Dose dependent x-ray luminescence in MgF2:Eu2+, Mn2+ phosphors

In MgF2:Mn2+, Eu2+ phosphors, the x-ray excited luminescence from Eu2+ is decreased while the emission from Mn2+ is increased in intensity with the increase of x-ray dose. In MgF2:Mn2+, the luminescence is also increased, and in MgF2:Eu2+, the emission of Eu2+ is also decreased in intensity with the increase of x-ray dose. However, the intensity changes with x-ray dose in the singly doped MgF2:Mn2+ and MgF2:Eu2+ phosphors are much less than those in the doubly doped MgF2:Mn2+, Eu2+ phosphors. The increase of Mn2+ emission in intensity is likely due to the breakdown of the forbidden transition by the defects created by x-ray irradiation. No conversion of Eu2+ ions to Eu3+ ions was observed in MgF2:Eu2+ phosphors during x-ray irradiation. The decrease of Eu2+ emission in intensity in MgF2:Mn2+, Eu2+ must be closely related to the interaction and the energy transfer to Mn2+ ions. The phenomenon observed is potentially interesting for the practical applications for radiation detection, as utilizing the ratio of the two emissions from Mn2+ and Eu2+ for radiation detection is more sensitive and more reliable than using emission intensity change only.