Scintillator Crystals

NaI:Tl
Sodium iodide activated by thallium has long been the scintillation standard. NaI:TI has good performance, economical price, high luminescence efficiency, very good spectroscopic performance and no significant self absorption of the scintillation light.

YAP:Ce
Yttrium aluminum perovkite Activated by cerium is fast, mechanically and chemically resistant scintillation material. Mechanical properties enable precise machining and entrance windows can be made with a very thin aluminum layer deposited directly on the entrance surface of the crystal.

YAG:Ce
Yttrium aluminum garnet activated by cerium is fast, mechanically and chemically resistant scintillator. Mechanical properties enable to produce YAG:Ce scintillation screens down to a thickness of 30 �m.

BGO
Bismuth germanate is intrinsic scintillation material with high absorption power. Due to its high effective atomic number and high density, BGO is a very efficient gamma absorber with high photoeffect fraction which results in a very good photo peak to Compton ratio.

Scintillator Data Table

Material Nal:Tl CsI:Tl CaF2:Eu BaF2 BGO YAG:Ce YAP:Ce CSO:Ce
Physical
Chemical Formula Nal CsI:Tl CaF2 BaF2 Bi4(GeO4)3 Y3Al5O12 YAlO3 Gd2SiO5
Density g/cm3 3.67 4.51 3.18 4.89 7.13 4.57 5.37 6.71
Hardness - Moh 2 2 4 3 5 8.5 8.6 5.7
Index of refraction 1.85 1.78 1.44 1.5/1.58 2.15 1.82 1.95 1.85
Crystal Structure Cubic Cubic Cubic Cubic Cubic Cubic Rhombic Monoclinic
Coef. Therm. Exp - PPM 47.5 50 19.5 18.4 70 80-90 40-110 40-120
Melting Point - Co 651 621 1360 1280 1050 1970 1875  
Luminescence
Integrated Light output - % Nal:Tl 100 45 50 20/2 15-20 15 40 20-25
Wavelength of max. emission - nm 415 550 435 325/220 480 550 370 440
Decay constant - ns 230 900 940 630/0.6 300 70 25 30-60
Afterglow - % at 6 ms 0.5-5 <2 <0.3 - <0.005 <0.005 <0.005 <0.005
Radiation length - cm 2.9 1.86 3.05 2.03 1.1 3.5 2.7 1.38
Photon yield @ 300K - 103 pH/MeV 38 52 23 10 2-3 8 10 8-10

Update 06.03.98

[RETURN TO MAIN PAGE]