Possibility of Influence of Anti-Neutrino Incidence on Beta Decay

Nuclear reactors generate a large quantity of high-levelnuclear waste such as fission products. It is important to transform the high-level nuclear waste into short-lived or stable nuclei. The anti-neutrinos from nuclear reactors may be usable for controlling the beta decay of radioisotopes through the weak interaction in future. To study this possibility we attempted to make imperfect the self-shielding of anti-neutrinos emitted from a nuclear reactor, and to irradiate them to a radioisotope to observe the influence on beta decay. An apparatus was constructed to modulate anti-neutrinos with ultrasonic wave in magnetically shielded circumstances. To study the fluctuation of beta decay rate, we measured gamma-rays from the radioisotope with a germanium detector. The full-energy peak counts in the gamma-ray spectrum were obtained, and the change in the beta disintegration rate was investigated. Although an anomaly in decay rate deviating from the exponential decay was observed to statistically meaningful degree, further experiments are required to study the reproducibility.