Standard glass will turn brown or grey when exposed to x-ray radiation which will in time render the lens unusable. Because of this phenomenon, radiation-resistant cerium doped glasses can be used to ensure the longest possible life for lenses for x-ray or synchrotron instrumentation. All Resolve Optics radiation resistant lenses are rated to an accumulative dose of 100,000,000 rad allowing them to remain fully operational for many years
Learn more: https://www.resolveoptics.com/radiation-resistance-what-does-it-mean/
