Crystals

Since the central Bragg angle range of the x-ray spectrometer is from 24.4 deg to 61.1 deg, several different crystals are needed to cover the 0.547 keV to 16.8 keV energy range. The crystal laminae (5 cm wide, 10 cm high and 0.2-1 mm thick ), permanently glued to an aluminum block machined to a precise concave cylindrical surface, have a nominal radius of 25.4 cm.

       Crystal      2d[Å]               Energy range [keV]

TlAP(001)    25.900                0.547 - 1.160

ADP(101)    10.642                1.315 - 2.849

SiO₂(110)    8.5096                1.645 - 3.563

LiF(200)      4.0280                3.475 - 7.528

Ge(220)      4.0004                3.540 - 7.502 

 Si(220)       3.8401                3.688 - 7.815 

 SiO₂(223)    2.7500                5.090 - 11.026

 LiF(420)      1.8010                7.772 - 16.836