Interesting. This is similar to how some X-ray and gamma ray detectors did work or work in astronomy. Because you can't focus with lenses, you use narrow tubes

Interesting. This is similar to how some X-ray and gamma ray detectors did work or work in astronomy. Because you can't focus with lenses, you use narrow tubes (collimators) to only gather the light from a certain region of the sky. Note that most x-ray telescopes use focusing Wolter optics nowadays, consisting of nested shells of reflective material. Collimating optics are also used to detect particles, I believe.