Reconstructed track from Cs-137!
What you can see in the pictures is an electron produced by the interaction of a 660 keV gamma from a Cs-137 radioactive source. The colour codes energy and the trajectory has been reconstructed with our new SiPM plane, the first optical-pixel tracking system in the field. Clearly visible is the random walk of the electron (due to multiple scattering) while depositing a constant amount of the energy (electron behaves like a mip for most of the trajectory). When the electron ranges out, a blob of energy, coded in red in the 3D projection is formed, giving the tell-tale signature of the electron (wire+blob, or spaghetti + ball). Notice that the signature for a bb0nu event would have two blobs (due to the two electrons ranging in the gas) providing a distinctive signature of the decay.