3
64 8 16
2 2 1
7.34
C
Gadolinium Oxysulfide is used as phosphor in screen-film combinations.
The phosphor is doped with Tb. The density of the crystal is 7.34 g/cm^3
and its thickness is 100 um (taken from B.A. Arnold, 
Physical Characteristics of Screen-Film Combinations in AAPM Physics
of Medical Imaging, 1979). The coating weight: 0.14 g/cm^2
(Yip et al. SPIE 2432, 33-52). Venema at Radiology 130:765 (1979)
reports 0.105 g/cm^2. 
