'A' Level Medical Option Questions - X-Rays


The figure below shows the design of an X-ray image intensifier. The main components are labelled A to D.

Name each component and state its purpose in the process of image intensification.

A: scintillator crystal(s)/fluorescent screen

It converts X-ray photons into light photons

B: photocathode

Incident light energy on the photocathose releases electrons. The number of electrons released is proportional to the X-ray intensity

C: anodes

They increase the kinetic energy of the electrons by accelerating them towards their positive charge. The are also positioned to focus the electrons to form an image

D: fluorescent screen

This converts the kinetic energy of the incident electrons into light photons

(Total 8 marks)