l., 2018; Khimchenko et al., 2016). The interaction of x-rays with the object is described by the continuous complex-valued index of refraction n⁢(𝐫)=1-δ⁢(𝐫)+i⁢β⁢(𝐫). Phase contrast capitalizes on the fact that for hard x-rays, the real-valued decrement δ is several order