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.