Interaction of VUV-FEL radiation with B4C and SiC at 32nm wavelength

The output fluence and pulse duration of XFELs such as LCLS and TESLA will pose significant challenges to the optical components which may be damaged by the XFEL beam [1]. It is expected that low-atomic-number materials such as SiC, B4C, and diamond exhibit weak absorption and therefore are damaged least. It has been suggested that the fundamental damage mechanism that determines the fluence damage threshold for single-shot exposures is thermal melting of the materials [2]. For multiple-shot exposures, the damage threshold is potentially lower than the melt threshold due to fatigue effects associated with mechanical stresses during to thermal cycling [3]