I used to have to work with transistors backed with BeO (beryllium oxide) ceramic. A very scary material, inhaling the dust once can cause a lung condition for

I used to have to work with transistors backed with BeO (beryllium oxide) ceramic. A very scary material, inhaling the dust once can cause a lung condition for life. It is second behind diamond in terms of electrical insulator, thermal conductor. https://en.wikipedia.org/wiki/Beryllium_oxide https://en.wikipedia.org/wiki/Beryllium_oxide