Analysis of Neutron-induced Backgrounds in ¹⁰⁰Mo for 0νββ study

In some isotopes, single beta decay (β−) is suppressed due to energy constraints. In such cases, Two Neutrino Double Beta Decay (2νββ), where two neutrons transform into two protons while emitting two electrons and two anti-neutrinos, becomes the dominant decay mode:

(Z, A) → (Z+2, A) + 2e⁻ + 2νˉe

However, in Neutrinoless Double Beta Decay (0νββ), the two neutrinos are not emitted:



(Z, A) → (Z+2, A) + 2e^-

This process is possible only if neutrinos are Majorana particles, implying lepton-number violation by two units and providing a potential explanation for the matter–antimatter imbalance in the universe. In double beta decay experiments, neutron-induced backgrounds can interfere with or mimic the detection signal. A major source arises from inelastic neutron scattering, where a fast neutron excites a nucleus that de-excites by emitting γ-rays. By measuring and analyzing neutron-induced γ-ray backgrounds in natural molybdenum, we can assess their impact and develop strategies for suppression in searches for 0νββ decay. These measurements were performed using 4.5 MeV-neutrons produced at TUNL in the shielded source area. We examined an ROI of ±5 keV around the 3034 keV Q-value and identified 3 potential candidates. We will report progress on the analysis of the neutron inelastic scattering on ^{95, 97}Mo, and ¹⁰⁰Mo.