DIN ISO 20956:2024-04

This document specifies the calibration methods under laboratory conditions for dosemeters used for environmental and area monitoring of X and gamma-rays with respect to the operational quantities of the International Commission on Radiation Units and Measurements (ICRU). This document extends the dose rate range of ISO 4037-1 down to 0,01 µSv/h. The specific uncertainty components are described taking into account the influence of natural background radiation and scattered radiation on the calibration for low dose rates. Three procedures are described for use in facilities on the earth's surface or in underground facilities, depending on the background dose rate and the intended measurement uncertainty. This document also covers regular on-site verification procedures for permanently installed environmental and ambient dose rate meters. This document does not deal with the special requirements for the calibration of spectrometer-based environmental dosemeters and passive dosemeters. The general procedures described in ISO 29661 are applied in this document as far as possible. The symbols used also comply with ISO 29661.