The active phosphor layer used in PSP plates belongs to the Ba fluorohalide family.

• A. True
• B. False
• C. Only partly
• D. Unknown

Answer: (A)

The active layer in PSP plates is europium-doped barium fluorobromide, BaFBr:Eu2+ (with related BaFBrI or BaFI:Eu2+ variants used in some plates). This places it in the Ba fluorohalide family, since the material is a barium-based host lattice containing fluorine and a halide (bromine or iodine) and activated by europium. When x-rays expose the plate, electrons are trapped in the Eu-doped sites, storing the image information. Later, a red laser stimulates the traps, releasing the stored energy as photostimulated luminescence that the reader converts into a digital image. Because the active phosphor is specifically a Ba fluorohalide material, the statement is correct.