Standard Test Method for Application of Ionization Chambers to Assess the Low Energy Gamma Component of Cobalt-60 Irradiators Used in Radiation-Hardness Testing of Silicon Electronic Devices

Importancia y uso:

4.1 Although Co-60 nuclei only emit monoenergetic gamma rays at 1.17 and 1.33 MeV, the finite thickness of sources, and encapsulation materials and other surrounding structures that are inevitably present in irradiators can contribute a substantial amount of low-energy gamma radiation, principally by Compton scattering (1, 2).3 In radiation-hardness testing of electronic devices this low-energy photon component of the gamma spectrum can introduce significant dosimetry errors for a device under test since the equilibrium absorbed dose as measured by a dosimeter can be quite different from the absorbed dose deposited in the device under test because of absorbed dose enhancement effects (3, 4). Absorbed dose enhancement effects refer to the deviations from equilibrium absorbed dose caused by non-equilibrium electron transport near boundaries between dissimilar materials.

4.2 The ionization chamber technique described in this method provides an easy means for estimating the importance of the low-energy photon component of any given irradiator type and configuration.

4.3 When there is an appreciable low-energy spectral component present in a particular irradiator configuration, special experimental techniques should be used to ensure that dosimetry measurements adequately represent the absorbed dose in the device under test. (See Practice E1249.)

Subcomité:

E10.07

Referida por:

F1190-24, F1892-12R18, E1854-19, E1249-15R21

Volúmen:

12.02

Número ICS:

31.020 (Electronic components in general)

Palabras clave:

absorbed dose; Co-60 irradiators; dose enhancement; ionization chamber; radiation hardness testing;