1 Radiation-hardened cameras, or lenses thereof, other than those specified in Dual-Use code 6A203.c., specially designed, or rated as radiation-hardened, to withstand a total radiation dose greater than 50 × 103 Gy (silicon) (5 × 106 rad (silicon)) without operational degradation. 2 In this paragraph, the term Gy (silicon) refers to the energy in Joules per kilogram absorbed by an unshielded silicon sample when exposed to ionising radiation.