X-Ray imaging photostimulable phosphor screen or panel.

摘要

In a method of preparing a phosphor or scintillator layer to become deposited on a support, a vapour depositing step is applied from a crucible unit by heating as phosphor precursor raw materials present in said crucible, a Cs(X,X') matrix compound and an activator or dopant precursor compound, wherein said crucible unit comprises at least a bottom and surrounding side walls as a container for phosphor precursor raw materials present in said crucible in liquefied form after heating said crucible, and wherein said Cs(X,X') matrix compound has a higher vapour pressure than said activator or dopant precursor compound, said method comprising a step of providing said activator or dopant compound in form of a precursor raw material represented by the formula Cs x Eu y X' (x+±y) , wherein x, y and ± are integers, wherein x/y is more than 0.25 and wherein ± is at least 2, wherein X represents Br and wherein X' stands for F, Cl, Br, I or a combination thereof; followed by an annealing step after a vapour depositing step, provided that said annealing step proceeds in an ambient atmosphere after cooling said phosphor or scintillator layer, deposited on said support; and wherein as a result a binderless needle-shaped Cs(X,X'):Eu phosphor or scintillator layer becomes provided, having on top of its needle-shaped phosphors, aligned in parallel, an average ratio of divalent to trivalent europium dopant of more than 1:1; wherein said average ratio decreases to an extent of less than 2% per hour, while being exposed to X-rays having an energy in the range from 1 to 100 keV.