Experimentally constrained ${}^{165,166}\text{Ho}(n,\gamma )$ rates and implications for the $s$ process

Abstract

The $\gamma$-ray strength function and the nuclear level density of ${}^{167}$Ho have been extracted using the Oslo method from a ${}^{164}\text{Dy}(\alpha ,p\gamma {)}^{167}$Ho experiment carried out at the Oslo Cyclotron Laboratory. The level density displays a shape that is compatible with %can be approximated with the constant temperature model in the quasicontinuum, while the strength function shows structures indicating the presence of both a scissors and a pygmy dipole resonance. Using our present results as well as data from a previous ${}^{163}\text{Dy}(\alpha ,p\gamma {)}^{166}$Ho experiment, the ${}^{165}\text{Ho}(n,\gamma )$ and ${}^{166}\text{Ho}(n,\gamma )$ MACS uncertainties have been constrained. The possible influence of the low-lying, long-lived 6~keV isomer ${}^{166}$Ho in the $s$ process is investigated in the context of a 2~$M_{\odot }$, [Fe/H]=-0.5 AGB star. We show that the newly obtained ${}^{165}\text{Ho}(n,\gamma )$ MACS affects the final ${}^{165}$Ho abundance, while the ${}^{166}\text{Ho}(n,\gamma )$ MACS only impacts the enrichment of ${}^{166,167}$Er to a limited degree due to the relatively rapid $\beta$ decay of the thermalized ${}^{166}$Ho at typical $s$-process temperatures.

11 pages, submitted to Physical Reviews C

References in corpus (8)

• The r-process of stellar nucleosynthesis: Astrophysics and nuclear physics achievements and mysteries
• Analysis of possible systematic errors in the Oslo method
• Databases and tools for nuclear astrophysics applications BRUSsels Nuclear LIBrary (BRUSLIB), Nuclear Astrophysics Compilation of REactions II (NACRE II) and Nuclear NETwork GENerator (NETGEN)
• Large-scale deformed quasiparticle random-phase approximation calculations of the $\gamma$-ray strength function using the Gogny force
• The SiRi Particle-Telescope System
• Quasicontinuum $\gamma$-decay of ${}^{91,92}$Zr: benchmarking indirect ($n,\gamma$) cross section measurements for the $s$-process
• Statistical properties of the well deformed ${}^{153,155}$Sm nuclei and the scissors resonance
• Indirect measurement of the $(n,\gamma {)}^{127}$Sb cross section

Cited by in corpus (1)

• Possible existence of pygmy dipole resonance built on excited states in a neutron-rich ${}^{80}$Ge nucleus