Several hours later, Chen Chen stood outside the institute's X-ray room, flipping through the X-ray films in his hands.
Most of the films were completely blank. A few showed only a tiny, densely packed dot, easy to miss if you weren't paying attention.
These X-ray films showed what the STEM chips looked like under X-rays.
X-rays were a form of electromagnetic radiation. Their wavelengths covered a broad range from 0.001 nm to 10 nm, placing them between ultraviolet rays and gamma rays on the electromagnetic spectrum, with corresponding energies ranging from 125 eV to 125 keV.
People working in related fields often referred to X-rays with wavelengths of 0.001–0.1 nm as hard X-rays, and those above 0.1 nm as soft X-rays.
Based on the proportion of X-rays that could penetrate carbon, soft X-rays with wavelengths above roughly 0.2 nm could reveal diamond-like substances more than 3 mm thick. The STEM's core processor was a diamond-like crystal measuring 3 mm in diameter.
The X-rays used in security screening were also low-energy soft X-rays, so in principle, an implanted chip would be visible.
What surprised Chen Chen, however, was that the STEM chip's motherboard was made from a special biocompatible material that could integrate with the human body.
In other words, even if someone with an implanted chip had an X-ray taken, only the chip's core processor would show up. The traces of its motherboard would be very difficult to detect.
And given that the core processor was no bigger than a sesame seed, it would be practically invisible unless someone deliberately looked for it.
It really was a high-tech chip from the future. They had even thought of that.
Chen Chen marveled silently. As it turned out, this was to his advantage. The chip's concealment would be reasonably secure even during