Investigation of neutron-induced backgrounds in isotopes of interest for 0νββ decay searches*

Even deep underground, neutron-induced reactions can occur in all components of detectors searching for rare events, such as neutrinoless double-beta (0νββ) decay.  The isotopes ⁷⁶Ge, ¹⁰⁰Mo, ¹³⁰Te, and ¹³⁶Xe are all in current or planned 0νββ-decay searches.  Additionally, even enriched detectors made from these isotopes may include other nuclides, such as ^95,97Mo or ¹³⁴Xe.  For ¹³⁶Xe (Q_ββ=2457.8 keV), a recently-discovered level in ¹³⁴Xe by Peters et al. [1] decays with the emission of a 2485.7 keV gamma ray.  For ¹³⁰Te, (Q_ββ=2527.5 keV), a neutron-induced excitation of the 2527.1 keV state was investigated.  In ¹⁰⁰Mo (Q_ββ=3034.4 keV), a nuclear level with energy 3039.4 ± 1.0 keV cascades to the ground state.  The isotopes ⁹⁵Mo and ⁹⁷Mo also have energy levels that lie within the region of interest:  3037 keV and 3035 keV respectively.  Finally, ⁷⁶Ge (Q_ββ=2039.1 keV) has a nuclear level at 3951.9 keV that has been reported to emit a 2040.7 keV gamma ray, but which was not observed in studies by Crider et al. [2].  Here, we will report our results from our cross-section measurements of neutron inelastic scattering (n,n'γ) on ^134,136Xe and ¹³⁰Te, and we will update our initial results from our investigation of gamma-ray cascades resulting from n,n'γ on ^natMo and ⁷⁶Ge.  

[1] E.E. Peters, et al., EPJ Web of Conferences, 93, 01027 (2015).

[2] B.P. Crider, et al., EPJ Web of Conferences, 93, 05001 (2015).