Instrumentation for the MeV Domain

Dr. Andreas Zoglauer

University of California at Berkeley

Designing instrumentation to detect gamma-rays in the MeV domain is a challenging task. First, the energy range is dominated by two different interaction mechanisms, Compton scattering and pair creation. Second, different science goals (such as line vs. continuum emission, polarization detection, transient detection, overall energy range) benefit from different detector design optimizations. Furthermore, low interaction cross sections, energy losses in passive material, several noise effects such as Bremsstrahlung and Rayleigh scattering, and high instrumental background especially in the Compton regime are additional challenges.

A plethora of detector concepts have been developed over the last decades covering a wide range of detector technologies and detector materials (various semi-conductors, scintillators, gases, etc.) with different optimizations to achieve their science goals and different adaptations to overcome the challenges in the MeV domain. The most promising candidates to cover the whole MeV energy band are combined Compton-scattering and pair-creation telescopes such as AMEGO and e-ASTROGAM. These employ a Silicon-based detector sub-system to track the created electron-positron pairs and the Compton recoil electrons, as well as a calorimeter to stop all secondaries. Other instrument concepts specialize either on the Compton energy range such as COSI, SMILE, and ASCOT, or on the pair regime such as Gamma-400 and AdEPT.

In the presentation, we will give an overview of the existing detector concepts for the MeV domain, focusing on the various trade-offs and adaptations these concepts make to achieve their science goals and to overcome the challenges in the MeV domain.