Upper limit on the cross section for reactor antineutrinos changing 22Na decay rates
Abstract
In this paper we present results of a long-term observation of the decay of 22Na in the presence of a nuclear fission reactor. The measurements were made outside the containment wall of and underneath the Koeberg nuclear power plant near Cape Town, South Africa. Antineutrino fluxes ranged from ~5*10^11 to 1.6*10^13 cm^-2 s^-1 during this period. We show that the coincidence summing technique provides a sensitive tool to measure a change in the total decay constant as well as the branching ratio between EC and beta+ decay of 22Na to the first excited state in 22Ne. We observe a relative change in count rate between reactor-ON and reactor-OFF equal to (-0.51+/-0.11)*10^-4. After evaluating possible systematic uncertainties we conclude that the effect is either due to a hidden instrumental cause or due to an interaction between antineutrinos and the 22Na nucleus. An upper limit of ~0.03 barn has been deduced for observing any change in the decay rate of 22Na due to antineutrino interactions.
Keywords
Cite
@article{arxiv.1409.6969,
title = {Upper limit on the cross section for reactor antineutrinos changing 22Na decay rates},
author = {R. J. de Meijer and S. W. Steyn},
journal= {arXiv preprint arXiv:1409.6969},
year = {2014}
}
Comments
22 pages, 12 figures, 4 tables. Submitted to Astroparticle Physics on 19 August 2014