Energy Distribution
Energy deposited by incident radiation in a material splits into paths that cause ionization and paths that cause atomic displacements. The non-ionizing energy loss represents the rate of energy transfer to the target lattice that results in atomic displacements per unit path length. This parameter is the core metric used to correlate displacement damage effects across different radiation environments.
Damage Calculation
Calculating the cumulative defect density involves multiplying the particle fluence by the energy loss value at each point in the radiation spectrum. The non-ionizing energy loss is analogous to the linear energy transfer used for ionizing radiation, but it excludes the electronic excitation and ionization of atoms. This calculation uses the Lindhard partition function to determine the fraction of energy allocated to atomic movement.
Standard software packages like SRIM can simulate these interactions to calculate the energy transfer rates.
Calibration Standard
Metrological laboratories use the energy loss profiles to scale radiation testing results to a common equivalent dose. The non-ionizing energy loss is typically expressed in kiloelectronvolts squared centimeter per gram or similar units. Calibration foils and dosimetry diodes are deployed during testing to verify that the delivered non-ionizing energy matches the target specification.
Material Variation
The energy deposition rate depends heavily on the atomic mass and crystal structure of the target material. Silicon and gallium arsenide exhibit different displacement thresholds, meaning a particle beam will produce different levels of non-ionizing energy loss in each material. This difference requires material-specific calibration factors to ensure accurate predictions of device lifetime.
