The ANITA instrument is a radio telescope to detect ultra-high energy cosmic-ray neutrinos from a scientific balloon flying over the continent of Antarctica. ANITA is the first NASA observatory for neutrinos of any kind.
Why Study Neutrinos?
Neutrinos are of great interest to astrophysicist as they are the only particle that can reach earth unattenuated at all energies. This is particularly of interest at high energies where other particles and photons will interact with the photons of the microwave background making them unable to propagate and survive over long astrophysical distances. In other words – if you want to see the ultra-high energy universe, you should view it through the “light” of neutrinos.
How does ANITA Detect Neutrinos?
The ANITA instrument detects these ultra-high energy neutrinos through the Askaryan effect. This effect predicts the production of a coherent radio emission from the cascade of particles produced in a high-energy particle interaction. In other words we’re detecting a ‘snap’ in the radio frequencies caused by the interaction of our ultra-high energy neutrino. In order to detect this radio emission (Askaryan pulses) we need a radio transparent medium for the interaction to occur in – and lots of it since these interactions are rare. Some materials that are radio transparent are salt, sand and ice. We also need a fairly radio quiet area as the Askaryan pulses are very faint signals.
- An Introduction to Neutrino Astronomy - by Dr. John Learned
- A Neutrino Timeline - by Dr. John Learned and Dr. Sandip Pakvasa