The device 17, wherein {HEAD ~ the downstream optical system} comprises {TAIL ~ an illumination optical system} of an X ray exposure apparatus 
comprises
The device 17 , wherein { HEAD ~ the downstream optical system } comprises { TAIL ~ an illumination optical system } of an X ray exposure apparatus
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH