Activity is verified using a NaI detector for which the efficiency has been established using NIST traceable standards. Each source is labeled to identify the radionuclide, activity (in both microCuries and DPM), assay date and lot number. Standards are made in groups which are matched by counts to ensure +/- 1% source matching. The match tolerance only applies to the sources of a specific group, and not to the sources of separate sets. Variability may be greater between sets, even if the sets have the same lot number. Orders should be placed based on the number of plates required with the +/- 1% source matching. Part numbers 5080225, 5080525 and 5081025 each have 2, 5, and 10 matching plates, respectively.

Pico-Calibrators are typically used for verifying detector counting efficiency and normalizing multi-detector gamma counters. The calibrators are supplied with a Pico-Calibrator log book that contains technical information as well as a template for quality assurance.