Radiation Measurement Technologies for Evaluating Soft Errors

Two radiation measurement technologies for estimating and lowering the occurrence rate of “soft errors” are introduced. Radiation such as fast neutrons (generated by cosmic rays) and α-rays (generated by the impurities in materials composing LSIs) cause incorrect operations—known as soft errors—in computer systems. Since soft errors undermine the reliability of mission-critical products such as backbone servers, it is necessary to estimate and reduce their occurrence rate. To enable experimental measurements of neutron and α-ray dose rates, my coworkers and I have developed and utilized a vacuum α-ray tracking method—for measuring the amount of α-rays with high sensitivity—as well as a cosmic ray neutron spectrometer. With these two technologies, it has become possible to measure the radiation dose rate in low-α-ray-emitting materials, which has been impossible until now, and the neutron dose rate in arbitrary environments such as mountainous regions and to estimate the soft error rate accurately. Moreover, these technologies make it possible to select materials with low α-ray emissivity and choose environments with a low neutron dose rate, thereby contributing to improvements in computer system reliability.