Thermal Analysis of the Diamond Compound Refractive Lens

Two dimensional compound refractive lenses (CRL) made out of single crystal diamond have been recently demonstrated [1, 2]. The use of a compound refractive lens is inevitably associated with high x-ray absorption. One of the benefits of diamond as a material for CRLs is its ability to withstand high instantaneous and average heat load. We used the finite element method to simulate thermal effects in the lens. A steady state simulation is done for high average heat load conditions of X-ray free electron lasers and ultimate storage rings. We compare diamond with beryllium, a common material for the x-ray refractive optics, and find that the diamond lens heats up less than equivalent beryllium one at energies above 18 keV. Due to lower thermal expansion coefficient diamond lens can maintain its performance also at lower energy spectrum 10 - 18 keV even though its temperature increase is higher than that of beryllium.