TAMBO

TAMBO (for Tau Air Shower Mountain-Based Observatory) is a concept for a neutrino observatory to be located in a deep valley in Peru (Colca Valley), designed to detect high-energy tau neutrinos by detecting and recording air showers within the valley. Tau neutrinos are the least likely of the three neutrino flavors to be detected by existing neutrino observatories, and the TAMBO concept makes use of the location to detect more of them and to detect the direction they came from.

Tau neutrinos are more likely to interact within dense matter (such as rock), an interaction that terminates the neutrino and produces (among other things) a tau particle. These products of the tau neutrino interaction dissipate within a small area, which limits the chance that sensors of a detector will catch them. The resulting tau particle continues along nearly the same trajectory, then decays back into a (slower) tau neutrino after only a short distance. TAMBO is designed to detect the air shower from this latter decay when it occurs within the air of the valley. One of the valley's rock walls provides the high material density to trigger some tau neutrino interactions, some of which will result in a tau particle emerging into the valley, some of which will decay there. A Cherenkov detector (tanks of water serving as scintillators with sensors for photons) on the opposite wall of the valley would sense the air showers. The overall configuration is sensitive to tau neutrinos from one general direction, that happen to interact sufficiently close to the valley (on the order of meters to kilometers) that their resulting tau particles emerge to create an air shower within their limited lifetime. The tau neutrinos this would detect would be Earth-skimming (coming through the Earth from slightly below the horizon). The observatory's effective survey field is extended by the rotation of the Earth.