RAY-TRACING STUDIES OF A COMPLETE PLANE GRATING MONOCHROMATOR BEAM LINE

Optical design of a plane grating monochromator beam line for X-ray sp ectroscopic studies to be installed on INDUS-1 is studied using ray tr acing technique. The main components of the beam line are pre- and pos t-elliptical mirrors and the plane mirror-grating dispersing system. T he ideal positions of the optical components are decided by using our analytical formulation of the Riemer's kinetic principle for reflectin g synchrotron radiation onto the same spot of the dispersing grating. The program is developed indigenously and can be used on a PC. The tan gent error and microroughness of the mirrors is explicitly accounted f or in the program. The wavelength dependent absorption of radiation at the different reflecting surfaces is also included for calculations o f the optical throughput. The dependence of the final image line shape and resolution on various beam line parameters is calculated. The res ults are useful in deciding the tolerances of the various beam line co mponents and their positions.