OVERVIEW As high velocity ions pass through an integrated circuit semiconductor die they produce a large number of electrons and holes that carry currents within these devices. One hole-electron pair is formed for every 3.6 eV of energy deposited in the semiconductor during the collision. The proper functioning of the semiconductor die relies upon controlling the currents flowing through the device by carefully regulating the available electrons and/or holes. If a large number of hole-electron pairs are introduced in sensitive regions like memory cells, it can alter the information stored in the computer and produce false commands. Non-mission-critical circuits may continue to function with false information. Nonetheless, it can be destructive if impacts happen in control systems or guidance circuits. Control systems can be switched into an undesired mode for which there is no reset option (called latch-up, worse than the blue screen of death), circuits may be burned out, and even worse effects can occur if propulsion or spacecraft positioning systems are involved. In addition, these impacts degrade the semiconductor material, limiting their useful on-orbit lifetime. What follows is a cursory view of this subject with a list of data sources and facilities in the below pages. Space Radiation Radiation Sources Radiation Test Data/Facilities Guide to Eight Disciplines DIE & WAFER MEMORY SPECIALISTS Copyright 2000-2008 Die Delivery and Services