A reanalysis of radioisotope measurements of the ${}^9$Be$(\gamma ,n{)}^8$Be cross-section

Abstract

The ${}^9$Be$(\gamma ,n{)}^8$Be reaction is enhanced by a near threshold $1/2^{+}$ state. Contradictions between existing measurements of this reaction cross-section affect calculations of astrophysical r-process yields, dark matter detector calibrations, and the theory of the nuclear structure of ${}^9$Be. Select well-documented radioisotope ${}^9$Be$(\gamma ,n)$ source yield measurements have been reanalyzed, providing a set of high-accuracy independently measured cross sections. A Breit-Wigner fit of these corrected measurements yields $E_R=1738.8\pm 1.9$ keV, ${\Gamma }_{\gamma }=0.771\pm 0.021$ eV, and ${\Gamma }_n=268\pm 15$ keV for the $1/2^{+}$ state. A virtual $1/2^{+}$ state is excluded with 99.3\% confidence.

7 pages, 4 figures, 4 tables

References in corpus (5)

• Dark Matter Search Results from the PICO-60 CF${}_3$I Bubble Chamber
• Astrophysical reaction rate for ${}^9$Be formation within a three-body approach
• Resonance parameters of the first 1/2+ state in 9Be and astrophysical implications
• The virtual-state character of the {9}^Be 1/2^+ state in the {9}^Be(γ,n){8}^Be reaction
• Photodisintegration cross section of ${}^9$Be up to 16 MeV in the $\alpha$ + $\alpha$ + n three-body model

Cited by in corpus (9)

• Measurement of the ionization produced by sub-keV silicon nuclear recoils in a CCD dark matter detector
• Germanium response to sub-keV nuclear recoils: a multipronged experimental characterization
• Measurement of the low-energy quenching factor in germanium using an ${}^{88}$Y/Be photoneutron source
• Measuring the Migdal effect in semiconductors for dark matter detection
• Ionization yield measurement in a germanium CDMSlite detector using photo-neutron sources
• Determining the bubble nucleation efficiency of low-energy nuclear recoils in superheated C${}_3$F${}_8$ dark matter detectors
• Role of resonances in the 8li(p,g)9be capture on reaction rate of the relevant astrophysical synthesis of 9be
• Low-threshold response of a scintillating xenon bubble chamber to nuclear and electronic recoils
• A portable and high intensity 24 keV neutron source based on ${}^{124}$Sb-${}^9$Be photoneutrons and an iron filter