What type of information is NOT needed when performing a source inventory?

In a source inventory, the primary concern is to track and manage the physical radioactive materials and their characteristics. Key information that is essential includes the location of the sources, the model to identify the type of radioactive material, and the maximum-rated mA to understand the operation limits of the equipment associated with the sources.

Employee ID is not directly relevant to the physical attributes or management of the sources themselves. The purpose of a source inventory is to ensure accountability and compliance concerning the radioactive materials, not to track individual personnel. Therefore, while employee information might be useful in some contexts, it is not necessary for the actual inventory of sources, making it the correct answer to the question.