An enhanced low dose rate effect (ELDRE) was observed in the radiation-sensitive field effect transistors (RADFETs) developed by the National Microelectronics Research Centre (NMRC) for a low total accumulated dose of less than similar to 45 Gy in silicon, or 45 Gy(Si). The effect was seen to persist even after similar to 8 days of annealing at room temperature, implying that it was not a transient effect but rather a permanent one. On the other hand, the ELDRE was seen to disappear at high total doses of above similar to 90 Gy(Si). (C) 2007 Elsevier B.V. All rights reserved.