Simulated response of multilayer x‐ray reflectors to damaging fluxes

A computer code ROMULS has been developed which computes the x‐ray reflectivity versus angle versus time response of multilayer x‐ray reflectors exposed to damaging, monochromatic, x‐ray fluxes for short pulse applications. The code employs exponential x‐ray absorption, hydrodynamic and thermodynamic modeling of structural and individual layer damage, and recursive calculation of the multilayer reflectivity. Comparison of simulations and experiments indicates that the code underestimates the useful life of multilayers by about a factor of 2. Simulations require approximately 1 min of MicroVAX II CPU time per multilayer layer pair per nanosecond of simulated time.