PMT array is attached to the _______________

PMT array is attached to the _______________

• A. Back of crystal/light pipe
• B. Front of crystal
• C. External housing
• D. Side of detector

Answer: (A)

Photodetectors like PMTs are placed at the end of the scintillating crystal (often with a light guide) so they can efficiently collect the light that the crystal emits after a gamma interaction. The light produced inside the crystal travels via total internal reflection toward the far end, where the PMT array is optically coupled. Attaching the PMT to the back of the crystal or through a light pipe maximizes light collection, preserves the crystal’s face for gamma entry, and keeps the detector compact. Placing the PMT on the front would interfere with the incoming radiation and distort light collection, while mounting it on the external housing or the side would not provide as direct or efficient optical coupling to the scintillation light.

Photodetectors like PMTs are placed at the end of the scintillating crystal (often with a light guide) so they can efficiently collect the light that the crystal emits after a gamma interaction. The light produced inside the crystal travels via total internal reflection toward the far end, where the PMT array is optically coupled. Attaching the PMT to the back of the crystal or through a light pipe maximizes light collection, preserves the crystal’s face for gamma entry, and keeps the detector compact. Placing the PMT on the front would interfere with the incoming radiation and distort light collection, while mounting it on the external housing or the side would not provide as direct or efficient optical coupling to the scintillation light.