Scientists at the University of Massachusetts Amherst have reported new results from Borexino, one of the most sensitive neutrino detectors currently, located deep beneath Italy's Apennine Mountains.
Neutrinos emitted by this chain signify an exclusive tool for solar and neutrino physics, since this is the first complete study of all the components of the pp-chain accomplished by Borexino. These components include not only the pp neutrinos, but others called Beryllium-7 (7Be), pep and Boron-8 (8B) neutrinos.
For past studies of pp, 7B, pep and 8B neutrinos, the team had concentrated on each one separately in directed studies of the collected data in controlled windows of energy. Solar neutrinos stream out of the Sun, at nearly the speed of light, with as many as 420 billion hitting every square inch of Earth's surface per second. But they pass through matter virtually unaffected.
The Borexino instrument detects neutrinos as they intermingle with the electrons of an ultra-pure organic liquid scintillator at the middle of a large sphere enclosed by 1,000 tons of water. Its great depth and multiple enclosed protective layers sustain the core as the most radiation-free medium on the planet.