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

Abstract

Phosphor screens find application in many fields because of their ability to convert incident radiation to wavelengths that are readily measured by modern detectors. While the response of such screens in the X-ray region has been widely studied, much work still remains to be done regarding their response in the vacuum ultraviolet and soft X-ray regions, where the response is predicted to be nonlinear owing to the presence of elemental absorption edges. Here, an experiment using synchrotron radiation to determine the response of thin Y3Al5O12:Ce (1-21 mg cm-2) and Y2O3:Eu (2.64 mg cm-2) powder phosphor screens in the spectral range 20-900 Å (13.8-620 eV) is reported. Also, a custom-built camera is described which permits simultaneous collection of the forward-and backward-emitted light and that enables measurements to be made at various positions across the screens and at several screen/incident beam angles. Finally, features in the response spectra are identified, and efficiencies across the spectral range indicated for different screen thicknesses and operating modes are plotted, before a curve of the intrinsic radiant efficiency of Y3Al5O12Ce is produced. The results are discussed in the context of other measurements.