A study of the response of Y3Al5O12 : Ce phosphor powder screens in the vacuum ultraviolet and soft X-ray regions using synchrotron radiation

Phosphor screens rnd application in many fields because of their ability to convert incident radiation to wavelengths that are readily measured by mod ern detectors. While the response of such screens in the X-ray region has b een widely studied, much work still remains to be done regarding their resp onse in the vacuum ultraviolet and soft X-ray regions, where the response i s predicted to be nonlinear owing to the presence of elemental absorption e dges. Here, an experiment using synchrotron radiation to determine the resp onse of thin Y3Al5O12:Ce (1-21 mg cm(-2)) and Y2O3:Eu (2.64 mg cm(-2)) powd er phosphor screens in the spectral range 20-900 Angstrom (13.8-620 eV) is reported. Also, a custom-built camera is described which permits simultaneo us collection of the forward- and backward-emitted light and that enables m easurements to be made at various positions across the screens and at sever al screen/incident beam angles. Finally, features in the response spectra a re identified, and efficiencies across the spectral range indicated for dif ferent screen thicknesses and operating modes are plotted, before a curve o f the intrinsic radiant efficiency of Y3Al5O12:Ce is produced. The results are discussed in the context of other measurements.