接测量了核天体物理相关的质子 俘获(p, γ)截面 [15,16] , 以及利用(p, d)转移反应尝试测量 了核天体物理相关的能态信息 [23] . EXL合作组取得的 这些成果展示出了储存环气体内靶核反应作为一个新 实验方式的独特之处.…”