High-energy particle telescopes
Advanced technology is pushing back the boundaries of high-energy astronomy
The limits of radio and optical telescopes have led scientists in exciting new directions in order to capture and decode natural signals from distant galaxies. One of the most notable is the X-ray telescope, which differs in its construction thanks to the inability of mirrors to reflect X-ray radiation, a fundamental necessity in all reflection-based telescopes. In order to capture X-ray radiation, instead of being directly reflected into a hypersensitive receiver for amplification and decoding, it is acutely reflected a number of times, changing the course of the ray incrementally each time. To do this a telescope must be built from several nested cylinders with a parabolic or hyperbolic profile, guiding rays into the receiver.
Crucially, all X-ray telescopes must be operated outside of Earth’s atmosphere, as it is opaque to X-rays. They must be mounted to high-altitude rockets or artificial satellites. Examples of orbiting X-ray telescopes include NASA’S Chandra X-ray Observatory and NUSTAR, a Small Explorer mission.
Other high-energy particle telescopes include gamma-ray telescopes, which study the cosmos through the gamma rays emitted by stellar processes, and neutrino telescopes, which detect the electromagnetic radiation formed as incoming neutrinos create an electron or muon –an unstable subatomic particle – when coming into contact with water.
Because of this, neutrino telescopes tend to consist of submerged phototubes – a gas-filled tube especially sensitive to ultraviolet and electromagnetic light – in large underground chambers to reduce interference from cosmic rays. The phototubes act as a recording mechanism, storing any Cherenkov radiation emitted from the interaction of the neutrino with the electrons or nuclei of water. Then, using a mixture of timing and charge information from each of the phototubes, the interaction vertex, ring detection and type of neutrino can be detected.