KamLAND: Studying Neutrino Oscillation with Reactors

Since the 1950's physicists have been using nuclear reactors to study the properties of anti-neutrinos. In 1956, one of the first such experiments, at the Savannah River Reactor Plant, proved the existence of anti-neutrinos. The original experiment was located only a few meters away from the reactor core, the source of the anti-neutrinos. In the years since, reactor neutrino experiments have steadily increased their baselines, with the goal to test and ultimately establish neutrino disappearance. That goal was reached in 2002, when KamLAND, a one kiloton liquid scintillator detector, reported the first observation of reactor anti-neutrino disappearance at an effective baseline of $\sim$180\,km. KamLAND uses 53 Japanese commercial power reactors as the source of anti-neutrinos. I will discuss KamLAND and present the results of a recently completed analysis of KamLAND data, showing evidence for spectral distortion. Spectral distortion in the neutrino energy is `smoking gun' evidence for neutrino oscillation. I will show that the KamLAND data further solidifies the case for oscillation as the mechanism for neutrino disappearance and give an outlook on future activities at the experiment.