The operational and performance requirements for backpack-based radiation-detection systems (BRDs) used in homeland security applications are specified in this standard. BRDs are typically worn by the user during operation to detect and possibly identify radiological and nuclear material. (In partnership with the Department of Homeland Security Domestic Nuclear Detection Office, the PDF of this standard is provided to the public at no charge. Visit https://ieeexplore.ieee.org/browse/standards/get-program/page for more details)