Potential neutron-induced γ-ray background on natural tellurium relevant to 130Te 0νββ decay searches at the CUORE and SNO plus detectors

Gamma-ray production cross-section data have been obtained for the inelastic neutron scattering reactions Te-126,Te-128,Te-130(n, n'gamma) at five neutron energies between 3.6 and 10 MeV. We report data for the gamma-ray energy region relevant to 0 nu beta beta decay of Te-130 with a Q(beta beta) value of 2527.515 keV, assuming natural-abundance tellurium, as used at CUORE and SNO+. The natural abundance of Te-130, Te-128, and Te-126 is 34%, 32%, and 19%, respectively. For CUORE the gamma-ray cascades from the excited state in Te-130 at 2527.06 keV and in Te-126 at 2533.85 keV are of concern. For SNO+, accounting for its inferior energy resolution, an additional four levels are important in Te-130, an additional nine levels in Te-128, and an additional eight levels in Te-126. Of these, we report neutron-induced gamma-ray production cross sections for the strongest transitions: the 2581.15 keV level in Te-130, the 2494.20, 2508.06, and 2630.14 keV levels in Te-128, and the 2496.83 and 2585.46 keV level in Te-126. The largest cross-section values were found for cascade gamma-ray transitions to the ground state, while direct transitions to the ground state are very weak and were not observed in the present work. Both the CUORE and SNO+ detectors, however, may not be able to distinguish between cascade transitions and direct transitions to the ground state, making the neutron-induced excitation of the 2527.06 keV state of Te-130 in particular a potential problem for 0 nu beta beta decay searches of Te-130, because it matches its Q(beta beta) value.

Automated summary

Gamma-ray production cross-section data have been obtained for inelastic neutron scattering reactions involving Te-126, Te-128, and Te-130; Specifically, the study highlights potential issues related to 0 nu beta beta decay in Te-130.