Published online by Cambridge University Press: 21 February 2011
The journey of YAP from interesting laboratory curiosity to a material with commercial possibilities has taken two full decades. The reported YAP properties which motivated this effort are its rapid (~ 27 ns) dominant (~ 97%) decay which results in negligible afterglow; high density (~ 5.55 g/cm3); brightness (~ 50% of NaI:Tl); energy resolution (~ 6% at 455 keV); physical ruggedness; and chemical nonreactivity. Lone among its draw backs as a practical scintillator is its emission which is centered in the UV (~ 350 nm). Three firms now offer YAP crystals of sufficient size and quality that industrial applications are becoming possible.
To date, the physical properties of YAP have only been published on small laboratory samples. Here we report a comprehensive and comparative evaluation of physical properties of material from all known commercial sources. Further, we speculate on the physical origin of variations among samples. Finally, we attempt to predict what can ultimately be expected from YAP as further refinements in its processing techniques are perfected.