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by roywiggins 1240 days ago
There are gamma-ray detectors that can determine direction:

> The LAT detects gamma rays by using Einstein’s famous E = mc2 equation in a technique known as pair production. When a gamma ray, which is pure energy, slams into a layer of tungsten in the detector, it can create a pair of subatomic particles (an electron and its antimatter counterpart, a positron). The direction of the incoming gamma ray is determined by projecting the direction of these particles back to their source using several layers of high-precision silicon tracking detectors.

https://fermi.gsfc.nasa.gov/

https://www.nasa.gov/pdf/221503main_GLAST-041508.pdf