It is industrial practice in radiation processing using photonic sources to heavily rely on Operational Qualification (OQ) dose maps of homogeneous products with different densities for the Performance Qualification (PQ). Reasons are manifold: first, it is expected to have much lower dose gradients compared to electron beam.  Moreover, full pallets require a large number of dose points to characterize the process load. Reusing OQ data can reduce PQ time and cost. Third, there is a simulation stake: To compute the absorbed dose, the Kerma water is often used. This quantity is an estimation of the absorbed dose in water based on the photon flux. It permits to get accurate results in a reasonable time. However, its utilization is only appropriate to estimate the absorbed dose in homogeneous products with densities equivalent to water.

The paper outlines a work plan and presents preliminary results to answer the following questions:

Is bulk product density a valid criterion to select a density of OQ dose map to use?
Is it possible to define a criterion for categorizing product and group it into a process category?
Does a high-density material in a homogeneous product significantly affects the dose distribution? The example of a metallic object in a homogeneous product has been taken to study the effect of metallic implants on the surrounding dose distribution.
What are the limitations of Kerma Water as absorbed dose estimator? By using the previous example, the interest is to know if the Kerma water is still a good estimator of the absorbed dose near the metallic implant.

Modelling studies will be performed using RayXpert, a Monte Carlo software developed by TRAD. Simulations results will be validated by experiments using the feerix® 7 MeV X-ray irradiation facility.