ASTM E668-05

Absorbed dose in a material is an important parameter that can be correlated with radiation effects produced in electronic components and devices that are exposed to ionizing radiation. Reasonable estimates of this parameter can be calculated if knowledge of the source radiation field (that is, energy spectrum and particle fluence) is available. Sufficiently detailed information about the radiation field is generally not available. However, measurements of absorbed dose with passive dosimeters in a radiation test facility can provide information from which the absorbed dose in a material of interest can be inferred. Under certain prescribed conditions, TLDs are quite suitable for performing such measurements.

Note 2—For comprehensive discussions of various dosimetry methods applicable to the radiation types and energy and absorbed dose-rate range discussed in this practice, see ICRU Reports 14, 17, 21, and 34.

1.1 This practice covers procedures for the use of thermoluminescence dosimeters (TLDs) to determine the absorbed dose in a material irradiated by ionizing radiation. Although some elements of the procedures have broader application, the specific area of concern is radiation-hardness testing of electronic devices. This practice is applicable to the measurement of absorbed dose in materials irradiated by gamma rays, X rays, and electrons of energies from 12 to 60 MeV. Specific energy limits are covered in appropriate sections describing specific applications of the procedures. The range of absorbed dose covered is approximately from 10² to 10 ⁴ Gy (1 to 10⁶ rad), and the range of absorbed dose rates is approximately from 10² to 10¹⁰ Gy/s (1 to 10¹² rad/s). Absorbed dose and absorbed dose-rate measurements in materials subjected to neutron irradiation are not covered in this practice. Further, the portion of these procedures that deal with electron irradiation are primarily intended for use in parts testing. Testing of devices as a part of more massive components such as electronics boards or boxes may require techniques outside the scope of this practice.

Note 1—The purpose of the upper and lower limits on the energy for electron irradiation is to approach a limiting case where dosimetry is simplified. Specifically, the dosimetry methodology specified requires that the following three limiting conditions be approached: (a) energy loss of the primary electrons is small, (b) secondary electrons are largely stopped within the dosimeter, and ( c) bremsstrahlung radiation generated by the primary electrons is largely lost.

1.2 This standard dose not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.