This part of IEC 60749 establishes a procedure for measuring the data retention capability of semiconductor devices with memory when subjected to energetic particles such as alpha radiation. Two tests are described; an accelerated test using an alpha radiation source and an (unaccelerated) real-time system test where any errors are generated under conditions of naturally occurring radiation which can be alpha or other radiation such as neutron. To completely characterize the soft error capability of an integrated circuit with memory, the device must be tested for broad high energy spectrum and thermal neutrons using additional test methods. This test method