Simulation and minimization of thermal deformation of mirrors in a resonator of free electron laser

A simulation code for thermal deformation of axisymmetric optical mirrors has been developed. It was found that the curvature of a mirror is conserved while heating, if its sizes are optimal. Optimization of the mirrors of BINP high-power FEL was considered. In the first-stage FEL optimization is useful, although the existing mirrors are useable. In the full-scale machine the optimized mirrors have better thermal durability compared to non-optimal ones.