Energy (TOF) and position sensitive detection of ultra cold neutrons with micrometric resolution using the TimePix pixel detector

Ultra-cold neutrons (UCN) are neutrons with very small kinetic energies (below 300 neV). The energy is so low that they are reflected from the surface of many materials under any angle of incidence. These neutrons can be thus trapped by an effective Fermi potential and stored inside material “bottles”. Recently bound quantum states of neutrons in the earth’s gravitational field have been observed with UCN. A detector with spatial resolution of around 1 μm is required to be able to resolve such individual states. Being uncharged and having very low energy, ultra-cold neutrons cannot be detected in the silicon pixel detector directly but can be converted into charged particles in a thin layer deposited onto the sensor surface.