In an intensification tube, which element absorbs electrons and emits light photons?

In an intensification tube, the element that absorbs electrons and emits light photons is the output phosphor. When the tube is in operation, the input phosphor initially converts incoming X-ray photons into visible light. This visible light then causes photoelectrons to be emitted from the photoemissive layer, which are directed towards the output phosphor.

Once these photoelectrons reach the output phosphor, they interact with it and are absorbed, resulting in the emission of light photons. This process significantly amplifies the energy of the initial X-ray exposure, allowing for better visibility in imaging applications. The efficiency and effectiveness of the output phosphor in converting electron energy to light are crucial for improving image quality in fluoroscopy.

Other elements listed have different roles. The accelerating anode helps in directing the flow of electrons from the cathode to the output phosphor, the electrostatic lens focuses the electron beam, and the input phosphor converts X-rays into visible light but does not directly emit light photons from electron absorption.