A Neutrino Beacon
A. A. Jackson (2020), JBIS, 73, pp.15-20
Keywords: Neutrinos, Gravitational Lens, SETI
Observational SETI has concentrated on using electromagnetism as the carrier, namely radio waves and laser radiation. Michael Hippke  has pointed out that it may be possible to use neutrinos or gravitational waves as signals. Gravitational waves demand the command of the generation of very large amounts of energy, Jackson and Benford . This paper describes a beacon that uses beamed neutrinos as a carrier for a signal. Neutrinos, like gravitational waves, have the advantage of extremely low extinction in the interstellar medium. To make use of neutrinos an advanced civilization can use a gravitational lens as an amplifier. The gravitational lens can be a neutron star or a black hole. Using wave optics one can calculate the advantage of gravitational lensing for amplification of a beam and along the focal axis , it is exceptionally large. Even though the amplification is very large the diameter of the beam is quite small, less than a centimeter. This implies that a large constellation of neutrino transmitters would have to enclose a local neutron star or black hole lens to make an approximate isotropic radiator. The operational energy needed is about .01 Solar, this means that such a beacon would have to be built by a Kardashev Type II civilization.