Which dopant is essential in PSP materials?

• A. Europium
• B. Cerium
• C. Neodymium
• D. Gadolinium

Answer: (A)

In PSP materials, the dopant acts as the activator that creates the luminescent centers and trap sites needed to store and later release energy. Europium is the dopant used in the common storage phosphor BaFBr:Eu2+. When exposed to X-rays, energy is trapped in defect sites and Eu2+ centers help form and stabilize these traps. Then, when a reader laser stimulates the plate, the stored energy is released as light from the Eu-related centers, producing the visible signal that encodes the image. Without europium, the material wouldn’t efficiently form the needed storage traps or emit the readout light in the PSP process. Other dopants like cerium, gadolinium, or neodymium appear in other phosphor systems, but they are not the essential activator for PSP materials.