Antineutrinos for Arms ControlCopyright: © Johannes Bosse
Decades of nuclear power plant operation have produced a large amount of radioactive waste that is foreseen to be stored in long-term geological repositories. This radioactive waste still contains weapongrade nuclides, entailing the risk of proliferation. Verification methods and surveillance techniques should ensure the integrity of these repositories. For the first few hundreds of years the dominant radioactivity of the waste comes from long-lived beta-decaying elements that are emitting antineutrinos in the low-energy region below 5 MeV.
In contrast to the other radiation particles, antineutrinos can only interact via weak force and therefore, they can not be shielded or deflected. That makes them a good candidate for monitoring the radioactive waste. Even though this advantage is also a challenge for designing an appropriate antineutrino detector due to the small interaction cross sections of antineutrinos.
In our project, we are investigating time projection chambers filled with an organic liquid aiming at a full reconstruction of antineutrino events via the inverse beta decay that has a clear signature for the identification. In addition, in the low energy region the direction of the outgoing neutron is strongly correlated to the incoming antineutrinos direction. For this we study to which extent the neutron can be reconstructed by its first few elastic scatterings and how it can be used in separating signal from background events.
Detecting antineutrinos in the low-energy domain is not only useful for monitoring radioactive waste, but also for safeguarding the operation of nuclear reactors. Furthermore, it is also of particular interest in fundamental research, e.g. for the investigation of solar neutrinos and geo-neutrinos. In this project we are working together with the TPC development group of the physics institute IIIB.