Random Voxel Pattern for Monitoring and Localizing GammaRay

Random Voxel Pattern for Monitoring and Localizing Gamma-Ray Transients Roi Rahin* Ehud Behar, Lee Yacobi, Shlomit Tarem, Luca Moleri * Ramon fellowship – Israel Space Agency

Gamma Ray Bursts ● ● ● Cosmological distances 10 -1000 ke. V photons Isotropic on the sky with no prior warning Transient, up to ~100 seconds Associated with Supernovae and Neutron star mergers

Gamma-ray detectors ● Scintillator crystal – Light emitted on interaction ● Photomultipliers detect light ● Silicon Photomultiplier - new in space applications. Size advantage over Photomultiplier tube

Effective Detector design ● Directionality from relative counts between detectors ● In a compact system, mutual occultation increases positioning accuracy

Simulations ● *MEGAlib The Medium Energy Gamma-ray Astronomy Library. Zoglaur et al. 2006 New Astronomy Reviews, Volume 50, Issue 7 -8, p. 629 -632.

Nano. Satellite detector concepts 4 cm diameter 6 mm Width 2 x 2 x 2 cm cube

Average accuracy – First concepts

Second iteration concepts 1 x 1 x 1 cm cube

Average Accuracy – New concepts Spheroid 50 cube detectors

What if we go larger? Spheroid 50 cube detectors 250 cube detectors

Experiments ● Laboratory experiments to find ideal detector size ● Planned experiment: ○ Complex mask to test simulation results

Summary ● The position accuracy is highly sensitive to the number of detectors ● The sensitivity of individual detectors is less important for accuracy ● The potential position accuracy of larger systems could allow for new science (such as polarization measurement)