HALO (the helium and lead observatory) uses lead blocks and helium to detect neutrinos. When a neutrino hits lead, it creates neutrons. These neutrons are then recorded by the helium neutron detectors in HALO, creating a signal in the data.
Did you know?
HALO is part of SNEWS (the supernova early-warning system), a group of detectors around the world that alert astronomers to supernovae so they can view them with telescopes.
The lead in HALO came from a cosmic ray experiment at Chalk River Laboratory.
Most supernova neutrino detectors are only sensitive to one flavour of neutrinos, but HALO is sensitive to all three (elecron, muon, and tau).
Photos of HALO
HALO detector with lead shielding blocks on either side and above.
Four tubes of He3 serve as neutron detectors for HALO.
HALO electronics, left, and detector, right.
Lead tube in HALO. These lead tubes were originally used in SNO.