Measurement of the ⁸⁶Kr(α,n)⁸⁹Sr cross section at energies relevant for the weak r-process

Abstract

The r-process has been shown to be robust in reproducing the abundance distributions of heavy elements, such as europium, seen in ultra-metal poor stars. In contrast, observations of elements 26 < Z < 47 display overabundances relative to r-process model predictions. A proposed additional source of early nucleosynthesis is the weak r-process in neutrino-driven winds of core-collapse supernovae. It has been shown that in this site (α,n) reactions are both crucial to nucleosynthesis and the main source of uncertainty in model-based abundance predictions. Aiming to improve the certainty of nucleosynthesis predictions, the cross section of the important reaction 86Kr(α,n)89Sr has been measured at an energy relevant to the weak r-process. This experiment was conducted in inverse kinematics at TRIUMF with the EMMA recoil mass spectrometer and the TIGRESS gamma-ray spectrometer. A novel type of solid helium target was used.

Synergistic Effect of He for the Fabrication of Ne and Ar Gas-Charged Silicon Thin Films as Solid Targets for Spectroscopic Studies

“…The results in this work are also important for applications of the “solid–gas” nanocomposite films as Ne (and Ar) solid targets for nuclear reaction experiments of interest in astrophysics and nuclear structure studies [ 28 , 29 , 32 , 33 ]. These solid targets can overcome the limitations of cryogenic or gas cell-based systems, which are bulky and difficult to handle, thus facilitating usage.…”

“…An exhaustive microstructural characterization also showed that gas content and nanobubble size and shape are finely tunable [ 17 , 24 , 25 ]. Due to the high density and pressure of He trapped in the nanobubbles [ 24 , 25 , 26 , 27 ], the He-charged Si films have been proposed as “solid targets” for nuclear reaction studies in our previous works [ 28 , 29 , 30 , 31 , 32 , 33 ].…”

“…Based on the results presented in this article, the investigated Si films are thought to be of interest for the study of spectroscopic properties of condensed noble gases without the need for cryogenic, high-pressure anvils or ion implanter devices. The fabrication of these Ne and Ar solid targets is also of interest for nuclear reaction studies [ 28 , 29 , 30 , 31 , 32 , 33 ].…”

Neutrino-driven Outflows and the Elemental Abundance Patterns of Very Metal-poor Stars

“…Psaltis et al (2022) went a step further and explored the impact of nuclear physics uncertainties on predictions of elemental abundance ratios and compared them with observations of Galactic metal-poor stars. Both studies have motivated several experimental studies in the nuclear astrophysics community (Kiss et al 2021;Szegedi et al 2021;Angus et al 2023, for example).…”

Synergistic Effect of He for the Fabrication of Ne and Ar Gas-Charged Silicon Thin Films as Solid Targets for Spectroscopic Studies

“…An exhaustive microstructural characterization also showed that gas content and nanobubbles size and shape are finely tunable [17,24,25]. Due to the high density and pressure of He trapped in the nanobubbles [24][25][26][27], the He-charged Si films have been proposed as "solid-targets" for nuclear reaction studies in our previous works [28][29][30][31][32][33].…”