YAP:Ce is a high density (5.5 g/cm 3 ) oxide crystal with a decay time about 10 times shorter than NaI(Tl). It is used in detectors for high count rate (up to several MHz) X-ray spectrometry. The non-hygroscopic nature of this material allows the use of thin mylar entrance windows and guarantees a long lifetime of the detector.

Physical Properties:

Density	-	5.55 g/cm3
Emission Max	-	350 nm
Decay Constant	-	27 µs
Refractive index	-	1.94
Conversion Effency	-	35-40
Hydroscopic	-	No