The Nuclear Compton Telescope (NCT) is an R&D project funded by NASA, its goal is to develop a high-resolution Compton telescope for nuclear astrophysics. The PI institute of NCT is the Space Science Laboratory (University of California Berkeley). NCT is designed to study astrophysical sources of gamma-ray emission in the 200 keV - 10 MeV energy range, with high spectral resolution (E/∆E 500), moderate angular resolution (2 degrees), and sensitivity to gamma-ray polarization.

The last long duration balloon flight was planned in 2008-2009. The heart of NCT is an array of cross-strip germanium detectors with full 3D position localization of photon interactions (resolution < 2 mm3). These detectors were surrounded by an anticoincidence shield made of bismuth germanate (BGO) and an active collimator made of cesium iodine (CsI). The NCT’s team in IRAP was in charge of providing the CsI collimator and the BGO shield electronics.


CsI scintillators of the NCT’s collimator

The next balloon flight of NCT is planned for spring 2014 from the South hemisphere to observe the central regions of our Galaxy (positron annihilation emission, gamma ray line from the decay of 26Al nuclei produced by massive stars,...) and Active Galactic Nuclei (Cen A, 2C273). For this flight, IRAP is in charge of the development of a new electronic box that analyzes the signals from the active shield, with a financial support from the CNES.

The in-flight performance of the NCT will validate the feasibility and the gain in sensitivity that could be achieved by a Compton Telescope in space for a next generation of gamma-ray observatory (e.g. Advanced Compton Telescope project - The scientific objectives of such an observatory include : study of galactic nucleosynthesis (supernovae, novae, massive stars), origin of galactic positrons, observation of cosmic-ray interactions with the interstellar medium, physics of compact objects (black-holes, neutron stars, AGN, blazars) and gamma-ray bursts.

Complementary information :

Contact : P. Jean (Professor)

IRAP Team : P. von Ballmoos (Professor), P. Mandrou (Engineer), G. Rouaix (Engineer), V. Waegebaert (Engineer), G. Roudil (Technician)

External collaborators : S. Boggs (Assistant Professor — PI of NCT)

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