The ''Nuclear Compton Telescope'' (NCT) is a balloon-borne Compton telescope to observe the

gamma-ray A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists ...

sky in the energy range from a few hundred keV to several MeV. Its main goals are to improve the understanding of Galactic

nucleosynthesis Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons (protons and neutrons) and nuclei. According to current theories, the first nuclei were formed a few minutes after the Big Bang, through nuclear reactions in ...

gamma-ray bursts In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme electromagnetic emissions are second o ...

supernovae A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion. The original ob ...

black holes A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...

, and more.

Instrumentation

The Compton telescope uses an array of twelve Germanium detectors with high spectral resolution to detect gamma rays. On its bottom half the detector is surrounded by a

Bismuth germanate Bismuth germanium oxide or bismuth germanate is an inorganic chemical compound of bismuth, germanium and oxygen. Most commonly the term refers to the compound with chemical formula (BGO), with the cubic crystal, cubic evlitine crystal structure, ...

scintillator to shield it from atmospheric gamma rays. The telescope has an overall

field of view The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to elec ...

(FOV) of 25% of the sky.

Flights

Since low-to-medium-energy gamma rays are only detectable from above the atmosphere, NCT is launched with a large Helium balloon into the stratosphere. So far NCT had two successful and one unsuccessful balloon campaigns: * A two-detector prototype was successfully test flown on 1 June 2005 from the Scientific Balloon Flight Facility,

Fort Sumner Fort Sumner was a Fortification, military fort in New Mexico Territory charged with the internment of Navajo and Mescalero, Mescalero Apache populations from 1863 to 1868 at nearby Bosque Redondo. History On October 31, 1862, Congress of the ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

. * On 19 May 2009, the full instrument successfully launched from Fort Sumner in New Mexico and was able to observe the

Crab pulsar The Crab Pulsar (PSR B0531+21 or Baade's Star) is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054.

. * Unfortunately, on 28 April 2010 a launch mishap occurred at

Alice Springs Alice Springs () is a town in the Northern Territory, Australia; it is the third-largest settlement after Darwin, Northern Territory, Darwin and Palmerston, Northern Territory, Palmerston. The name Alice Springs was given by surveyor William ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, when the gondola release mechanism failed, leading to the partial destruction of the gondola.

References

{{reflist Telescopes