Which material is commonly used to convert incoming radiation to a signal in solid-state detector imaging?

• A. Scintillator
• B. Photodiode
• C. Quartz
• D. Lens

Answer: (A)

In solid-state detector imaging, the element that directly turns incoming radiation into a signal is the scintillator. It absorbs high-energy photons (like X-rays or gamma rays) and re-emits that energy as visible light. This light is then sensed by a photodetector, such as a photodiode, which converts the light into an electrical signal. So the scintillator is the material doing the radiation-to-signal conversion. The photodiode only converts light to electricity, not the radiation itself; quartz isn’t a practical scintillator for this purpose, and a lens doesn’t detect radiation at all.