Positioned within the casing 52 is {TAIL ~ a main optical housing} 56, {HEAD ~ a detector dewar} 58, a scanner 60, an imager housing assembly 62, switching motor mechanism 64 and the reflecting assembly switching assembly 66 
Positioned within the casing 52 is { TAIL ~ a main optical housing } 56 , { HEAD ~ a detector dewar } 58 , a scanner 60 , an imager housing assembly 62 , switching motor mechanism 64 and the reflecting assembly switching assembly 66
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