Do superconductivity alters the X-ray transparency of a material?
If i remember correctly, conducting materials are opaque to EM radiation because the EM field interacts with the free electrons, losing energy during this process, and so the field gets weaker (attenuated) as it enters the material. If it were thick enough, we can say (almost) no EM radiation passes through it. Also, the more conducting the material, more attenuated the EM radiation is. So, we would conclude that a superconductor, which has zero resistivity, would be a perfect shield for EM radiation.
But if i remember correctly, this effect somehow stops working at very high frequencies (like X-rays or gamma rays), because the electrons are not "fast enough" to interact (and thus to absorb energy) from the EM radiation, and so it passes through the material as if were transparent.
So, my question is, do this also happens with a superconductor? Is it as transparent to X-rays as it would be if it were not a superconductor?