What type of signal conversion occurs in the photocathode of a scintillation detector?

In a scintillation detector, the primary function of the photocathode is to convert incoming photons, typically produced by scintillation events, into an electrical signal. When scintillation material absorbs high-energy radiation, it emits light (photons) in response. The photocathode, which is a component of the detector, is sensitive to this light; when photons strike it, they cause the emission of electrons through the photoelectric effect. This conversion is crucial because the electrical signal produced by the photocathode can then be amplified and processed further to provide data on the radiation detected.

Understanding the photocathode's role in transforming light (photons) into an electrical signal is fundamental in the operation of scintillation detectors. This conversion is critical for detecting the intensity and energy of radiation, ultimately allowing for accurate measurement and analysis in radiation detection applications.

The other types of conversion mentioned—such as electrical to sound, X-ray to light, and light to chemical signals—do not accurately describe the primary function of the photocathode in this context, making the conversion of photon to electrical signal the correct choice.